tag:theconversation.com,2011:/nz/topics/tetrahydocannabinol-17216/articlesTetrahydocannabinol – The Conversation2016-12-05T01:01:02Ztag:theconversation.com,2011:article/667742016-12-05T01:01:02Z2016-12-05T01:01:02ZCould a cannabis pill reduce chemotherapy-induced nausea and vomiting? Here’s how we find out<p>For some cancer patients undergoing chemotherapy, the thought of joining their loved ones for a meal can be, quite literally, sickening. Nausea and vomiting due to chemotherapy can cause devastating physical side effects and wreck a patient’s social and family life.</p>
<p>Patients say they find it difficult to manage the expectations of well-meaning family members and friends who want to “feed them up”, when their favourite foods become tasteless.</p>
<p>We need to do more to make chemotherapy as comfortable as possible for patients.</p>
<p>That’s why our research team at <a href="http://www.mylifehouse.org.au/">Chris O’Brien Lifehouse</a> in Sydney is about to embark on the largest and most definitive Randomised Controlled Trial ever in the world of medicinal cannabis for the prevention of chemotherapy-induced nausea and vomiting. With the help of more than 300 patients from several NSW hospitals, we hope to learn more over the next few years about how effective medicinal cannabis may or may not be for preventing chemotherapy-induced nausea and vomiting.</p>
<h2>New strategies for an old problem</h2>
<p>Cancer kills more Australians than any other disease. Almost half the 100,000 people diagnosed each year will be offered chemotherapy as an integral part of their treatment. While there have been significant advances in anti-nausea drugs over the past decade, more than one-third of patients receiving potent intravenous chemotherapy still suffer from nausea or vomiting.</p>
<p>Our team includes leading Australian researchers from Chris O'Brien Lifehouse, the University of Sydney and Royal Prince Alfred Hospital, specialising in cancer, addiction medicine and clinical toxicology.</p>
<p>We’re hoping to determine if giving patients an oral capsule of medicinal cannabis reduces nausea and vomiting during and after intravenous chemotherapy for cancer.</p>
<h2>Jury still out</h2>
<p>The jury is still out on the ability of cannabis and cannabis-derived medicines to treat a range of debilitating illnesses – and how to do it safely and effectively.</p>
<p>Despite dozens of trials internationally, the <a href="http://www.cochrane.org/CD009464/GYNAECA_cannabis-based-medicine-nausea-and-vomiting-people-treated-chemotherapy-cancer">evidence</a> is unconvincing. Some <a href="http://www.cochrane.org/CD009464/GYNAECA_cannabis-based-medicine-nausea-and-vomiting-people-treated-chemotherapy-cancer">research</a> failed to compare cannabis medicine against the best standard treatment of today. Some research had design flaws, such as failure to adequately account for the placebo effect, inappropriate dosing, small sample sizes and poor documentation of side effects and harms.</p>
<p>There remain many potentially valid reasons to use medicinal cannabis products. But we still don’t know how best to formulate and administer the drug, how well it might work, how safe it is and what the long-term side effects could be.</p>
<p>This is not to say medicinal cannabis for therapeutic use is a pipe dream – we just need to do the work first, and do it properly. And that takes time.</p>
<h2>A scientific approach</h2>
<p>However, using a scientific approach will give the best hope for patients and their families. It will give us better understanding of side effects and ideal dosages.</p>
<p>Producers of medicinal cannabis products will be encouraged to develop the most suitable formulations, delivery methods, and cannabinoid content.</p>
<p>Australian regulatory and funding authorities will have the evidence they need to decide which formulations of medicinal cannabis should be approved for which conditions, so they can be made safely available to the patients who need them.</p>
<p>Clearly, more research needs to be done. NSW is doing groundbreaking research on the use of medicinal cannabis for treatment-resistant childhood epilepsy, palliative care and chemotherapy-induced nausea and vomiting.</p>
<p>Many of my patients do not use illegal cannabis preparations because they are concerned about breaking the law. But if we were to pursue broad legalisation, as opposed to a medical pathway based on scientific evidence, we would miss the opportunity to create a safe, secure supply of cannabis medicines.</p>
<p>These medicines could be supervised by qualified practitioners to maximise the benefit to patients and manage side effects, and could potentially be subsidised under the Pharmaceutical Benefits Scheme.</p>
<p>Many of the cannabinoid products available overseas have little quality control, testing or certification.</p>
<h2>Relaxed but not “stoned”</h2>
<p>The cannabis plant varies considerably depending on its type and how it is grown. The cannabis plant contains hundreds of compounds, more than 60 of which are cannabinoids. The main cannabinoids studied in trials are delta-9-tetrahydrocannabidiol (THC), and cannabidiol (CBD).</p>
<p>THC is the type of cannabis that can make people feel “stoned”, while cannabidiol can make people feel relaxed and can hopefully relieve nausea.</p>
<p>Older cannabis medicines, such as Dronabinol and Nabilone, are made of synthetic THC. They are still sometimes used overseas as last-line options for treating nausea and vomiting caused by chemotherapy, but they’re not very effective, and can cause a lot of side effects.</p>
<p>The oral capsule for our NSW government-funded study contains equal amounts of THC and CBD. We think this will be more effective and have fewer side effects.</p>
<p>We worked with the Canadian company <a href="https://www.tilray.ca/">Tilray</a>, which developed the capsule to our specifications. It aims to minimise THC levels that have mood-altering characteristics, which means our patients are less likely to get “stoned”.</p>
<p>The trial is building on a small <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2997305/">Spanish study</a> which found that a spray form of cannabis medicine containing THC and CBD in equal amounts (not routinely available in Australia) seemed to dramatically reduce nausea and vomiting in cancer patients receiving chemotherapy. The results, which found a 50% reduction in the number of patients suffering these effects, seem too good to be true, and need to be repeated in a rigorous clinical trial using a capsule that is available in Australia.</p>
<p>The NSW clinical trials exploring the use of medicinal cannabis are very significant. We don’t want to repeat past mistakes, and we want the investment in time and money to be worthwhile.</p>
<p>We can’t predict the outcome. The trials could show a benefit of medicinal cannabis, but they could also show that medicinal cannabis doesn’t work or has overwhelming side effects.</p>
<p>We are hopeful that, at the very least, NSW patients will be given a clear, scientific basis upon which to make important decisions about their treatment in the future.</p><img src="https://counter.theconversation.com/content/66774/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Grimison is a medical oncologist from Chris O`Brien Lifehouse cancer hospital and The University of Sydney and is leading the research team for the NSW Government’s clinical trial into the role of cannabis-derived medicines in chemotherapy-induced nausea and vomiting. The University of Sydney and Chris O'Brien Lifehouse receives funding from NSW Health to conduct a clinical trial of cannabis for chemotherapy-induced nausea and vomiting, for whom Tilray have provided the study drug.</span></em></p>NSW is about to embark on the largest and most definitive clinical trial ever of medicinal cannabis for chemotherapy-induced nausea and vomiting.Peter Grimison, Medical oncologist from Chris O`Brien Lifehouse cancer hospital, Lead researcher NSW Government clinical trial into the role of cannabis-derived medicines in chemotherapy-induced nausea and vomiting, Clinical Associate Professor., University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/678382016-11-01T02:36:36Z2016-11-01T02:36:36ZUsing DNA to unlock the mysteries of cannabis and reduce the risk of dodgy ‘medical’ products<p>The federal government will now <a href="http://www.health.gov.au/internet/ministers/publishing.nsf/Content/health-mediarel-yr2015-ley123.htm">accept licence applications</a> for groups wanting to grow cannabis locally for scientific and medical purposes.</p>
<p>Cannabis <a href="http://www.health.gov.au/internet/ministers/publishing.nsf/Content/health-mediarel-yr2015-ley123.htm">remains an illegal drug</a> in Australia for recreational use and there no plans to change that. But the reforms are part of a broader effort to enable a sustainable supply of safe medicinal cannabis products to Australian patients.</p>
<p>There is limited high quality evidence on how cannabis medicines may help people suffering problems such as chemotherapy-induced nausea or paediatric epilepsy. New South Wales’ upcoming medicinal cannabis <a href="https://www.medicinalcannabis.nsw.gov.au/about">trials</a> aim to find out more about its therapeutic potential. </p>
<p>Against this background, plant scientists in Australia are working to understand better the chemical make up of this complex plant and the incredible variation within the species. </p>
<p>Many questions remain unanswered, underscoring the potential risks of black market products. The composition of these products may be unknown, or vary wildly between products or batches. They may also be laced with pesticides and heavy metals. </p>
<p>This lack of quality control and quality assurance is a significant public health concern, especially for vulnerable patients who may not necessarily have a medical professional helping guide their treatment choices.</p>
<h2>One species, hundreds of strains</h2>
<p>You may think you know what a cannabis plant looks like, but even experts are still learning about how one plant may differ from the next in its chemical profile.</p>
<p>The two most well-known compounds in a cannabis plant are the psychoactive tetrahydrocannabinol, or <a href="https://theconversation.com/au/topics/thc-29805">THC</a>, and the non-psychoactive cannabidiol, or CBD. THC is the compound that delivers the “high”, while CBD is believed to have a relaxing effect. THC and CBD are part of a group of compounds that scientists call “cannabinoids”.</p>
<p>On the spectrum of variation, there are some plants that are high in THC and some that are high in CBD. But even for these two cannabinoids, there is much more of a <a href="http://link.springer.com/article/10.1007/s10681-015-1585-y">continuum</a> than most people realise. </p>
<p>You may read on the internet that there are two main types of cannabis – indica and sativa – and that one is more or less medically beneficial than the other. But this terminology is not backed by strong evidence. </p>
<h2>Heavy metals, pesticides</h2>
<p>Many existing products available on the black market may promise miraculous results without any compelling scientific evidence, regulation or product quality assurance standards. Some of the tinctures, oils or floral buds available on the black market may also be badly contaminated by pesticides, heavy metals and germs. </p>
<p>Some of the research <a href="http://sydney.edu.au/news-opinion/news/2016/08/18/pioneering-study-of-cannabis-extracts-in-treating-epileptic-kids.html">underway</a> in Australia is investigating just how variable the amounts of active ingredients may be in some of these products.</p>
<h2>Tracing the history, mapping the present</h2>
<p>All forms of cannabis currently growing have been domesticated at some point in the past few thousand years.</p>
<p>We can now use state-of-the art DNA technologies and detailed information on cannabinoid chemistry to help trace the domestication history of hemp, hempseed, recreational and now medicinal forms of cannabis.</p>
<p>Our research aims to map the details of the wide range of cannabinoid compositional profiles that may be found in the different cultivated forms (also known as cultivars or “strains”). We want to help create a better way of assessing the amount of CBD and other cannabinoids in different cannabis strains. We are developing tools to distinguish between different cannabis cultivars by DNA and chemical profiling.</p>
<p>Our researchers are working with a collection of over 200 strains of cannabis cultivars collated by the firm Ecofibre (one of our research funders and collaborators). This collection represents a large proportion of the <a href="http://journal.frontiersin.org/article/10.3389/fpls.2016.01113/full">worldwide cannabis gene pool</a>.</p>
<h2>How to measure the dose?</h2>
<p>There is still no single standard way of measuring cannabinoid composition. That makes it hard to know the relative “dose” of THC or CBD or other compounds in any given plant.</p>
<p>There is an urgent need to develop and adopt nationally and internationally agreed standards for the benefit of all involved, be they regulators, cultivators, processors, dispensers, prescribers or patients. </p>
<p>Without a systematic framework it is very hard to understand how growers could cultivate cannabis with a consistent composition and yield, leading to a predicable dose. Scientists also still don’t know enough about the shelf-life of various forms of medicinal cannabis.</p>
<p>Our research team surveyed the available reliable and systematic scientific literature on what factors help drive variation in cannabinoid content in a plant.</p>
<p>We found that there is little high quality scientific evidence out there on this question, despite what you may read on the internet. Many websites make bold claims about the “evidence” on cannabis plant science but most of this material is poorly formalised or does not bear scrutiny in terms of valid statistical design.</p>
<h2>New research to answer old questions</h2>
<p>For cultivators and manufacturers there is a need to be able to ensure production cycles can be predictable throughout the year to meet demand. For pharmacists and prescribers there is a need to know more about a product’s shelf-life. Patients must have confidence in the consistency and traceability of product – from plant through to the processing and supply chain – and prescribers need to be able to predict with certainty what effect a product will have on a patient.</p>
<p>The effect that a cannabis product will have on a person is the result of complex interplay between the original plant’s genetic composition, and environmental factors during cultivation and processing.</p>
<p>For a medicinal cannabis cultivation and processing industry to work best, we need to understand better – in a systematic and reproducible way – the interaction between the genetic composition and the environmental factors that may determine the level of THC and CBD in a plant.</p><img src="https://counter.theconversation.com/content/67838/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Graham King receives funding at Southern Cross University from the company Ecofibre Industries Operations Pty Ltd and the Australian government. He is on the advisory council of the NSW Centre for Medicinal Cannabis Research and Innovation.</span></em></p>The Australian government will now accept licence applications for groups wanting to grow cannabis for scientific and medical purposes. But there’s still a lot we don’t know about this complex plant.Graham King, Director, Southern Cross Plant Science, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/606002016-09-23T15:33:47Z2016-09-23T15:33:47ZWhat is Spice and why is the drug so dangerous?<p>Synthetic cannabis, of which Spice is an example, is linked to serious health issues ranging from difficulties breathing to psychotic episodes. But, despite well-known issues, these drugs are still in demand and homeless people, particularly, are at risk of mental health issues from their use. So what exactly are these drugs made of and why do they cause such violent reactions.</p>
<p>Spice is not a single drug, but a range of laboratory-made chemicals that mimic the effects of tetrahydrocannabinol (THC), the main psychoactive component of cannabis. <a href="http://ki.se/en/research/spice-a-hundred-times-more-potent-than-cannabis">Research suggests</a> that Spice and other forms of synthetic cannabis are capable of producing much more intense and prolonged effects at much lower doses than natural cannabis. This is because, while the THC in natural cannabis only partially reacts with the body, synthetic cannabis reacts far more fully. </p>
<p>To understand the biology behind the intense reaction to Spice we need to look at the parts of the body’s central nervous system that react to cannabis – the cannabinoid receptors – and the chemical part of the drug that reacts with the body – the “agonist”. </p>
<p>While THC is a “partial agonist” (it only partially reacts with cannabinoid receptors), synthetic cannabis is often a “full agonist”. In this way, the more adverse effects observed with synthetic cannabis use stem from its ability to completely saturate and activate all of the body’s cannabinoid receptors at a lower dose. </p>
<p>Although the consequences of long-term regular use are not well defined, <a href="http://onlinelibrary.wiley.com/doi/10.1002/jcph.827/epdf">experts believe</a> that synthetic cannabis has the potential to develop, or cause a relapse of mental illness, especially if there is a family history of mental disorders.</p>
<h2>Where does Spice come from?</h2>
<p>In 2008, the first synthetic cannabinoid – which reacts with the body in the same way as cannabis – was identified on the recreational drug market. JWH-018 was an aminoalklindole originally developed by <a href="http://pubs.rsc.org/en/Content/ArticleLanding/2015/AN/C5AN00797F#!divAbstract">John Huffman of Clemson University</a> in the US and sold under the brand name: Spice. Aminoalkylindoles – the most common sub-family of synthetic cannabinoids –- are produced, in kilogram quantities, through quick and simple chemical reactions using legal substances. These substances are produced on a large-scale by chemical companies based in China and then shipped, as bulk powders, to Europe by air or sea. Once in Europe, the synthetic cannabinoids are mixed with (or sprayed onto) plant material using solvents such as acetone or methanol to dissolve the powders. The combination is then dried, packaged and sold as either incense or smoking mixtures. </p>
<p>JWH-018 is now a controlled substance in many countries under narcotics legislation. But the prevalence of next-generation synthetic cannabinoids – now known colloquially as Spice or Mamba – continue to be the largest group of new psychoactive substances (NPS) in common usage. As of December 2015, 14 different sub-families of cannabinoid agonists have been identified – indicating that there are potentially hundreds of these types of substances circulating via the internet and often across international borders.</p>
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<img alt="" src="https://images.theconversation.com/files/125590/original/image-20160607-7438-1yw2w1s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/125590/original/image-20160607-7438-1yw2w1s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/125590/original/image-20160607-7438-1yw2w1s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/125590/original/image-20160607-7438-1yw2w1s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/125590/original/image-20160607-7438-1yw2w1s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/125590/original/image-20160607-7438-1yw2w1s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/125590/original/image-20160607-7438-1yw2w1s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Spice – a particular problem among the homeless.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&search_tracking_id=Q1owmDE5ORIXMQV19XaSJg&searchterm=homeless%20london&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=301238456">Elena Rostunova/Shutterstock.com</a></span>
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</figure>
<h2>Why is it so dangerous?</h2>
<p>Different brands of smoking mixtures can have very different effects, but the strength of a specific brand appears to owe more to the ratio of cannabinoids to chemically inactive plant material in the mixture, rather than the variation in the <a href="https://www.unodc.org/documents/scientific/NPS_2013_SMART.pdf">chemical structure of compounds</a> themselves. In other words, the specific type of chemical in the mixture is less important than how much chemical there is compared to what has been put in to provide bulk. </p>
<p>Due to the high potency of some synthetic cannabinoids, the amount needed for each “hit” can be as little as a few tens of milligrams (about the size of a match head). The intoxicating effects of more potent brands – such as Clockwork Orange, Pandora’s Box and Annihilation – can be quite overpowering. Some people experience difficulty breathing, rapid heart rate, and shakes and sweats, all of which can lead to a severe <a href="http://dx.doi.org/10.3109/15563650.2015.1110590">panic attacks</a>. At higher doses, balance and coordination can be severely affected. Users can experience a loss of feeling and numbness in their limbs, nausea, collapse and unconsciousness. </p>
<p>Continued use of synthetic cannabinoids can cause psychotic episodes, which in extreme cases can last for weeks, and may exacerbate existing mental-health illnesses in susceptible users. But most reports of severe mental health, addiction and acts of violence as a result of regular use tend to be among <a href="https://www.theguardian.com/society/2015/nov/07/cheap-spice-strengthens-grip-northern-towns-blackpool-synthetic-cannabinoid">prisoners and homeless people</a>. These groups are much more likely to report high rates of drug dependency, self-define as having addictive personalities and disclose a range of diagnosed mental-health issues including “dual diagnosis” (drug dependence and at least one mental-health disorder, or at least two personality or psychotic disorders) and existing offences for violence. </p>
<p>Because of the substantial risks of synthetic cannabinoids, many countries have already outlawed their production, possession and distribution. But it is unlikely that the “war on drugs” will show any sign of relenting, given the <a href="https://theconversation.com/fast-market-for-legal-highs-poses-challenge-for-scientists-17709">rapidly evolving nature</a> of the recreational drugs market and the lack of globalised drug-control legislation. Only by working collectively can scientists, medical professionals and law makers help to stem the flow of these dangerous compounds before they pose a serious threat to health of vulnerable groups in society.</p><img src="https://counter.theconversation.com/content/60600/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New psychoactive substances, same problematic users.Oliver Sutcliffe, Senior Lecturer in Psychopharmaceutical Chemistry, Manchester Metropolitan UniversityRobert Ralphs, Reader in Criminology, Manchester Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/646982016-09-02T11:00:27Z2016-09-02T11:00:27ZIt’s official: one joint of cannabis makes you lazy … but only in the short term<figure><img src="https://images.theconversation.com/files/136288/original/image-20160901-1023-1vl3akv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-193975568/stock-photo-man-slumped-on-sofa-with-drug-paraphernalia-in-foreground.html?src=4lTlzDiUlhpOsAbP4X6h_A-1-6">Monkey Business Images/Shutterstock</a></span></figcaption></figure><blockquote>
<p>I was gonna go to work but then I got high <br>
I just got a new promotion but I got high <br>
Now I’m selling dope and I know why <br>
‘Cause I got high <br>
Because I got high <br>
Because I got high <br></p>
</blockquote>
<p>Afroman’s 2001 hit Because I Got High tells a potentially important story: smoking cannabis makes you lazy and demotivated. In fact, the fable of the lazy stoner has been around for decades. But is there good evidence in support of it?</p>
<p>Two studies we have been working on have investigated the claim that cannabis leads to <a href="http://link.springer.com/article/10.1007/s00213-016-4383-x">reduced motivation</a>. We found that when you give people the equivalent of one spliff’s worth of cannabis, under controlled conditions in a laboratory, they are less willing to work for money. In other words, they are not as motivated as usual. However, we also compared people who are addicted to cannabis with a control group (non-cannabis drug users). We found that when neither group had used drugs for at least 12 hours, they did not differ in their motivation for money.</p>
<p>Our results suggest that when you have recently smoked cannabis, it reduces your motivation in the short-term. On the other hand, long-term cannabis use may not impair your motivation, as long as you stop smoking it for at least 12 hours.</p>
<h2>'Amotivational syndrome’</h2>
<p>In the late 1950s and 1960s, as cannabis became a popular recreational drug, academic reports of cannabis’s “amotivational syndrome” appeared. <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1323020/">Clinicians stated</a> that “regular marihuana [sic] use may contribute to the development of more passive, inward turning, amotivational personality characteristics”. However, these reports simply relied on observations of cannabis users and their lazy behaviour. Research was needed to investigate the short and long-term effects of cannabis.</p>
<p>Early research into the short-term effects of cannabis on motivation surprisingly found both <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0773.1974.tb03315.x/abstract">motivating</a> and <a href="http://psycnet.apa.org/index.cfm?fa=buy.optionToBuy&id=2002-00353-004">demotivating</a> effects of cannabis. Having said that, these studies were poorly controlled and sometimes rather bizarre in their design; one involved getting people stoned and asking them to <a href="http://psycnet.apa.org/index.cfm?fa=buy.optionToBuy&id=2002-00353-004">make stools</a> as quickly as possible. A <a href="http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0006598">more recent study</a> gave cannabis to people in a placebo-controlled experiment and reported reduced motivation for money. However, this experiment used a very small sample of five participants.</p>
<p>Our new study used a double-blind, placebo-controlled design to examine the effects of cannabis on motivation for money in a larger sample of 17 participants. Through a balloon, participants inhaled cannabis vapour on one occasion and a placebo cannabis vapour on a separate occasion. Straight after, they completed a task designed to measure their motivation for earning money. This was a <a href="http://jpn.ca/wp-content/uploads/2016/08/41-6-150363.pdf">real-life task</a> as the participants were given money they had earned at the end of the experiment. In each trial, they could decide whether to complete low or high-effort options to win varying sums of money. The low-effort option involved pressing the spacebar key 30 times in seven seconds to win 50p. The high-effort option involved 100 space bar presses in 21 seconds for rewards varying from 80p to £2.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/136306/original/image-20160901-1018-15d4cwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/136306/original/image-20160901-1018-15d4cwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/136306/original/image-20160901-1018-15d4cwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/136306/original/image-20160901-1018-15d4cwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/136306/original/image-20160901-1018-15d4cwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/136306/original/image-20160901-1018-15d4cwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/136306/original/image-20160901-1018-15d4cwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">One hundred spacebar presses equals more cash.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-165222797/stock-photo-finger-pushing-the-space-bar-button-of-keyboard.html?src=LWXJawrpg2BRejXzgfuA0A-1-1">BaLL LunLa/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>We found that people on cannabis were significantly less likely to choose the high-effort option. On average, volunteers on placebo chose the high-effort option 50% of the time for a £2 reward, whereas volunteers on cannabis only chose the high-effort option 42% of the time. In other words, they had reduced motivation for the money available when they were stoned. Although it has been a long-held belief that getting high makes you lazy, this is the first time it has been reliably demonstrated using a suitable sample size.</p>
<h2>No difference</h2>
<p>The question of whether long-term cannabis use makes people demotivated, even when they’re not high, is a more difficult one to answer. We cannot carry out randomised controlled trials in which some people are given cannabis for ten years while another group receive placebo for ten years. That would, of course, be unethical. Therefore, we have to rely on observational studies, where we look at associations between natural cannabis consumption and motivation levels. Some previous research has <a href="http://www.ncbi.nlm.nih.gov/pubmed/16722561">failed to find a link</a> between cannabis use and altered motivation, although in <a href="http://www.ncbi.nlm.nih.gov/pubmed/11729021">one study</a> earlier cannabis consumption predicted later anhedonia (difficulty experiencing pleasure).</p>
<p>In our observational study (that is, one that does not have an experimental manipulation), we compared 20 people who were addicted to cannabis against a control group of 20 people who were not addicted to cannabis. The control group used other drugs, including MDMA and cocaine, a similar amount to the cannabis group. These participants completed the same motivation task as in the previous study after they had been clean of all drugs (apart from tobacco and caffeine) for at least 12 hours. We found no difference between the groups in their willingness to work for money. This suggests that long-term cannabis use may not reduce motivation after 12 hours of abstinence from the drug.</p>
<p>However, there are some important limitations with this study. Firstly, the sample sizes were small. Secondly, the study was cross-sectional, so we only investigated the participants at one point in time. An improved study would have used a longitudinal design, in which people’s motivation and cannabis use are measured at different time points as they grow up. This would have allowed for a better understanding of how cannabis consumption affects future motivation. Longitudinal research is needed to draw stronger conclusions.</p>
<p>What do our results mean to the average cannabis user? After years of being told that getting high makes you lazier, we’ve provided some of the first solid evidence that it’s true. Importantly though, it doesn’t eradicate your motivation altogether – it makes you slightly, yet significantly, more apathetic. On the bright side, your long-term cannabis use may not erode your drive like some people claim, so long as you can put your joint down for a while.</p><img src="https://counter.theconversation.com/content/64698/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Will Lawn received funding from the BBSRC.</span></em></p>A new study found that people who are high on cannabis are less likely to opt for a task with a larger reward if the task requires more effort.Will Lawn, Post-doctoral researcher, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/570842016-05-16T01:06:02Z2016-05-16T01:06:02ZWhat counts as ‘medical marijuana’ varies from state to state – and that’s a problem<p>On April 17, Pennsylvania became the latest state to pass <a href="http://www.post-gazette.com/news/state/2016/04/17/Pennsylvania-Gov-Tom-Wolf-signs-legislation-legalizing-medical-marijuana/stories/201604170229">medical marijuana legislation</a>, which will take effect <a href="https://www.mpp.org/states/pennsylvania/">this month</a>. And recently Ohio’s House of Representatives has passed a plan <a href="http://www.dispatch.com/content/stories/local/2016/05/10/medical-marijuana-vote.html">to permit medical marijuana in the state</a>. </p>
<p>Research suggests that marijuana – or more specifially compounds in marjuana – may have potential as a treatment for <a href="http://dx.doi.org/10.1016/j.expneurol.2011.11.047">epilepsy</a> and <a href="http://dx.doi.org/10.1111/j.1365-2125.2011.03970.x">chronic pain</a>, among other conditions. However, more research is needed to fully understand any potential health benefits from the substance. </p>
<p>As of this writing, 41 states have legislation that <a href="http://www.ncsl.org/research/health/state-medical-marijuana-laws.aspx#3">permits medical marijuana</a> in some form. However, the law in <a href="http://dfw.cbslocal.com/2015/05/18/texas-house-approves-flawed-medical-marijuana-bill-measure-goes-to-gov-abbott/">Texas</a> is not considered functional, because it requires a physician to prescribe marijuana. Since marijuana is illegal under federal law, doctors can’t prescribe it. They can only recommend it to patients. Louisiana’s law had the same flaw, but the state’s House of Representatives just voted on new legislation that should <a href="http://www.nola.com/politics/index.ssf/2016/05/medical_marijuana_house_vote_1.html">correct this problem</a>. </p>
<p>As the director of the <a href="http://www.buffalo.edu/ria.html">Research Institute on Addictions</a> at the University at Buffalo and a researcher who studies social factors in the development of addictions, I follow many of the emerging trends in substance use.</p>
<p>When New York state <a href="http://www.nytimes.com/2014/05/28/nyregion/assembly-backs-use-of-marijuana-for-illnesses.html">passed legislation allowing for medical marijuana</a> late in 2015, I began to collect information on the ways that the states were approaching this controversial issue. </p>
<p>As medical marijuana laws become more common in the U.S., it’s good to understand what, exactly, these state laws allow – and what they don’t. States are trying to strike a balance between access to medical marijuana for patients who might benefit, while also ensuring that these laws don’t become a backdoor to full legalization. And, as I have found, there is a lot of variation in terms of what states mean by “medical marijuana.” This can affect whether and how patients can access it and what conditions it can be used to treat. </p>
<h2>What is medicinal about marijuana?</h2>
<p>Let’s start by looking at what medicinal properties marijuana actually has.</p>
<p>Marijuana consists of several hundred chemical components, but the most well known is tetrahydrocannabinol (THC), which causes marijuana’s “high.” It can also be used to treat nausea and vomiting. In fact, there are two FDA-approved synthetic versions of THC, <a href="https://www.nlm.nih.gov/medlineplus/druginfo/meds/a607054.html">Dronabinol</a> (also called Marinol) and <a href="http://www.accessdata.fda.gov/drugsatfda_docs/label/2006/018677s011lbl.pdf">Cesemet</a>, which are prescribed to treat nausea and vomiting for patients undergoing chemotherapy for cancer or to stimulate appetite for patients with AIDS. A side effect of these drugs is euphoria, which means they can make you high.</p>
<p>At the federal level, only these two medications are legal. THC or other extracts, whether synthetic or derived from the marijuana plant, are not. </p>
<p>The other marijuana compound with known medical applications at present is cannabidiol (CBD). Unlike THC, CBD does not produce a high. There are no FDA-approved medications based on CBD yet, although it is being studied as promising treatment for <a href="http://www.ncbi.nlm.nih.gov/pubmed/850145">severe epilepsy</a> and pain. </p>
<p>Proponents of medical marijuana <a href="http://norml.org/marijuana/medical/marinol-vs-natural-cannabis">argue</a> that the combination of the chemical components present in the plant itself provides the most effective treatment for some medical symptoms. However, the amount of the medically important components differs from one plant to the next, and other potentially harmful components may also be present in the natural product. Research examining this issue is critically needed.</p>
<h2>In some states ‘medical marijuana’ means marijuana</h2>
<p>The phrase “medical marijuana” might give you the image of people buying plants or dried marijuana to smoke. That’s the case in some states with medical marijuana laws, but not all.</p>
<p>In 21 states and the District of Columbia as of this writing, people can <a href="https://www.mpp.org/issues/medical-marijuana/state-by-state-medical-marijuana-laws/">possess marijuana in plant form for medical purposes</a>. But, of course, there is plenty of variation between these 21 states.</p>
<p>For instance, in 15 of those states, laws permit people to <a href="https://www.mpp.org/issues/medical-marijuana/state-by-state-medical-marijuana-laws/state-by-state-medical-marijuana-laws-report/">cultivate marijuana plants for medicinal use</a>. Limits on the number of plants vary from state to state, but most of the states <a href="http://medicalmarijuana.procon.org/view.resource.php?resourceID=000881#summary">allow for 6-12 plants</a>. And some of those states limit the number of mature versus immature or seedling plants people are allowed to have. </p>
<p>Several of these 15 states allow home cultivation only under certain circumstances. For example, Massachusetts allows <a href="http://www.mass.gov/eohhs/gov/departments/dph/programs/hcq/medical-marijuana/">patients to cultivate plants</a> if a state dispensary is not nearby or for financial reasons. Other states require the cultivation to be in a locked area or have other restrictions.</p>
<p>In six other states, medical marijuana laws allow people to possess usable marijuana, but prohibit them from cultivating the plant. </p>
<p>Still with me? Good. Those are just the states that permit people to possess marijuana or to cultivate plants to some degree or another. </p>
<h2>And in other states ‘medical marijuana’ means a marijuana extract</h2>
<p>In 15 states, medical marijuana laws allow people to possess <a href="http://www.ncsl.org/research/health/state-medical-marijuana-laws.aspx">only one specific marijuana extract, CBD</a>, the component that does not produce a high. Possessing marijuana itself or cultivating plants isn’t allowed. </p>
<p>If you live in <a href="http://www.health.state.mn.us/topics/cannabis/patients/index.html">Minnesota</a>, <a href="https://www.health.ny.gov/regulations/medical_marijuana/faq.htm">New York</a> or <a href="http://www.post-gazette.com/news/state/2016/04/17/Pennsylvania-Gov-Tom-Wolf-signs-legislation-legalizing-medical-marijuana/stories/201604170229">Pennsylvania</a>, state laws prohibit “smokeable marijuana” but do allow marijuana extracts in nonsmokeable forms, such as oils that can be vaporized, oral solutions and capsules. These products are manufactured with specific amounts of THC and CBD. </p>
<p>Now that we have sorted out the different types of medical marijuana states permit, let’s move on to the next major variation in medical marijuana legislation – what conditions medical marijuana can treat.</p>
<h2>What do states say medical marijuana can treat?</h2>
<p>Most states that allow people to possess or cultivate marijuana for medical purposes allow its use to treat many medical conditions, including pain, nausea, HIV/AIDS, seizures and glaucoma. As of now, nine states also allow for the use of <a href="http://www.reuters.com/article/us-usa-colorado-marijuana-idUSKCN0PQ0CC20150716">marijuana for post-traumatic stress disorder</a>. </p>
<p>The most liberal of the states, California, goes a step further. Not only is medical marijuana permitted to treat all of these conditions, but also for <a href="http://www.mbc.ca.gov/Licensees/Prescribing/Medical_Marijuana.aspx">any other major illness where marijuana has been</a> “deemed appropriate and has been recommended by a physician.”</p>
<p>Remember, in some states the only “medical marijuana” permitted is an extract, CBD. One of these states, Kentucky, allows CBD only for people <a href="http://medicalmarijuana.procon.org/view.resource.php?resourceID=000881#details">in a state-sponsored clinical trial</a>.</p>
<p>The other <a href="https://www.mpp.org/issues/medical-marijuana/state-by-state-medical-marijuana-laws/state-by-state-medical-marijuana-laws-report/">14 states that</a> allow the use of CBD allow it only for “debilitating,” “severe” or “intractable” epilepsy. Most of these states do not have dispensaries where CBD can be purchased, or they have one single source, usually a a medical school. So if a physician in these states determines that a patient would benefit from CBD, a patient would have to travel to another state with a dispensary that sells CBD. </p>
<p>And, of course, it gets even more complicated. Many of the states with legal dispensaries of CBD are not permitted to provide it to nonresidents. That means that even CBD though is legal in some states, it is effectively unavailable for most who might benefit.</p>
<h2>Why is there so much variation between the states?</h2>
<p>Marijuana is classified as a <a href="http://www.dea.gov/druginfo/ds.shtml">Schedule 1 Drug</a>, a category reserved for substances with “no currently accepted medical use and a high potential for abuse.” This makes research on marijuana medical applications <a href="http://www.popsci.com/science/article/2013-04/why-its-so-hard-scientists-study-pot">difficult</a>. </p>
<p>As Nora Volkow, the Director of the National Institute on Drug Abuse, <a href="http://www.huffingtonpost.com/nora-volkow/cannabidiol_b_7834066.html">pointed out,</a></p>
<blockquote>
<p>medical research can and is being done with schedule I substances; however, there are strict regulations and administrative hurdles associated with this status.</p>
</blockquote>
<p>With research about medical marijuana moving so slowly, states, often based on citizen lobbying efforts, have acted, creating legislation that might be based more on opinion than on evidence.</p>
<p>Whatever your opinion is on the legalization of marijuana for recreational purposes, the array of state and federal laws regarding the use of medical marijuana is confusing and problematic for those who might benefit from such a program. It is vitally important that we clear the hurdles to clinical research on marijuana, and that we accelerate research addressing the potential benefits and harms.</p><img src="https://counter.theconversation.com/content/57084/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kenneth E. Leonard has received funding from the National Institutes on Health to conduct research on alcohol and marijuana. </span></em></p>The phrase ‘medical marijuana’ might give you the image of people buying plants or dried marijuana to smoke. But that’s not always the case.Kenneth E. Leonard, Director, Senior Research Scientist at the Research Institute on Addictions, University at BuffaloLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/406412015-05-27T20:04:54Z2015-05-27T20:04:54ZRemind me again, how does cannabis affect the brain?<figure><img src="https://images.theconversation.com/files/82489/original/image-20150521-17347-ak7k2m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Heavy cannabis use is consistently associated with poorer attention and memory, and increased rates of metal health problems.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-241089565/stock-photo-man-smoking-marijuana-cigarette-soft-drug-in-amsterdam-netherlands.html?src=X31_VC-Es_e6H8u4JcavSA-1-8">Pe3k/F/Shutterstock</a></span></figcaption></figure><p>Governments and communities worldwide are softening their views on cannabis use. Trials of medicinal cannabis have been approved in <a href="http://www.parliament.vic.gov.au/publications/research-papers/9111-drugs-poisons-and-controlled-substances-amendment-clinical-trials-bill-2014">Victoria</a>, <a href="http://www.qld.gov.au/health/conditions/all/clinical-trials/medicinal-cannabis/index.html">Queensland</a> and <a href="http://www.parliament.nsw.gov.au/prod/parlment/committee.nsf/0/FDB7842246A5AB71CA257B6C0002F09B">New South Wales</a>. And the Australian parliament is currently debating legislation to introduce a government regulator of <a href="http://www.aph.gov.au/Parliamentary_Business/Bills_LEGislation/Bills_Search_Results/Result?bId=s987">medicinal cannabis</a>.</p>
<p>This follows decriminalisation of cannabis in Portugal and its legalisation in Uruguay and several US states. </p>
<p>Cannabis is still the product of choice for many illicit drug users in Australia. <a href="http://www.aihw.gov.au/alcohol-and-other-drugs/ndshs-2013/ch5/">Five times</a> as many people use cannabis rather than cocaine or methamphetamines. </p>
<p>But debate remains about the long-term effect the drug has on the brain, cognition and mental health. Most cannabis users start as teenagers and there is a widespread perception that this can disrupt critical developmental processes to leave a lasting negative impact on the brain. </p>
<p>Let’s look at what the latest research has to say about the long-term harms, whether they can be reversed, and the possibility of making the drug safer. </p>
<h2>How does it affect the developing brain?</h2>
<p>Studies have shown that individuals who begin regular and heavy cannabis use in their teenage years have a lower level of <a href="http://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366%2814%2970307-4/abstract">educational attainment</a> and <a href="http://www.pnas.org/content/109/40/E2657.full">IQ</a>, earn a lower wage, and are more likely to engage in heavy alcohol or hard drug use, suffer from mental health problems, or end up in <a href="http://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366%2814%2970307-4/abstract">prison</a>.</p>
<p>Heavy cannabis use – defined as daily use for at least one year – is consistently associated with poorer <a href="http://www.pnas.org/content/109/40/E2657.full">attention and memory</a>, as well as earlier and increased rates of mental health problems, especially psychotic symptoms. </p>
<p>Researchers have also identified <a href="http://www.ncbi.nlm.nih.gov/pubmed/18519827">differences in the brain</a> associated with these cognitive and mental health impairments.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/82536/original/image-20150521-5921-gxfcyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/82536/original/image-20150521-5921-gxfcyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/82536/original/image-20150521-5921-gxfcyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/82536/original/image-20150521-5921-gxfcyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/82536/original/image-20150521-5921-gxfcyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/82536/original/image-20150521-5921-gxfcyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/82536/original/image-20150521-5921-gxfcyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">It’s difficult to tell whether cannabis use or other factors caused the problems.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-244966882/stock-photo-sad-woman-in-the-city.html?src=TfTGXDn_spEXc9emVh-fPg-1-55">Shutterstock</a></span>
</figcaption>
</figure>
<p>However, there are a range of factors that can influence cognition, mental health and brain structure. These include age, use of other substances, rate of exercise, education level, family history, childhood abuse and neglect, pre-existing neurological differences, and the chemical composition of the cannabis itself.</p>
<p>It’s often not possible to account for all these factors when undertaking cannabis research. So it’s difficult to tell how much of the difference in a participants’ performance on a cognitive task, mental health and brain structure is attributable to their level of cannabis use and how much can be explained by other factors.</p>
<h2>Are the impairments reversible?</h2>
<p>We are only just beginning to understand how well-equipped the human brain is for adapting to environmental demands or stresses. This capacity, known as brain plasticity, means that our brain is constantly striving to optimise its functioning, even when it is damaged or injured. </p>
<p>A stroke, for instance, can harm certain areas of the brain but it is possible that at least some functioning of that region may be restored as neural connections are rewired in an attempt to compensate for the damage. </p>
<p>Similar recovery mechanisms may operate in cases where the brain has been harmed from long-term and heavy cannabis exposure. Though just a handful of researchers have investigated this possibility in the context of cognition. </p>
<p>One <a href="http://www.ncbi.nlm.nih.gov/pubmed/21749524">large-scale study</a> conducted over eight years found that heavy cannabis use was associated with memory impairments, but individuals had shown improvements in their memory once they stopped using the drug. </p>
<p><a href="http://www.ncbi.nlm.nih.gov/pubmed/20621421/">Other studies</a> have shown that as little as <a href="http://www.ncbi.nlm.nih.gov/pubmed/2801665">three to six weeks of abstinence</a> was sufficient for memory improvements. </p>
<p>Yet <a href="http://www.ncbi.nlm.nih.gov/pubmed/15734274">another study</a> found no cognitive deficits in former users after only three months of abstinence. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/82535/original/image-20150521-5946-1rxhpi3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/82535/original/image-20150521-5946-1rxhpi3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/82535/original/image-20150521-5946-1rxhpi3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/82535/original/image-20150521-5946-1rxhpi3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/82535/original/image-20150521-5946-1rxhpi3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/82535/original/image-20150521-5946-1rxhpi3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/82535/original/image-20150521-5946-1rxhpi3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The psychoactive substance THC is responsible for the ‘high’ associated with cannabis.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-230872459/stock-photo-detail-of-a-cannabis-plant-lemon-og-marijuana-strain-huge-indoor-flower-head.html?src=W8Q56_b3DYWtpNAbijP7yw-1-16">Iriana Shiyan/Shutterstock</a></span>
</figcaption>
</figure>
<p>Heavy cannabis use has also been suggested to disrupt neural functioning associated with memory. But again, a <a href="http://www.ncbi.nlm.nih.gov/pubmed/21053763">six-week period of abstinence</a> was sufficient to show some recovery at the neural level. </p>
<p>However, a <a href="http://www.pnas.org/content/109/40/E2657.full">large study</a> that followed cannabis users over nearly four decades found that there are limits to the ability of the brain to recover in those who begin using during early adolescence. Although cognition was improved in long-term cannabis users after 12 months of abstinence, cognitive impairments did persist, particularly in those who began using cannabis early.</p>
<p>Surprisingly, no studies to date have investigated whether the persistent effects of heavy cannabis use on brain structure can also recover with abstinence. </p>
<p>Stimulating brain plasticity is a major interest to neuroscientists. Some of the interventions to induce plasticity may facilitate the recovery from heavy cannabis use. Exercise is well established in <a href="http://www.sciencedirect.com/science/article/pii/S0166223609000563">promoting brain health</a>, including the growth and development of neurons. It is possible that reversing cannabis-related harm through abstinence could be augmented with interventions such as exercise.</p>
<p>But while there is some evidence for recovery of function, it’s an area that remains inconsistent and under-studied. More research is required before such an idea could bare any practical significance.</p>
<h2>What’s in your cannabis?</h2>
<p>Cannabis contains a wide variety of psychoactive substances. The most prominent are the cannabinoids D9-tetrahydrocannabinol (THC) and cannabidiol (CBD). </p>
<p>Police seizures indicate <a href="http://www.ncbi.nlm.nih.gov/pubmed/23894589">there has been a sharp rise</a> in the level of THC relative to CBD in smoked cannabis in recent decades. This could be due to a number of factors such as changes in the way people are growing the plant, using the different parts of the plant, or how they are preparing it for use.</p>
<p>THC is responsible for the “high” associated with cannabis, but also causes <a href="http://www.ncbi.nlm.nih.gov/pubmed/19335936">psychotic symptoms and cognitive impairments</a>. CBD is believed to <a href="http://www.ncbi.nlm.nih.gov/pubmed/22716143">limit the adverse impact of THC</a> on the brain. But we don’t know what proportion of CBD is necessary to mitigate these adverse effects. Nor do we know the extent to which these effects can be mitigated by CBD alone.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/82537/original/image-20150521-5940-sefswn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/82537/original/image-20150521-5940-sefswn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/82537/original/image-20150521-5940-sefswn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/82537/original/image-20150521-5940-sefswn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/82537/original/image-20150521-5940-sefswn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/82537/original/image-20150521-5940-sefswn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/82537/original/image-20150521-5940-sefswn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">We still don’t know whether the harm from cannabis use can be reversed.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-193975568/stock-photo-man-slumped-on-sofa-with-drug-paraphernalia-in-foreground.html?src=mj6FU6GRgW0O4WzAH4fN8g-1-23">Monkey Business Images/Shutterstock</a></span>
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<p>The creation of a well-regulated cannabis market, as has occurred in Colorado, may give researchers access to reliable information about the chemical composition of the cannabis that an individual is consuming. This will make it possible to directly investigate whether CBD has a role to play in limiting the damage or even aiding recovery from the cannabis-related harm to the brain from heavy use.</p>
<p>Establishing the long-term impact of cannabis on the brain is a research priority for neuroscientists. Answers are needed to largely untouched questions such as whether any potential harm could be reversed (through exercise or other interventions) and whether increasing the concentration of CBD can limit the negative impact caused by cannabis high in THC. </p>
<p>The legislative changes poised to increase the availability of cannabis are outpacing our understanding of the impact that the drug has on the brain. Without addressing these shortfalls in our knowledge, a fully informed debate about the likely consequences of increased cannabis use, whether it be for medical or recreational use, will not be possible.</p><img src="https://counter.theconversation.com/content/40641/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Murat Yücel receives funding from the National Health and Medical Research Council, the Australian Research Council and Monash University.</span></em></p><p class="fine-print"><em><span>Aaron Kandola is affiliated with the University of Amsterdam and Monash University.</span></em></p><p class="fine-print"><em><span>Adrian Carter receives funding from the National Health and Medical Research Council, the Australian Research Council and Monash University.</span></em></p>The legislative changes poised to increase the availability of cannabis are outpacing our understanding of the impact that the drug has on the brain.Murat Yücel, Professor and Clinical Neuropsychologist, Monash UniversityAaron Kandola, PhD candidate, UCLAdrian Carter, Senior Research Fellow, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/420992015-05-25T12:43:00Z2015-05-25T12:43:00ZFour years from now, your child will be at her commencement. Here are steps for you to take now<figure><img src="https://images.theconversation.com/files/82748/original/image-20150522-32572-104sron.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Between now and college years, there are many steps that you can take as a parent.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&search_tracking_id=3At77Z-zYu8kK3S_vznCVw&searchterm=graduation%20&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=95717242">Graduation image via www.shutterstock.com</a></span></figcaption></figure><p>It’s your daughter’s high school graduation. In a cap and gown, she stands beside a podium and proudly takes her diploma, beaming over the fact that she is moving on to a new, exciting phase of life. </p>
<p>Eyes tearing up and many disparate thoughts whirling through your head, you snap her picture.</p>
<p>Here, I would like to insert a different thought – a question you need to ask yourself: “What do I want my child to be like four years from now, when she is graduating from college?” </p>
<h2>What you can do as a parent</h2>
<p>Now is the time to take a mental snapshot of what you envision for your child when he or she completes that bachelor’s degree. And this summer is the time to develop a plan regarding how you, as a parent, will support your child as he or she emerges into young adulthood. </p>
<p>As a mother of two college students and a psychiatrist who has provided clinical care to college students for the last 20 years, I have a unique perspective. </p>
<p>As a mother, I expect my children to go through college with success, but as a psychiatrist, I have seen how easily young adults can be derailed by academic problems, mental health issues and even bad luck. In fact, only <a href="https://nces.ed.gov/fastfacts/display.asp?id=40">59% of college graduates</a> starting in 2006 took six years or less to graduate from a four-year program. </p>
<p>Your strategy as a parent can make a big difference in the outcome of the college years. Based on past research and my experience, here are some suggestions: </p>
<ul>
<li><p><a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3117230/pdf/nihms292117.pdf">Be there</a> – When children move toward autonomy, they need some parental guidance, a navigation system of sorts. Parents should tell their children when they are heading in the wrong direction and announce, “Take the next U-turn.”</p></li>
<li><p>But <a href="http://www.acui.org/publications/bulletin/article.aspx?issue=28134&id=14773">don’t</a> be there too much. Too much monitoring, such as doing her homework or checking every test grade, is not good for your child. It could result in your child being less autonomous and less successful in college. </p></li>
<li><p>Avoid “free range parenting” – the opposite extreme of “helicopter parenting.” Free range parenting is even more hazardous to your undergraduate child. I have seen parents look the other way as their children continue to fail academically or get deeper into drugs. </p></li>
</ul>
<p>Like so many things in life, your best bet is the middle ground. </p>
<h2>Here is a simple checklist</h2>
<ul>
<li>Check your child’s grades at the end of every semester: </li>
</ul>
<p>I am not saying be a tiger mom or dad, demanding nothing short of “A"s from your child. Rather, use the end of semester grades to check how your child is progressing academically and emotionally, and encourage him or her to get help if needed. </p>
<p>Your child can let you see the grades online by sharing a password or sending a screen shot. Don’t rely on their verbal report. I have seen many students go through multiple semesters of doing poorly, but hiding their problems, even lying to their parents, out of shame or embarrassment. </p>
<p>Once you know there is a problem, you can help your child assess the cause, which could include a general lack of maturity, poor high school preparation, poor study skills, a learning disability or Attention Deficit/Hyperactivity Disorder (ADHD), depression or anxiety, or excessive drug use. Helpful campus resources include academic advising, tutoring services and the counseling center. </p>
<ul>
<li>Check your child’s social life:</li>
</ul>
<p>You can’t view a social report card, but you can ask about friendships and dating experiences. Encourage your child to join at least one campus club, activity, religious group or intramural sport. </p>
<p>Freshman year can be a particularly lonely time for some students. A <a href="http://www.heri.ucla.edu/monographs/theamericanfreshman2014.pdf">2014 survey</a> of freshmen showed that compared with 1987, they are spending far less time in face-to-face contact with other students and more time on social media.</p>
<p>In 1987, 37.9% of freshmen socialized at least 16 hours per week with friends. In 2014, only 18% of freshmen spent at least 16 hours per week socializing face-to-face with friends; 27.2% spent at least six hours per week on online social networks, up from 18.9% in 2007. </p>
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<img alt="" src="https://images.theconversation.com/files/82458/original/image-20150520-11422-vpu2x3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/82458/original/image-20150520-11422-vpu2x3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/82458/original/image-20150520-11422-vpu2x3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/82458/original/image-20150520-11422-vpu2x3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/82458/original/image-20150520-11422-vpu2x3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/82458/original/image-20150520-11422-vpu2x3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/82458/original/image-20150520-11422-vpu2x3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The role of parents during college years is crucial.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&search_tracking_id=xaaV7Y3oopYSbKD0vzAF0g&searchterm=college%20parent&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=20999887">Teenager image via www.shutterstock.com</a></span>
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<p>I have seen homesick freshmen who want to leave school benefit from increased parent visits or phone contacts. Most students eventually find their social group, but parents can be crucial to that initial adjustment.</p>
<ul>
<li>Check your child’s mental health:</li>
</ul>
<p>Mental health issues have increased to record highs on college campuses. <a href="http://www.acha-ncha.org/docs/NCHA-II_WEB-PAPER_SPRING2014_UNDERGRAD_REFERENCEGROUP_EXECUTIVESUMMARY.pdf">In 2014</a>, 14.3% of college students reported being diagnosed with anxiety and 12.1% with depression at some point in the previous year – an increase from 10.5% of students who reported anxiety and 10.1% with depression in 2009. </p>
<p>If your child seems to be depressed or stressed, encourage her to seek an evaluation at the college campus counseling center. If she is having suicidal thoughts – and 11% college students do in a year – take this very seriously. <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2709750/">Encourage an assessment</a> as soon as possible. </p>
<h2>This can make a difference</h2>
<p>With the right help, students can make remarkable progress and have a successful college experience. </p>
<ul>
<li>Check your child’s marijuana and alcohol use:</li>
</ul>
<p>I have a strong belief about marijuana in the college student: parents should just say no. This is a tough stance to take, given that 36% of <a href="http://ns.umich.edu/new/releases/22362-college-students-use-of-marijuana-on-the-rise-some-drugs-declining">college students</a> surveyed in 2013 reported using marijuana at least once in the previous year, with 5% of these students using it on a near daily basis. </p>
<p>Today’s marijuana has tetrahydocannabinol (the chemical responsible for marijuana’s effects) levels <a href="http://www.forbes.com/sites/alicegwalton/2015/03/23/pot-evolution-how-the-makeup-of-marijuana-has-changed-over-time/">three times higher</a> than a few decades ago, greatly increasing the risk of a first psychotic episode. I have seen several students over the years become psychotic after heavy marijuana use, necessitating hospitalization.</p>
<p>Far more common and just as damaging, marijuana has <a href="http://www.psychiatrictimes.com/special-reports/marijuana-and-madness-clinical-implications-increased-availability-and-potency/page/0/3?GUID=1C7ACAB0-88D4-469A-8F24-B709701CA7E6&rememberme=1&ts=05052015">negative effects</a> on memory, motivation and concentration. College students who smoke marijuana at least every other day have a much higher rate of dropping out of school than those who don’t use marijuana.</p>
<p><a href="http://ns.umich.edu/new/releases/22362-college-students-use-of-marijuana-on-the-rise-some-drugs-declining">Alcohol abuse</a> can also have a variety of negative consequences for college students. In 2013, 76% of college students reported consuming alcohol at least once in the previous year. During the same period, 58% of students had been drunk at least one time. This increases their chance of injury or sexual assault. </p>
<p>If you believe your child has a drug or alcohol problem, encourage early and aggressive treatment. I have seen parents turn their children’s lives around by staying involved. </p>
<p>As a parent, you continue to have an important role in creating your child’s college senior portrait. By taking a middle-of-the-road approach throughout the college years, keeping your parent checklist in mind, you will see your child blossom into the wonderful, mature adult you have always envisioned. </p>
<p>And on the next graduation day, it is most likely you will see an ethical, responsible, self-sufficient individual walking to receive his or her certificate.</p><img src="https://counter.theconversation.com/content/42099/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marcia Morris does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Young adults can be easily derailed. Close to 60% students take six years to finish their four-year undergraduate program. How can you help?Marcia Morris, Psychiatrist, University of FloridaLicensed as Creative Commons – attribution, no derivatives.