At times of anxiety and trauma an increase in unusual or vivid dreams and nightmares is not surprising.
To some extent, shell-shock still shapes our understanding of PTSD today.
Many hope that marijuana will help their insomnia. A sleep psychologist examines the evidence.
Niamh, age 7, wants to know why we have scary dreams. But after 200 years of study, dreams are still very much a mystery.
Even indirect exposure to the terrorist attacks of September 11 has left profound and deep impact on those too young to remember a world before that.
A recent survey suggests that a third of UK parents avoid reading their children scary stories. Is this a worrying trend?
Before we can understand night terrors and nightmares, we need to understand normal sleep.