Here's something else of interest...
Cannabis-like chemicals in the brain play a key role in erasing nasty memories, a study has found. Researchers in Germany have found that cannabinoids, produced naturally in the brain, help to manage fear.
They believe that a lack of these chemicals may explain why some people have difficulty forgetting painful events and suffer from post-traumatic stress disorder or phobias.
The finding might have implications for treating anxiety disorders in humans
Dr Pankaj Sah, Australian National University
The researchers suggest that new drugs to increase the production of cannibanoids in the brain could help these patients to forget their painful memories.