Ecstasy to treat post-traumatic stress disorder?
18 September 2012 Last updated at 08:06 BST
Prof David Nutt explains why the drug ecstasy or MDMA is being studied in clinical research and how it could be useful for treating post-traumatic stress disorder by controlling intrusive, traumatic memories.
Professor Nutt is a psychiatrist and one of the country's leading experts on the effects of drugs on the brain. He was sacked in 2009 as the government's chief drugs adviser after criticising its decision to reclassify cannabis.
Hear the full interview with David Nutt on BBC Radio 4's The Life Scientific.