How can psychedelic drugs be used to treat mental illness? Former government drugs tsar Professor David Nutt is investigating how psilocybin – the active ingredient in magic mushrooms – could be used to rev...

How can psychedelic drugs be used to treat mental illness? Former government drugs tsar Professor David Nutt is investigating how psilocybin – the active ingredient in magic mushrooms – could be used to revolutionise treatment for depression. David explains why he thinks it's working and the bureaucracy involved in researching illegal substances that leave him "treated like a drug dealer".