Depression. Addiction. Anxiety. OCD. Anorexia. Psilocybin, the active ingredient in magic mushrooms, is being used to treat a wide range of mental-health disorders, with some very promising results. But what is the experience like in these sessions that can last as long as eight hours? And what exactly does it offer people? And why does a single dose help 80 per cent of people quit smoking or 6 per cent of people recover from severe depression? Producer Eric Bombicino visits "the most beautiful room" in Toronto General Hospital and finds out how this psychedelic is changing people's minds.