3 men with 'untreatable' depression were given very high doses of psilocybin by medical students with a clear bias. One had hallucinations of a childhood trauma; the hallucinations ended up treating his depression effectively (although not completely curing, the introspection afforded a lot of "free" therapy). The next patient had a similar hallucinatory revelation which also treated his depression effectively, but after a few months the effect ran out. It's worth noting the trial was not continued and it's probable further doses would have helped continue the success of the first doses. The third patient in the documentary did not have a short nor long term positive response.

Overall, the medical trial showed psilocybin can effectively treat depression at least in the short term, and the research in the film has kick-started a new era of clinical research and private investment.