Psilocybin has been demonstrated to have a rapid effect on patients with major depressive disorder. In 2016, it was also shown to decrease anxiety and depression in people with life-threatening cancer.
A 2014 study found that when used as part of a cognitive behavioral therapy program, psilocybin was very effective at helping patients quit smoking. 80% of the long-term smokers who participated in the study were still abstinent after six months. This is compared to only 35% for varenicline (Chantix), the most effective smoking cessation drug on the market. Psilocybin has also been found to curb alcohol abuse.