Cannabinoids (eg CBD and THC) are the primary psychoactive compound in cannabis/marijuana. Stories about cannabinoids are often in the news – some saying it can help treat depression and schizophrenia and some saying it can make things worse. A new study looked at all of the high quality evidence and concluded that there is no evidence that cannabinoids help in depression. The study also suggested that cannabinoids can make some of the symptoms of schizophrenia worse. However, there are smaller studies that do suggest some people may find benefits as well.
Black N, Stockings E, Campbell G, Tran LT, Zagic D, Hall WD, Farrell M, Degenhardt L. Cannabinoids for the treatment of mental disorders and symptoms of mental disorders: a systematic review and meta-analysis. The Lancet Psychiatry. 2019 Oct 28.