The meta-analyses included studies over 38 years from 1980-2018. The search included MEDLINE, Embase, PsychINFO, the Cochrane Central Register of Controlled Clinical Trials, and the Cochrane Database of Systematic Reviews. The search also included unpublished data from Clinical Trials.gov, the EU Clinical Trials Register, and the Australian and New Zealand Clinical Trials Registry. Studies with participants at a minimum of 18 years of age looking at depression, anxiety, attention-deficit hyperactivity disorder (ADHD), Tourette syndrome, post-traumatic stress disorder (PTSD), or psychosis were included. The primary outcomes were remission or changes in symptoms from these mental disorders. The safety of medicinal cannabinoids for these mental disorders was also examined. The evidence from randomized controlled clinical trials was synthesized as odds ratios (ORs) for disorder remission, adverse events, and withdrawals. The evidence was also synthesized as standardized mean differences (SMD) for change in symptoms. The evidence quality was assessed using the Cochrane risk bias tool and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.