Problematic cannabis use (e.g. cannabis use disorder (CUD)) is much higher in individuals with mental illness, including schizophrenia, mood and anxiety disorders, personality disorders and post-traumatic stress disorder, compared to the general population [14, 17, 22, 68, 92]. Psychiatric symptoms have been shown to predict not only problematic cannabis use, but also the perception of cannabis as harmless [11, 133]. Additionally, as cannabis use becomes more clinically severe, a stronger correlation has been described between a diagnosis of CUD and concurrent psychiatric disorder [68]. Despite this high prevalence, well-controlled studies have suggested more harms than therapeutic benefits from recreational cannabis use in these populations; however, further research is needed.
