Is There a Link Between Marijuana Use and Psychiatric Disorders?

The link between cannabis (marijuana) use and psychiatric disorders is complex, and more research is needed to fully understand its short- and long-term effects on mental health. While not all studies agree, there is significant evidence that cannabis use may lead to an earlier onset of psychosis in individuals with genetic risk factors for conditions like schizophrenia. It may also worsen symptoms in people already diagnosed with such disorders. Additionally, although findings are less consistent, cannabis use has been associated with other mental health issues, including self-harm and suicidal thoughts or behaviors.

People experiencing mental health symptoms are more likely to use cannabis, but the exact nature of this relationship remains unclear. Various factors – such as dosage, frequency of use, THC content, product type, and the age at which someone begins using cannabis – can all influence its impact on mental health. Likewise, elements that affect mental health in general, like genetics, trauma, and stress, can also increase the likelihood of cannabis use. These overlapping genetic and environmental influences make it essential to conduct long-term, prospective studies to understand better whether, how, and for whom cannabis use may contribute to poor mental health outcomes.

Evidence suggests that cannabis use may increase the risk of earlier development of psychotic disorders, especially in those with a family history. High doses of cannabis can also trigger temporary psychotic episodes in some individuals, and such experiences may raise the likelihood of developing a lasting psychotic condition. Genetic factors may contribute to this vulnerability.

The association between cannabis use and other mental health conditions is less definitive. Some studies indicate a higher risk of depression in adolescents who use cannabis. More consistently, research has found links between cannabis use and suicidal thoughts and behaviors, particularly among teens and U.S. military veterans.