At the other end of the spectrum is the plethora of studies that have found negative associations between marijuana use and health. They are listed below. Daily marijuana use is believed to exacerbate existing symptoms of bipolar disorder among people who have this mental health problem. However, the National Academies of Sciences, Engineering, and Medicine report suggests that among people with no history of the condition, there is only limited evidence of a link between marijuana use and developing bipolar disorder. Moderate evidence suggests that regular marijuana users are more likely to experience suicidal thoughts, and there is a small increased risk of depression among marijuana users.

Marijuana use is likely to increase risk of psychosis, including schizophrenia. But a curious finding among people with schizophrenia and other psychoses is that a history of marijuana use is linked with improved performance on tests assessing learning and memory.

Resourse: Medical News Today