A large genetic study reveals that cannabis use disorder (CanUD) is strongly linked to increased risk for multiple psychiatric disorders, including depression, PTSD, ADHD, and schizophrenia. By analyzing global and local genetic correlations, colocalization, Mendelian randomization, and structural equation modeling, researchers showed CanUD has distinct genetic signatures compared to casual cannabis use.

The findings suggest bidirectional causal relationships between CanUD and many psychiatric conditions, raising concerns about the mental health risks of heavy and prolonged cannabis use. These results highlight the need for caution as cannabis becomes more widely used and legalized, particularly for individuals vulnerable to mental health disorders.