Study: Cannabis use by teens preceded and increased risk of mental disorders

Cannabis use in adolescence is associated with increased risk of psychiatric disorders, particularly psychotic and bipolar disorders. A cohort study of 463,396 adolescents ages 13 to 17 found that those who had used cannabis in the past year were more likely to have new cases of severe psychiatric disorders. The study could help educate parents, adolescents, and clinicians, the researchers concluded, adding that it could also help set policies to delay or prevent cannabis use.