Pot Smoking Is Still Bad for Teenage Mental Health

Cannabis use is usually accompanied by cigarette smoking, and both tobacco and cannabis have been associated with psychosis; but whether the link to psychosis is attributable to marijuana or tobacco is unknown. Researchers examined longitudinal data on 5300 U.K. adolescents who repeatedly self-reported their cigarette and cannabis use between ages 14 and 19 and were assessed on structured interviews for psychotic experiences at ages 12 and 18.

Compared with no use of cigarettes or cannabis (66% of the sample), both cigarette use (without cannabis use) beginning only early in adolescence and marijuana use (typically with cigarette use) beginning either early or late in adolescence were significantly associated with psychotic symptoms at age 1…