A study by Lancaster University found long-term use of the psychoactive substance harms the brain.
The effect on cognition of cannabis use by adolescents and young adults is small and temporary, a new study claims.
Medical marijuana appears to have put a dent in the opioid abuse epidemic.
Cannabis use was associated with an increased initiation of cigarette smoking.
Substance use in children with ADHD begins at an earlier age, researchers found.