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.
Studies show an increased risk of psychosis among marijuana and tobacco smokers.
Substance use in children with ADHD begins at an earlier age, researchers found.