Mental Health Impacts

This page provides information on the connection between marijuana and mental health problems.


Psychosis is a loss of touch with reality, including:

  • Hallucinations
  • Delusions
  • Paranoia
  • Catatonia
  • Thought disorders

Psychosis may be seen with:

  • Schizophrenia
  • Bipolar disorder
  • Depression
  • Various medical conditions
  • Other psychiatric conditions
  • Independent of other conditions

Marijuana And Bipolar Disorder

  • New research suggests marijuana causes manic symptoms in those with bipolar disorder.
  • Marijuana use is associated with a 3-fold increase in the risk for the new onset of manic symptoms.
  • Marijuana use may worsen the severity and/or duration of  manic phases for people with bipolar disorder.
  • This underscores the importance of discouraging marijuana use among those with bipolar disorder.

Marwaha, Cannabis use and mania symptoms: A systemic review and meta-analysis. Journal of Affective Disorders, September 24, 2014.

Marijuana And Schizophrenia

  • Marijuana use is associated with an increased risk of developing schizophrenia
    • To a degree consistent with a causal relationship
    • One study found 13% of schizophrenia cases could be averted if marijuana use was prevented
  • Risk factors include:
    • Genetic predisposition to schizophrenia/psychosis
    • Early marijuana use, especially before age 15
    • Frequent, heavy, and/or high-THC marijuana use
  • Marijuana use worsens positive symptoms of schizophrenia, including hallucinations and delusions

Marijuana And Other Mental Illness

  • Regular, and in particular, heavy (quantity or potency or both) cannabis use may be linked to:
    • Depression
    • Suicidal thoughts/suicide attempts
    • Anxiety disorder
    • Panic attacks

All information was obtained through research compiled in the 2017 report published by the National Academies of Sciences and Medicine titled The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations.