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March 2016

Effects of Cannabis Use on Human Behavior, Including Cognition, Motivation, and Psychosis: A Review

Author Affiliations
  • 1National Institute on Drug Abuse, National Institutes of Health, Bethesda, Maryland
  • 2Child Development Center, University of California, Irvine
  • 3Center for Addiction Medicine, Department of Psychiatry, Massachusetts General Hospital, Boston
  • 4Harvard Medical School, Boston, Massachusetts
  • 5Veterans Affairs Boston Healthcare System, Harvard Medical School, Brockton, Massachusetts
  • 6Department of Psychology, Arizona State University, Tempe
  • 7Center for Children and Families, Department of Psychology, Florida International University, Miami
  • 8Division of Psychiatry, University College London, London, England
  • 9Psychiatric Imaging Group, Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, England
  • 10Clinical Psychopharmacology Unit, Clinical Health Psychology, University College London, London, England
JAMA Psychiatry. 2016;73(3):292-297. doi:10.1001/jamapsychiatry.2015.3278

With a political debate about the potential risks and benefits of cannabis use as a backdrop, the wave of legalization and liberalization initiatives continues to spread. Four states (Colorado, Washington, Oregon, and Alaska) and the District of Columbia have passed laws that legalized cannabis for recreational use by adults, and 23 others plus the District of Columbia now regulate cannabis use for medical purposes. These policy changes could trigger a broad range of unintended consequences, with profound and lasting implications for the health and social systems in our country. Cannabis use is emerging as one among many interacting factors that can affect brain development and mental function. To inform the political discourse with scientific evidence, the literature was reviewed to identify what is known and not known about the effects of cannabis use on human behavior, including cognition, motivation, and psychosis.