title: Medical marijuana programs - Why might they matter for public health and why should we better understand their impacts?
abstract: OBJECTIVE
  Although cannabis is an illegal drug, 'medical marijuana programs' (MMPs) have proliferated (e.g., in Canada and several US states), allowing for legal cannabis use for therapeutic purposes. While both health risks and potential therapeutic benefits for cannabis use have been documented, potential public health impacts of MMPs - also vis-à-vis other psychoactive substance use - remain under-explored.
  
  
  METHODS
  We briefly reviewed the emerging evidence on MMP participants' health status, and specifically other psychoactive substance use behaviors and outcomes.
  
  
  RESULTS
  While data are limited in amount and quality, MMP participants report improvements in overall health status, and specifically reductions in levels of risky alcohol, prescription drug and - to some extent - tobacco or other illicit drug use; at the same time, increases in cannabis use and risk/problem patterns may occur.
  
  
  CONCLUSIONS
  MMP participation may positively impact - for example, by way of possible 'substitution effects' from cannabis use - other psychoactive substance use and risk patterns at a scale relevant for public health, also influenced by the increasing population coverage of MMPs. Yet, net overall MMP-related population health effects need to be more rigorously and comprehensively assessed, including potential increases in cannabis use related risks and harms.
authors: Centre for Applied Research in Mental Health and Addictions (CARMHA), Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia V6B 5K3, Canada; Social & Epidemiological Research, Centre for Addiction & Mental Health (CAMH), Toronto, Ontario M5S 1S1, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada.
authors: Benedikt
authors: B
authors: Fischer
authors: Centre for Applied Research in Mental Health and Addictions (CARMHA), Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia V6B 5K3, Canada; Social & Epidemiological Research, Centre for Addiction & Mental Health (CAMH), Toronto, Ontario M5S 1S1, Canada.
authors: Yoko
authors: Y
authors: Murphy
authors: Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Mental Health & Addiction Research Program, Institute of Clinical Evaluative Sciences, Toronto, Ontario M4N 3M5, Canada.
authors: Paul
authors: P
authors: Kurdyak
authors: Centre for Applied Research in Mental Health and Addictions (CARMHA), Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia V6B 5K3, Canada.
authors: Elliot
authors: E
authors: Goldner
authors: Social & Epidemiological Research, Centre for Addiction & Mental Health (CAMH), Toronto, Ontario M5S 1S1, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Dalla Lana School of Public Health, University of Toronto, Ontario M5T 3M7, Canada.
authors: Jürgen
authors: J
authors: Rehm
keywords: Cannabis; Medical marijuana; Population health; Risk factors; Substance use