title: A literature review and meta-analyses of cannabis use and suicidality.
abstract: BACKGROUND
  We lack a review of the epidemiological literature on cannabis use (acute use and chronic-usual quantity/frequency and heavy use) and suicidality (suicide death, suicide ideation, suicide attempt).
  
  
  METHODS
  The English language literature on Medline, PsychInfo, Google Scholar, and public-use databases was searched for original articles, critical review reports, and public use data on cannabis use and suicide for the period ranging from 1990-2015 (February). Odds ratios (OR) from random effects in meta-analyses for any cannabis use and heavy cannabis use were calculated.
  
  
  RESULTS
  The acute cannabis-suicidality literature mostly includes descriptive toxicology reports. In terms of death by suicide, the average positive cannabis rate was 9.50% for studies sampling from all suicides, with higher cannabis detection rates amongst suicide decedents by non-overdose methods. We found only 4 studies providing estimates for any chronic cannabis use and death by suicide (OR=2.56 (1.25-5.27)). After deleting duplicates we found 6 studies on any cannabis use and suicide ideation (OR=1.43 (1.13-1.83)), 5 studies on heavy cannabis use and suicide ideation (OR=2.53 (1.00-6.39)), 6 studies on any cannabis use and suicide attempt (OR=2.23 (1.24-4.00)) and 6 studies on heavy cannabis use and suicide attempt (OR=3.20 (1.72-5.94)).
  
  
  CONCLUSIONS
  We currently lack evidence that acute cannabis use increases imminent risk for suicidality. The evidence tends to support that chronic cannabis use can predict suicidality, but the lack of homogeneity in the measurement of cannabis exposure and, in some instances, the lack of systematic control for known risk factors tempered this finding.
authors.affiliation: Senior Researcher and Professor, National Institute of Psychiatry and Metropolitan Autonomous University, Mexico City, Mexico. Electronic address: guibor@imp.edu.mx.
authors.forename: Guilherme
authors.initials: G
authors.lastname: Borges
authors.affiliation: Associate Professor, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Mississippi, USA.
authors.forename: Courtney L
authors.initials: CL
authors.lastname: Bagge
authors.affiliation: Researcher, National Institute of Psychiatry, Mexico City, Mexico.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Orozco
mesh_terms: D002188:Cannabis; D004200:Diseases in Twins / Q000235:genetics; D006801:Humans; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000523:psychology*; D012307:Risk Factors; D012931:Social Environment; D019966:Substance-Related Disorders; D059020:Suicidal Ideation; D013405:Suicide / Q000523:psychology* / Q000706:statistics & numerical data*; D013406:Suicide, Attempted / Q000706:statistics & numerical data