title: Cannabis use and first manic episode.
abstract: BACKGROUND
  Cannabis is the most commonly abused drug among patients with bipolar disorder. Available data has shown that the risk of psychotic disorders increases with the frequency and intensity of cannabis abuse. The present purpose was to review relevant studies to investigate whether cannabis use can be linked to the onset of mania in bipolar disorder.
  
  
  METHODS
  Articles published between 1972 and December 2013 were searched on Medline and PsychInfo using the following keywords: first manic episode, or onset mania, or bipolar disorder and cannabis. Relevant papers cited in the references of selected articles were further considered for inclusion into the review.
  
  
  RESULTS
  Lifetime use of cannabis among bipolar patients appears to be around 70% and approximately 30% of patients with a bipolar disorder present a comorbidity of cannabis abuse or dependence. Cannabis use is associated with younger age at onset of first mania and with more frequent depressive or manic episodes, although the evidence is somewhat inconsistent. Likewise cannabis consumption is related to poorer outcome and an increased risk of rapid cycling or mixed episodes. In contrast, neuro-cognitive functioning seems to be positively affected in patients with psychiatric comorbidity. While cannabis use often precedes first manic episodes, the causal direction remains to be determined.
  
  
  CONCLUSIONS
  Variations in definition of cannabis use/dependence. Lack of controlled studies limiting definite conclusions about a putative causal relationship between cannabis and onset of mania.
  
  
  CONCLUSIONS
  Further investigations are needed to clarify the relationships between cannabis use and first manic episode.
authors.affiliation: Division of Addiction Psychiatry, Department of Mental Health and Psychiatry, Geneva University Hospitals, Switzerland.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bally
authors.affiliation: Division of Addiction Psychiatry, Department of Mental Health and Psychiatry, Geneva University Hospitals, Switzerland.
authors.forename: Daniele
authors.initials: D
authors.lastname: Zullino
authors.affiliation: Mood Disorders Unit, Division of Psychiatric Specialties, Department of Mental Health and Psychiatry, Geneva University Hospitals, 20 Bis, Rue de Lausanne, CH-1201 Geneva, Switzerland. Electronic address: jean-michel.aubry@hcuge.ch.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Aubry
mesh_terms: D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000209:etiology* / Q000523:psychology; D002188:Cannabis / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000150:complications*; D008875:Middle Aged
keywords: Bipolar disorders; Cannabis; Marijuana; Onset mania