title: [The influence of cannabis on the course of bipolar disorder: a longitudinal analysis].
abstract: BACKGROUND
  Research shows that the use of cannabis has a negative impact on the onset and outcome of schizophrenia, but little is known about possible effects on mood disorders.
  
  
  OBJECTIVE
  To study the influence of cannabis use on clinical and social treatment outcomes in patients with bipolar disorders who had been treated for a period of 12 months.
  
  
  METHODS
  3459 bipolar patients were enrolled in an observational study. The influence of cannabis on various clinical and social treatment outcomes was examined over a period of one year. In addition, tests were applied in order to find out whether third, mediating variables had effects on possible associations between cannabis use and treatment outcomes.
  
  
  RESULTS
  During 12 months of treatment cannabis users showed less compliance and higher levels of illness severity, mania and psychosis than did non-users. In addition, cannabis users were less satisfied with their lives and had less chance of forming relationships than non-users. There was little evidence that associations between cannabis use and treatment outcomes were mediated by third variables.
  
  
  CONCLUSIONS
  Cannabis use clearly had an independent impact on clinical treatment outcomes in patients with bipolar disorder, but the impact on social outcomes was only modest.
authors.affiliation: Lilly Nederland B.V., Houten. winter_van_rossum_inge@lilly.com
authors.forename: I
authors.initials: I
authors.lastname: Winter-van Rossum
authors.forename: M M
authors.initials: MM
authors.lastname: Boomsma
authors.forename: D E
authors.initials: DE
authors.lastname: Tenback
authors.forename: C
authors.initials: C
authors.lastname: Reed
authors.forename: J
authors.initials: J
authors.lastname: van Os
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use*; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000188:drug therapy* / Q000473:pathology / Q000523:psychology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008385:Marijuana Smoking / Q000009:adverse effects*; D008875:Middle Aged; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D000927:Anticonvulsants; D014150:Antipsychotic Agents