title: Cannabis and bipolar disorder: does quitting cannabis use during manic/mixed episode improve clinical/functional outcomes?
abstract: OBJECTIVE
  To examine whether bipolar disorder patients who stop cannabis use during a manic/mixed episode have better clinical and functional outcomes than continued use or never use.
  
  
  METHODS
  Data from the European Mania in Bipolar Longitudinal Evaluation of Medication (EMBLEM), a 2-year prospective observational study in adults with a manic/mixed episode of bipolar disorder, was used. Three cannabis use groups were: current use (between 12-week and 24-month visits); no current but previous use (during first 12 weeks); and never use. Associations between cannabis use and outcomes were analyzed using regression models.
  
  
  RESULTS
  Of 1922 patients analyzed, 6.9% were current users, 4.6% previous users, and 88.5% never users. Clinical outcomes differed between groups (P<0.019): previous users had highest rates of remission (68.1%) and recovery (38.7%), and lowest rates of recurrence (42.1%) and relapse (29.8%). Logistic regression showed previous users had similar outcomes to never users (all P>0.05), whereas current users had lower recovery (P=0.004) and remission (P=0.014), higher recurrence (P=0.014), greater work impairment (P=0.016), and were more likely not to be living with partner (P=0.006) than never users.
  
  
  CONCLUSIONS
  Bipolar patients who stop using cannabis during manic/mixed episode have similar clinical and functional outcomes to never users, while continued use is associated with higher risk of recurrence and poorer functioning.
authors.affiliation: International Mood Disorders Research Centre, Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Hospital Santiago Apóstol, University of the Basque Country, Vitoria, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Zorrilla
authors.forename: J
authors.initials: J
authors.lastname: Aguado
authors.forename: J M
authors.initials: JM
authors.lastname: Haro
authors.forename: S
authors.initials: S
authors.lastname: Barbeito
authors.forename: S
authors.initials: S
authors.lastname: López Zurbano
authors.forename: A
authors.initials: A
authors.lastname: Ortiz
authors.forename: P
authors.initials: P
authors.lastname: López
authors.forename: A
authors.initials: A
authors.lastname: Gonzalez-Pinto
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000453:epidemiology* / Q000523:psychology; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000009:adverse effects / Q000453:epidemiology* / Q000523:psychology; D011379:Prognosis; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D012008:Recurrence; D012307:Risk Factors
keywords: bipolar disorder; cannabis; functioning; relapse; remission