title: Cannabis use in first-treatment bipolar I disorder: relations to clinical characteristics.
abstract: OBJECTIVE
  The aim of this study was to investigate the associations between recent cannabis use, current symptomatology and age at onset of first manic, depressive and psychotic episodes in a large sample with first-treatment bipolar I disorder (BD I).
  
  
  METHODS
  One hundred one patients with first-treatment Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) bipolar I disorder were included as part of the Thematically Organized Psychosis study. The Structural Clinical Interview for DSM-IV was used for DSM-IV diagnosis and identification of episodes of illness. Earlier suicide attempts were recorded. Manic, depressive and psychotic symptoms were rated using the Young Mania Rating Scale, Inventory of Depressive Symptoms and Positive and Negative Syndrome Scale correspondingly. Cannabis use within the six last months was recorded.
  
  
  RESULTS
  After controlling for confounders, recent cannabis use was significantly associated with lower age at onset of first manic and psychotic episode, but not with onset of first depressive episode (both P < 0.05). Recent use was also associated with more lifetime suicide attempts (P < 0.01). No group differences were found on symptom levels.
  
  
  CONCLUSIONS
  The present study confirms earlier findings of an association between cannabis use and a lower age at onset. Recent cannabis use was also associated with more lifetime suicide attempts. The current findings suggest that recent cannabis use is associated with a more severe course of illness in the early phase of BD I.
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo.
authors.forename: Levi R
authors.initials: LR
authors.lastname: Kvitland
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Melle
authors.affiliation: Division of Mental Health Services, Akershus University Hospital, Lørenskog, Norway.
authors.forename: Sofie R
authors.initials: SR
authors.lastname: Aminoff
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo.
authors.forename: Trine V
authors.initials: TV
authors.lastname: Lagerberg
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo.
authors.forename: Ole A
authors.initials: OA
authors.lastname: Andreassen
authors.affiliation: Division of Mental Health and Addiction, Oslo University Hospital, Oslo.
authors.forename: Petter A
authors.initials: PA
authors.lastname: Ringen
mesh_terms: D000328:Adult; D017668:Age of Onset; D001714:Bipolar Disorder / Q000150:complications* / Q000175:diagnosis* / Q000523:psychology / Q000628:therapy; D016022:Case-Control Studies; D017831:Diagnosis, Dual (Psychiatry) / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000150:complications* / Q000523:psychology*; D013406:Suicide, Attempted; D055815:Young Adult
keywords: age at onset; bipolar I; cannabis; first treatment