title: Impact of Cannabis Use on Long-Term Remission in Bipolar I and Schizoaffective Disorder.
abstract: OBJECTIVE
  To investigate the impact of regular cannabis use on long-term remission of mood symptoms in bipolar spectrum disorders.
  
  
  METHODS
  The 24-month prospective observational study included patients (n=239) with bipolar I disorder and schizoaffective disorder, bipolar type. Participants were classified as regular cannabis users (three times or more per week) or non-users. The primary outcome measure was the achievement of remission on the evaluations during the 24 months.
  
  
  RESULTS
  Of the 234 participants for whom data was available, 25 (10.7%) were regular cannabis users, and the group comprised significantly more males than females. In the total population, cannabis use was significantly associated with decreased likelihood of remission during the 24-month follow-up period. Subgroup analyses showed that cannabis use was significantly associated with lower remission rates on the Hamilton Depression Rating Scale in females (n=139) and patients prescribed mood stabilizers alone (n=151), whereas in males (n=95) and patients prescribed olanzapine and/or a mood stabilizer (n=83), cannabis use was significantly associated with lower remission rates on the Young Mania Rating Scale. Remission rates were lowest in the concurrent cannabis and tobacco smoking group (n=22) followed by the tobacco smoking only group (n=97), and the non-smoker group (n=116). The post-hoc analysis revealed that all remission rates were significantly lower in the concurrent cannabis and the tobacco smoking group compared to the non-smoker group.
  
  
  CONCLUSIONS
  Cannabis use negatively affects the long-term clinical outcome in patients with bipolar spectrum disorders. A comprehensive assessment and integrated management of cannabis use are required to achieve better treatment outcomes for bipolar spectrum disorders.
authors.affiliation: Department of Psychiatry, Chonnam National University Medical School, Gwangju, Republic of Korea.
authors.forename: Sung-Wan
authors.initials: SW
authors.lastname: Kim
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia. ; Department of Psychiatry, University of Melbourne, Melbourne, Australia.
authors.forename: Seetal
authors.initials: S
authors.lastname: Dodd
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia. ; Department of Psychiatry, University of Melbourne, Melbourne, Australia. ; Centre for Mental Health and Wellbeing Research, School of Psychology, Faculty of Health Deakin University, Geelong, Australia.
authors.forename: Lesley
authors.initials: L
authors.lastname: Berk
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred Hospital and Monash University, Melbourne, Australia.
authors.forename: Jayashri
authors.initials: J
authors.lastname: Kulkarni
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred Hospital and Monash University, Melbourne, Australia.
authors.forename: Anthony
authors.initials: A
authors.lastname: de Castella
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred Hospital and Monash University, Melbourne, Australia.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fitzgerald
authors.affiliation: Department of Psychiatry, Chonnam National University Medical School, Gwangju, Republic of Korea.
authors.forename: Jae-Min
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, Chonnam National University Medical School, Gwangju, Republic of Korea.
authors.forename: Jin-Sang
authors.initials: JS
authors.lastname: Yoon
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia. ; Department of Psychiatry, University of Melbourne, Melbourne, Australia. ; Orygen Youth Health Research Centre, Melbourne, Australia. ; Florey Institute for Neuroscience and Mental Health, Melbourne, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Berk
keywords: Bipolar disorder; Cannabis; Observational study; Remission; Schizoaffective disorder; Substance