title: A systematic review and meta-analysis of prospective transition from major depression to bipolar disorder.
abstract: OBJECTIVE
  Some people with major depressive disorder (MDD) may be at a pre-onset stage for bipolar disorder (BD), where early identification or prevention efforts may be feasible. We aimed to identify rates and characteristics predictive of transition to BD in prospective follow-up studies of people with MDD.
  
  
  METHODS
  Using a systematic search strategy, we identified studies with a diagnostic ascertainment of MDD and BD of an adequate standard, and where the minimum length of follow-up was 6 months. We examined the incidence and point prevalence of BD and the pooled odds ratios (OR) for baseline predictors.
  
  
  RESULTS
  From 5554 unique publications, 56 were included. Nearly a quarter of adults (22.5%) and adolescents with MDD followed up for a mean length of 12-18 years developed BD, with the greatest risk of transition being in the first 5 years. The meta-analysis identified that transition from MDD to BD was predicted by family history of BD (OR = 2.89, 95% CI: 2.01-4.14, N = 7), earlier age of onset of depression (g = -0.33, SE = 0.05, N = 6) and presence of psychotic symptoms (OR = 4.76, 95% CI: 1.79-12.66, N = 5).
  
  
  CONCLUSIONS
  Participants with the identified risk factors merit closer observation and may benefit from prevention efforts, especially if outcomes broader than BD are considered.
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Vic.|Centre for Youth Mental Health, University of Melbourne, Melbourne, Vic.
authors.forename: A
authors.initials: A
authors.lastname: Ratheesh
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Vic.|Centre for Youth Mental Health, University of Melbourne, Melbourne, Vic.
authors.forename: C
authors.initials: C
authors.lastname: Davey
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Vic.|Centre for Youth Mental Health, University of Melbourne, Melbourne, Vic.
authors.forename: S
authors.initials: S
authors.lastname: Hetrick
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Vic.|Centre for Youth Mental Health, University of Melbourne, Melbourne, Vic.
authors.forename: M
authors.initials: M
authors.lastname: Alvarez-Jimenez
authors.affiliation: Royal Melbourne Hospital Library, Melbourne, Vic., Australia.
authors.forename: C
authors.initials: C
authors.lastname: Voutier
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Cologne.|Department of Psychiatry, Psychotherapy and Psychosomatics, Vivantes Hospital am Urban and Vivantes Hospital im Friedrichshain, Charite Universitätsmedizin, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bechdolf
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Vic.|Centre for Youth Mental Health, University of Melbourne, Melbourne, Vic.
authors.forename: P D
authors.initials: PD
authors.lastname: McGorry
authors.affiliation: University of Newcastle, Newcastle upon Tyne, UK.
authors.forename: J
authors.initials: J
authors.lastname: Scott
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Vic.|Centre for Youth Mental Health, University of Melbourne, Melbourne, Vic.|Florey Institute of Neuroscience and Mental Health, Parkville, Vic.|Impact Strategic Research Centre, Deakin University, Geelong, Vic, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Berk
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Vic.|Centre for Youth Mental Health, University of Melbourne, Melbourne, Vic.
authors.forename: S M
authors.initials: SM
authors.lastname: Cotton
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001714:Bipolar Disorder / Q000523:psychology*; D003865:Major Depressive Disorder / Q000523:psychology*; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: affective disorders; bipolar disorder; depression; meta-analysis; risk factors