title: Longitudinal course of bipolar I disorder: duration of mood episodes.
abstract: BACKGROUND
  The phenomenology of bipolar I disorder affects treatment and prognosis.
  
  
  OBJECTIVE
  To describe the duration of bipolar I mood episodes and factors associated with recovery from these episodes.
  
  
  METHODS
  Subjects with Research Diagnostic Criteria bipolar I disorder were prospectively followed up for as long as 25 years. The probability of recovery over time from multiple successive mood episodes was examined with survival analytic techniques, including a mixed-effects grouped-time survival model.
  
  
  METHODS
  Five US academic medical centers.
  
  
  METHODS
  Two hundred nineteen subjects with bipolar I disorder.
  
  
  METHODS
  Level of psychopathology was assessed with the Longitudinal Interval Follow-up Evaluation every 6 months for the first 5 years of follow-up and annually thereafter.
  
  
  RESULTS
  The median duration of bipolar I mood episodes was 13 weeks. More than 75% of the subjects recovered from their mood episodes within 1 year of onset. The probability of recovery was significantly less for an episode with severe onset (psychosis or severe psychosocial impairment in week 1 of the episode) (hazard ratio [HR] = 0.746; 95% confidence interval [CI], 0.578-0.963; P = .02) and for subjects with greater cumulative morbidity (total number of years spent ill with any mood episode) (HR = 0.917; 95% CI, 0.886-0.948; P < .001). Compared with the probability of recovery from a major depressive episode, there was a significantly greater probability of recovery from an episode of mania (HR = 1.713; 95% CI, 1.373-2.137; P < .001), hypomania (HR = 4.502; 95% CI, 3.466-5.849; P < .001), or minor depression (HR = 2.027; 95% CI, 1.622-2.534; P < .001) and, conversely, a significantly reduced probability of recovery from a cycling episode (switching from one pole to the other without an intervening period of recovery) (HR = 0.438; 95% CI, 0.351-0.548; P < .001).
  
  
  CONCLUSIONS
  The median duration of bipolar I mood episodes was 13 weeks, and the probability of recovery was significantly decreased for cycling episodes, mood episodes with severe onset, and subjects with greater cumulative morbidity.
authors.affiliation: UpToDate, Inc, Waltham, Massachusetts, USA. dasolomon@lifespan.org
authors.forename: David A
authors.initials: DA
authors.lastname: Solomon
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Leon
authors.forename: William H
authors.initials: WH
authors.lastname: Coryell
authors.forename: Jean
authors.initials: J
authors.lastname: Endicott
authors.forename: Chunshan
authors.initials: C
authors.lastname: Li
authors.forename: Jess G
authors.initials: JG
authors.lastname: Fiedorowicz
authors.forename: Lara
authors.initials: L
authors.lastname: Boyken
authors.forename: Martin B
authors.initials: MB
authors.lastname: Keller
mesh_terms: D000328:Adult; D000339:Affect; D001714:Bipolar Disorder / Q000523:psychology*; D003863:Depression / Q000523:psychology; D018450:Disease Progression; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D012008:Recurrence; D012075:Remission, Spontaneous; D013997:Time Factors; D014481:United States