title: Episode cycles with increasing recurrences in first-episode bipolar-I disorder patients.
abstract: BACKGROUND
  Preliminary review of a century of studies of the course of manic-depressive syndromes produced 40 reports, of which approximately one-third report evidence of shortening wellness intervals or cycle-lengths with more recurrences, and two-thirds did not.
  
  
  METHODS
  We evaluated inter-episode intervals (cycle-length) in 128 clinically-treated, DSM-IV bipolar-I disorder patients followed prospectively and systematically over 5.7 years, with 6.5 episodes/person.
  
  
  RESULTS
  As expected, cycle-length varied inversely with total cycle-count/person; however, multivariate linear regression found only longer initial hospitalization and fewer total cycles to be associated with cycle-length, whereas cycle-number (1, 2, 3, etc.), sex, intake-age, and first-episode polarity were not. Regression of within-subject cycle-length versus cycle-number yielded individual slope-functions with pseudo-random distribution (28% fell within ±1 month/cycle of the null [zero-slope]). Mean duration of early and late euthymic intervals (cycles 2 vs. 5) in patients with matched recurrence-counts was nearly identical.
  
  
  CONCLUSIONS
  The course of bipolar-I disorder from onset was largely random or chaotic over nearly 6 years from onset. Only a minority of patients showed either cycle-acceleration or slowing, without changes in wellness intervals. The findings may be influenced by treatment-effects, but seem to indicate that most current bipolar-I disorder patients are unlikely to show progressive shortening of recurrence-cycles.
authors.affiliation: Department of Psychiatry, Harvard Medical School, International Consortium for Bipolar Disorder Research, McLean Division of Massachusetts General Hospital, Boston, MA, United States. Electronic address: rbaldessarini@mclean.harvard.edu.
authors.forename: R J
authors.initials: RJ
authors.lastname: Baldessarini
authors.affiliation: Department of Psychiatry, Harvard Medical School, International Consortium for Bipolar Disorder Research, McLean Division of Massachusetts General Hospital, Boston, MA, United States; Section of Psychiatry, Department of Neuroscience, University of Parma, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Salvatore
authors.affiliation: Department of Psychiatry, Harvard Medical School, International Consortium for Bipolar Disorder Research, McLean Division of Massachusetts General Hospital, Boston, MA, United States.
authors.forename: H-M K
authors.initials: HK
authors.lastname: Khalsa
authors.affiliation: Department of Psychiatry, Vittoria Medical Center, Vittoria, Spain.
authors.forename: H
authors.initials: H
authors.lastname: Imaz-Etxeberria
authors.affiliation: Department of Psychiatry, Vittoria Medical Center, Vittoria, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Gonzalez-Pinto
authors.affiliation: Department of Psychiatry, University of Texas Health Sciences Center, San Antonio, TX, United States.
authors.forename: M
authors.initials: M
authors.lastname: Tohen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D013997:Time Factors; D055815:Young Adult