title: Clinical correlates of first-episode polarity in bipolar disorder.
abstract: OBJECTIVE
  To determine the clinical and long-term implications of mood polarity at illness onset.
  
  
  METHODS
  During a 10-year follow-up prospective study, systematic clinical and outcome data were collected from 300 bipolar I and II patients. The sample was split into 2 groups according to the polarity of the onset episode (depressive onset [DO] vs manic/hypomanic onset [MO]). Clinical features and social functioning were compared between the 2 groups of patients.
  
  
  RESULTS
  In our sample, 67% of the patients experienced a depressive onset. Depressive onset patients were more chronic than MO patients, with a higher number of total episodes and a longer duration of illness. Depressive onset patients experienced a higher number of depressive episodes than MO patients, who in turn had more manic episodes. Depressive onset patients made more suicide attempts, had a later illness onset, were less often hospitalized, and were less likely to develop psychotic symptoms. Depressive onset was more prevalent among bipolar II patients. Bipolar I patients with DO had more axis II comorbidity and were more susceptible to have a history of psychotic symptoms than bipolar II patients with DO.
  
  
  CONCLUSIONS
  The polarity at onset is a good predictor of the polarity of subsequent episodes over time. A depressive onset is twice as frequent as MO and carries more chronicity and cyclicity.
authors.affiliation: Clinical Institute of Neuroscience, Hospital Clinic, University of Barcelona, Villarroel 170, 08036 Barcelona, Spain.
authors.forename: Claire
authors.initials: C
authors.lastname: Daban
authors.forename: Francesc
authors.initials: F
authors.lastname: Colom
authors.forename: Jose
authors.initials: J
authors.lastname: Sanchez-Moreno
authors.forename: Margarita
authors.initials: M
authors.lastname: García-Amador
authors.forename: Eduard
authors.initials: E
authors.lastname: Vieta
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D012919:Social Behavior; D013030:Spain; D013223:Statistics as Topic; D013406:Suicide, Attempted / Q000523:psychology / Q000706:statistics & numerical data