title: American tertiary clinic-referred bipolar II disorder versus bipolar I disorder associated with hastened depressive recurrence.
abstract: BACKGROUND
  Bipolar disorder (BD) is a chronic, frequently comorbid condition characterized by high rates of mood episode recurrence and suicidality. Little is known about prospective longitudinal characterization of BD type II (BD II) versus type I (BD I) in relation to time to depressive recurrence and recovery from major depressive episode. We therefore assessed times to depressive recurrence/recovery in tertiary clinic-referred BD II versus I patients.
  
  
  METHODS
  Outpatients referred to Stanford BD Clinic during 2000-2011 were assessed with Systematic Treatment Enhancement Program for BD (STEP-BD) Affective Disorders Evaluation and with Clinical Monitoring Form during up to 2 years of naturalistic treatment. Prevalence and clinical correlates of bipolar subtype in recovered (euthymic ≥8 weeks) and depressed patients were assessed. Kaplan-Meier analyses assessed the relationships between bipolar subtype and longitudinal depressive severity, and Cox proportional hazard analyses assessed the potential mediators.
  
  
  RESULTS
  BD II versus BD I was less common among 105 recovered (39.0 vs. 61.0%, p = 0.03) and more common among 153 depressed (61.4 vs. 38.6%, p = 0.006) patients. Among recovered patients, BD II was associated with 6/25 (24.0%) baseline unfavorable illness characteristics/mood symptoms/psychotropics and hastened depressive recurrence (p = 0.015). Among depressed patients, BD II was associated with 8/25 (33.0%) baseline unfavorable illness characteristics/mood symptoms/psychotropics, but only non-significantly associated with delayed depressive recovery.
  
  
  CONCLUSIONS
  BD II versus BD I was significantly associated with current depression and hastened depressive recurrence, but only non-significantly associated with delayed depressive recovery. Research on bipolar subtype relationships with depressive recurrence/recovery is warranted to enhance clinical management of BD patients.
authors.affiliation: Department of Psychiatry, University of Milan, Fondazione IRCCS Ca'Granda, Ospedale Maggiore Policlinico, Milan, Italy. bernardo.dellosso@unimi.it.|Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA. bernardo.dellosso@unimi.it.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Dell'Osso
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Saloni
authors.initials: S
authors.lastname: Shah
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Dennis
authors.initials: D
authors.lastname: Do
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Laura D
authors.initials: LD
authors.lastname: Yuen
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Farnaz
authors.initials: F
authors.lastname: Hooshmand
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Po W
authors.initials: PW
authors.lastname: Wang
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Shefali
authors.initials: S
authors.lastname: Miller
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Terence A
authors.initials: TA
authors.lastname: Ketter
keywords: Bipolar disorder; Bipolar subtype; Time to depressive recurrence; Time to recovery