title: Does hypomania distinguish bipolar II disorder from major depressive disorder?
abstract: BACKGROUND
  Recent epidemiological/clinical studies have not found clear boundaries between bipolar II disorder (BP-II) and major depressive disorder (MDD), as subsyndromalhypomanic episodes were more common than syndromalhypomania. The aim of the study was to test if hypomania could still be used to split categorically BP-II and MDD.
  
  
  METHODS
  274 consecutive remitted BP-II and 129 MDD outpatients were interviewed by the Structured Clinical Interview for DSM-IV on the most common symptoms and duration of hypomanic episodes (lasting at least 2 days, having at least 2 symptoms), in a private practice.
  
  
  RESULTS
  As expected by definition, BP-II versus MDD had significantly more episodic hypomanic symptoms. However, MDD had episodes of subsyndromalhypomanic symptoms (median number of symptoms 3). In the entire sample, frequency of episodes of hypomanic symptoms, according to the number of symptoms per episode, was normally, not bimodally,distributed. A grading(r = 0.57, p < 0.001) of the number of episodic hypomanic symptoms was found.
  
  
  CONCLUSIONS
  Findings question the splitting of BP-II and MDD based on hypomania, as hypomania (at least as defined by DSM-IV) seems more a dimensional than a categorical disorder.
authors.affiliation: Hecker Psychiatry Research Center and Department of Psychiatry, National Health Service, Forli, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Benazzi
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000523:psychology*; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000523:psychology*; D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D012720:Severity of Illness Index