title: DSM-5-defined 'mixed features' and Benazzi's mixed depression: which is practically useful to discriminate bipolar disorder from unipolar depression in patients with depression?
abstract: OBJECTIVE
  Irritability, psychomotor agitation, and distractibility in a major depressive episode (MDE) should not be counted as manic/hypomanic symptoms of DSM-5-defined mixed features; however, this remains controversial. The practical usefulness of this definition in discriminating bipolar disorder (BP) from major depressive disorder (MDD) in patients with depression was compared with that of Benazzi's mixed depression, which includes these symptoms.
  
  
  METHODS
  The prevalence of both definitions of mixed depression in 217 patients with MDE (57 bipolar II disorder, 35 BP not otherwise specified, and 125 MDD cases), and their operating characteristics regarding BP diagnosis were compared.
  
  
  RESULTS
  The prevalence of both Benazzi's mixed depression and DSM-5-defined mixed features was significantly higher in patients with BP than it was in patients with MDD, with the latter being quite low (62.0% vs 12.8% [P < 0.0001], and 7.6% vs 0% [P < 0.0021], respectively). The area under the receiver operating curve for BP diagnosis according to the number of all manic/hypomanic symptoms was numerically larger than that according to the number of manic/hypomanic symptoms excluding the above-mentioned three symptoms (0.798; 95% confidence interval, 0.736-0.859 vs 0.722; 95% confidence interval, 0.654-0.790). The sensitivity/specificity of DSM-5-defined mixed features and Benazzi's mixed depression for BP diagnosis were 5.1%/100% and 55.1%/87.2%, respectively.
  
  
  CONCLUSIONS
  DSM-5-defined mixed features were too restrictive to discriminate BP from MDD in patients with depression compared with Benazzi's definition. To confirm this finding, studies that include patients with BP-I and using tools to assess manic/hypomanic symptoms during MDE are necessary.
authors.affiliation: Department of Psychiatry, Kouseiren Takaoka Hospital, Takaoka, Japan; J Clinic, Kanazawa, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Takeshima
authors.forename: Takashi
authors.initials: T
authors.lastname: Oka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001714:Bipolar Disorder / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D003866:Depressive Disorder / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D003865:Major Depressive Disorder / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D055815:Young Adult
keywords: DSM-5; bipolar disorder; depression; mixed depression; mixed states