title: Mixed features in patients with a major depressive episode: the BRIDGE-II-MIX study.
abstract: OBJECTIVE
  To estimate the frequency of mixed states in patients diagnosed with major depressive episode (MDE) according to conceptually different definitions and to compare their clinical validity.
  
  
  METHODS
  This multicenter, multinational cross-sectional Bipolar Disorders: Improving Diagnosis, Guidance and Education (BRIDGE)-II-MIX study enrolled 2,811 adult patients experiencing an MDE. Data were collected per protocol on sociodemographic variables, current and past psychiatric symptoms, and clinical variables that are risk factors for bipolar disorder. The frequency of mixed features was determined by applying both DSM-5 criteria and a priori described Research-Based Diagnostic Criteria (RBDC). Clinical variables associated with mixed features were assessed using logistic regression.
  
  
  RESULTS
  Overall, 212 patients (7.5%) fulfilled DSM-5 criteria for MDE with mixed features (DSM-5-MXS), and 818 patients (29.1%) fulfilled diagnostic criteria for a predefined RBDC depressive mixed state (RBDC-MXS). The most frequent manic/hypomanic symptoms were irritable mood (32.6%), emotional/mood lability (29.8%), distractibility (24.4%), psychomotor agitation (16.1%), impulsivity (14.5%), aggression (14.2%), racing thoughts (11.8%), and pressure to keep talking (11.4%). Euphoria (4.6%), grandiosity (3.7%), and hypersexuality (2.6%) were less represented. In multivariate logistic regression analysis, RBDC-MXS was associated with the largest number of variables including diagnosis of bipolar disorder, family history of mania, lifetime suicide attempts, duration of the current episode > 1 month, atypical features, early onset, history of antidepressant-induced mania/hypomania, and lifetime comorbidity with anxiety, alcohol and substance use disorders, attention-deficit/hyperactivity disorder, and borderline personality disorder.
  
  
  CONCLUSIONS
  Depressive mixed state, defined as the presence of 3 or more manic/hypomanic features, was present in around one-third of patients experiencing an MDE. The valid symptom, illness course and family history RBDC criteria we assessed identified 4 times more MDE patients as having mixed features and yielded statistically more robust associations with several illness characteristics of bipolar disorder than did DSM-5 criteria.
authors.affiliation: Clinica Psichiatrica Università Di Pisa, Via Roma 67, 56100, Pisa, Italy giulio.perugi@med.unipi.it.
authors.forename: Giulio
authors.initials: G
authors.lastname: Perugi
authors.forename: Jules
authors.initials: J
authors.lastname: Angst
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Azorin
authors.forename: Charles L
authors.initials: CL
authors.lastname: Bowden
authors.forename: Sergey
authors.initials: S
authors.lastname: Mosolov
authors.forename: Joao
authors.initials: J
authors.lastname: Reis
authors.forename: Eduard
authors.initials: E
authors.lastname: Vieta
authors.forename: Allan H
authors.initials: AH
authors.lastname: Young
mesh_terms: D000328:Adult; D000352:Africa, Northern / Q000453:epidemiology; D001208:Asia / Q000453:epidemiology; D001714:Bipolar Disorder / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology; D005060:Europe / Q000453:epidemiology; D006801:Humans