title: Diagnostic conversions from major depressive disorder into bipolar disorder in an outpatient setting: results of a retrospective chart review.
abstract: BACKGROUND
  The aim of the study was to check the stability of a diagnosis of major depressive disorder (MDD) in an outpatient setting, as well as to assess the scope of diagnostic conversions into bipolar disorder (BD).
  
  
  METHODS
  Retrospective chart review of 122 patients with a primary diagnosis of MDD.
  
  
  RESULTS
  Diagnostic conversion from MDD into BD was noticed in 40 subjects (32.8%), 25 patients (20.5%) were treatment-resistant. Mean time to the conversion was 9.27±8.64 years. A negative correlation between the age of illness onset and time to diagnostic conversion was observed (-0.41; p<0.05). Earlier onset of MDD was associated with higher risk of diagnostic conversion (<30vs≥30 years of age at onset: 69% vs 28%, p=0.0001; <35vs≥35 years of age: 50% vs 25%, p=0.0065). Treatment-resistance was more prevalent in the BD conversion group (40% vs 11%; p=0.0002). Diagnostic conversion into BD was also related longer duration of treatment received, higher number of illness episodes, and higher number of hospitalizations.
  
  
  CONCLUSIONS
  Retrospective design of the study.
  
  
  CONCLUSIONS
  The problem of diagnosis evolution from MDD to BD was observed in about 1/3 of patients, and was associated with treatment-resistance of depression, earlier onset of depression, longer time of treatment, higher number of depressive episodes and hospitalizations. The variables above may be a useful predictor of bipolar diathesis.
authors.affiliation: Adult Psychiatry Department, University Hospital, Cracow, Poland; Department of Psychiatry, Jagiellonian University, Collegium Medicum, Cracow, Poland. dominika.dudek@poczta.fm
authors.forename: Dominika
authors.initials: D
authors.lastname: Dudek
authors.forename: Marcin
authors.initials: M
authors.lastname: Siwek
authors.forename: Daria
authors.initials: D
authors.lastname: Zielińska
authors.forename: Rafał
authors.initials: R
authors.lastname: Jaeschke
authors.forename: Janusz
authors.initials: J
authors.lastname: Rybakowski
mesh_terms: D000328:Adult; D017668:Age of Onset; D000553:Ambulatory Care / Q000706:statistics & numerical data*; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000628:therapy; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome