Depressive personality and treatment outcome in major depressive disorder

Depressive personality disorder (DPD) is currently included in the DSM-IV Appendix B, Criteria Sets and Axes Provided for Further Study. Evidence of the clinical utility of DPD will likely play an important role in the determination of whether it warrants inclusion in future editions of DSM. The current investigation examines the capacity of DPD traits to predict overall and preferential treatment outcome for patients with Major Depressive Disorder (MDD) (N = 120) using data from a randomized control trial, which included cognitive behavioral therapy (CBT), interpersonal therapy (IPT), and antidepressant medication (ADM) treatment arms. Patients were treated for 16-20 weeks and completed the Structured Clinical Interview for DSM-IV Axis II Personality Disorders Questionnaire (SCID-II/PQ) and the 17-item Hamilton Rating Scale for Depression immediately before and after treatment. Higher scores on a dimensionalized SCID-II/PQ subscale assessing DPD traits were associated with poor outcome for IPT, but not CBT or ADM. This result remained after accounting for variance associated with other personality disorder (PD) traits; none of the other 10 main text PDs predicted treatment outcome.