Dysfunctional attitudes and personality disorder comorbidity during long-term treatment of MDD.

A key component of how depression may impact personality pathology involves an understanding of how cognition and dysfunctional attitudes may change as a result of experiencing a depressive state, and how these changes may affect reporting of personality disorder symptoms. This study examines whether dysfunctional attitudes are related to the stability of personality disorder diagnoses. The sample comprised 64 outpatients who were treatment responders following an 8-week acute treatment phase for major depressive disorder (MDD), met criteria for remission throughout a 26-week continuation phase, and completed a personality disorder assessment Structured Clinical Interview for DSM-III-R Axis II Disorders (SCID-II) at the beginning and end of each treatment phase. The Dysfunctional Attitude Scale (DAS) was given to patients at the beginning of the continuation phase. We found that following successful treatment of the MDD, individuals with stable personality disorder diagnoses (e.g., meeting criteria for a personality disorder at both the beginning and endpoint of continuation treatment) had greater severity of dysfunctional attitudes (P =.001) at the beginning of the continuation treatment compared to those who never met criteria for a personality disorder during continuation treatment. Though there was no significant relationship between DAS scores and the stability of a Cluster A or Cluster B personality disorder diagnosis, there was a significant relationship between DAS scores and the stability of a Cluster C personality disorder diagnosis (P <.001). Outpatients who had a stable Cluster C personality disorder diagnosis had higher scores on the DAS at the beginning of continuation treatment compared to outpatients who never met criteria for a Cluster C diagnosis. This finding suggests that dysfunctional attitudes that persist beyond remission of MDD may be a marker for certain personality disorders that are stable across long-term treatment.