Personality disorders and depression

Personality disorders (PDs) were assessed among depressed out-patients by clinical interview before and after antidepressant treatment with fluoxetine to assess the degree of stability of PD diagnoses and determine whether changes in PD diagnoses across treatment are related to the degree of improvement in depressive symptoms.

Three hundred and eighty-four out-patients (55% women; mean age = 39.9 +/- 10.5) with major depressive disorder (MDD) diagnosed with the SCID-P were enrolled into an 8 week trial of open treatment with fluoxetine 20 mg/day. The SCID-II was administered to diagnose PDs at baseline and endpoint.

A significant proportion (64%) of our depressed out-patients met criteria for at least one co-morbid personality disorder. Following 8 weeks of fluoxetine treatment, there was a significant reduction in the proportion of patients meeting criteria for avoidant, dependent, passive-aggressive, paranoid and narcissistic PDs. From baseline to endpoint, there was also a significant reduction in the mean number of criteria met for paranoid, schizotypal, narcissistic, borderline, avoidant, dependent, obsessive-compulsive, passive aggressive and self-defeating personality disorders. While changes in cluster diagnoses were not significantly related to improvement in depressive symptoms, there were significant relationships between degree of reduction in depressive symptoms (percentage change in HAM-D-17 scores) and degree of change in the number of criteria met for paranoid, narcissistic, borderline and dependent personality disorders.

Personality disorder diagnoses were found to be common among untreated out-patients with major depressive disorder. A significant proportion of these patients no longer met criteria for personality disorders following antidepressant treatment, and changes in personality disorder traits were significantly related to degree of improvement in depressive symptoms in some but not all personality disorders. These findings suggest that the lack of stability of PD diagnoses among patients with current MDD may be attributable in part to a direct effect of antidepressant treatment on behaviours and attitudes that comprise PDs.