Depression symptoms' impact on personality disorder treatment: Depression symptoms amplifying the interpersonal...

While there is some evidence that patients with elevated depression symptoms experience greater benefits from negative-affect expression, this amplifying effect has not been investigated within a psychotherapeutic context. This is particularly notable considering the substantial evidence linking affect expression with desired outcomes across psychotherapeutic approaches. The primary purpose of the present study was to investigate if depression symptoms amplified (i.e., moderated) the association between negative-affect expression and reductions in interpersonal problems for patients in a psychiatric day treatment for personality disorders. The secondary purpose was to investigate milieu (i.e., other patients concurrently enrolled) negative-affect intensity and its association with patients' reductions in interpersonal problems.

Participants (N = 239) were patients consecutively admitted into a psychiatric day treatment program for people with personality disorders. Patients completed measures of (1) depression symptoms at pre-treatment, (2) interpersonal problems at pre- and post-treatment, and (3) negative-affect expression each week of treatment.

The association between patient negative-affect expression and reductions in interpersonal problems was amplified by depression symptoms. Depression symptoms also amplified the association between milieu negative-affect intensity and reductions in interpersonal problems.

Our findings indicate that depression symptoms amplified the therapeutic value of negative-affect expression and amplified the value of an affectively intense milieu. Practical and theoretical implications are discussed.