THE IMPACT OF PERSONALITY PATHOLOGY ON TREATMENT RESPONSE TO THERAPEUTIC LIFESTYLE CHANGE (TLC) FOR DEPRESSION

Abstract

The present study investigated the impact of personality pathology on adherence and treatment response to a novel group-based intervention for depression, Therapeutic Lifestyle Change (TLC). Based on existing empirical literature documenting poor adherence and treatment outcome associated with comorbid Axis II pathology, patients with elevated levels of personality pathology were expected to exhibit less adherence and response to TLC for depression. Contrary to expectations, however, no significant association between Axis II pathology and treatment adherence was observed. It is possible that certain features of TLC, such as its highly structured approach, may facilitate adherence among personality-disordered patients. Nevertheless, despite similar levels of treatment adherence in comparison with the rest of the study sample, patients with elevated levels of personality pathology on either Cluster A or Cluster B responded significantly less well to TLC, even when controlling for initial depression severity. Failure of TLC elements to adequately target important features of Cluster A and Cluster B pathology, such as affective dysregulations and substantial interpersonal difficulties, may be responsible, in large part, for the observed differential treatment response.