Borderline Personality Disorder and Unipolar Affective Disorder Long-Term Effects of Comorbidity

This study tracks the baseline clinical presentation and long-term course (average 15 years) of three patient groups defined largely by DSM-III from the Chestnut Lodge follow-up study: unipolar affective disorder (UNI, N = 22), borderline personality disorder (BPD, N = 55), and a comorbid cohort (UNI/BPD, N = 21). Comorbid BPD effects on UNI include earlier onset and absence of psychotic symptoms at baseline and more substance abuse and use of psychiatric treatment at follow-up. Comorbid UNI effects on BPD include better premorbid instrumental functioning, later onset at baseline, and a higher risk for suicide over the long term. Other noteworthy findings are a low rate of suicide (2%) among the noncomorbid BPD patients and a high rate of diagnostic instability (68%) among the noncomorbid UNI patients. Findings demonstrate a lack of syndromal stability within and among all three study groups and highlight the shortcomings of DSM-III for the investigation of comorbidity.