Affect instability in adults with a borderline personality disorder.

This study describes the pattern of affect instability in adults with borderline personality disorder (BPD). Clinical histories and the Diagnostic Inventory for Borderlines were used to identify 3 groups: 1) BPD (N = 15), 2) Asymptomatic (N = 10), and 3) Non-BPD, Anorexia Nervosa Clinical Control (N = 4). An experience sampling procedure (Hormuth, 1986) was used to obtain 50 measures of affect over 10 days. The findings showed that BPD subjects experienced higher levels of unpleasant affects and greater short-term fluctuations in unpleasant affects than the asymptomatic subjects. However, BPD and asymptomatic subjects experienced more fluctuations in the pleasant affects than the AN subjects. These findings support the hypothesis that BPD is associated with a unique pattern of affect dysregulation.