• acute treatment;
  • bipolar disorder;
  • borderline personality disorder;
  • pharmacotherapy;
  • psychotherapy

Objective:  Patients suffering from both bipolar I disorder and borderline personality disorder (BPD) pose unique treatment challenges. The purpose of this matched case–control study was to compare acute treatment outcomes of a sample of patients who met standardized diagnostic criteria for both bipolar I disorder and BPD (n = 12) to those who met criteria for bipolar I disorder only (n = 58).

Method:  Subjects meeting criteria for an acute affective episode were treated with a combination of algorithm-driven pharmacotherapy and weekly psychotherapy until stabilization (defined as four consecutive weeks with a calculated average of the 17-item version of the Hamilton Rating Scale for Depression and Bech-Rafaelsen Mania scale totaling ≤7).

Results:  Only three of 12 (25%) bipolar-BPD patients achieved stabilization, compared with 43 of 58 (74%) bipolar-only patients. Two of the three bipolar-BPD patients who did stabilize took over 95 weeks to do so, compared with a median time-to-stabilization of 35 weeks in the bipolar-only group. The bipolar-BPD group received significantly more atypical mood-stabilizing medications per year than the bipolar-only group (Z = 4.3, p < 0.0001). Dropout rates in the comorbid group were high.

Conclusions:  This quasi-experimental study suggests that treatment course may be longer in patients suffering from both bipolar I disorder and BPD. Some patients improved substantially with pharmacotherapy and psychotherapy, suggesting that this approach is worthy of further investigation.