Background: Recent studies indicate that atypical neuroleptics may be safe and useful in treating many symptoms of borderline personality disorder (BPD), including impulsivity, which can constitute the core dimension of this pathology. This study aimed to evaluate the efficacy and safety of quetiapine in patients with well-defined BPD. It was hypothesized that quetiapine would reduce impulsivity (primary hypothesis) and also affective and micropsychotic symptoms, resulting in improved social and global functioning (secondary hypothesis).

Method: Twenty-three outpatients with BPD according to DSM-IV criteria and the revised Diagnostic Interview for Borderlines completed a 12-week open-label study with quetiapine. The study was conducted from May 2001 to May 2003. The clinical efficacy was assessed using the following: Hamilton Rating Scales for Depression and Anxiety, Hopelessness Scale, Brief Psychiatric Rating Scale, Barratt Impulsivity Scale, Buss-Durkee Hostility Inventory, Temperament and Character Inventory, Social Adjustment Scale, and Global Assessment of Functioning.

Results: The mean daily dose of quetiapine (251 ± 50 mg; range, 175 - 400 mg) was well tolerated. Impulsivity was significantly improved by quetiapine (p = .0015), as were most of our outcome measures: hostility, depression, anxiety, character dimensions, and social and global functioning (p < .05). In the small subgroup of patients with psychotic symptoms at baseline, there was a significant reduction in these symptoms (N = 8, p = .018).

Conclusion: In a sample of patients with severe BPD without or with only few psychotic symptoms, a low dose of quetiapine was associated with a strong positive clinical impact, including improvement of impulsivity.

J Clin Psychiatry 2005;66(10):1298-1303