We examined the efficacy and safety of low vs. moderate olanzapine doses for the treatment of borderline personality disorder (BPD) in the largest controlled clinical trial ever conducted in this population.

This 12-week, double-blind trial involved patients 18-65 years with a diagnosis of DSM-IV BPD randomized to receive 2.5mg/day olanzapine (N=150), 5-10mg/day olanzapine (N=148), or placebo (N=153). The primary efficacy measure was the change from baseline-to-endpoint (last-observation-carried-forward) on the Zanarini Rating Scale for BPD (ZAN-BPD) total score. Rate of response and time-to-response were also examined (response defined as a >=50% reduction in ZAN-BPD total score).

Mean baseline ZAN-BPD total scores ranged from 17.01 to 17.42, indicating moderate symptom severity. Treatment with OLZ5-10 was associated with significantly greater mean change from baseline-to-endpoint in ZAN-BPD total score than placebo (-8.50 vs. -6.79, p=.010). Response rates were significantly higher for OLZ5-10 (73.6%) than for OLZ2.5 (60.1%, p=.018) and placebo (57.8%, p=.006). Time-to-response was significantly shorter for OLZ5-10 than placebo (p=.028). Treatment-emergent adverse events seen more frequently in the olanzapine groups included somnolence, increased appetite, and weight gain. Mean weight change from baseline-to-endpoint was 2.09kg for OLZ 2.5, 3.17kg for OLZ5-10, and 0.02kg for placebo.

The results of this study suggest that moderate doses of olanzapine (5-10mg/day) are effective in the treatment of overall borderline psychopathology. Also, the types of adverse events observed with olanzapine treatment were similar to those seen previously in adult populations.