Olanzapine monotherapy in posttraumatic stress disorder: efficacy in a randomized, double‐blind, placebo‐controlled study

Abstract

Although there have been important advances in the treatment of posttraumatic stress disorder (PTSD), many patients fail to respond to first-line pharmacotherapy. Limited evidence suggests that second generation antipsychotics may have a role to play as monotherapy in PTSD. We undertook a randomized, placebo-controlled study using flexible-dose olanzapine monotherapy for 8 weeks in 28 adult male and female participants (mean age: 40.75 ± 11.59 years) with non-combat related chronic PTSD. Data were analysed with repeated measures analysis of variance, using an intention to treat, last observation carried forward approach. The olanzapine group (n = 14) demonstrated significantly greater improvement on the Clinician Administered PTSD Scale from baseline to endpoint than the placebo group (n = 14) (F = 5.71, p = 0.018). Olanzapine was generally well tolerated, with no serious adverse events recorded. Substantial weight gain (6-10 kg) was, however, reported in 6/14 participants in the olanzapine group. To our knowledge, this is the first controlled evidence of the efficacy of olanzapine monotherapy in an exclusively non-combat related chronic PTSD group. Despite the small sample size, these data suggest that olanzapine may have a role in the treatment of PTSD. These findings warrant replication in a larger sample.