An Open-Label Study of Mirtazapine as Treatment for Combat-Related PTSD

Background: Posttraumatic stress disorder (PTSD) is common among war veterans. Antidepressants are effective in reducing symptoms and associated disability for some patients. Objective: To assess the effectiveness of mirtazapine for combat-related PTSD among veterans treated in an Australian hospital. Methods: This open-label prospective study assessed the effectiveness of mirtazapine as empirical treatment for combat-related PTSD. The initial dose was 15 mg at night, titrated against response to 15–45 mg. PTSD symptoms were assessed using the Mississippi Scale for Combat-Related Posttraumatic Stress Disorder and the Clinician-Administered PTSD Scale (CAPS). Subjects also completed the Hospital Anxiety and Depression Scale (HADS). Body weight and biochemical assessments, including fasting blood glucose (FBG), total serum cholesterol, and serum triglycerides, were also measured. Baseline measurements were repeated after 12 weeks. Results: During the 18-month recruitment phase, 17 subjects were enrolled and 13 completed the protocol. The CAPS measurement decreased from a mean pretreatment score of 87.5 to 64.4 (p = 0.01). In 4 cases, the CAPS score decreased to below the diagnostic cut-point, consistent with a remission of PTSD. The Mississippi scale measurement decreased from a mean pretreatment score of 126.6 to 115.5 (p < 0.01). The mean HADS anxiety score decreased from 15.6 ± 4.2 to 13.5 ± 5.6 (p = 0.016), although the proportion of subjects with scores above the diagnostic cut-point remained high. The mean HADS depression score at baseline was not significantly different from the postintervention score. One subject had a postintervention FBG of 155 mg/dL (consistent with diabetes mellitus), which was increased from the baseline level of 83 mg/dL. All subjects experienced an increase in body weight. One subject had an increase in body weight of 8.75 kg (8.4%) from baseline. Conclusions: Although small and with methodological limitations, this study suggests that mirtazapine is an effective treatment for combat-related PTSD. Additional research incorporating an appropriately powered, double-blind, placebo-controlled study design is required.