Objective: To study the efficacy and tolerability of mirtazapine (Remeron) in the treatment of PTSD.

Research Design: This is an 8-week randomized, double-blind, placebo-controlled treatment trial of mirtazapine for the treatment of PTSD as defined on the Clinical Assessment of PTSD Scale (CAPS).

Methodology: After signing an informed consent and meeting all inclusion/exclusion criteria, the patient is randomized to either mirtazapine versus placebo for 8-week duration. During the study a pharmacist maintains the randomization log and verifies the order for the placebo or mirtazapine in look-a-like tablets. Patients' symptoms, side effects and compliance are assessed bi-weekly. Based on symptomology and occurrence of side effects, the investigator increases the medication in 15 mg increments, as tolerated, until a maximum therapeutic benefit is achieved, not to exceed 45 mg/day. The dosing is at bedtime. Compliance is assessed by bi-weekly pill count at week 4 and week 8. Patients are given supportive clinical management during the clinic visits. An investigator is available by telephone 24 hrs a day in case of emergency. Patients may be seen more often if needed. Efficacy will be measured by the following assessment scales: Montgomery-Asberg Depression Rating Scale (MADRS), Hamilton Anxiety Scale (Ham-A), Clinical Global Impression Severity of Illness (CGI-s), Clinical Global Impression of Improvement (CGI-I), Global Assessment of Functioning (GAF), CAPS, Treatment Outcome PTSD rating scale (TOP-8), and Davidson Trauma Scale (DTS).

Clinical Significance: Mirtazapine has shown promise in treating PTSD in an open label trial. This study is the next step in proving mirtazapine's efficacy in treatment of PTSD.