The primary objective is to evaluate the efficacy and tolerability of mirtazapine (Remeron) in the treatment of PTSD. Primary Hypothesis to be tested: Veterans with PTSD will have improvement in their symptomatology after 8 weeks of treatment with mirtazapine compared to those treated with placebo. After completion of the placebo-controlled phase, patients who agree to continue in the study will be treated with open-label mirtazapine for an additional 8 weeks.

After meeting inclusion criteria, the patients enter an 8-week randomized, double-blind, placebo-controlled treatment trial of mirtazapine. After completion of the placebo-controlled phase, patients may continue study participation in an open-label mirtazapine for an additional 8 weeks.

The VA Pharmacy has an established working relationship with the investigators. The pharmacist maintains the randomization log and verifies the order for the placebo or mirtazapine (15mg) in look-a-like capsules. The investigators and patients are kept blind to the contents of the capsules until the end of the entire study. See procedure grid in attached Work Proposed Section attached. Based on symptomology and occurrence of side effects, the investigator increases the medication in 15 mg (one capsule) increments every week, as tolerated, until a maximum therapeutic benefit is achieved, not to exceed 45 mg/day (3 capsules). The dosing is at bedtime. Compliance is assessed by biweekly pill count. 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. At the end of the placebo-controlled phase, if the patients agree to continue in the study (confirmed at every visit) and they have not experienced an intolerable side effect related to the study medication, the patient will stop the placebo-controlled medication and begin open label mirtazapine, starting with 15mg at bedtime and titrating as tolerated to a maximum of 60mg/day.

• Drug: Mirtazapine
• Drug: Placebo

• Placebo Comparator: Placebo vs. Mirtazapine
• Active Comparator: Mirtazapine vs. Placebo

Inclusion Criteria:

• Diagnosis of PTSD, confirmed by MINI and CAPS
• Age 19 or older
• No substance abuse/dependence for the previous 4 weeks (except for nicotine and caffeine)
• Free of psychotropic medication for 2 weeks (except 4 weeks for fluoxetine)
• Clinically normal physical and laboratory examination (lab profile listed below). LFTs up to 2.5 times the normal limit will be allowed.
• Women of childbearing potential must be using medically approved methods of birth control (such as a condom, birth control pill, Depo-Provera, or diaphragm with spermicides)
• Signed informed consent
• Male or female, any race or ethic origin

Exclusion Criteria:

• Lifetime history of bipolar I, psychotic, or cognitive disorders
• Actively suicidal, homicidal, or psychotic
• History of sensitivity to mirtazapine
• Unstable general medical conditions
• Score ≥ 6 on Question #10 of MADRS regarding suicidal ideation
• Women who are pregnant, planning to become pregnant or breastfeed during the study