The Effect of Add-on Memantine in New Onset Combat-Related Posttraumatic Stress Disorder Core Symptoms: A Pilot Study

 Studies using standard neuropsychological instrumentation have shown memory deficits in posttraumatic stress disorder (PTSD) patients. We examined the efficacy and safety of memantine in new cases of combat-related PTSD in the military by conducting a 16-week prospective double-blind randomized controlled trial.

 Twenty-six new combat-related PTSD cases were recruited from among the military personnel based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Patients were assigned to memantine and Placebo groups. They were monitored at baseline, week eight, and week 16. Memantine was added to each patient's current medication with an initial dosage of 5 mg/day, raised by 5 mg/day every week until it reached the maintenance level of 20 mg/day. The concurrent drugs were essentially kept unchanged during the trial. The primary outcome was PTSD severity as assessed by the Clinician-administered PTSD Scale (CAPS). The CAPS is a valid and reliable tool for the diagnosis of PTSD and measurement of its severity according to the DSM–4.

 CAPS mean score in baseline (P = 0.811) and weeks eight (P = 0.389) and 16 (P = 0.066) did not show any significant differences between the two groups. The mean CAPS score in the memantine group significantly (P = 0.006) decreased (Mean differences = -8.79) compared to the placebo group, showing that intervention with memantine was effective. The mean total CAPS in weeks eight (Mean differences = -14.21) and 16 (Mean differences = -27) were less than the baseline, which was significantly meaningful (P < 0.001).

 Findings of this study suggest that add-on memantine can be effective in veteran patients with PTSD. So our data provide useful insight into the management of new cases of combat-related PTSD.