Subjects initially received memantine 5 mg once daily, which was increased weekly by 5 mg/day in divided doses to a dose of 20 mg/day. Memory was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) [Randolph, 1998] using both forms A and B at baseline, end of week 8, and end of week 16. The RBANS is composed of 10 subtests that yield a total score and five index scores: immediate memory, visuospatial/constructional, language, attention, and delayed memory. Each index score has a normal mean of 100 and standard deviation of 15 based on the performance of a standardization sample matched to the U.S. Census on sex, ethnicity, and level of education. Alternative forms of the RBANS (Forms A and B) were used to avoid bias due to practice effects. We administered Clinician Administered PTSD Scale (CAPS), Hamilton Depression Scale (HAM-D), Hamilton Anxiety Scale (HAM-A), Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), and Sheehan Disability Scale (SDS) to assess the secondary measures. Changes in the scores over time with repeated measures were estimated with mixed-effects models. The primary outcome measures of interest were index and percentile scores in RBANS total and subscale scores. The repeated measures model included visit (as a categorical variable) as a fixed effect. An unstructured covariance matrix was used to fit the within patient repeated measures effect. Tukey's method was used to compare pair-wise means.