Sex Differences in NMDA-enhancing Treatment of Schizophrenia

Schizophrenia differs between sexes in clinical symptoms and functional outcome. Negative symptoms, the core pathology of this disease, principally determine the patients' prognoses. NMDAR dysfunction is a key factor in negative symptoms. Whether NMDAR-enhancing treatment can improve negative symptoms and whether there is sex difference need to be studied. The subjects are the schizophrenia patients with predominantly negative symptoms. They will continue their original treatment and be double-blindly, randomly assigned to receive 12-week: (1) NMDAE (N = 60), or (2) placebo (N = 30). There will be half men and half women in each group. We will measure clinical manifestations and side effects at weeks 0, 4, 8, and 12 using Scale for Assessment of Negative Symptoms (the primary outcome), Positive and Negative Syndrome Scale-negative subscale, Clinical Global Impression, Quality of Life Scale, Global Assessment of Function, and scale of side effects. At week 0 and week 12, we will assess 7 cognitive domains. Chi-square (or Fisher's exact test) will be used to compare differences of categorical variables and t-test (or Mann-Whitney test if the distribution is not normal) for continuous variables between treatment groups. Mean changes from baseline in repeated-measure assessments will be assessed using the generalized estimating equation (GEE). All p values for clinical measures will be based on two-tailed tests with a significance level of 0.05.