Biomarkers in Schizophrenia

16 in- or outpatients with DSM-IV-TR schizophrenia or schizoaffective disorder and prominent negative symptoms will be recruited for this study. This study will consist of a randomized trial of D-serine (60 mg/kg/d) vs. placebo using a crossover design with a 2-week baseline lead-in, and two 6-week intervention arms separated by a two week, placebo controlled washout period. Biomarkers will be assessed at baseline for each treatment arm, acutely (day 7) following treatment initiation, and following 6 weeks of treatment (6 biomarker sessions total). Primary biomarker outcome measures will include 1) amplitude of the mismatch negativity (MMN) waveform and 2) amplitude of the visual P1 potential. Symptomatic outcome measures will include PANSS and composite score of the MATRICS neuropsychological battery. The study will be supported from ongoing NIMH-funded Cooperative Drug Development Grant (CDDG) to the PI.