Symptoms and side effects will be rated biweekly with the CGI, PANSS, BPRS, SAS, AIMS, and UKU. Before and after the trial subjects will undergo neuropsychological assessments. Baseline and post-trial levels of amino acids relevant to glutamatergic neurotransmission (glutamate, glutamine, aspartate, glycine, serine, alanine) will be assessed.