 N-methyl-D-aspartate NMDA-type glutamate receptors are thought to play a pivotal role in neurocognitive dysfunction associated with schizophrenia. Further, several novel glutamate-based classes of compound are presently in development as potential novel treatments for persistent negative and cognitive symptoms. The study will assess effectiveness of a NMDA-based intervention on biomarkers related to schizophrenia as a mechanism for developing appropriate outcome batteries for future trials of novel compounds. 