The present protocol proposes study of the recently approved compound sodium oxybate (Xyrem), a gamma-aminobutyric acid type b (GABAB) and a g-hydroxybutyric acid (GHB) receptor agonist, for the study of persistent symptoms of schizophrenia. Sodium oxybate is a central nervous system depressant currently approved for treatment of narcolepsy associated with cataplexy and excessive daytime sleepiness. In addition to evaluating effects on sodium oxybate on persistent symptoms and neurocognitive deficits in schizophrenia, the study will test the hypothesis that this medication may be particularly effective in combating Insomnia Related to Schizophrenia, and in normalizing symptomatic and polysomnographic manifestations of sleep-related brain dysfunction in schizophrenia.