 We want to relate disturbances in first-episode schizophrenic patients in serotonin 5-HT2A receptors, brain structure, brain function, and information processing to each other and to psychopathology. Additionally, we want to examine the influence of 5-HT2A receptor blockade on these disturbances. We expect disturbances in the serotonergic system at baseline to correlate with specific structural and functional changes and with disruption in information processing as measured with psychophysiological and neurocognitive methods - and we expect 5-HT2A receptor blockade to reverse some of the functional and cognitive impairments. We do not expect any effect of treatment on brain structure 