AUDITORY SENSORY GATING, HIPPOCAMPAL VOLUME, AND CATECHOLAMINE METABOLISM IN SCHIZOPHRENICS AND THEIR SIBLINGS

Schizophrenia may result from the concerted action of several pathophy siological factors. This pilot study compared the distribution of meas urements of three such putative factors in 11 schizophrenics and their siblings: a neurophysiological deficit in auditory sensory gating, di minished hippocampal volume, and increased catecholamine metabolism. A bnormal auditory sensory gating was found in all schizophrenics in the 11 families studied and in 8 of their 20 siblings. Compared with the schizophrenics, the clinically unaffected siblings with abnormal audit ory gating had larger hippocampal volume. There was no similar differe nce for the siblings with normal gating. The siblings with abnormal au ditory gating also had lower homovanillic acid levels than the other s iblings. The data suggest that a familial neuronal deficit, identified by diminished sensory gating, may be a necessary, but not sufficient factor in the pathogenesis of schizophrenia. Individuals with this def icit are generally clinically unaffected, except for schizophrenics, w ho also have other abnormalities, such as diminished hippocampal volum e and increased catecholamine metabolism.