Co-distribution of sensory gating and impaired niacin flush response in the parents of schizophrenics.

Complex illnesses may result from the interaction or addition of multiple factors. We examined the familial co-distribution of two abnormalities common in schizophrenia: impaired auditory sensory gating and impaired flush response to niacin. In ten families, the obligate carrier parent had sensory-gating deficits, while eight of the ten parents without a family history of schizophrenia had impaired flush response. No parents had both deficits. The data are consistent with a theory suggesting the interaction of these two factors in some cases of schizophrenia.