The use of endophenotypes (intermediate quantitative traits) is one strategy that may provide valuable information about the neural mechanisms underlying disease etiology and facilitate discovery of susceptibility genes. For a trait to be an appropriate endophenotype, several key features should exist. In this article we discuss validating potential electrophysiological endophenotypes for schizophrenia based on conventionally accepted criteria. We focus on applying a twin study design and model fitting techniques to evaluate whether three event-related potential paradigms (P300, P50, and MMN) meet criteria as valid endophenotypes of schizophrenia.
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