In multiple regression equations, there were no significant interaction term effects between the characteristics of full sample versus reduced sample and the diagnostic effect (schizophrenia versus controls) on odor discrimination or odor identification (DNMT1 odor identification F = 2.70 df = 1, p = 0.10, odor discrimination F = 2.10, df = 1, p = 0.15; GAD1 odor identification F = 2.11 df = 1, p = 0.15, odor discrimination F = 0.49, df = 1, p = 0.48). This evidence concerns the gene GAD1 and schizophrenia.