TNF and schizophrenia: In a stepwise logistic regression analysis for relationships between attempted suicide and TNF-alpha polymorphisms, with age, gender, education, BMI, smoking, and clinical symptoms of schizophrenia as covariates, it was of particular interest to show that -1031C>T genotype distributions (beta = 0.65, df = 1, Wald χ2 = 4.3, p = 0.024) and PANSS total scores (beta = 0.032, df = 1, Wald χ2 = 8.9, p = 0.003) reached significantly different values in the subgroup analysis.