ObjectiveTo test the hypothesis that similar differences in psychopathology are present across cultures among men and women with schizophrenia (SZ).MethodsSex based differences were tested systematically in two independent samples from the Northeastern USA and North India using the same procedures. The clinical variables were obtained from five interview instruments.ResultsAmong the US participants, the number of significant differences exceeded chance predictions (15/240 variables significant at p<0.02, 6.25%; expected number of significant differences: 5). Similarly, a greater than expected number of variables differed significantly between men and women among the Indian subjects (13/230 differences at p<0.02, 5.65%; expected: 5). One of these variables significantly differed in both samples (lifetime abuse of cannabis). When multivariate analyses were conducted in the combined US and Indian samples sex based differences remained for only four variables: course of the illness, history of inappropriate emotions, marital status and number of children.ConclusionSex based differences in SZ/schizoaffective disorder are present in the USA and India at greater than chance probabilities. The majority of the variables differ across the samples. The biological underpinnings of these variables need further investigation.

Genetic association studies of schizophrenia typically utilize diagnostic status as the trait of interest. Among Indian schizophrenia (SZ) participants, we evaluated genetic associations (selected single nucleotide polymorphisms (SNPs) associated with SZ) with selected indices of severity and symptom pattern. Ordinal logistical regression enabled us to analyze variables with multiple categories as outcome variables, while incorporating key demographic variables; this form of analysis may be useful in future genetic association studies. No significant associations were detected following corrections for multiple comparisons.

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