Exposure to prenatal infections, genetics and the risk of systematic and periodic catatonia

Summary.

The meaning of heterogeneity in schizophrenia and the impact of genetic and environmental factors on etiology are a matter of continuous debate in psychiatric research. Different clinical and birth history variables were investigated in a sample of 68 patients with chronic catatonic schizophrenia according to DSM III-R, classified into Leonhard's systematic schizophrenia (n = 32) and periodic catatonia (n = 36). Parental transmission of the disease was evident in 44% of the periodic catatonia cases compared to one case in systematic catatonia (3%; p = 0.0003). In systematic catatonia, 34% of the index cases were exposed to prenatal infections compared to 8% in periodic catatonia (p = 0.008). Using logistic regression analysis exposure to gestational maternal infections predicted diagnosis of systematic catatonia at p = 0.008, and parental psychosis predicted diagnosis of periodic catatonia in the index cases at p = 0.0001. The latter finding is substantiated by the recent mapping of a periodic catatonia-susceptibility locus on chromosome 15q15 with evidence for autosomal dominant transmission. These findings support the hypothesis that distinct schizophrenia phenotypes are based on different etiological mechanisms.