Gender specificity of geographical variation in morbid risk for schizophrenia in rural Ireland.

The morbid risk for schizophrenia was determined separately for men and women within each of 36 contiguous district electoral divisions of a rural Irish county in which all cases of schizophrenia satisfying DSM-III-R criteria had been sought. The distribution of morbid risk values for men (0.0-19.2 per 1000) was in accordance with a statistical model for random occurrences in space, while for women (0.0-38.3 per 1000) it deviated markedly from such a model; thus, morbid risk for schizophrenia showed very prominent geographical variations in women, but not in men. These findings may have a basis in factors that can show both spatial inhomogeneity and gender specificity in their consequences for schizophrenia.