Familial relatedness of schizophrenia and schizotypal states

Abstract

The types and expectancy of mental disorders in the siblings of 74 probands with chronic schizophrenia were examined. The siblings were classified according to whether both parents had schizotypal personality disorder, 1 parent had the disorder and 1 was normal or both parents were normal. Siblings whose parents both had the disorder were at significantly greater risk for schizophrenia and schizotypal personality disorder than siblings with at least 1 normal parent. Similarly, the expectancy of schizotypal personality disorder alone and combined with schizophrenia was higher among siblings with 1 parent with the disorder than in siblings with 2 normal parents. Evidently, schizotypal traits may be genetically related to schizophrenia.