A multivariate perspective on schizotypy and familial association with schizophrenia: a review

Although generally accepted that schizotypal personality disorder diagnosis is more prevalent among relatives of individuals with schizophrenia and may be associated with genetic liability to schizophrenia, it seems likely that this diagnosis is itself heterogeneous and thus perhaps not as useful in identifying genes that affect schizophrenia risk (i.e. endophenotypes) as it could be. In contrast, symptoms and dimensions of schizotypal personality disorder may be more etiologically homogeneous, and thus more useful in genetic studies. The current review evaluated and consolidated evidence to date regarding specific symptoms and dimensions of schizotypal personality disorder among non-psychotic relatives of schizophrenia patients. Comparisons were made with relatives of affective disorder patients and non-psychiatric controls. Findings indicate strong support for elevation of social-interpersonal schizotypal symptoms among relatives of schizophrenia patients versus other groups along with moderate specificity. Results suggest only a small elevation of cognitive-perceptual and disorganized symptoms in relatives of schizophrenia patients and results for disorganized symptoms were inconsistent across studies. Thus, evidence to date supports further investigation of genetic associations between symptoms of schizotypal personality disorder and schizophrenia, and suggests that social-interpersonal symptoms may be particularly promising in genetic analyses of schizophrenia.