Genetic and environmental influences on schizotypy: A community based twinstudy

This study investigated the factor structure and etiology of four self-repo rt schizotypy questionnaires during young adulthood (age 18-27) in 98 monoz ygotic and 59 same-sex dizygotic twin pairs from the community. A single ph enotypic factor was identified that was primarily associated with Perceptua l Aberration, Magical Ideation, and the Rust Inventory of Schizotypal Cogni tions scales, and less so with Social Anhedonia. Univariate etiologic model s suggested that in addition to nonshared environmental influences, Percept ual Aberration and Social Anhedonia were significantly influenced by either genes or shared family environment, whereas Magical Ideation and the Rust Inventory were influenced by shared family environment, but not genes. Mult ivariate twin analyses detected a common schizotypy factor, primarily defin ed by Perceptual Aberration, Magical Ideation, and the Rust Inventory scale s, that was influenced by genes or shared environment as well as nonshared environment. Contrary to expectations, these results suggest that, at least in community-based samples, these "positive" schizotypy questionnaires are not strongly genetically influenced.