Genetic and environmental influences on anxiety dimensions in Italian twins evaluated with the SCARED questionnaire.

This study explored the factorial structure of the Italian version of the Screen for Child Anxiety-Related Emotional Disorders questionnaire (SCARED), and investigated the contributions of genetic and environmental influences of individual variation of anxiety dimensions as reported in the SCARED. Three hundred and seventy-eight twin pairs aged 8-17 from the Italian Twin Registry filled in the SCARED through a mail survey. Four, distinct empirical factors, that corresponded closely to the original SCARED subscales of Generalized Anxiety (GAD), Panic (PD), Social Phobia (SP), and Separation Anxiety (SAD) disorder emerged from Exploratory Factor Analysis. The empirically derived scores were analyzed by structural equation modeling; moderate-to-high heritability, without age or sex differences, emerged for all dimensions with the exception of GAD, for which an age effect was found. The DSM-IV anxiety dimensions identified by the SCARED have a psychometric structure that can be replicated in the Italian culture, and are influenced at different extents by genetic and nonshared environmental determinants.