The Michigan State University Twin Registry (MSUTR): an update.

The primary aim of the Michigan State University Twin Registry (MSUTR) is on understanding developmental changes in genetic, environmental, and neurobiological influences on internalizing and externalizing disorders, with antisocial behavior and disordered eating representing our particular areas of interest. The MSUTR has two broad components: a large-scale, population-based registry of child, adolescent, and adult twins and their families (current N ~20,000) and a series of more focused and in-depth studies drawn from the registry (current N ~4,000). Participants in the population-based registry complete a family health and demographic questionnaire via mail. Families are then recruited for one or more of the intensive, in-person studies from the population-based registry based on their answers to relevant items in the registry questionnaire. These in-person assessments target a variety of biological, genetic, and environmental phenotypes, including multi-informant measures of psychiatric and behavioral phenotypes, census and neighborhood informant reports of twin neighborhood characteristics, buccal swab and salivary DNA samples, assays of adolescent and adult steroid hormone levels, and/or videotaped interactions of child twin families. This article provides an overview of the MSUTR and describes current and future research directions.