Genetic influences on measures of the environment: a systematic review

Background. Traditional models of psychiatric epidemiology often assume that the relationship between individuals and their environment is unidirectional, from environment to person. Accumulating evidence from developmental and genetic studies has made this perspective increasingly untenable. Method. Literature search using Medline, PsycINFO, article references and contact with experts to identify all papers examining the heritability of measures of environments of relevance to psychiatry/psychology. Results. We identified 55 independent studies organized into seven categories: general and specific stressful life events (SLEs), parenting as reported by child, parenting reported by parent, family environment, social support, peer interactions, and marital quality. Thirty-five environmental measures in these categories were examined by at least two studies and produced weighted heritability estimates ranging from 7% to 39%, with most falling between 15% and 35%. The weighted heritability for all environmental measures in all studies was 27%. The weighted heritability for environmental measures by rating method was: self-report 29%, informant report 26%, and direct rater or videotape observation (typically examining 10 min of behavior) 14%. Conclusion. Genetic influences on measures of the environment are pervasive in extent and modest to moderate in impact. These findings largely reflect 'actual behavior' rather than 'only perceptions'. Etiologic models for psychiatric illness need to account for the non-trivial influences of genetic factors on environmental experiences.