Am J Psychiatry 1997; 154:1398-1404
Copyright © 1997 by American Psychiatric Association
Social support: a genetic-epidemiologic analysis
KS Kendler
Virginia Institute for Psychiatric and Behavioral Genetics, Richmond, USA. kendler@gems.vcu.edu
OBJECTIVE: Social support is a widely used construct in the fields of
mental health, sociology, and medicine and has typically been
conceptualized as an environmental factor that influences the risk for
dysfunction and disease. In this study a longitudinal twin design was used
to clarify the etiology of social support. METHOD: A 16-item social support
inventory was administered at personal interview to a population-based
sample of female twins twice, approximately 5 years apart. A twin
measurement model-which permits an estimation of the etiologic role of
genetic and environmental factors correcting for errors of measurement or
short-term temporal fluctuations-was applied to these data. RESULTS: Six
factors, which were moderately stable over time, were found: relative
problems, friend problems, relative support, confidants, friend support,
and social integration. The best-fitting twin measurement models indicated
that genetic factors were of substantial etiologic significance for all six
social support scales. Heritabilities of the stable component of social
support ranged from 43% to 75%. Familial-environmental factors contributed
to twin resemblance only for relative problems and relative support. No
evidence was found for significant biases in the twin method. CONCLUSIONS:
Measures of social support are moderately stable over time. When short-term
fluctuations are corrected for, heritable factors are of substantial
etiologic importance for social support as measured at personal interview.
Treating social support solely as an environmental measure is probably
incorrect. Through genetically influenced traits such as temperament,
individuals play a substantial role in creating their own social
environments.
