Understanding Associations among Family Support, Friend Support, and Psychological Distress

Abstract

Emotional support from family and friends is associated with lower psychological distress. This study examined whether genetic and environmental influences explain associations among family support, friend support, and psychological distress. Data were drawn from the Midlife Development in the United States (MIDUS) study and included 947 pairs of MZ, same-sex DZ, and opposite-sex DZ twins. Results showed that a genetic factor explains the relationship between friend support and psychological distress, independent of family support. Alternatively, a nonshared environmental factor accounts for an association among family support, friend support, and psychological distress. Thus, heritable factors shape a distinct relationship between friend support and psychological distress, but unique experiences contribute to a link among family support, friend support, and psychological distress.

Figure 1

Cholesky Decomposition. This figure includes latent genetic (A1, A2, A3), shared environmental (C1, C2, C3), and nonshared environmental (E1, E2, E3) factors. The paths between factors A1, A2, and A3 for Twins 1 and 2 were constrained to 1.0 for monozygotic (MZ) twins and 0.5 for dizygotic (DZ) twins. The paths between factors C1, C2, and C3 for Twins 1 and 2 were constrained to 1.0 to reflect that shared environments are shared in common by twins. The paths between factors E1, E2, and E3 were not correlated to reflect that nonshared environments are not shared by twins and include measurement error. The paths estimates were constrained to be equal for Twin 1 and Twin 2. Genetic, shared environmental, and nonshared environmental influences on the associations among family support, friend support, and psychological distress are denoted by the path estimates a₁₁, a₂₁, a₃₁, c₁₁, c₂₁, a₃₁, e₁₁, e₂₁, e_21. Genetic, shared environmental, and nonshared environmental influences on the association between friend support and psychological distress, independent of family support, are denoted by the path estimates a₂₂, a₃₂, c₂₂, c₃₂, e₂₂, e₃₂. Residual variance in psychological distress is denoted by the path estimates a₃₃, c₃₃, e₃₃.

Figure 2

Parameter Estimates and 95% Confidence Intervals from the Best-Fitting Model for one twin in a pair. The best-fitting model included dropping all paths that were not significantly different from 0. Path estimates and 95% confidence intervals in parentheses correspond to results from the reduced model in Table 2. Path estimates that were not significantly different from 0 are not included in Figure 2.