Cross-transmission for anxiety disorder includes genetic, rearing effects

Both genetic and rearing effects appear in cross-generational transmission for anxiety disorder (AD) and its major subtypes, a recent study has shown.

“In traditional analyses, AD and major depression (MD) demonstrate highly correlated genetic and rearing effects,” the authors said. “The genetic correlation weakened when applying a diagnostic hierarchy.”

This study explored Swedish national samples to identify offspring born 1960‒1992 and their parents from six family types (ie, intact, not-lived-with biological father or mother, lived-with stepfather or stepmother, and adoptive). The authors obtained diagnoses from national medical registers.

Three sources of parent-child relationships were evaluated: genes plus rearing, genes only, and rearing only. The authors examined the comorbidity effects by assigning single diagnoses in comorbid cases based on frequency and recency.

For AD-to-AD parent-child transmission, best-estimate tetrachoric associations for genes plus rearing, genes only, and rearing only were 0.16 (95 percent confidence interval [CI], 0.16‒0.16), 0.12 (95 percent CI, 0.10‒0.13), and 0.06 (95 percent CI, 0.04‒0.07), respectively. Results for MD-to-MD transmission were similar overall.

Cross-disorder, cross-generation correlations were moderately lower: genetic and rearing correlations for AD and MD were 0.83 (95 percent CI, 0.76‒0.90) and 0.83 (95 percent CI, 0.69‒0.96), respectively. The results were similar in analyses for panic disorder and generalized anxiety disorder (GAD); the genetic association with MD was modestly higher for GAD than panic disorder.

“Applying a diagnostic hierarchy to comorbid cases resulted in a decline in cross-disorder cross-generation transmission with the estimated genetic correlation equalling 0.46 (95 percent CI, 0.30‒0.62),” the authors said.