The heritability of insomnia: A meta-analysis of twin studies.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational twin studies
PubMed 33222383 · doi:10.1111/gbb.12717
What was done
Authors searched five electronic databases through January 2020, screening 5,644 abstracts and 160 full-text papers for twin studies reporting heritability of insomnia disorder or insomnia symptoms in the general population. Twelve independent papers met inclusion criteria. Intraclass correlations for monozygotic and dizygotic twins were meta-analyzed to estimate overall heritability and evaluate moderation by sex, age, reporter type, and specific insomnia symptom.
What was found
The pooled meta-analytic heritability estimate for insomnia was 40%. Moderation analyses showed significantly stronger heritability in females compared to males, and for parent-reported symptoms compared to self-reported symptoms. Other tested moderators showed no statistically significant effects.
Why it matters
This synthesis reconciles previous heterogeneous estimates to show that approximately 40% of the variance in insomnia vulnerability is attributable to genetic factors, highlighting sex and informant source as meaningful moderators.
Limits
The total number of individual twin pairs is not reported in the abstract. Only 12 papers met inclusion criteria, limiting statistical power to detect smaller moderator effects. Results are constrained by variability in insomnia definitions and measurement across the included studies.
Cited by
- supports Between 28% and 45% of insomnia susceptibility is attributable to genetics.