The heritability of insomnia: A meta‐analysis of twin studies. (3rd December 2020)

• Record Type: Journal Article
• Authors: Barclay, Nicola L.; Kocevska, Desi; Bramer, Wichor M.; Van Someren, Eus J. W.; Gehrman, Philip
• Is Part Of: Genes, brain, and behavior. Volume 20:Number 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-03
• Subjects: behavioural genetics -- environment -- genes -- inheritance patterns -- sleep -- sleep initiation and maintenance disorders; Behavior genetics -- Periodicals; Neurogenetics -- Periodicals; 616.8
• DOI: 10.1111/gbb.12717
• Languages: English
• ISSNs: 1601-1848

Abstract

Abstract: Twin studies of insomnia exhibit heterogeneity in estimates of heritability. This heterogeneity is likely because of sex differences, age of the sample, the reporter and the definition of insomnia. The aim of the present study was to systematically search the literature for twin studies investigating insomnia disorder and insomnia symptoms and to meta‐analyse the estimates of heritability derived from these studies to generate an overall estimate of heritability. We further examined whether heritability was moderated by sex, age, reporter and insomnia symptom. A systematic literature search of five online databases was completed on 24 January 2020. Two authors independently screened 5644 abstracts, and 160 complete papers for the inclusion criteria of twin studies from the general population reporting heritability statistics on insomnia or insomnia symptoms, written in English, reporting data from independent studies. We ultimately included 12 papers in the meta‐analysis. The meta‐analysis focussed on twin intra‐class correlations for monozygotic and dizygotic twins. Based on these intra‐class correlations, the meta‐analytic estimate of heritability was estimated at 40%. Moderator analyses showed stronger heritability in females than males; and for parent‐reported insomnia symptoms compared with self‐reported insomnia symptoms. There were no other significant moderator effects, although this is likely because of the small number of studies that were comparable across levels of the moderators. Our meta‐analysis provides a robust estimate of the heritability of insomnia, which can inform future research aiming to uncover molecular genetic factors involved in insomnia vulnerability. Abstract : This is the first meta‐analysis of behavioural genetic studies aiming to estimate the heritability of insomnia. Numerous twin studies to date have provided estimates of heritability, but vast heterogeneity exists between studies. Based on 12 papers, we provide a meta‐analytic estimate of heritability of insomnia at 40%, with the remaining source of variance because of the non‐shared environment. Forest plots show the monozygotic and dizygotic twin pair correlations from 40 effects.