Sleep duration and depressive symptoms: a gene-environment interaction

• Published in: Sleep (New York, N.Y.) N.Y.), 2014-02, Vol.37 (2), p.351-358
• Main Authors: Watson, Nathaniel F, Harden, Kathryn Paige, Buchwald, Dedra, Vitiello, Michael V, Pack, Allan I, Strachan, Eric, Goldberg, Jack
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Depression - genetics; Depression - physiopathology; Depression - psychology; Environment; Female; Gene-Environment Interaction; Humans; Male; Middle Aged; Models, Genetic; Registries; Sleep - genetics; Sleep - physiology; Sleep Duration and Depressive Symptoms: A Gene-Environment Interaction; Time Factors; Twins, Dizygotic - genetics; Twins, Dizygotic - psychology; Twins, Monozygotic - genetics; Twins, Monozygotic - psychology; Young Adult
• ISSN: 0161-8105; 1550-9109
• DOI: 10.5665/sleep.3412

We used quantitative genetic models to assess whether sleep duration modifies genetic and environmental influences on depressive symptoms. Participants were 1,788 adult twins from 894 same-sex twin pairs (192 male and 412 female monozygotic [MZ] pairs, and 81 male and 209 female dizygotic [DZ] pairs] from the University of Washington Twin Registry. Participants self-reported habitual sleep duration and depressive symptoms. Data were analyzed using quantitative genetic interaction models, which allowed the magnitude of additive genetic, shared environmental, and non-shared environmental influences on depressive symptoms to vary with sleep duration. Within MZ twin pairs, the twin who reported longer sleep duration reported fewer depressive symptoms (ec = -0.17, SE = 0.06, P < 0.05). There was a significant gene × sleep duration interaction effect on depressive symptoms (a'c = 0.23, SE = 0.08, P < 0.05), with the interaction occurring on genetic influences that are common to both sleep duration and depressive symptoms. Among individuals with sleep duration within the normal range (7-8.9 h/night), the total heritability (h2) of depressive symptoms was approximately 27%. However, among individuals with sleep duration within the low (< 7 h/night) or high (≥ 9 h/night) range, increased genetic influence on depressive symptoms was observed, particularly at sleep duration extremes (5 h/night: h2 = 53%; 10 h/night: h2 = 49%). Genetic contributions to depressive symptoms increase at both short and long sleep durations.