“Genetic and Environmental Influences on Sleep-Wake Behaviors in Adolescence”, Victoria S. O’Callaghan, Narelle K. Hansell, Wei Guo, Joanne S. Carpenter, Haochang Shou, Lachlan T. Strike, Jacob J. Crouse, Kerrie McAloney, Katie L. McMahon, Enda M. Byrne, Jane M. Burns, Nicholas G. Martin, Ian B. Hickie, Kathleen R. Merikangas, Margaret J. Wright2021-10-22 (, ; similar)⁠:

Objectives: To investigate the influence of genetic and environmental factors on sleep-wake behaviors across adolescence.

Method: 495 participants (aged 9 to 17; 55% females), including 93 monozygotic (MZ) and 117 dizygotic (DZ) twin pairs, and 75 unmatched twins, wore an accelerometry device and completed a sleep diary for 2 weeks.

Results: Individual differences in sleep onset, wake time, and sleep midpoint were influenced by both additive genetic (44–50% of total variance) and shared environmental (31–42%) factors, with a predominant genetic influence for sleep duration (62%) and restorative sleep (43%). When stratified into younger (aged 9–14) and older (aged 16–17) subsamples, genetic sources were more prominent in older adolescents. The moderate correlation between sleep duration and midpoint (rp = −0.43, rg = 0.54) was attributable to a common genetic source. Sleep-wake behaviors on school and non-school nights were correlated (rp = 0.44–0.72) and influenced by the same genetic and shared environmental factors. Genetic sources specific to night-type were also identified, for all behaviors except restorative sleep.

Conclusion: There were strong genetic influences on sleep-wake phenotypes, particularly on sleep timing, in adolescence. Moreover, there may be common genetic influences underlying both sleep and circadian rhythms. The differences in sleep-wake behaviors on school and non-school nights could be attributable to genetic factors involved in reactivity to environmental context.

[Keywords: sleep, adolescence, heritability, twins, genetics, actigraphy]