Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

Research has consistently demonstrated that environmental influences are important for explaining the variability in sleep quality observed in the general population. Although there is substantial evidence assessing associations between sleep quality and a host of environmental variables, it is possible that their effects are mediated by genetic influence. A monozygotic twin differences design was used to assess the specific contribution of nonshared environmental influences on sleep quality, whilst controlling for genetic and shared environmental effects in a sample of 380 monozygotic twins (mean age 19.8 years, SD = 1.26, range = 18-22 years). Participants completed the Pittsburgh Sleep Quality Index and questionnaires assessing several candidate "environmental" measures. When controlling for genetic and shared environmental effects, within monozygotic twin-pair differences in sleep quality were associated with within monozygotic twin-pair differences in general health for males (β = 1.56, p < 0.001) and relationship satisfaction for females (β = 1.01, p < 0.05). For the remaining environmental measures the results suggest that these seemingly "environmental" influences are actually in part dependent on genetics and/or the shared environment. These findings give insight into how specific environments affect sleep and the possible mechanisms behind these associations.

Original publication




Journal article


Behav Genet

Publication Date





234 - 244


Adolescent, Environment, Female, Gene-Environment Interaction, Humans, Male, Sleep, Surveys and Questionnaires, Twins, Monozygotic, Young Adult