title: Quantitative genetic research on sleep: a review of normal sleep, sleep disturbances and associated emotional, behavioural, and health-related difficulties.
abstract: Over the past 50 years, well over 100 twin studies have focussed on understanding factors contributing to variability in normal sleep-wake characteristics and sleep disturbances. Whilst we have gained a great deal from these studies, there is still much to be learnt. Twin studies can be used in multiple ways to answer questions beyond simply estimating heritability. This paper provides a comprehensive review of some of the most important findings from twin studies relating to sleep to date, with a focus on studies investigating genetic and environmental influences contributing to i) objective and subjective measures of normal sleep characteristics (e.g., sleep stage organisation, sleep quality); as well as sleep disturbances and disorders such as dyssomnias (e.g., insomnia, narcolepsy) and parasomnias (e.g., sleepwalking, bruxism); ii) the persistence of sleep problems from childhood to adulthood, and the possibility that the aetiological influences on sleep change with age; iii) the associations between sleep disturbances, emotional, behavioural and health-related problems; and iv) processes of gene-environment correlation and interaction. We highlight avenues for further research, emphasising the need to further consider the aetiology of longitudinal associations between sleep disturbances and psychopathology; the genetic and environmental overlap between sleep and numerous phenotypes; and processes of gene-environment interplay and epigenetics.
authors.affiliation: Northumbria Centre for Sleep Research, Department of Psychology, School of Life Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK. nicola.barclay@northumbria.ac.uk
authors.forename: Nicola L
authors.initials: NL
authors.lastname: Barclay
authors.forename: Alice M
authors.initials: AM
authors.lastname: Gregory
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D002653:Child Behavior Disorders / Q000235:genetics / Q000523:psychology; D004200:Diseases in Twins / Q000235:genetics / Q000523:psychology; D004644:Emotions; D044127:Epigenesis, Genetic / Q000235:genetics; D059647:Gene-Environment Interaction; D036281:Genetic Research; D005838:Genotype; D006305:Health Status Indicators; D006801:Humans; D010641:Phenotype; D017286:Polysomnography; D012890:Sleep / Q000235:genetics*; D012893:Sleep Wake Disorders / Q000145:classification / Q000150:complications* / Q000235:genetics* / Q000523:psychology*; D012919:Social Behavior; D018433:Twin Studies as Topic