Genetics may play a role in the development of insomnia in adults, according to a new study published in the journal Sleep, with higher heritability seen in females than males.

Study authors from Virginia Commonwealth University in Richmond used twin modeling to conduct a genetically informative longitudinal analysis of insomnia symptoms in both sexes. They evaluated data from the Virginia Adult Twin Studies of Psychiatric and Substance Use Disorders that included twin data set of about 7,500 participants. Researchers evaluated past-month insomnia symptoms at 2 non-overlapping time points with the shortened version of the Symptom Checklist-90 to calculate a composite score for the insomnia items (eg, trouble falling asleep, restless or disturbed sleep, early morning awakenings). 

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Data from the longitudinal measurement model showed an estimated heritability of 59% for females and 38% for males. Findings support the notion that genes may play a bigger role in insomnia development for women than for men. With evidence indicating sex differences, “it may be useful to specifically target female for sleep interventions,” Mackenzie Lind, doctoral candidate, noted. Though heritability estimates are notable, “unique environmental factors continue to account for a large amount of variance in insomnia symptoms.” 

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