STUDY OBJECTIVES: Determine the genetic and environmental contributions to sleep reactivity and insomnia. DESIGN: Population-based twin cohort. PARTICIPANTS: 1782 individual twins (988 monozygotic or MZ; 1,086 dizygotic or DZ), including 744 complete twin pairs (377 MZ and 367 DZ). Mean age was 22.5 ± 2.8 years; gender distribution was 59% women. MEASUREMENTS: Sleep reactivity was measured using the Ford Insomnia Response to Stress Test (FIRST). The criterion for insomnia was having difficulty falling asleep, staying asleep, or nonrefreshing sleep "usually or always" for ≥ 1 month, with at least "somewhat" interference with daily functioning. RESULTS: The prevalence of insomnia was 21%. Heritability estimates for sleep reactivity were 29% for females and 43% for males. The environmental variance for sleep reactivity was greater for females and entirely due to nonshared effects. Insomnia was 43% to 55% heritable for males and females, respectively; the sex difference was not significant. The genetic variances in insomnia and FIRST scores were correlated (r = 0.54 in females, r = 0.64 in males), as were the environmental variances (r = 0.32 in females, r = 0.37 in males). In terms of individual insomnia symptoms, difficulty staying asleep (25% to 35%) and nonrefreshing sleep (34% to 35%) showed relatively more genetic influences than difficulty falling asleep (0%). CONCLUSIONS: Sleep reactivity to stress has a substantial genetic component, as well as an environmental component. The finding that FIRST scores and insomnia symptoms share genetic influences is consistent with the hypothesis that sleep reactivity may be a genetic vulnerability for developing insomnia.
STUDY OBJECTIVES: Determine the genetic and environmental contributions to sleep reactivity and insomnia. DESIGN: Population-based twin cohort. PARTICIPANTS: 1782 individual twins (988 monozygotic or MZ; 1,086 dizygotic or DZ), including 744 complete twin pairs (377 MZ and 367 DZ). Mean age was 22.5 ± 2.8 years; gender distribution was 59% women. MEASUREMENTS: Sleep reactivity was measured using the Ford Insomnia Response to Stress Test (FIRST). The criterion for insomnia was having difficulty falling asleep, staying asleep, or nonrefreshing sleep "usually or always" for ≥ 1 month, with at least "somewhat" interference with daily functioning. RESULTS: The prevalence of insomnia was 21%. Heritability estimates for sleep reactivity were 29% for females and 43% for males. The environmental variance for sleep reactivity was greater for females and entirely due to nonshared effects. Insomnia was 43% to 55% heritable for males and females, respectively; the sex difference was not significant. The genetic variances in insomnia and FIRST scores were correlated (r = 0.54 in females, r = 0.64 in males), as were the environmental variances (r = 0.32 in females, r = 0.37 in males). In terms of individual insomnia symptoms, difficulty staying asleep (25% to 35%) and nonrefreshing sleep (34% to 35%) showed relatively more genetic influences than difficulty falling asleep (0%). CONCLUSIONS: Sleep reactivity to stress has a substantial genetic component, as well as an environmental component. The finding that FIRST scores and insomnia symptoms share genetic influences is consistent with the hypothesis that sleep reactivity may be a genetic vulnerability for developing insomnia.
Authors: Thomas Roth; Catherine Coulouvrat; Goeran Hajak; Matthew D Lakoma; Nancy A Sampson; Victoria Shahly; Alicia C Shillington; Judith J Stephenson; James K Walsh; Ronald C Kessler Journal: Biol Psychiatry Date: 2010-12-31 Impact factor: 13.382
Authors: A N Vgontzas; E O Bixler; H M Lin; P Prolo; G Mastorakos; A Vela-Bueno; A Kales; G P Chrousos Journal: J Clin Endocrinol Metab Date: 2001-08 Impact factor: 5.958
Authors: Nathaniel F Watson; Vishesh Kapur; Lester M Arguelles; Jack Goldberg; Douglas F Schmidt; Roseanne Armitage; Dedra Buchwald Journal: Sleep Date: 2003-05-01 Impact factor: 5.849
Authors: Indrani Halder; Karen A Matthews; Daniel J Buysse; Patrick J Strollo; Victoria Causer; Steven E Reis; Martica H Hall Journal: Sleep Date: 2015-08-01 Impact factor: 5.849