Onset of regular cannabis use and young adult insomnia: an analysis of shared genetic liability

• Published in: Sleep (New York, N.Y.) Vol. 43; no. 5; p. 1
• Main Authors: Winiger, Evan A, Huggett, Spencer B, Hatoum, Alexander S, Friedman, Naomi P, Drake, Christopher L, Wright, Kenneth P, Hewitt, John K
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01.05.2020
• Subjects: Adolescent; Adult; Analysis; Cannabis; Development and progression; Diseases in Twins - epidemiology; Diseases in Twins - genetics; Environmental associations; Female; Genetic research; Humans; Insomnia; Insomnia and Psychiatric Disorders; Legal liability; Male; Marijuana; Sleep; Sleep - genetics; Sleep Initiation and Maintenance Disorders - epidemiology; Sleep Initiation and Maintenance Disorders - genetics; Twin studies; Twins; Twins - genetics; Young Adult; Young adults; Youth; Colorado; cannabis onset; short sleep duration; development; twin studies; insomnia
• ISSN: 0161-8105; 1550-9109; 1550-9109
• DOI: 10.1093/sleep/zsz293

Abstract Study Objectives Estimate the genetic and environmental influences on the relationship between onset of regular cannabis use and young adult insomnia. Methods In a population-based twin cohort of 1882 twins (56% female, mean age = 22.99, SD = 2.97) we explored the genetic/environmental etiology of the relationship between onset of regular cannabis use and insomnia-related outcomes via multivariate twin models. Results Controlling for sex, current depression symptoms, and prior diagnosis of an anxiety or depression disorder, adult twins who reported early onset for regular cannabis use (age 17 or younger) were more likely to have insomnia (β = 0.07, p = 0.024) and insomnia with short sleep on weekdays (β = 0.08, p = 0.003) as young adults. We found significant genetic contributions for the onset of regular cannabis use (a2 = 76%, p < 0.001), insomnia (a2 = 44%, p < 0.001), and insomnia with short sleep on weekdays (a2 = 37%, p < 0.001). We found significant genetic correlations between onset of regular use and both insomnia (rA = 0.20, p = 0.047) and insomnia with short sleep on weekdays (rA = 0.25, p = 0.008) but no significant environmental associations between these traits. Conclusions We found common genetic liabilities for early onset of regular cannabis use and insomnia, implying pleiotropic influences of genes on both traits.