Etiologies of Associations Between Childhood Sleep and Behavioral Problems in a Large Twin Sample

Objective To examine the etiologies of covariation of childhood sleep problems and other behavioral/emotional problems in young children. Method The parents of more than 6,000 twin pairs provided information on their twins’ anxiety, conduct, and hyperactivity at ages 3, 4, and 7 by completing the Strengths and Difficulties Questionnaire. Information on sleep problems was obtained at age 3/4. Results Phenotypic correlations in preschool years between sleep problems and anxiety, conduct, and hyperactivity ranged from 0.17 to 0.22. These correlations were largely due to shared environmental factors (0.72–0.96) and less to heredity (0.05–0.26) and nonshared environment (0.00–0.06). Sleep problems at age 3/4 years predicted at age 7 years anxiety (β = .12, p < .001), conduct problems (β = .09, p < .001), and hyperactivity (β = .07, p < .001), after accounting for stability of these problems. These predictive associations were also mainly mediated by shared environment (0.16–0.91), although genetic (0.02–0.84) and nonshared environmental (−0.03–0.09) factors were also influential. Conclusions The modest associations between early sleep problems and later behavioral/emotional problems are largely accounted for by common psychosocial risk factors. Further research on which specific risks may mediate these connections is needed