Sleep Disturbance in Children and Adults with ASD in the EU-AIMS LEAP Cohort: Association with Symptomatology, Comorbidities, Quality of Life, and Intellectual Ability

Background: Rates of sleep problems in individuals with ASD range between 40%-80% (Johnson et al. 2009). Recent studies report the importance of sleep in the manifestation of ASD core symptoms (e.g. repetitive behaviours and communication; Park, et al., 2012; Tudor, et al., 2012) and sensory abnormalities (Mazurek et al., 2015). Psychiatric comorbidities have also been shown to be associated with sleep problems in neurodevelopmental conditions (e.g. challenging behaviours are more likely to co-exist in individuals with ASD who suffer from sleep disturbances; Lundqvist, 2013), ultimately impacting family life. Although some studies have shown sleep problems throughout the life span (e.g. Øyane, & Bjorvatn, 2005), to date, most of the studies focus on children and little attention has been given to the continuity and impact of these problems in adulthood.

Objectives: 1) To investigate the type and severity of sleep problems in individuals with and without ASD in relation to age, and ability level; 2) To study the associations of sleep problems on ASD core symptoms and psychiatric comorbidities (i.e. depression, anxiety, ADHD) as well as quality of life and adaptive functioning.

Methods: 294 individuals with ASD and 204 individuals with typical development or mild intellectual disability, with IQ ranging from 40-148 and aged 6-30 years were recruited as part of the multi-centre EU-AIMS Longitudinal European Autism Project (Charman et al., 207; Loth et al., 2017). Autism symptomatology was characterized with the ADOS, ADI-R, Social Responsiveness Scale, Short Sensory Profile, and Repetitive Behaviours Scale. Sleep disturbances were studied with the Child Sleep Habits Questionnaire (parent report version for 6-11 years-olds) or the self-report adolescent version in individuals over 11 years of age of IQ above 75, and parent reported for those below. Quality of life was measured with the Columbia Impairment Scale, and adaptive functioning with the Vineland adaptive behaviour interview. Comorbidities were characterized using the ADHD DSM-5 checklist, and Beck questionnaires for Anxiety and Depression.

Results: Children with ASD showed significantly greater overall sleep disturbances than controls, in particular, anxiety around sleep time, quality of waking (e.g. feeling rested, difficulties waking up, etc.), parasomnias, and daytime sleepiness (all p_corrected < .037). Adolescents and adults with ASD reported poorer quality of waking than controls (p_corrected = .004). Repetitive behaviours and sensory abnormalities correlated moderately with the total sleep time across ages, as reported by parents (all r > .44, all p_corrected < .004), but not on self-reports. In children, sleep correlated to adaptive behaviour (r = -.35, p_corrected = .005). Across ages, the total sleep time was moderately correlated to anxiety, depression and ADHD (all r > .42, all p_corrected < .005), as well as quality of life (all r > .36, all p_corrected < .004), but only on individuals of IQ > 75.

Conclusions: Sleep problems are linked to ASD core symptoms and adaptive behaviour in children with ASD, but sensory anomalies, and frequent comorbidities across the ages. Future analyses will examine whether the effect of sleep on clinical symptoms may be mediated by differences in cognitive or emotional processes.