Sleep problems and mental health in middle-aged and older autistic and non-autistic adults

Background: Sleep is a vital biological function, and impaired sleep can lead to a range of problems, including poor health and wellbeing. Poor sleep and higher rates of sleep disorders are often reported by autistic children and adults, as well as middle-aged and older people with high autistic traits. However, these experiences and problems have seldom been studied in diagnosed autistic populations in midlife and old age. Methods: This study used data from the first wave of the AgeWellAutism cohort, from a sample of 265 autistic and 167 age- and gender-matched non-autistic adults aged 40 to 93 years (mean = ~60 years; ~50% female). Participants completed widely used and standardised measures of sleep quality and mental health symptoms. Results: The autistic group reported significantly more sleep difficulties than the non-autistic group, including poorer sleep quality, longer time to fall asleep, shorter duration, lower efficiency, more disturbances, greater reliance on sleep medication, and increased daytime tiredness and dysfunction. These differences remained significant after controlling for age and poor mental health (measured by symptoms of anxiety, depression and PTSD). Poor sleep was also associated with older age and mental health issues in both groups, with a stronger association between sleep problems and anxiety symptoms in the autistic versus non-autistic group. Conclusions: Consistent with prior autism trait-based research in the general population, middle-aged and older autistic adults report more extensive sleep problems and worse sleep quality than non-autistic adults. Sleep problems were associated with older age and poorer mental health. Though the study is cross-sectional, the findings highlight the need to explore causal links through intervention. Addressing anxiety, and mental health problems more broadly, may improve sleep quality in ageing autistic populations.