Circadian preference and quality of life in adults with autism spectrum disorder: a Brazilian cross-sectional self-reported survey

PURPOSE: Adults with Autism Spectrum Disorder (ASD) often experience significant challenges that affect their quality of life (QoL), including mental health issues, socioeconomic strain, and circadian rhythm disruptions. Chronotype, or an individual’s biological preference for sleep-wake patterns, has been associated with well-being in neurotypical populations but remains underexplored in adults with ASD. This study aimed to investigate the association between chronotype and perceived QoL in Brazilian adults with ASD. METHODS: We conducted a cross-sectional, web-based survey as part of the SOLACE-ASD Brasil project. A total of 439 adults (≥ 18 years) with a self-reported diagnosis of ASD completed standardized questionnaires assessing chronotype (Morningness-Eveningness Questionnaire) and QoL (EUROHIS-QOL 8). Sociodemographic, behavioral, and clinical variables were also collected. Associations were examined using multiple linear regression and ANCOVA, adjusting for potential confounders. RESULTS: Intermediate chronotype was the most prevalent (40.1%), followed by evening (38.7%) and morning (21.2%) chronotypes. Overall, 60.4% of participants reported low QoL. Evening-type individuals had significantly lower overall and physical health QoL scores than morning and intermediate types. In multivariate analysis, evening chronotype, unemployment, low income, tobacco use, and physical inactivity were independently associated with lower QoL. CONCLUSION: Chronotype is an independent predictor of QoL in adults with ASD, with evening preference linked to worse outcomes. These findings highlight the importance of considering circadian biology in public health strategies and suggest that chronotype-targeted interventions could improve QoL in this population.