Social jet lag is associated with core symptoms in 2-3-year-old children with autism spectrum disorders

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by social communication deficits, restricted interests, and repetitive behaviors. Sleep disturbances, including delayed sleep onset, frequent nighttime awakenings, and circadian rhythm disruptions, are prevalent in ASD. Circadian regulation (biological clock in the suprachiasmatic nucleus) and sleep homeostasis govern sleep. Misalignment between internal biological clocks and social schedules leads to social jet lag (SJL), typically reflected as differences between weekday and weekend sleep timing (SJL = |weekend sleep midpoint − weekday sleep midpoint|). SJL has been associated with adverse mental and physical health outcomes (e.g., metabolic, cardiovascular, sleep, anxiety, depression) mainly in adult and adolescent populations, with limited evidence in children and particularly in ASD. Prior work in preschoolers and ADHD indicates SJL relates to emotional/behavioral problems and cognitive/core symptoms, respectively. In ASD, one study (ages 5–21 years) examined SJL’s relation to age and sleep but not core symptoms. Given autistic children’s social impairments and adaptation difficulties, they may experience more severe consequences of SJL. This study aims to: (1) characterize weekday vs weekend sleep patterns in children with ASD, (2) examine age-related differences in sleep patterns and SJL, and (3) explore associations between SJL and ASD core symptoms and developmental level. The goal is to inform guidance for parents and clinicians to promote regular routines.

The introduction summarizes relevant literature: SJL, defined as misalignment between biological and social time, has been linked to adverse outcomes including sleepiness, metabolic and cardiometabolic risks, anxiety/depression, and behavioral/emotional problems in children and adolescents. In preschool children, longer SJL was associated with greater emotional and behavioral problems. In ADHD, SJL correlated with cognitive performance and core symptoms. In ASD, a prior study (ages 5–21) reported overall SJL (~0.72 h) and its correlation with age and sleep but did not examine core symptoms. These gaps motivated investigation of SJL’s relationship with core ASD symptoms and developmental level in young children.

Design: Cross-sectional study in Chongqing, China. Participants: Children aged 2–7 years with DSM-5-confirmed ASD diagnosed by developmental-behavioral pediatricians. Inclusion: age 2–7, confirmed ASD, caregiver consent. Exclusion: serious comorbid diseases; incomplete questionnaires. Ethics/Registration: Approved by the Ethics Committee of Children’s Hospital of Chongqing Medical University (No. 121-1/2018). Registered at the Chinese Clinical Trial Registry (ChiCTR2000031194). Sleep assessment: Children’s Sleep Habits Questionnaire (CSHQ), 33 scored items plus weekday/weekend bedtime and wake time. Sleep problem cutoff: CSHQ total score ≥48 based on recent validation literature. Sleep duration: interval between bedtime and wake time. Sleep midpoint = wake time – (sleep duration/2). Social jet lag (SJL) = weekend sleep midpoint − weekday sleep midpoint (absolute difference used descriptively). Sleep adequacy: per American Academy of Sleep Medicine/National Sleep Foundation recommendations: toddlers 11–14 h; ages 3–6 ~10 h; ages 6–14 ~9 h. Core symptoms: Childhood Autism Rating Scale (CARS; 15 items, autism severity), Social Responsiveness Scale (SRS; 65 items; domains: social awareness, social cognition, social communication, social motivation, autistic mannerisms; total 0–195), Autism Behavior Checklist (ABC; 57 items; domains: sensory, relating, body/object use, language, social/self-help; total 0–158). Developmental level: Gesell Developmental Scale (GDS), domains: adaptive behavior, gross motor, fine motor, language, personal-social; total developmental quotient (DQ) = mean of five domains. Statistical analysis: SPSS 25.0. Continuous variables as mean±SD or median (P25–P75); group comparisons via ANOVA or Kruskal–Wallis. Categorical variables as n (%); chi-square tests for group differences. Within-subject weekday–weekend comparisons via paired t-tests, Wilcoxon signed-rank tests, or McNemar’s tests per data characteristics. Bonferroni correction for multiple comparisons. Correlations via Pearson or Spearman based on distribution; significance at P<0.05. Age groups analyzed: 2–3, 3–4, 4–5, and ≥5 years; due to similarity, 3–4, 4–5, and ≥5 groups merged (≥3 years) for some correlational analyses.

Sample: 701 recruited; 36 excluded for missing data; final analytic sample n≈665 (reported 545 boys, 121 girls). Median age 3.82 (3.13, 4.61) years. Sleep problems prevalence 49.8%; mean CSHQ total 48.04. Weekday vs weekend sleep patterns (n=665): Significant differences with later sleep and wake times on weekends; longer sleep duration; lower sleep insufficiency on weekends. Median sleep times: weekdays 22:00 (21:30–22:30) vs weekends 22:03 (21:45–23:00) (Z=−14.772, P<0.001); wake times: weekdays 07:30 (07:00–08:00) vs weekends 08:00 (07:30–08:50) (Z=−15.353, P<0.001); sleep duration: weekdays 9.67 (9.00–10.00) h vs weekends 10.00 (9.33–10.50) h (Z=−8.672, P<0.001). Sleep insufficiency: weekdays 59.40% vs weekends 49.17% (χ²=21.811, P<0.001). Late bedtime (after 21:00): weekdays 87.22% vs weekends 92.48% (χ²=32.529, P<0.001). Age-group patterns: Bedtime earliest in ≥5y group (weekdays 21:30 [21:00–22:07]; weekends 22:00 [21:30–22:30]; P<0.01), though late sleep remained prevalent (81.5%–90.7% after 21:00). Sleep duration did not differ across age groups (weekdays ~9.5–9.83 h; weekends ~10 h), yet sufficiency thresholds are higher for younger children. Sleep insufficiency highest in 2–3y: weekdays 80.77%; weekends 82.17% vs 44.44%–57.92% (weekdays) and 31.48%–44.58% (weekends) in older groups (P<0.001). Social jet lag (SJL) medians: 2–3y: 0.25 (0, 0.5) h; 3–4y: 0.5 (0.08, 0.75) h; 4–5y: 0.42 (0.01, 0.75) h; ≥5y: 0.5 (0.08, 0.75) h (H=15.06, P=0.002). 2–3y SJL significantly lower than 3–4y and ≥5y. Correlations (Spearman) between SJL and core symptoms: In 2–3y group (n=130), SJL positively correlated with ABC relating (r=0.178, P=0.050), ABC language (r=0.297, P=0.001), ABC total (r=0.178, P=0.050); SRS communication (r=0.163, P=0.065), SRS motivation (r=0.181, P=0.039), SRS autistic mannerisms (r=0.215, P=0.014), SRS total (r=0.208, P=0.018). No correlations in ≥3y group (n=535) between SJL and core symptom scores. Correlations with developmental level (GDS): In ≥3y group, extremely weak correlation only with personal-social domain (r=0.100, P=0.042); otherwise no significant associations. In 2–3y group, no significant correlations with GDS domains or total DQ.

Children with ASD showed pronounced weekday–weekend discrepancies: later bedtimes and wake times on weekends, longer sleep, and reduced sleep insufficiency—likely reflecting more relaxed weekend schedules and compensatory sleep. However, such variability may disrupt circadian rhythms and overall sleep quality, underscoring recommendations for consistent sleep–wake routines and earlier bedtimes. Late bedtime was highly prevalent across all ages. The 2–3-year-old group exhibited the highest sleep insufficiency despite similar absolute sleep durations across ages, highlighting that younger children require more sleep. Although 2–3-year-olds had the smallest SJL magnitude, SJL showed the strongest associations with ASD core symptoms in this age group, especially language/communication-related domains, suggesting heightened vulnerability to routine disruptions during rapid neurodevelopment before age 3. In children ≥3 years, higher SJL was not associated with core symptoms, potentially due to structured kindergarten/behavioral interventions and greater circadian resilience mitigating SJL impact. Findings align with broader literature linking SJL to emotional/behavioral problems and ADHD symptoms, extending relevance to ASD and emphasizing the importance of routine regularity in early childhood.

This study demonstrates, for the first time, that social jet lag correlates with core ASD symptoms in 2–3-year-old children, particularly in language and communication domains, indicating a potentially negative impact of SJL on early ASD symptomatology. Given the high prevalence of late bedtimes and weekday–weekend variability, promoting regular, earlier sleep routines is crucial—especially for younger children. Future research should further elucidate mechanisms and test interventions to reduce SJL and improve outcomes in ASD.

Sleep timing was assessed via caregiver-reported questionnaires, introducing potential reporting bias; future work will incorporate actigraphy for objective measures and parental sleep profiles. The study provides preliminary exploration of SJL in ASD and its association with core symptoms; more comprehensive, multimodal research (e.g., neuroimaging of social brain networks, gene–environment interactions) is needed. Generalizability may be limited to the sampled region and age range.