Effects of Full Moon on Behavior of Children with Autism Spectrum Disorder: A Longitudinal Study

Abstract Background Cultural beliefs have historically linked full moon phases with behavioural changes. However, limited empirical evidence exists regarding its effect on children with Autism Spectrum Disorder(ASD), a group often characterised by heightened sensory sensitivity and circadian rhythm dysregulation. Objective To evaluate whether full moon phases are associated with measurable behavioural alterations in children diagnosed with ASD. Methods Thirty children ( ages 5–12 years) with confirmed ASD diagnoses were followed over 12 lunar cycles. Behavioral changes were tracked using daily Aberrant Behavior Checklist(ABC) scores provided by caregivers and verified by clinicians. Sensory sensitivity was assessed via the Sensory Profile 2. A repeated-measures ANOVA and K-means clustering were performed using SPSS v27. Results No significant differences were observed in overall behaviour scores between full moon and non-full moon periods(p > 0.05). However, hyperactivity scores were significantly elevated during full moon phases (Mean = 18.5, SD = 5.1) compared to non-full moon phases(Mean = 17.1, SD = 4.7), F (1, 29) = 4.42, p = 0.041, η² = 0.13. Subgroup analysis revealed 26.7% of participants with elevated sensory sensitivity showed a ≥ 20% increase in hyperactivity, supported by significantly higher Sensory Profile 2 scores (p < .01). Conclusion While overall behavior in children with ASD did not vary with lunar phases, a sensory-sensitive subgroup demonstrated increased hyperactivity during full moons. These findings suggest lunar-related environmental changes may influence behavior in certain ASD phenotypes.