ULTRAVIOLET LIGHT EXPOSURE AS A MODULATOR OF SOCIAL BEHAVIOR IN AUTISM

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by impairments in social interaction, repetitive behaviors, and anxiety-related traits. While genetic risk is substantial, environmental factors, such as ultraviolet (UV) exposure remain incompletely understood. The aim of this study is to examine whether seasonal variation in ambient ultraviolet (UV) exposure is associated with behavioral and molecular differences in children with ASD. Behavioral and clinical data were collected from children diagnosed with ASD hospitalized in a closed pediatric psychiatric unit, together with non-ASD neuropsychiatric control patients (n=50 in each group). Standardized behavioral assessments, including measures of aggression and overall behavioral severity, were obtained at admission. In parallel, serum samples were subjected to mass spectrometry-based proteomic profiling. We found a strong seasonal association between behavioral severity and environmental UV exposure, with increased behavioral severity observed during periods of higher UV exposure in children with ASD. No seasonal UV-associated behavioral effects were observed in non-autistic control group. Proteomic analysis of blood serum collected during high- and low-UV periods from autistic children demonstrated a significant induction of a UV-related molecular signature. Together, these findings suggest that environmental UV exposure may be associated with behavioral variability and systemic molecular changes in children with ASD, supporting a biologically relevant link between skin-mediated environmental signals and neuropsychiatric function.