Predictors of Change in Severity of Self-Injurious Behaviors in Preschool-Aged Autistic Children.

Self-injurious behaviors (SIBs) affect up to 50% of autistic individuals and significantly impact quality of life and everyday functioning. Cross-sectional studies link the presence of SIB to lower IQ, altered sensory responsivity, and poor emotion regulation, yet their effect on changes in SIB severity from early childhood to school age in autism remains poorly understood. We examined SIBs in 325 autistic children assessed at age 2-5 years (T1) and 161 autistic children at 4-9 years (T3). This included a subset of 122 autistic children evaluated longitudinally at both time points. SIBs were classified into subgroups based on severity of SIB (no-SIB, mild, moderate, severe). We assessed cognitive ability, dysregulation, and sensory features at each time point. Cross-sectional and longitudinal analyses were used to examine group differences. At T1, 74% of the sample were characterized as having mild, moderate, or severe SIB. At T3, 67% had mild, moderate, or severe SIB. There was substantial variability in SIB severity subgroup membership across time; however, only 9% did not have SIBs at either timepoint. At both timepoints, children with more severe SIBs had increased dysregulation (p < 0.001) and sensory features (p < 0.001), but differences in developmental/intellectual quotient (DQ/IQ) emerged only at T3. Longitudinally, improvement in sensory features (p = 0.026) and higher T3 IQ (p = 0.039) significantly raised odds of decreasing SIB severity. Of the baseline measures of sensory features, dysregulation, DQ, and SIB severity, higher baseline SIB severity was the only predictor of increasing SIB severity. SIBs are highly prevalent in preschool-aged autistic children. Sensory responsivity and dysregulation predict severity of SIBs, and reductions in sensory features may lead to decreased SIB severity across time.