Longitudinal relationships between social anhedonia and internalizing symptoms in autistic children: results from the Autism Biomarkers Consortium for Clinical Trials.

Abstract

Background: Social anhedonia, indicating reduced pleasure from social interaction, is heightened in autistic youth and associated with increased internalizing symptoms transdiagnostically. The stability of social anhedonia over time and its longitudinal impact on internalizing symptoms in autism have never been examined.

Methods: Participants were 276 autistic children (M_age = 8.60, SD_age = 1.65; 211 male) with IQ ≥ 60 (M_IQ = 96.74, SD_IQ = 18.19). Autism severity was measured using the Autism Diagnostic Observation Schedule, Second Edition. Caregivers completed the Child and Adolescent Symptom Inventory, Fifth Edition (CASI-5) at baseline, 6 weeks, and 6 months. The CASI-5 includes a social anhedonia subscale derived from relevant items across domains. ICC (Intraclass Correlation Coefficient) analysis assessed stability, while cross-lagged panel models examined associations among social anhedonia, depression, and social anxiety across time.

Results: At baseline, social anhedonia correlated with autism severity, as well as parent-reported social anxiety and depression. Social anhedonia showed relative stability (ICC = 0.763) over 6 months, with a significant decline between baseline and 6 weeks (β = -0.52, p < .001). Cross-lagged models revealed a bidirectional relationship between social anhedonia and depression over time, while social anxiety displayed concurrent, but not predictive, associations across time.

Conclusions: Social anhedonia demonstrated stability over 6 months, suggesting that it may be a relatively stable characteristic in autistic children. Concurrent relationships were observed between social anhedonia and depression, as well as social anxiety and attention-deficit/hyperactivity disorder. Only depression demonstrated a bidirectional longitudinal association with social anhedonia. This bidirectional relationship aligns with developmental models linking early negative social experiences to subsequent internalizing symptoms in autistic children, underscoring the clinical significance of social anhedonia assessment in this population.