Multi-informants are essential for capturing the full range of adaptive functioning abilities necessary for daily living and independence. However, discrepancies within parent-child dyads, specifically comparing parent-reports to child self-reports, can cloud interpretation from assessments and hinder support planning. This study examines discrepancies in parent-youth perceptions of adaptive functioning, focusing on the social domain, and investigates associations among parents, youth, and independent ratings, considering factors like IQ, autism severity, and parental education. The study included 132 individuals (66 autistic, 66 non-autistic) aged 16-24 years. Adaptive functioning was measured using the Adaptive Behavior Assessment System-3 across the conceptual, practical, and social domains. Agreement between reporters was assessed using paired-sample t-tests, intraclass-correlations, and Bland-Altman plots. Spearman's correlations examined associations between raters, while the effects of IQ, autism severity, and parental education on discrepancies were analyzed using linear regression. Autistic self- and parent-reports showed lower adaptive functioning than non-autistic dyads. Autistic youth reported higher social and less practical adaptive skills compared to parents. Autistic self-reports in the social domain correlated significantly with independent assessment. Increased autistic symptoms were associated with greater parent-child discrepancies. This study underscores the importance of multi-informant assessments to understand the full range of adaptive functioning in autistic individuals. Discrepancies in social and practical domains highlight the need for both perspectives, because parents may not observe all behaviors and may overlook autistic individuals' perception of support needs in the practical domain. Understanding these differences is crucial for improving supports planning and enhancing quality of life for autistic individuals.

Background

We extended our study of trajectories of intellectual development of autistic individuals in early (mean age 3 years; T1), and middle childhood (mean age 5 years, 7 months; T2) into later middle childhood/preadolescence (mean age 11 years, 6 months; T3) in the longitudinal Autism Phenome Project cohort. Participants included 373 autistic children (115 females).

Methods

Multivariate latent class growth analysis was used to identify distinct IQ trajectory subgroups. Baseline and developmental course group differences and predictors of trajectory membership were assessed using linear mixed effects models with repeated measures with pairwise testing, multinomial logistic regression models, and sensitivity analyses.

Results

We isolated three IQ trajectories between T1 and T3 for autistic youth that were similar to those found in our prior work. These included a group with persistent intellectual disability (ID; 45%), a group with substantial increases in IQ (CHG; 39%), and a group with persistently average or above IQs (P-High; 16%). By T3, the groups did not differ in ADOS-2 calibrated severity scores (CSS), and there were no group differences between Vineland (VABS) communication scores in CHG and P-High. T1-T3 externalizing behaviors declined significantly for CHG, however, there were no significant T3 group differences between internalizing or externalizing symptoms. T1 correlates for CHG and P-High versus ID group membership included higher VABS communication and lower ADOS-2 CSS. A T1 to T2 increase in VABS communication scores and a decline in externalizing predicted CHG versus ID group membership at T3, while T1 to T2 improvement in VABS communication and reduction in ADOS-2 CSS predicted P-High versus ID group membership.

Conclusions

Autistic youth exhibit consistent IQ developmental trajectories from early childhood through preadolescence. Factors associated with trajectory group membership may provide clues about prognosis, and the need for treatments that improve adaptive communication and externalizing symptoms.