Restricted and Repetitive Behaviors and Interests Differ By Sex and Age in High Functioning Children with ASD

Background:

Restricted and repetitive behaviors and interests (RRBs) are a core feature of Autism Spectrum Disorders (ASD) required to meet diagnostic criteria for ASD according to the DSM-5. Research suggests RRBs are a heterogeneous group of behaviors with subtypes having differential developmental trajectories. Patterns of findings across studies are not consistent regarding age-related changes in RRBs. Understanding the developmental trajectory of RRB subtypes in girls and high functioning children and adolescents has implications for better understanding symptom progression across the ASD spectrum.

Objectives:

Data are from a multi-site study focusing on multimodal neurogenetic exploration of girls (and boys) with ASD. In a sample of children with ASD without intellectual impairment, we explore the effects of child age and gender on parent report of RRBs in three domains: stereotyped, ritualistic, and restricted behavior.

Methods:

Preliminary data were analyzed from a sample of children who participated in the NIMH ACE network GENDAAR study, across 4 U.S. research sites. In order to analyze the influence of child gender, we matched a subsample of 40 ASD males and 40 ASD females on age (8-17 years) and IQ (mean IQ=102.95, SD=22.47). Subjects were divided into 2 cross-sectional age groups: 8-12.9 years (children) and 14-17.9 years (adolescents). Parents completed the Repetitive Behavior Scale – Revised (RBS-R) about their child. All subjects met diagnostic criteria for ASD on the ADOS-2 and the ADI Revised. Final analyses will include additional subjects and measures of RRBs.

Results:

On the stereotyped behavior subscale, male children (M=4.55, SD=3.561) scored significantly higher (worse) than male adolescents (M=1.20, SD=1.240) (p=.001), while girls’ stereotyped behavior scores did not differ across age groups (p=.106). On the ritualistic behavior subscale, male children (M=5.25, SD=4.587) scored significantly higher (worse) than male adolescents (M=2.50, SD=2.439) (p = .025), however girls’ ritualistic behavior scores did not differ across age groups (p=.528). On the restricted behavior subscale, males’ scores (M=3.50, SD=3.211) were also significantly higher (worse) than females’ scores (M=2.13, SD=2.127), regardless of age group (p=.026).

Conclusions:

In our sample, male children scored higher (worse) than male adolescents on measures of stereotyped and ritualistic behaviors. In contrast, females’ scores on stereotyped and ritualistic behaviors did not differ between age groups. Additionally, males scored higher (worse) than females on restricted behaviors. These findings suggest that the level of RRBs in ASD may vary based on age andgender, with males showing (overall) higher (worse) scores. Age and gender may be important factors in the developmental trajectory of RRBs in children and adolescents with ASD without intellectual disability.