Behavioral Subtypes and Challenging Behaviors

Background:  Children diagnosed with an autism spectrum disorder (ASD) often exhibit challenging behaviors. Engagement in these behaviors has a high economic and emotional cost for families and communities. Unfortunately, the vast symptom heterogeneity among children with ASD confounds attempts to create targeted treatments for the reduction of these behaviors. Many studies have previously attempted to reduce this heterogeneity through the creation of more behaviorally homogenous subgroups of ASD (Beglinger & Smith, 2001). Few, however, included information from the Autism Diagnostic Interview-Revised (ADI-R), or limited their analyses solely to the core symptoms of autism (i.e., measures of problem behavior, adaptive behavior, IQ, and developmental history were generally included). Fewer still divided repetitive behaviors and restricted interests (RRBs)—considered one of the best predictors of challenging behaviors (Kanne & Mazurek, 2011)—into the repetitive sensorimotor (RSM) and insistence on sameness (IS) sub-categories identified by Richler, Bishop, Kleinke, and Lord (2007). Finally, none of the studies attempted to relate the resulting subtypes back to an outcome measure of challenging behavior.

Objectives:  (a) To reduce heterogeneity among children with autism through the creation of more homogenous subgroups within the broad population based on patterns of engagement in the core symptoms of ASD as measured by the ADI-R with RRBs separated into the RSM and IS categories; (b) To determine whether the resulting subgroups display differential engagement in challenging behaviors.

Methods:  Data was analyzed for children with ASD (probands; N = 1778; M age = 6.8 years, SD = 1.7 years, range = 4—10 years) who participated in the Simons Simplex Collection (SSC). The RRB domain of the (ADI-R) was divided into RSM and IS scales. These scales along with the current behavior algorithm score in the area of reciprocal social interaction -- labeled the Social Abnormalities (SA) scale for brevity -- on the ADI-R were entered into a cluster analysis.

Results:  The cluster analysis indicated a five-cluster solution. Two clusters, labeled Low Impairment and High Impairment, had low and high scores, respectively, on all three of the scales included in the analysis. The other three clusters, labeled Social Abnormalities, Insistence on Sameness, and Repetitive Sensorimotor + Social Abnormalities, all displayed elevated scores on the scales for which they were labeled. These clusters varied in a systematic and consistent way in their associations with core and associated features of ASD. Notably,  the two clusters with relatively high scores on the IS scale (Insistence on Sameness and High Impairment) displayed high levels of emotional and behavioral problems relative to the other groups, but showed no differences from one another on multiple measures of problem behaviors. Surprisingly, these two groups significantly differed from each other on every other variable used in the study (e.g., IQ, communication skills, and adaptive behaviors).

Conclusions:  Presently, many treatment packages for challenging behaviors among children with ASD focus on the promotion of communication and social skills. The results of the present study suggest that deficits in these areas or in overall intellectual functioning have little impact on engagement in challenging behaviors in comparison to IS behaviors.