Follow-up of Maladaptive Behaviors in Youth with Autism Spectrum Disorders: Changes and Predictors Over Two to Eight Years

Background: Ample evidence suggests that young people with autism spectrum disorders (ASDs) present with maladaptive behaviors beyond the core symptoms defining the disorder. Such behaviors represent additional impairments and are associated with increased caregiver stress. In spite of their prevalence and significance, the natural course of maladaptive behaviors is not well delineated in the ASD literature. 

Objectives:  We conducted a follow-up study to: (1) Examine the stability of and changesin maladaptive behaviors in a sample of children and adolescents with ASDs from initial contact (T1) to follow-up (T2); (2) Assess variables that might predict maladaptive behavior levels at T2.

Methods:  Participants were recruited using patient records at an UCEDD-affiliated diagnostic clinic, where potential participants were given an ASD diagnosis two-to-eight years previously. All individuals seen had a measure of maladaptive behavior on file, assessed using the Nisonger Child Behavior Rating Form (NCBRF; Aman, Tassé, Rojahn, & Hammer, 1996). We conducted follow-ups on 342 potential participants and collected data from 143 of these individuals (41.8% response rate). Follow-up data included current parent-rated NCBRF and supplementary demographic information.

Results:  The final sample ranged in age from 5 to 17 years at follow-up. Results from paired t-tests indicated significant differences between T1 and T2 NCBRF scores for all six subscales. Scores on three of the subscales (Conduct, Hyperactivity, and Self-injury/Stereotypic) showed significant improvement over time. Scores on the remaining three subscales (Insecure/Anxious, Self-isolated/Ritualistic, and Overly Sensitive) deteriorated at follow-up. Interestingly, a significantly greater proportion of those with Asperger’s disorder and PDD–NOS (as compared to autism) deteriorated on these subscales.

Using units of 0.50 SD to denote improvement, no change, and worsening (Shattuck et al., 2007), the greatest proportion of participants were found to improve on Hyperactivity (61.5%), followed by Conduct (43.3%). The highest proportion worsened on Self-isolated/Ritualistic (66.4%), followed by worsening on Insecure/Anxious (58%). Scores on Self-injury/Stereotypic were the most stable over time with 67.8% of participants showing no change. Levels of maladaptive behaviors varied considerably based on gender, ASD subtype, and language abilities of participants.

As far as predictors of maladaptive behavior change, results from a series of hierarchical regression analyses indicated that tested models accounted for 39% to 50% of the variance in T2 NCBRF subscale scores. T1 scores on the respective NCBRF subscales were the most consistent predictors of scores at follow-up, suggesting that a child’s individual levels of T1 maladaptive behavior were the best predictor of maladaptive behavior over time. Other variables that significantly predicted T2 scores on one or more NCBRF subscales included T1 age, ASD subtype, and T1 language ability.

Among other salient findings, parents reported high rates (68.5%) of comorbid psychiatric conditions in this community sample unselected for psychiatric disorders and also a high rate of psychotropic medication use (52.4%). The most common comorbid disorders were anxiety disorders (37.8%) and ADHD (31.5%).

Conclusions:  Findings from this study provide additional clarification on the natural course of maladaptive behavior in ASDs and have implications for clinicians, parents, and service providers in anticipating change over time and planning interventions.