Repetitive Behaviors in Autism Spectrum Disorder: Associations with Internalizing Symptoms
Objectives: The goal of the current study was to examine potential behavioral markers of depression and anxiety in terms of RRBs. We hypothesized that youth with clinically significant depressive and anxiety symptoms would be demonstrate greater RRBs relative to youth with sub-clinical levels of internalizing symptoms.
Methods: Participants included children ages three to seventeen years (M = 7.25, SD = 3.85). The children and adolescents were predominantly male (82.46%) and Caucasian (87.72%). Parents completed a series of measures including the Child Behavior Checklist (CBCL; Achenbach, 1991) and Repetitive Behavior Scale-Revised (RBS-R; Bodfish, Symons, & Lewis, 1999). The affective and anxiety subscales of the CBCL and all subscales of the RBS-R were used for the current analyses.
The institutional review board for human subject research approved the larger study (i.e. assessment database). Two Multivariate Analysis of Variances (MANOVA) were conducted to examine group status (i.e., ASD+/-Depression and ASD+/-Anxiety) as the independent variable and the six RBS-R sub-scale scores as dependent variables.
Results: The multivariate results demonstrated significant findings for group status comparing ASD+D to ASD-D as well as ASD+A to ASD-A. For comparisons in co-morbid depression, Univariate F-tests indicated a significant difference between the groups for Self-Injurious Behavior, F(1,43) = 19.56, p =.001, Compulsive Behavior, F(1,43) = 9.71, p =.003, and Sameness Behavior, F(1,43) = 5.91, p = .02. Additionally, for anxiety groups, significant difference between the ASD plus high anxiety and ASD low anxiety groups for Self-Injurious Behavior, F(1,43) =8.7, p = .01, Compulsive Behavior, F(1,43) = 16.43, p < .01, Ritualistic Behavior F(1,43) = 8.79, p = .01, and Sameness Behavior, F(1,43) = 12.88, p < .01.
Conclusions: The presence of clinically elevated levels of co-occurring depression and anxiety in youth with ASD, when compared to individuals with ASD and sub-clinical internalizing symptoms, reveals significant differences in parent report of observable core ASD symptomology. It is unclear, however, whether depression and anxiety lead to increases in RRBs or more severe ASD symptomology leads to increased anxiety and depression.