Differences In Symptom Presentation In Children with ASD with and without Co-Morbid Behavior Disorders

Background:  

Up to 65 % of children with autism spectrum disorders have been reported to have co-occurring psychiatric problems (Simonoff et al., 2008).  Less is known about the developmental historical factors, level of intellectual and adaptive behavior functioning, and magnitude of autistic symptoms associated with the presence of co-morbid behavioral disorders in children with autism spectrum disorders. 

Objectives:  

The goal of the present study was to investigate whether children with autistic spectrum disorder with and without co-morbid behavioral problems have different patterns of demographic/developmental histories, levels of intellectual and adaptive behavior functioning, and magnitude of autistic symptoms.  

Methods:  

Participants were 200 children (161 males) who were referred for psychological assessments in order to rule out ASD. Children ranged in age from 48 to 206 months (mean = 81.2, SD = 31.4). Children and their primary caregivers participated in a comprehensive neuropsychological evaluation.  All participants had met DSM-IV TR and ADI-R criteria for an autism spectrum disorder.   Eighty-six (43%) of these children also met DSM-IV TR criteria for a co-morbid behavioral disorder (ASD+BD) as assessed by structured interview.  Demographic/developmental history, diagnostic information (ADI-R), magnitude of autistic symptoms (Social Responsiveness subscales), and magnitude of associated symptoms (CBCL) were also acquired for each child.  Group differences were tested via six separate one-way MANOVAs, one each for demographic/ developmental historical  variables (age, gender, birthweight,  age walked, age of single words, age of phrases), ADI-R domains, intellectual functioning (FSIQ, VCI, PRI), adaptive behavior (VABS-2 subdomains), SRS subdomains, and CBCL subscales (Anxiety/Depression, Somatic Complaints, Attention Problems,  Aggressive Behavior, Affective Problems).   

Results:  

The groups did not differ on age or gender.  Not unexpectedly, the overall test for associated symptoms (CBCL subscales) was significant (F(5, 194)=11.97; p<0.001).  Follow up tests revealed that the ASD+BD group had increased problems on all of the subscales except for Attention Problems.  The only other significant overall test was for magnitude of autistic symptoms (SRS subscales, F(5, 194)=3.65; p=0.007).  Follow up tests revealed that the ASD+BD group had significantly increased scores (increased caregiver-reported symptoms) on the Social Motivation (p=0.029) and Autistic Mannerisms (p<0.001) subscales.  There were no significant between-group differences on any of the developmental variables, intellectual functioning, ADI-R subscales, or adaptive behavior subdomains. 

Conclusions:  

Results revealed few differences between children with an autism spectrum disorder with and without a co-occurring behavior disorder.  Other than increased behavior problems, the latter group was distinguished by the presence of elevated problems in social motivation and increased autistic mannerisms.   Future studies will investigate whether specific behavioral diagnoses (i.e., oppositional defiant disorder) are associated with distinct patterns on neuropsychological and behavioral assessment.