Many children with oppositional defiant disorder but not autism nevertheless exhibit elevated symptoms of autism spectrum disorder as well as schizophrenia spectrum disorder.

Moreover, children rated by mothers or teachers to have characteristics of anger and irritability associated with their oppositional defiant disorder (ODD) also had more severe symptoms of autism spectrum disorder and schizophrenia spectrum disorder as did children with the noncompliant aspect of ODD, according to a study in the July-August issue of Research in Developmental Disabilities.

“These results provide additional support for the notion that anger/irritability symptoms and noncompliance symptoms represent divergent phenomena in non-ASD clinically referred youth, and extend this observation to ASD (autism spectrum disorder) and SSD (schizophrenia spectrum disorder) symptoms,” wrote the researchers (Res. Dev. Disabil. 2012;33:1157-68).

Dr. Kenneth D. Gadow of Stony Brook University, in Stony Brook, N.Y., and Dr. Deborah A.G. Drabick of Temple University, Philadelphia, looked at 1,160 children between the ages of 6 and 18 years who were consecutive referrals to a university hospital child psychiatry outpatient service. The researchers divided subjects who met the DSM criteria for oppositional defiant disorder into two subtypes: those with an angry/irritable symptomatology and those whose personality was primarily characterized by noncompliance.

Subjects rated as “often” or “very often” losing temper, becoming angry and resentful, or being touchy and easily annoyed by others were placed in the angry/irritable subgroup. The noncompliant subgroup consisted of youths who met ODD criteria, but who had two or fewer angry/irritable criteria. Both groups were compared to similar students without symptoms.

Mothers and teachers of the referred children rated the subject’s autism and schizophrenia symptoms using the Child and Adolescent Symptom Inventory-4R. The responses were summed to create symptom severity scores for autism spectrum disorder (ASD) and schizophrenia spectrum disorder (SSD).

The authors then conducted two separate analyses. The first looked at youth classified as having the angry/irritable subtype based on either a mother’s or a teacher’s report, but not both. These children were compared with noncompliant subtype youths and controls.

Youths in the angry/irritable subtype as well as those in the noncompliant subtype were rated as having more severe ASD and SSD symptoms than did controls. However, especially among younger patients, angry/irritable subtypes scored higher on the ASD and SSD scales as did the oppositional subtype and controls.

Next, the researchers compared youth rated as the angry/irritable subtype by both mothers’ and teachers’ ratings and youth who met the angry/irritable criteria according to just one source, but not the other.

The angry/irritable and noncompliant dichotomy is sometimes referred to as the affective and behavioral aspects of ODD, respectively. These symptom groups may pertain to different types of affect with unique neurobiologic substrates and phylogenetic histories, the researchers said. For example, noncompliance may be more likely to be associated with novelty-seeking and exploratory behaviors.

Regarding the second analysis and its finding that ODD youth may vary based on informer (teacher vs. mother) and environment (school vs. home), the researchers cautioned that “different strategies for defining clinical phenotypes may lead to very different conclusions about similarities and differences between diagnoses and inferences about the magnitude of therapeutic improvement,” they added.

The emotion dysregulation and interpersonal conflicts that define ODD may share similarities with the communication and social skills deficits of ASD and SSD, the researchers said. Social interactions are challenging for these youth, “and thus generate a range of intense emotional reactions. It is also possible that ASD and SSD represent divergent extremes of similar processes. Our expectation that source–specific symptom groups based on teachers’ vs. mothers’ ratings would reveal more pronounced group differentiation was not supported.”

Differences between anger/irritability symptoms and noncompliant symptoms were observed more frequently among mother-defined groups (anger/irritability symptoms exceeded noncompliant symptoms for 7 of 10 comparisons) than among teacher-defined groups (anger/irritability symptoms exceeded noncompliant symptoms for 1 of 10 comparisons).

Dr. Gadow disclosed being a shareholder in Checkmate Plus, the publisher of the Child and Adolescent Symptom Inventory-4R. Dr. Drabick reported having no conflict of interest.