Dimensions of Oppositionality in Autism Spectrum Disorder

Background:

Oppositional Defiant Disorder (ODD) is amongst the most common comorbid conditions amongst children with autism spectrum disorder (ASD) and is a strong predictor of both internalizing and externalizing psychopathology. Recent attempts to understand the multifinality (i.e. range of developmental outcomes) of ODD in the general population of children has suggested that it should be parsed into three distinct ‘irritable’, ‘headstrong’ and ‘hurtful’ dimensions. These dimensions appear to have distinct cross-sectional and longitudinal correlates, such that irritability is associated with internalizing difficulties; whilst headstrong and spiteful behaviors predict conduct disorder.  The value of parsing ODD when assessing and formulating comorbid difficulties in ASD has not previously been examined.

Objectives:

To test whether irritable, headstrong and hurtful symptom domains have distinct patterns of associated psychopathology in a sample of children with ASD. We predicted that the irritable dimension would be most strongly associated with internalizing problems and that headstrong and hurtful dimensions would be most strongly associated with conduct disorder symptoms.

Methods:

Cross-sectional data were examined for 217 (82% males) young people (mean age = 9 years) with a high-functioning ASD. A well-standardised parent-report interview (the 3Di) was used to measure ASD, ODD and conduct disorder symptoms. The strengths and difficulties questionnaire was used to measure internalising difficulties by parent and teacher report.

Results:

Irritable, headstrong and hurtful behavior were not correlated with 3Di measures of autism triadic symptoms (all ps>.29). In a regression model with the three ODD domains as predictors, irritiability (β=.20) and headstrong (β=.24) behavior were significant predictors of conduct disorder symptoms. By contrast, of the three ODD domains, only irritability (β=.27) predicted internalizing problems by parent report. Similarly only irritability (β=.26) predicted teacher report internalizing problems.

Conclusions:

The three domains of oppositionality we investigated are relevant to understanding comorbidity in ASD, and are independent to autistic symptom severity. Irritability appears to be an important construct in this population, and is associated with both internalizing and externalizing psychopathology. By contrast, headstrong behaviours are a specific risk factor for more serious conduct problems in ASD. Clinical assessment of irritable and headstrong behaviours in ASD populations may help identify children most at risk of developing further psychiatric disorders and inform the development of appropriate treatment packages for children with ASD.