Three dimensions of oppositionality in autism spectrum disorder.

In autism spectrum disorder (ASD), symptoms of oppositional defiant disorder (ODD) are common but poorly understood. DSM-5 has adopted a tripartite model of ODD, parsing its features into 'angry and irritable symptoms' (AIS), 'argumentative and defiant behavior' (ADB) and 'vindictiveness'. This was based on findings in non-autistic populations that each of these dimensions of oppositionality has a distinct constellation of associations with internalising and externalising psychopathology. We applied the tripartite DSM-5 ODD model to ASD to test its generalisability beyond non-ASD populations; and to elucidate the nature of ODD symptoms in ASD. Participants were 216 verbally-fluent young people (mean age = 9.6 years, range 3.0 to 16.2 years, 82 % male) with ASD. Cross-sectional parent-and teacher-report data were analysed using bootstrap multiple regression to test the following predictions, derived from studies of non-ASD young people: (1) AIS will be the main predictor of internalising problems; (2) ADB will be the main predictor of ADHD symptoms; (3) all ODD traits will independently predict conduct disorder symptoms; (4) vindictiveness will be the main predictor of aggressive conduct problems. Our findings using both parent and teacher data were consistent with the non-ASD ODD literature. AIS were associated with internalising but not externalising problems; ADB and vindictiveness were associated with externalising but not internalising problems; and vindictiveness was the main predictor of aggression. The DSM-5 tripartite model of ODD appears to be generalisable to ASD: for people with an autistic disorder, AIS, ADB and vindictive dimensions of oppositionality have distinct associations with concurrent psychopathology, suggesting the need to assess them as separate constructs.