The Relationship Between the Core Features of ASD and Maladaptive Behaviours Measured Using the Diagnostic Interview for Social and Communication Disorders

Background: One in four children with ASD are reported to meet diagnostic criteria for Oppositional Defiance Disorder or Conduct Disorder and aggression affects 53% of individuals with ASD.  The Diagnostic Interview for Social & Communication Disorders (DISCO) is a semi-structured diagnostic interview, that focuses on symptoms relevant for an ASD diagnosis (social communication and repetitive, restricted behaviours) and items measuring other behaviours necessary for a broader range of co-morbid conditions such as attention deficit hyperactivity disorder (ADHD), pathological demand avoidance (PDA), Catatonia, Tic disorders,  developmental coordination disorder (DCD) and a range of maladaptive behaviours. 

Objectives: The aims of the current study were to: establish the reliability and factor structure of the maladaptive scale of the DISCO; compare the rates of challenging behaviours in individuals with ASD in comparison to clinical and typically developing controls; and determine the relationship between maladaptive behaviours and core features of ASD.  Additional analyses assessed the correlations between maladaptive behaviours and DISCO defined co-morbid conditions.

Methods: Two UK datasets were used.  Sample 1 - 36 individuals with ASD, 31 clinical comparison controls (18 individuals with an intellectual disability 17 with a language impairment) and 15 typically developing controls.  Sample 2 -200 DISCO interviews of individuals referred to a UK national ASD assessment centre.

Results: The 16 maladaptive behaviour items in the DISCO created a reliable scale (Cronbachs α = .92,), the maladaptive total score was significantly higher in the ASD group than the clinical or typical control groups.  Maladaptive behaviours were significantly predicted by core ASD domain scores as measured using the DISCO. Principal Components Analysis resulted in a two factors solution: behaviours affecting other people (ten items; e.g. behaviour in public places, wanders, lack of co-operation) and communicative disruptive behaviours (six items; e.g. interrupts conversations, talks to strangers).  Scores for both factors significantly differed between the diagnostic groups. Regression analyses revealed the first factor was significantly predicted by social interaction score; the second by both communication and repetitive behaviour scores as well as age.Maladaptive behaviour score was positively associated with the number of co-morbid conditions as identified using the DISCO.  Both maladaptive factors were positively related to PDA, catatonia and ADHD scores, whereas TIC disorder scores were related to “behaviours affecting other people” only and scores for DCD were related with the “communicative disruptive” factor only.

Conclusions: This data support the prevalence of maladaptive behaviours in ASD and identifies sub-groups of these behaviours that have different associations with the core features of ASD.  Individuals with high rates of maladaptive behaviours also appear to have more behaviours associated with co-morbid clinical conditions. The DISCO is a semi-structured interview that provides a framework for collecting parent/carer information on behaviours relevant for a diagnosis of ASD and a much broader range of behaviours required when considering possible co-occurring conditions. This diagnostic tool has potential benefits for clinical and research practice.