Exploring the Associated Features of ASD

Background:  The Diagnostic Interview for Social & Communication Disorders (DISCO) is a semi-structured diagnostic interview conducted with parents or caregivers that assesses the broad range of symptoms present in individuals with ASD.  It covers all ages and levels of development.  The DISCO allows measurement of both symptoms relevant for a diagnosis (social communication, social interaction and repetitive or restricted behaviours) as well as a number of symptoms that are associated with ASD, using a three scale severity rating (no/minor/marked problem).  Such associated symptoms include sensory atypicalities emotional problems, motor atypicalities and impaired daily living skills (such as feeding, dressing & washing).  

Objectives:  The aim of the current study was to establish the prevalence of associated symptoms in individuals with ASD in comparison to clinical and typically developing controls as well as determine the relationship between associated and core features.  

Methods:  DISCO interviews collected from parents of 200 individuals during clinical diagnosis were analysed.  In addition an ASD sample of 33 (17 High Functioning Autism, 16 Low Functioning Autism) were compared against individuals with a developmental delay (DD;19) or language delay (LD;15) and typically developing (TD;15) individuals in order to assess the uniqueness of these symptoms to the ASD sample. 

Results:  The frequency of associated problems in ASD was high, with 80% of the sample having at least 1 marked motor problem, 86.5% 1 marked impairment in their daily living skills, 92.5% at least 1 marked sensory atypicality and 85% 1 marked emotional problem. Comparisons between groups revealed significant differences in presence of associated symptoms between LD/DD and ASD groups for emotional and sensory atypicalities and between ASD and TD samples for impairments in motor behaviours and daily living skills.  Regression analyses of the larger (n=200) sample were conducted to assess if the associated symptoms were uniquely related to any of the core symptoms of ASD that are required for diagnosis (social interaction, communication & repetitive behaviours).  Specific significant associations were found between sensory processing atypicalities and all of the core features (separate significant associations with social interaction, communication & repetitive behaviours). There were also significant specific associations between social interaction score and emotional problems; and between repetitive behaviours score and impairments in daily living skills.  

Conclusions:  The wider clinical implications highlight the need to screen individuals for associated as well as core ASD features. For example, assessment of emotional problems could provide indication of anxiety and depressive symptoms, which would require independent treatment.  Including measures of associated symptoms will also improve both management and intervention plans for individuals with ASD.  The DISCO already provides such measures as part of a developmental history interview and should be considered in clinical practice for diagnosis as well as research of associated symptoms.