Social Communication Competence and Functional Adaptation in a General Population of Children

Background: The incidence of autism seems to be increasing. Population estimates of prevalence may underestimate autistic characteristics of lesser severity, for two main reasons. First, cases are usually ascertained from secondary screening, based on initial selection of children with severe and obvious symptoms. Consequently, mild or moderate deficits in social and communicative competence may be missed, especially if associated with marked comorbidity such as conduct problems and ADHD.  Second, methods of ascertainment are designed to maximise the distinction between valid cases of autism, defined according to conventional criteria, and to exclude conditions that do not quite reach diagnostic significance.

Objectives: The proportion of schoolchildren with mild deficits in social and communicative competence far exceeds the number diagnosed with an autistic spectrum disorder (ASD). We aimed to ascertain both the population distribution of such deficits, and their association with functional adaptation, in middle childhood.

Methods: Parents of children (7-8 years) in ALSPAC, the prospective Avon Longitudinal Study of Parents and Children, completed the Social and Communication Disorders Checklist (SCDC) (n=8094). We correlated severity of impairment with: i) cognitive abilities; ii) independent clinical diagnoses of ASD; iii) teacher ratings of maladaptive behaviour.

Results: SCDC scores were continuously distributed in the general population; boys had mean scores 30% higher than girls. Cases of ASD were predicted with a specificity of 91% and a sensitivity of 88%. Deficits in social and communicative competence were associated with functional impairment at school, especially in domains of ADHD and Conduct Disorders

Conclusions: Social and communicative deficits are of prognostic significance, in terms of behavioural adjustment at school, for both boys and girls. Their high prevalence in the general population emphasises the potential importance of measuring such traits, and evaluating their significance for management, among clinically referred children who do not meet diagnostic criteria for an ASD.