UK researchers studying a large population of children concluded that many children have a measurable lack of social and communication skills that is not severe enough to meet the clinical criteria for autistic spectrum disorder (ASD), but can nevertheless affect their adjustment and behaviour at school. They also found that unlike boys, girls with above average verbal IQ were less likely to be hampered by such deficits.

The study was the work of Dr David Skuse, professor and head of the Behavioural and Brain Sciences Unit at the Institute of Child Health, University College, London, and colleagues, and is published in the February issue of the Journal of the American Academy of Child & Adolescent Psychiatry.

Research has already established there are a lot more school age children with mild but measurable autistic traits or “social communicative deficits” than there are children clinically diagnosed with autistic spectrum disorder (ASD). But what was not yet clear was how many such children there might be and how possessing such deficits might hamper their development and adjustment.

For the study, Skuse and colleagues asked the parents of over 8,000 children to fill in a Social and Communication Disorders Checklist about their child. The parents and children were already taking part in the Avon Longitudinal Study of Parents and Children. The researchers then compared results from this parent-report checklist with independently diagnosed cases of ASD in the cohort, plus assessments of cognitive ability and teacher ratings of adaptation in the classroom.

The results showed that:

  • Social and Communication Disorders Checklist scores were evenly spread throughout the population: boys had mean scores that were 30 per cent higher than girls (the higher the score, the higher the degree of social communication impairment).
  • Impairment measured on this Checklist was linked with functional impairment at school, and particularly with hyperactivity and conduct disorders.
  • Girls with higher verbal IQ appeared to be protected against such impairment, across the range of abilities, but not boys.

The authors concluded that that measurable deficits in social and communication skills in boys and girls social communicative deficits are significantly linked to behavioural adjustment at school, perhaps to the point of being predictive. Also, the high prevalence of such deficits in the general population emphasized:

“The importance of measuring such traits among clinically referred children who do not meet diagnostic ASD criteria,” wrote the authors.

“Above-average verbal IQ seems to confer protection against social communication impairments in female subjects but not in male subjects,” they added.

According to a BBC report, Skuse told the media that their study did not undermine the impact of severe autism.

“What this does suggest is that drawing a dividing line between those with autism and the rest of the population involves taking an arbitrary decision,” said Skuse, explaining that professionals who work with children should be aware that there are kids who don’t have autism but may have higher levels of autistic traits, and this finding suggests they could be more likely to experience behavioural and development problems.

Washington University Professor John Constantino suggested in an accompanying editorial that autism lay at the severe end of a naturally-distributed spectrum of abilities. Other scientists have also suggested this. Genes for instance, could determine whereabouts on the spectrum we are, with autism at the severe end and “sub-threshold autistic impairments” in the less severe region.

Such an understanding of childhood autism and autistic traits could help teachers and families show “more appropriate and supportive responses than typically occur when antisocial motives are presumed”, wrote Constantino.

“Social Communication Competence and Functional Adaptation in a General Population of Children: Preliminary Evidence for Sex-by-Verbal IQ Differential Risk.”
David Skuse, William Mandy, Colin Steer, et al.
Journal of the American Academy of Child & Adolescent Psychiatry February 2009 – Volume 48 – Issue 2 – pp 128-137.
doi: 10.1097/CHI.0b013e31819176b8

Click here for Abstract.

Sources: Journal abstract, BBC News.

Written by: Catharine Paddock, PhD