Screening for autism spectrum disorders (ASDs) at three years of age only identifies those with significant developmental delay and does not benefit those with less severe autism. The finding, from analysis of data from the Norwegian Mother, Father and Child Cohort Study, conflicts with previous theories.
The study measured the sensitivity and specificity of the 40-item Social Communication Questionnaire (SCQ) to screen for ASD at 36 months.
It found that among the children of 58,520 mothers, the distribution of SCQ scores in those with ASD and other children had large degrees of overlap. With the cut-off of 15 recommended in the SCQ manual, screening sensitivity was 20 per cent for ASD overall.
For children with ASD who had not developed phrase speech at 36 months, sensitivity was 46 per cent, whereas it was just 13 per cent for children with ASD with phrase speech. Screening specificity was 99 per cent.
With the currently recommended cut-off of 11, sensitivity increased to 42 per cent for ASD overall, 69 per cent for ASD without phrase speech and 34 per cent for ASD with phrase speech. Specificity was 89 per cent.
Writing in BJPsych Open , the authors concluded that available evidence does not support universal early screening programmes for ASD.