Can IQ scores from childhood predict how an individual will be as an adult with autism? Probably, according to research lead by Catherine Lord, lead investigator at the Institute for Brain Development at New York-Presbyterian Hospital. In a 17-year longitudinal study, Lord’s team assessed children with autism. They found that the IQ scores from age two and three are effective for projecting how that child’s future function as an adult on the spectrum. The findings underscore the importance of early interventions and suggest that education and familial involvement can make a difference for later functioning.

The researchers evaluated 85 individuals with autism from North Carolina and Illinois. The initial assessment took place at ages two and three. Subsequent evaluations were conducted at ages nine and 19. The participants completed tasks to measure the severity of their autism-related symptoms and completed a number of IQ assessments in verbal and non-verbal aptitudes. Their families reported on whether they were receiving medication or interventions. After the tests, the researchers grouped the children by IQ: 53 children who had a verbal IQ of 70 or lower were in one group and the 32 children who scored higher than 70 were in the other group.

In general, the scores of the two- and three-year-olds were correlated to abilities in early adulthood. Ninety-one percent of toddlers who had a low verbal IQ and 85% of the two-year-olds assessed with a low verbal and non-verbal IQ, poor adaptive skills, and severe autism-related symptoms exhibited a significant intellectual disability at the age of 19.

Children’s IQ scores were not as predictive for the higher IQ group; there was a 66% accuracy for children assessed at age two and 82% accuracy for children assessed at age three. These children gained an average of 23 points in verbal IQ between ages two and three. In contrast to the majority of the participants, at age 19, eight boys in this group no longer met the diagnostic criteria for autism.

The results emphasize the importance of early intervention for long-term outcomes. This study also indicates that that therapy alone is not enough to improve outcomes; family support and access to quality education are also critical.

This research was published in the Journal of Child Psychology and Psychiatry.

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