Socioeconomic status and intelligence quotient as predictors of psychiatric disorders in children and adolescents with high-functioning autism spectrum disorder and in their siblings.

Rosa et al. (2016) tracked the kids with high-functioning ASD and 147 of their brothers or sisters. They asked two questions: who later gets ADHD, mood, or anxiety disorders, and do family income or IQ scores change those odds?

Doctors gave each child a full IQ test and parents filled out a form about money and schooling. The team then counted new psychiatric diagnoses for up to five years.

Children with ASD had triple the ADHD rate of typical peers. Their siblings also carried double the risk.

Low-income families and kids with IQ scores under 85 added extra danger. For each drop of one IQ band, the odds of a second diagnosis jumped 18 percent.

Jokiranta et al. (2014) saw the same stacking of risk. They showed that epilepsy plus ASD plus ID raises illness rates even higher, pointing to a rule: more cognitive hit, more comorbidity.

Laugeson et al. (2014) helps explain why. In a low-IQ clinic sample, every small gain in general intelligence lifted daily-living skills. Lower skills, shown here again, open the door to extra diagnoses.

Bachrach et al. (2026) carries the idea into school life. Israeli teams place autistic preschoolers by IQ and irritability, not autism severity, echoing Mireia’s warning that cognitive level keeps steering the child’s path.

When you see a low IQ or hear a parent’s money worries, treat those as red flags for ADHD, anxiety, or mood issues in your ASD clients. Screen siblings too—they share the risk. Add brief IQ checks and family-resource questions to your intake, then watch for early signs so you can start behavior plans or refer sooner.