Intellectual functioning at age six predicts internalizing and externalizing problems at age 9 in children with autism.

Title: Level of Intellectual Functioning Predicts Patterns of Associated Symptoms in School-Age Children With Autism Spectrum Disorder
Source: Journal on Mental Retardation. Vol 112(6) Nov 2007, 439-449.
Authors: Estes, Annette Mercer; Dawson, Geraldine; Sterling, Lindsey; Munson, Jeffrey.
University of Washington

A very innovative study from the University of Washington. They examined how intellectual functioning at age 6 predicted internalizing (depression and anxiety) and externalizing (conduct problems, adhd) behavior problems at age 9 in 57 children with autism. It appears that high verbal IQ at age 6 was actually associated with HIGHER levels of depression and anxiety at age 9, but non-verbal IQ was not associated with internalizing problems. However, lower verbal and non-verbal IQ was associated with HIGHER externalizing problems at age 9, specially ADHD. What is surprising about this study is that high verbal IQ was related to elevated levels of depression at age 9. A possible interpretation is that the high verbal intellectual skills of these kids paradoxically leads to a better understanding of their social limitations, specially rejections from peers, which may lead them to experience more anxiety and sadness.