Researchers followed a group of girls from childhood into young adulthood to see if early thinking skills predicted later life outcomes. The group was 228 girls. Of these, 140 had carefully diagnosed childhood ADHD and 88 were matched comparison girls. They were ethnically and economically diverse. The girls were 6 to 12 years old at the start (average about 9.6 years), when their executive function was tested. Almost all of them stayed in the study, with 216 of 228 (95%) followed up about 10 years later at ages 17 to 23.
Two childhood measures stood out. One was a broad measure of executive function, based on copying a complex figure. The other was working memory, tested by repeating numbers backward. Both predicted young adult school achievement and employment, even after accounting for IQ and whether a girl had an ADHD diagnosis. The broad executive function measure, but not working memory, also predicted later school suspensions or expulsions.
The links were generally small to medium in size, with correlations around 0.1 to 0.3. Having an ADHD diagnosis mattered for only two of the links. Those two held in the ADHD group but not in the comparison group. This was an observational study, so other factors cannot be ruled out.
Source: Miller M, Nevado-Montenegro A, Hinshaw S. Childhood Executive Function Continues to Predict Outcomes in Young Adult Females with and Without Childhood-Diagnosed ADHD. Journal of Abnormal Child Psychology (2011). doi:10.1007/s10802-011-9599-y