The non-exposed comparison groups (ADHD, CON) were screened for prenatal alcohol exposure and were included only if there was less than minimal exposure (defined as one drink per week on average and never more than two drinks on a single occasion) throughout gestation. In addition to group-specific criteria, all subjects had the following exclusion criteria: non-fluent in English, history of significant head injury or loss of consciousness > 30 minutes, adopted from abroad after age 5 or < 2 years before assessment, evidence of other known causes of mental deficiency (e.g. congenital hypothyroidism, chromosomal abnormalities, neurofibromatosis), or psychiatric or physical disability that prevented study completion.
