Neuropsychological Test Performance and Other Predictors of Adult Outcome in a Prospective Follow-Up Study of Children with ADHD

The present research is a prospective follow-up study which investigates the neuropsychological test performance of children with Attention Deficit/Hyperactivity Disorder (ADHD) and examines whether test performance and severity of childhood disruptive behaviors predict adult psychiatric status and functioning in major domains (educational, social, and occupational). Participants were 100 middle-class, White boys (mean age = 9) of average intelligence diagnosed with ADHD without comorbid conduct disorder (CD) diagnoses. Childhood predictors were teacher behavioral ratings and performance on a variety of neuropsychological tests. Participants were later assessed at mean age 25 by clinicians blind to childhood status. Linear and logistic regression analyses were used to determine the impact of childhood predictor variables on adult outcome. Results showed no significant impairment on measures of neuropsychological functioning, nor was neuropsychological test performance generally correlated with severity of disruptive behaviors. ADHD boys with low ratings of conduct disorder behaviors (not at all, just a little) demonstrated lower verbal ability than those without CD behaviors. Severity of childhood CD behaviors emerged as the most consistent predictor of adult functioning and prevalence of psychiatric disorders. Measures of working memory and attention (Working Memory Index and Freedom from Distractibility Factor of the WISC-R) inconsistently predicted functioning in some areas, although this may reflect the well-known relationship between childhood IQ and later adult functioning. Taken together, the findings suggest that in boys with ADHD who are of average intelligence and have intact neuropsychological functioning, even low levels of CD behaviors are associated with poor prognosis in adulthood.