Date of Award


Document Type

Open Access Dissertation


Health Promotion, Education and Behavior

First Advisor

Ken W. Watkins


Introduction. Despite a substantial prevalence of subthreshold Attention-Deficit/Hyperactivity Disorder (ADHD) and research indicating that many youth with this disorder have impaired functioning and negative outcomes, few studies have considered patterns of symptom and functioning change for youth with probable ADHD, subthreshold ADHD and youth without ADHD transitioning from childhood to adolescence. Additionally, we are not aware of any studies examining predictors of impairment severity among youth with subthreshold ADHD, and few studies have examined predictors of treatment utilization and patterns of symptom and functioning change based on medication status for youth with subthreshold ADHD compared to youth with ADHD. Methods. This study utilized data from the South Carolina Project to Learn about ADHD in Youth (SCPLAY). After a two-phase screening, a sample of children at high and low risk (frequency-matched on gender) of ADHD and parents/caregivers were invited for interviews. The Jacobson & Traux reliable change index (RCI) and chi-square tests were used to examine patterns of (ADHD) symptom and functional impairment change and logistic regression methods were used to identify predictors of impairment severity and medication use. Results. At baseline interview, children were identified who met symptom criteria for subthreshold ADHD (N=84), probable ADHD (186), and probable non-ADHD (n=211) and patterns of change in symptoms and functioning were examined at follow-up (starting three years later) (n=292). Subthreshold ADHD symptoms were seen in as many as 17% (N = 84) of the youth studied at baseline. Youth (both non-ADHD and subthreshold ADHD at baseline) who achieved probable ADHD status at follow-up are more likely to show impaired functioning than individuals achieving subthreshold ADHD or non-ADHD status. Thirty three percent of youth who were subthreshold at baseline remained in that category at follow-up and 12%-21% showed significant decline in at least one domain of functioning. Youth who were subthreshold ADHD at baseline who were subthreshold at follow-up and taking medication (year prior to follow-up) declined in four of the five domains of functioning and youth who were subthreshold ADHD at baseline and probable ADHD at follow-up (and medicated the year prior to follow-up) declined in three out of five domains of functioning. Change in functioning, both improved functioning and worsened functioning, often occurred when there was no reliable or significant change in symptoms. In multivariable analyses, severe impairment was significantly predicted by psychiatric comorbidity among probable ADHD cases, being male among subthreshold ADHD, and primary parent psychiatric history and medication use among individuals without ADHD at follow-up. Use of ADHD medication the year prior to follow-up was significantly predicted by parent perceived burden in the subthreshold ADHD model and female gender in the probable ADHD model. Conclusions. The findings show the importance of examining both symptom and functioning constructs in the consideration of their unique contributions to ADHD and subthreshold ADHD diagnoses and of acknowledging the need to examine nuanced changes in diagnostic status during development. These findings may be relevant to efforts to intervene earlier in childhood and to help identify high-risk individuals who may be good candidates for targeted interventions.