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Date of Award

1-1-2026

Document Type

Dissertation - NSU Access Only

Degree Name

Doctor of Psychology (PsyD)

First Advisor

Charles Golden

Keywords

Attention deficit hyperactivity disorder; Cerebral blood flow; SPECT

Abstract

Globally, ADHD affects approximately 5% of children, making it the most common mental disorder among this age group (Polanczyk et al., 2007). Moreover, about two-thirds of these children continue to exhibit ADHD symptoms into adulthood (Faraone et al., 2006). Despite the widespread use of neuropsychological assessments for diagnosing ADHD, the role of neuroimaging remains contentious, with limited research comparing ADHD manifestations in children and adults through brain imaging techniques. This study aimed to address this gap by investigating average resting cerebral blood flow (rCBF) levels in children and adults with ADHD using single-photon emission computed tomography (SPECT). The present study measured rCBF across both hemispheres and multiple brain regions, including the cerebellum, frontal lobe, occipital lobe, parietal lobe, temporal lobe, and vermis, to identify potential differences and similarities in ADHD presentation across different age groups. Multiple regression analyses tested five hypotheses: (1) the relationship between age and rCBF; (2) age and symptom severity; (3) the moderating effect of symptom severity on age-based rCBF differences; (4) age and hemisphere-based rCBF discrepancies; and (5) the ability of rCBF to distinguish children from adults, using principal component and discriminant analyses. Alpha levels for all analyses were 0.05 and effect sizes were measured with partial eta squared. Results supported Hypotheses I, II, and V. Younger individuals with ADHD exhibited significantly higher rCBF levels across most brain regions compared to older individuals, with the exception of the right frontal lobe and vermis. Age also significantly predicted symptom severity, accounting for 38.6% of the variance. However, Hypotheses III and IV were not supported; symptom severity did not moderate the relationship between age and rCBF, and age did not predict hemisphere-specific rCBF discrepancies. Finally, rCBF patterns significantly discriminated between children and adults with ADHD, with a discriminant function correctly classifying 76.2% of cases and demonstrating strong generalizability. The present findings highlight age-related neurobiological differences in ADHD and suggest that resting cerebral blood flow may serve as a meaningful marker for developmental variation in symptom presentation.

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