The PMHNP is evaluating a 6-year-old boy with suspected ADHD. Which of the following biological findings should she expect to find that might help confirm diagnosis?

Choice A reason: Neuroimaging studies in children with ADHD often show reduced total brain volume, particularly in the prefrontal cortex, basal ganglia, and cerebellum, supporting neurodevelopmental involvement in the disorder. Choice B reason: Slow-wave activity on EEG may be altered in some neurodevelopmental disorders, but decreased slow-wave activity is not a specific marker for ADHD. Choice C reason: Thalamic volume reduction is not consistently associated with ADHD; abnormalities are more commonly observed in cortical and subcortical structures. Choice D reason: ADHD is associated with delayed cortical maturation, particularly in the prefrontal cortex, rather than early posterior-to-anterior cortical maturation.