AHRQ

ADHD diagnosis: Value of biomarkers, MRI, EEGs, and certain other tests remain unclear

July 24, 2025

Key points from AHRQ's systematic review of evidence on diagnosis of attention deficit hyperactivity disorder (ADHD) in children and adolescents:

• Multiple approaches showed promising diagnostic performance (e.g., using parental rating scales), but estimates of performance varied considerably across studies, and the strength of evidence was generally low.
• Diagnostic test performance likely depends on whether youth with attention deficit hyperactivity disorder are being differentiated from typically developing children or from clinically referred children who had some kind of mental health or behavioral problem.
• Rating scales for parent, teacher, or self-assessment as a diagnostic tool for ADHD have high internal consistency but poor to moderate reliability between raters, indicating that obtaining ratings from multiple informants (the youth, both parents, and teachers) may be valuable to inform clinical judgment.
• Studies evaluating neuropsychological tests of executive functioning (e.g., Continuous Performance Test) used study-specific combinations of individual cognitive measures, making it difficult to compare performance across studies.
• Diagnostic performance of biomarkers, EEG, and MRI scans show great variability across studies, and their ability to aid clinical diagnosis for ADHD remains unclear. Studies have rarely assessed test-retest reliability, no findings have been replicated prospectively using the same measure in independent samples, and real-world effectiveness studies of diagnostic performance have not been conducted.
• Very few studies have assessed performance of diagnostic tools for ADHD in children under the age of seven years, and more research is needed.
• The identified diagnostic studies did not assess the adverse effects of being labeled correctly or incorrectly as having a diagnosis of ADHD.

Source:

Systematic Review: ADHD Diagnosis and Treatment in Children and Adolescents. Content last reviewed November 2024. Effective Health Care Program, Agency for Healthcare Research and Quality, Rockville, MD. https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research