Can medical tests reliably determine whether my child has ADHD?

No, ADHD is determined by a clinical diagnosis based on interviews and a child’s personal history from teachers, parents, and others who are involved with the child on a day-to-day basis. Research studies using an electroencephalogram (EEG) to measure brain electrical activity, magnetic resonance imaging (MRI) to assess brain structure, and functional magnetic resonance imaging (fMRI) to measure where things happen in the brain have demonstrated some minor differences between the brains of ADHD children and those without ADHD (Question 9). These differences are found in brain regions we think are important for attention. However, EEG,MRI, and fMRI can not be used to make a diagnosis at this time. The findings are not consistent enough to be useful. Perhaps in the future this will change. In addition, even though research studies suggest neurotransmitter and neuroreceptor differences between children with and without ADHD, no blood tests are available to use to make the diagnosis. Although it is possible that researchers will develop some diagnostic laboratory test that can simplify diagnosis, it is unlikely to happen in the near future. Furthermore, even when we document the gene(s) causing ADHD, having the gene will not necessarily mean having ADHD. The human nervous system is just too complex for a simple onetoone effect. Ultimately, a diagnosis of ADHD relies on the experience and judgment of the physician who examines the child, not medical tests or scans.