A study published in JAMA Psychiatry analyzed brain scans and neurochemical signals from 1,154 people with attention deficit hyperactivity disorder (ADHD) and found evidence for three distinct biological subtypes, or biotypes, of the condition. The investigators report that ADHD does not affect everyone’s brain activity the same way; each biotype shows different patterns of structural and chemical brain alterations.
The three biotypes identified are:
– Severe combined with emotional dysregulation
– Predominantly hyperactive/impulsive
– Predominantly inattentive
Key brain and neurochemical findings
– The predominantly inattentive biotype showed alterations in regions involved in sustaining attention and filtering distractions, consistent with difficulties in focus and task persistence.
– The hyperactive/impulsive biotype showed disruption in circuits that support impulse control and action regulation, aligning with behavioral issues such as impulsivity and motor restlessness.
– The severe combined biotype with emotional dysregulation showed the most widespread brain changes, persistent emotional dysregulation over time, and preliminary signals of higher rates of mood disorder comorbidity. Neurochemically, this group appeared to involve multiple neurotransmitter systems at once — including serotonin, dopamine, acetylcholine, and histamine — which could help explain why some people with ADHD do not respond well to stimulant medication alone.
Clinical implications and caution
Experts not involved in the study say the findings are promising for moving ADHD care away from a one-size-fits-all approach. If distinct neural circuits and neurotransmitter systems underlie different biotypes, treatments targeted to those biological patterns might be more effective than current practice, which often begins with diagnosing ADHD and adjusting stimulant doses.
However, researchers and clinicians stress that these results are an important step rather than a final answer. The study shows correlational links between neural networks and symptom clusters; large, well-controlled clinical trials will be necessary to prove that particular treatments or drugs benefit specific biotypes or symptom profiles.
Practical notes about diagnosis and current treatment
– There is no single test for ADHD. Diagnosis typically involves clinical interviews, symptom rating scales, and gathering information from caregivers, teachers, or others.
– Treatment commonly combines behavioral therapies and medication and varies by age. For children under 6, parent training in behavior management is the usual first-line option before medication. For children aged 6 and older, best practice often includes behavioral therapy plus medication when appropriate.
– Behavioral therapies focus on building self-regulation and coping skills and frequently include parent training and school-based supports. Medications include stimulant and non-stimulant options; families and clinicians weigh benefits, side effects, and functional needs when choosing therapy.
Bottom line
The JAMA Psychiatry study adds biological evidence that ADHD is heterogeneous and may consist of multiple neurobiological subtypes. That raises the possibility of more personalized treatment strategies in the future, but translating these findings into specific clinical recommendations will require further research and controlled treatment trials.
