Diagnoses have increased in both children and adults, but medication does not work for everyone. Scientists have been trying to understand why.
A new study, based on neuroimaging data, suggests that Hyperactivity Disorder and Attention Deficit Disorder (ADHD) may not be a single, homogeneous condition, but rather a set of at least three distinct subtypeswith different clinical and neurological profiles.
The authors of the research, in JAMA Psychiatry, argue that this new differentiation can pave the way for more personalized support and treatment strategies focused on the needs of each patient.
ADHD is a form of neurodivergence whose diagnosis has increased worldwide, both in children and adults, largely thanks to greater public and scientific awareness. But debate has also grown over whether current diagnostic criteria can capture the full diversity of manifestations of the condition.
There is, for example, a historical discrepancy between diagnoses in boys and girls: for decades, ADHD was associated mainly with school-age boys, and early signs in girls were more easily ignored, in part because they tended to be classified as “inattentive” rather than “disturbed”.
In this new work, researchers led by a team from West China Hospital, Sichuan University, analyzed data from hundreds of children with and without a diagnosis of ADHD. The team started with an initial group of 446 children with ADHD and 708 without a diagnosis. Validated the results in a second group with 554 children with ADHD and 123 controls.
From this analysis, they identified “three biotypes” with specific patterns of changes in brain structures and networks, associated with different symptom profiles.
The three subtypes include a profile “severe-combined” with emotional dysregulationa profile predominantly hyperactive/impulsive and a profile predominantly inattentive.
Hyperactivity/impulsivity can translate, for example, into restlessness, talking excessively, interrupting frequently or motor agitation. Inattention can manifest itself through forgetfulness, difficulty maintaining focus, losing important objects (such as cell phones or glasses) and less tolerance for prolonged tasks.
According to , the study authors recognize, however, that many participants were taking or had taken medication for ADHD. Although they consider a determining impact on neuroimaging results unlikely, they admit that it is not possible to completely exclude this influence.
Currently, the most common treatments include stimulants such as methylphenidate (known, for example, by the brand name Ritalin), which is effective for some people but not all, which is what also motivated the new research.
