Research defines SEVERE ADHD SUBTYPE; "emotional dysregulation"
- May 8
- 2 min read
The need to re-examine diagnostic criteria for Attention-Deficit/Hyperactivity Disorder (ADHD), which rely on behavioral observation and questionnaires, has been raised. An analysis of structural brain images revealed that the ADHD patient group is distinctly divided into three biological subtypes, and a new 'severe type' accompanied by emotional dysregulation, not previously defined, has been identified. The severe type was found to have nearly twice as many areas of brain abnormality as the other types.
On the 30th of last month (local time), the Washington Post comprehensively reported on a study that biologically classified ADHD subtypes using structural brain imaging, along with expert opinions.
A research team from Sichuan University in China conducted a study to biologically classify ADHD using structural brain images, moving away from diagnostic methods that rely on behavioral observation and surveys. By analyzing magnetic resonance imaging (MRI)-based structural brain image data from 1,154 children and adolescents, the team confirmed that ADHD is divided into three subtypes.
In addition to the existing 'inattentive type' and 'hyperactive-impulsive type,' they newly defined a 'severe type' characterized by difficulties in regulating and responding to emotions. The study's findings were published on February 25th in JAMA Psychiatry, an international journal of the American Medical Association.
The analysis showed that the severe type exhibited more extensive structural brain abnormalities than the other types. It had a total of 45 areas with abnormal patterns, far more than the inattentive and hyperactive-impulsive types (26 areas each). Abnormalities in the brain's connective circuits in the medial prefrontal cortex and pallidum, which are involved in emotion and behavior regulation, were particularly prominent.
The research team argued that the structural differences in the severe type should not be interpreted merely as 'more severe symptoms.' They explain that it is likely a biologically distinct subtype.
ADHD is difficult to diagnose and treat because its symptoms are diverse and often overlap with other disorders. Researchers explain that the diagnostic difficulty increases further when emotional regulation problems are also considered.
The team expressed hope that moving away from behavior-based diagnosis to a biological analysis of ADHD based on structural brain changes could lower diagnostic difficulty and provide personalized treatment for patients. As similar attempts to classify subtypes are ongoing in autism spectrum disorder research, the possibility of a shift in the diagnostic framework for childhood neurodevelopmental disorders as a whole is also being raised. . . .
Most researchers agree that the more ADHD subtypes are refined, the more effective treatment becomes possible. Xavier Castellanos, an adjunct professor of child and adolescent psychiatry at New York University who participated in creating the DSM-5, the diagnostic manual for mental disorders, stated, "A growing body of reliable evidence is accumulating," and predicted that "it could lead to a redefinition of ADHD."
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