3 Different Types Identified in New Study

• A recent study suggests there may be three different biotypes of ADHD.
• The findings suggest that each biotype (subtype) of ADHD may have its own distinct chemical reactions in the brain.
• Experts say that more research is needed, but the study could mark a shift in how ADHD is diagnosed and treated.

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder.

Symptoms of ADHD can vary in severity, and around 6 in 10 children have moderate to severe symptoms.

Current treatment for ADHD is typically categorized by age group. However, it generally involves a combination of medications and behavioral therapies.

A recent study published in JAMA Psychiatry suggests that there may be three distinct subtypes of ADHD.

“This could mark the beginning of the end for one-size-fits-all ADHD treatment,” said Rod Mitchell, a registered psychologist and founder of Emotions Therapy, Calgary, AB, Canada, who was not involved in the study.

“If each biotype involves different neural circuits and neurotransmitter systems, then the standard ‘diagnose, prescribe stimulant, adjust dose’ approach may only be well-suited to one of the three groups,” he told Healthline.

The study looked at the chemical and structural patterns of the brains of 1,154 participants with ADHD.

When they analyzed brain scans and neurochemical signals, they found that ADHD did not affect everyone’s brain activity the same way.

They noticed that three distinctive patterns seemed to emerge.

The three subtypes of ADHD that they found were:

• severe combined with emotional dysregulation
• predominantly hyperactive/impulsive
• predominatly inattentive

“Each biotype tells a distinct neurobiological story,” said Mitchell.

He explained that the predominantly inattentive type showed alterations in a region tied to sustained attention and filtering distraction.

The predominantly hyperactive/impulsive type showed disruption in circuitry that governs impulse braking and action regulation. Both broadly align with what clinicians have observed for years.

“Interestingly, their phenotypes mirror the DSM-5,” said David Goodman, MD, assistant professor of Psychiatry and Behavioral Sciences at the Johns Hopkins University School of Medicine in Baltimore, MD, and a clinical associate professor at the Department of Psychiatry at Norton School of Medicine, State University of New York, Syracuse, NY. Goodman wasn’t involved in the study.

“In some way, these findings support the utility of the DSM-5 when pursuing this research population,” Goodman told Healthline.

The severe-combined type with emotional dysregulation is where this study breaks new ground.

This type showed the most widespread brain alterations, the most persistent emotional dysregulation over time, and preliminary signals of elevated mood disorder comorbidity — all underpinned by involvement across serotonin, dopamine, acetylcholine, and histamine pathways simultaneously, explained Mitchell.

“That neurochemical complexity helps explain why these are often the clients who don’t respond to stimulant medication alone,” Mitchell said.

The researchers note that understanding subtypes of ADHD may, “ultimately create a path toward developing personalised therapeutic strategies.”

“The correlation of neural networks and 3 biotypes in this study supports ongoing research with this concept … until a large, well-controlled clinical study demonstrates the clear benefit of one compound over another for a specific symptom cluster, this current research contributes to the evolution of ADHD neuroscience with guarded clinical applicability,” said Goodman.

Diagnosing ADHD involves several steps. The CDC states that there is no single test to diagnose the condition.

Treatment for ADHD most often involves a combination of behavioral therapy and medications.

This can depend on the age at which a person is diagnosed, however. For example, for children under 6, parent training in behavior management is generally the first line of treatment before medication.

For children ages 6 years and over, treatment generally involves a combination of therapy and medications. Behavior therapy helps the child learn how to reduce certain behaviors and increase self-regulation skills. It also typically involves training for parents.

There are two types of medications for ADHD: stimulant and non-stimulant.

It’s important for parents to work closely with healthcare professionals to find the right treatment for their child.