MRI findings detail distinct ADHD subtypes
New MRI findings offer objective evidence supporting the theory that the effects of attention deficit hyperactivity disorder (ADHD) on the brain vary widely between individuals.
As it stands, children with ADHD are categorized into three clinical presentations: predominantly inattentive, predominantly hyperactive/impulsive and combined. However, a recent paper in General Psychiatry suggests that these categories may not fully explain the entire spectrum of ADHD-related behaviors. In it, experts use structural MR imaging to analyze how brain structure varies among individuals who have the same ADHD diagnosis but different behavioral symptoms.
Findings from the study provide new insight into the heterogeneity of the disorder, which could help explain why some children seem to respond better to common treatments than others. Experts involved in the analysis suggested their findings could be used to inform more effective management.
“This study revealed structural heterogeneity in ADHD with distinct causal patterns that may underlie different behavioral aspects of the disorder, emphasizing the need for subtype-specific diagnostic and therapeutic strategies,” Weizhao Lu, with the Second Affiliated Hospital of Shandong First Medical University, in China, and colleagues noted.
For their work, the group compared brain imaging from young people with an ADHD diagnosis to the scans of a neurotypical cohort. Paying close attention to gray matter volume—an important measure indicative of neurodevelopment—the team analyzed how variations in brain structure related to participants’ reported symptoms. ADHD subtypes were identified based on GMV using a clustering algorithm to address neuroanatomical heterogeneity.
This revealed two neuroanatomical subtypes based on imaging that differed from the scans of the neurotypical controls. The first subtype was linked to inattentiveness; this presented in the form of increased gray matter volume in the frontal cortex and cerebellum. Subtype 2 was associated with greater disease severity and showed reduced gray matter volume primarily in the cerebellum and hippocampus. This subtype was consistent with multiple symptoms, rather than inattentiveness alone.
“These findings reveal structural heterogeneity in ADHD, suggesting distinct causal patterns linked to different behavioral domains and emphasizing the need for subtype-specific interventions tailored to their specific neural mechanisms,” the group wrote. “Translating these findings into clinical practice could offer tentative but targeted guidance for future clinical strategies.”
Read more from the study here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.