Gray Matter Volume Alterations Found in Adults With ADHD and Bipolar Disorder

ADHD and bipolar disorder independently led to distinct grey matter volume patterns and showed no common abnormal grey matter volumes.

Altered grey matter volume (GMV) in the frontal-striatal and frontal-parietal circuits is evident in adult patients with attention-deficit/hyperactivity disorder (ADHD) and altered GMV in the prefrontal-amygdala circuit exists in adult patients with bipolar disorder type I (BD-I), according to study findings published in Journal of Psychiatric Research.

Researchers conducted a review and meta-analysis of 4580 potential records from EMBASE, PubMed, Web of Science, and PsycINFO databases from January 2018 to September 2021. They identified 25 whole-brain voxel-based morphometry studies that comprised 677 patients with ADHD (healthy controls, n=566) and 452 patients with BD-I (healthy controls, n=659), respectively. Using anisotropic effect-size signed differential mapping software, these studies compared GMV patterns between ADHD and BD-I, between BD-I and healthy controls, and between ADHD and healthy controls.

Researchers noted in the ADHD studies, there were more men in the patient cohort (61.2% vs 50.4%; P =.05), while mean age was comparable between patients and healthy controls (29.5±10.8 vs 31.0±1.2; P =.12). Mean age and sex were found to be comparable between the 79 patients with ADHD who were medication-naive and the 69 healthy controls (24.2±5.0 vs 26.2±6.6; P =.18; 83.5% vs 75.4%; P =.74).

In the BD-I studies, mean age and sex were comparable (30.6±11.1 vs 32.8±11.3; P =.26; 43.8% vs 50.8%; P =.44). Between 98 patients with BD-I in manic-state and 186 healthy controls there were more women in the patient cohort (51.0% vs 43.5%; P <.01), while mean age was comparable (25.4±6.8 vs 27.1±7.7; P =.99). There were more men in the ADHD cohort for interpatient comparison (P <.01), while mean age was comparable in interpatient comparison (P =.10).

ADHD was closely associated with frontal-striatal and frontal-parietal circuits, and the decreased regional GMVs tended to gradually increase.

Patients with ADHD showed smaller GMV in the anterior cingulate cortex (ACC) and supramarginal gyrus, but a larger caudate nucleus than healthy controls. In the subgroup analysis of the medication-naive group, lower GMV in the right striatum was observed.

Patients with BD-I showed smaller GMV in the orbitofrontal cortex, parahippocampal gyrus, and amygdala than healthy controls. In the subgroup analysis of the patients in manic-state, the researchers found a larger GMV in the right insula.

There were no common GMV alterations between patients with ADHD and patients with BD-I. Patients with ADHD showed smaller ACC and larger amygdala than patients with BD-I.

In subgroup analysis, insula was shown to be in patients with BD-I who were manic and was positively associated with the Young Mania Rating Scale. A positive association was observed with the ages in ADHD with decreased median cingulate cortex (MCC), and a negative association was observed with the ages in BD-I with MCC.

Limitations of the study include use of only cross-sectional data, and nonanalysis of disease course and potential medication effects.

Study authors concluded, “ADHD was closely associated with frontal-striatal and frontal-parietal circuits, and the decreased regional GMVs tended to gradually increase. BD-I was more concerned with the PFC-amygdala emotional circuit, and the abnormality seemed to continuously deteriorate.”

This article originally appeared on Psychiatry Advisor

References:

Xie H, Cao Y, Long X, et al. A comparative study of gray matter volumetric alterations in adults with attention deficit hyperactivity disorder and bipolar disorder type I. J Psychiatr Res. Published online September 24, 2022. doi:10.1016/j.jpsychires.2022.09.015