Distinct and similar multimodal brain alterations of function and structure in autism spectrum disorder and obsessive-compulsive disorder.

This large study compared brain scans from people with autism and OCD to typical brains. It found that autism and OCD affect some of the same brain areas (particularly regions involved in social communication and emotional processing) but in different ways. Autism showed decreased brain activity in key areas, while OCD showed increased activity. Both conditions were linked to changes in brain chemicals like serotonin and dopamine.

This helps explain why autism and OCD can sometimes appear similar but are actually different conditions affecting the brain differently.

This comprehensive meta-analysis examined brain function and structure differences in autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD) compared to neurotypical controls. Analyzing 87 studies for functional changes and 114 studies for structural changes, researchers found distinct patterns: ASD showed decreased brain activity in left insula and inferior frontal regions, while OCD showed increased activity in similar areas plus anterior cingulate cortex. Structurally, ASD displayed reduced gray matter in cerebellum, while OCD showed reductions in frontal and cingulate regions. Both conditions shared overlapping changes in left inferior frontal gyrus and insula.

These alterations were associated with multiple neurotransmitter systems including serotonin, dopamine, GABA, and glutamate, suggesting shared biological pathways despite different clinical presentations.

Findings support distinct neurobiological profiles for ASD and OCD despite some overlapping features. This may inform differential diagnosis and suggest that treatments targeting shared neural pathways (like insula and inferior frontal regions) could benefit both conditions. The neurotransmitter associations provide rationale for medication choices and highlight potential targets for future therapeutic development.

Individual study sample sizes not reported. Meta-analysis methodology details not provided in abstract. Cross-sectional nature of included studies limits causal inferences. Potential heterogeneity across studies in diagnostic criteria and neuroimaging protocols not addressed.

Resting-state functional and structural brain alterations in autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD) are commonly reported, thus necessitating a meta-analysis to summarize their shared and distinct alterations. We conducted a whole-brain meta-analysis to identify resting-state regional homogeneity (ReHo) and gray matter volume (GMV) alterations between ASD/OCD and neurotypical control participants (NCs). We included 17 ReHo studies of ASD and 18 ReHo studies of OCD for functional analysis, and 52 studies of ASD and 62 studies of OCD for structural analysis. Overall, ASD individuals demonstrated decreased ReHo mainly in the left insula and inferior frontal gyrus (IFG).

OCD individuals demonstrated increased ReHo mainly in the left IFG, insula, and bilateral anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC). ASD individuals displayed decreased GMV in the left cerebellum, and OCD individuals displayed decreased GMV in the bilateral IFG, insula, and ACC/mPFC. Overlapping analysis revealed that ASD and OCD exhibited convergent ReHo changes in the left IFG and insula. Furthermore, both functional and structural alterations in ASD and OCD were spatially associated with serotonergic, dopaminergic, GABAergic, and glutamatergic neurotransmitter systems in the brain.

The multimodal meta-analysis identified distinct and similar patterns in the functional and structural alterations in ASD and OCD individuals, and found alterations associated with neurotransmitter systems in the brain.