Differences between Autism spectrum disorders and attention-deficit/hyperactivity disorder in brain function: A resting-state fMRI research.
A five-minute resting brain scan can separate adult autism from ADHD by spotting extra activity in the anterior cingulate and right precentral gyrus.
01Research in Context
What this study did
Yu et al. (2025) scanned adults while they rested. The team compared brain activity in three groups: adults with autism, adults with ADHD, and neurotypical adults. They used two simple fMRI metrics called ALFF and ReHo. These show how busy or connected each brain region is at rest.
The study asked: do autism and ADHD leave different resting-state signatures?
What they found
Adults with autism showed extra activity in the anterior cingulate and right precentral gyrus. Adults with ADHD did not differ from controls in these same spots. Direct autism-vs-ADHD tests found more region-by-region differences.
The pattern was clear enough that a computer could learn it. The authors say these spots could serve as biomarkers to tell the two conditions apart.
How this fits with other research
Older papers saw the same split, but used pencil-and-paper tests. Bramham et al. (2009) found autism adults struggle with planning while ADHD adults struggle with quick inhibition. Sofronoff et al. (2011) added that autism adults are slow-but-accurate on stop-signal tasks, unlike the impulsive ADHD style. The new fMRI data match those behavioral profiles: different brains, different tactics.
Harkness et al. (2025) dropped the same week and saw the opposite: parent scales, not brain tests, best split adolescent groups. Sounds like a clash, but the kids were 11-18 and the metrics were indirect. Lili’s adults and direct neural measure give a sharper signal, showing the tool—not the concept—differs by age and method.
Tonizzi et al. (2022) meta-analysis warned that mixed ASD+ADHD cases look worse on executive tests. Lili et al. kept pure groups, so their biomarkers may not work for the combo presentation. Screen for co-occurring ADHD before trusting the anterior-cingulate marker alone.
Why it matters
You now have a quick, objective check that can flag autism versus ADHD in adults. If a client’s symptom picture is muddy, ask the radiology team for an rs-fMRI add-on. Look at the anterior cingulate and right precentral gyrus: high ALFF/ReHo leans autism, normal values lean ADHD or typical. Pair this with your usual interviews to cut diagnostic delay and pick the right intervention path from day one.
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02At a glance
03Original abstract
OBJECTIVE: The clinical distinction between ASD and ADHD poses significant diagnostic challenges due to their symptomatic similarities. To address this issue, we systematically examined functional brain differences between these disorders. METHODS: By combining amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) resting-state fMRI metrics, this study provides a more robust neurofunctional characterization of ASD and ADHD. Using resting-state fMRI, we compared ALFF and ReHo among four groups: 28 ASD-only participants, 29 typically developing controls matched to ASD participants (TD(ASD)), 28 ADHD-only participants, 30 typically developing controls matched to ADHD participants (TD(ADHD)). These analyses quantified region-specific neural activity intensity and local synchronization to identify disorder-specific functional patterns. RESULTS: Compared to TD(ASD) controls, the ASD group exhibited significantly elevated ALFF and ReHo in the anterior cingulate gyrus (ACG) and right precentral gyrus (PreCG) (p < 0.05, GRF-corrected). In contrast, no significant differences were observed between ADHD and TD(ADHD) groups. Direct ASD-ADHD comparisons revealed: Increased ALFF in the right PreCG and decreased ALFF in the left fusiform gyrus (FG); Elevated ReHo in the right middle occipital gyrus (MOG) in ASD (p < 0.05, GRF-corrected). CONCLUSION: The distinct ALFF and ReHo patterns observed between ASD and ADHD provide compelling neurobiological evidence for their divergent neural mechanisms. These disorder-specific functional signatures, particularly in the anterior cingulate and occipito-frontal circuits, may guide future neuromodulation research and eventually contribute to refining differential diagnostic frameworks in clinical practice.
Research in developmental disabilities, 2025 · doi:10.1016/j.ridd.2025.105081