ADHD

Functional MRI studies have found clear similarities between ADHD and autism. Both go back to differences in signal processing in the brain.

Overlap

• Dual diagnoses (autism + ADHD) are common.
• This makes sense: ADHD focuses on problems with attention regulation and concentration.
• People with ADHD are more easily distracted by additional stimuli, while in autism the context processing itself is less integrated.

Diagnosis preference

In practice, it appears that the diagnosis of "ADHD" is sometimes more easily accepted than "autism".

• ADHD is more often seen as something temporary or treatable.
• Autism, on the other hand, sounds heavier and more permanent.

However, both are variants in signal processing, which in some cases overlap considerably. The classification says little about the unique person and his/her concrete strengths or vulnerabilities.

Note: This again shows the limitation of the DSM classifications. The label someone is given can depend on interpretation or even preference, while the underlying neurocognitive mechanisms largely overlap.