Is there any evidence that clinicians can reliably detect faking? Anecdotally I know several people who faked learning disabilities and got official diagnoses in order to get accommodations in school.
Those with ADHD will respond positively in the tracked markers when given medication. Those without ADHD will respond worse.
This is coupled by response time markers as well as success rate.
Do a bit of research on ADHD. Maybe look into mortality rates between medicated and unmedicated ADHD. Consider for a moment why stimulants are prescribed for ADHD in the first place, and not for anything else.
If you do the above and still can’t see how a simple test like this is more accurate and scientific than a subjective quiz that can be studied against, then I hate to inform you but you are not as objective a thinker as you might expect you are.