I know this is kind of an obvious follow up to your comment, but, have you been tested for ADHD? You described exactly how my brain reacts to mixed amphetamine salts (AKA Adderall). Caffeine doesn’t really do much for me, either, incidentally.
I was diagnosed last year and the psychiatrist I was seeing worked at a clinic that primarily sees inner city patients with much different health profiles than a mild mannered engineer. This is one of my favourite exchanges from the intake meeting:
“So, the first time you tried cocaine, were you surprised that you didn’t react the way everyone else did? Did it calm you down instead of getting you keyed up?”
“I’ve never done cocaine”
“Look, yes, some doctors might disqualify you for stimulant prescriptions for admitting to past substance abuse, but it doesn’t bother me at all. I actually do some research at $local_university specifically looking at how properly managed ADHD dramatically reduces the chance of substance abuse.”
“Serious, I’ve smoked pot, I’ve done mushrooms, but I’ve never tried coke. Had lots of opportunities if I wanted to, but it didn’t appeal to me”
“Huh! With lots of the patients that come through here, they see me for the first time after casually mentioning to a GP that they’re worried they’re weird when coke doesn’t work right for them!”
I was diagnosed twice, both times in adulthood. The first time was by a neuropsychologist who did something like 8-10 hours of testing over about 3 days. I’m not even sure if she ever asked me about any sort of drug use.
The second person to diagnose me was a physician at the student health center where I was a graduate student. Believe it or not, he was actually a pediatrician! I think he may have asked me about my caffeine consumption (excessive!), while also being impressed by my shockingly normal blood pressure (almost always between 110/70 and 125/83). I actually think going on Adderall might have lowered my BP overall, due to the increased ability it gave ume to tolerate and problem solve my way through stressful situations.