I have naturally occurring hyper-charged neurons , but am currently jacked on major drugs to slow my brain down because of frequent minor seizures . I loved my hyper brain. Though the seizures are addicting and I get into them and days of them results in psychosis --a total break from reality.
My current drug cocktail that blocks chemicals in my neural synapses increases my concentration. And, people that pound too much coffee offended get frazzled and perform poorly. But steady small amounts of coffee equals more study time that will rocket a GPA. But better concentration in a super chilled out brain will too.
If I get a build up of drugs in my system, the side effect flip and I get insomnia and have lots of other issues. Also if you research migraine or ADHD drugs, they are nasty on another level. I can't think of a drug that alters the chemistry in the brain that does not have wicked side effects.