So I have ADD, and I can't tell you if my brain is different or not. But I have exactly zero withdrawal from methylphenidate after years of use. If I don't take it, I simply don't get anything done. I have stopped taking it for several week at one point, and then I start spiraling down to my pre-diagnosis state since I forger to eat and sleep.

I get much less impulsive also, car rental managd my own mood much better. My blood pressure add resting heartrate has also improved since I started with the stimulants. A bit unusual according to my doctors.

YMMV - the medication is crude, but being without is not really an option - it's really nice to start being able to plan, and actually decide what actions to take instead of simply doing whatever feelt good at the time.