supposedly you get stimmed out of your head
I can't speak for anyone elses experience.
I'm not sure I buy the whole...if you have add you get more focused, but if you don't it will eff you up line of thinking and its just a heavy stim.
when I first started ritalin I was very comfortably focused and was thrilled I seemed to see ..idk what, something I was greatly lacking, then very quickly got steadily more disjointed and unable to do really anything...upping the dose worked until it didn't. Then I switched to adderall which was a disaster right off the bat. I'm not even sure why I took it again.
I tried switching back to ritalin and it never really worked for me ever again for more than an hr.
an hr of focus seemed like a shitty trade off.