I have a long history of suffering from Major Depression, which I fully disclosed at my appointments and testing leading up to the prescription, because I do take medication for depression
and have for a number of years. Well, not even 3 days into taking
Ritalin (I recall it was a smallish dose) and I went full blown, off the charts Manic. It is rare, but some people have a pre-disposition to bipolar disorder/manic depression, and somehow the Ritalin triggered this in me.