epilepsy
"Good points: reduced my seizures and made me feel overall a lot more confident.  If I ever had a seizure, I tended to know when it might occur and my 'trigger' points.   

Bad points:  It made me in some ways over confident, to the point of feeling careless.  Not so much suicidal, but thoughtless and self-indulgent.  I would get angry easily.  I work in a professional place and therefore had to taper down from it, though am still on a low dose."