Greetings,
Despite what others may possess, one can succeed at anything he/she truly puts his/her positive effort towards. Yes, one may not ever be professionaly ranked as high as others, due to certain disablilities, though, if a trophy/medal(so to speak) is all one is truly after when trying to succeed, especially when it comes to a profession that was created to help the unfortunate, such as many who are mentally ill, then he/she will never truly be successful. In my own personal opinion, of course.
Have a good one.