People change. A change may or may not be the result of mental illness.
I know many people who have changed greatly for the better because of life experiences or their own choices, and many people who have changed for the worse. We all do it to some extent, though maybe not dramatically or publicly.
Exactly. Don't use "mental illness" as an excuse, he's just incredibly arrogant.
But when the same person was extremely professional, kind and helpful, six months before a sudden shift in behaviour?
People change. A change may or may not be the result of mental illness.
I know many people who have changed greatly for the better because of life experiences or their own choices, and many people who have changed for the worse. We all do it to some extent, though maybe not dramatically or publicly.