This sounds similar to a close relative of mine who, over the course of a few months, became more and more manic (as in, actual, diagnosed manic-depressive diso

This sounds similar to a close relative of mine who, over the course of a few months, became more and more manic (as in, actual, diagnosed manic-depressive disorder). Eventually it was blindingly obvious to everyone who knew him that he was not at all in his right mind. Lost his job, wife, house, and came close to being homeless. As you mention, in hindsight there were definitely signs, just not nearly as obvious.