Personal Opinion: Philosophy is about truth and logic. Psychology is a study of the human mind but the only tool we have to do that is the same human mind. It is questionable as to how much truth we can garner out of studying ourselves.
I think philosophy has a lot to do with how much signifigance we put on psychology. Psychology is an art but if, the "truth will set you free," psychology has a long way to go before it gains the moral authority to call itself a science.