Shifting Paradigms: Solid Ground?

Another quotation from Charles Barber, lecturer in psychiatry at Yale: 

Sea changes such as the advent of biopsychiatry are not unusual in the history of American psychiatry.  In fact, they have been common.  One paradigm replaces another, and each one is embraced with certainty and passion.  Only in hindsight are the revolutions questioned and discredited.

With this in view, how much stock should one put in the present state of affairs in the world of psychiatry or psychology?  Just wait a little while, and with equal passion a new theory or model will be shoved down your throat as unquestioned scientific fact.