AbstractProgress in biological psychiatry is contingent upon progress in neurobiology and progress in research of proper characterization and assessment of abnormal behavior. Advances in neurobiology are rapid and steady; however, advances are few and far between in psychopathology. In many ways, developments over the past two decades run counter to what I believe to be diagnostic pre-requisites for fruitful biological research in psychiatry. I presume this to be a major reason why thus far biology has made no significant contributions to the diagnoses of mental disorders.For progress to occur in biological psychiatry, the traditional diagnostic philosophies and attitudes must be reevaluated and alternative diagnostic approaches put into practice. This and the diagnostic method of functional psychopathology are reviewed in this article, with a focus on how the functional psychopathological approach could contribute to the advancement of the diagnostic process in psychiatry, and the opportunities it provides for biological psychiatric research.