An evaluation of evidence on depressive classification and some alternative suggestions from physiology.

The wealth of material on depressive classification provides both researcher and clinician with a sorting task of monumental proportions. Moreover the criticisms which have been fired at studies of depressive classification using symptoms as a data base, also require systematic sorting and elucidation. An attempt has been made to review the major studies of depressive classification in a systematic way, together with the principal criticisms which have been made of them. The survey is not exhaustive but aims at providing a relatively ordered overview of the area. The most critical issue, that of subjectivity of data collection is taken up, and it is suggested that biological measures may form a more objective data base for studies of depressive classification than ratings of symptoms and behaviour.