ABSTRACT
CLASSIFICATION AND diagnosis have been so derided in psychiatry that the subject of our discussion today is almost a shady one. No doubt the shadow under which it lies comes also from the solid difficulties, which are plain when any of the current ways of differentiating between depressions are applied to a series of cases. It is, I think, at all events correct to say that (although a fair amount has been written) no fresh light has been cast on the subject for several years, since it is much easier to show the inadequacy of proposed methods than to substitute for them a useful and valid one. Useful and valid are the two epithets which any classification should deserve. In considering them the opportunities and difficulties can be brought into clearer view.
