Depression: some proposals for future research.

The argument has been advanced that pathological states of anxiety and mania are both characterized by a failure on the part of the patient to attach appropriate levels of significance to changes occurring in the immediate environment. There is, it is suggested, a tendency for environmental features to be regarded as important even though, viewed objectively, they may have little relevance to the patient and his needs. Depression, it is further proposed, may be viewed as an extreme defense reaction to the intense anxiety which results from attaching too much significance to environmental events. In depressive state, patients are often characterised by their lowered responsiveness to stimulation and their lack of interest in, or concern about, their surroundings: it may be that, in such state, information processing has been blocked or reduced. The daytime drowsiness of the depressed patients, as well as his night-time sleep disturbance and the frequently observed recurrent or cyclic nature of certain kinds of depressed state, suggest that this blocking of sensory processing may be brought about by the involuntary intervention of mechanisms responsible, under normal circumstances, for sleep induction. This view of the nature of depression has been recast into the form of five potentially testable hypotheses. Speculation is always easy; providing convincing demonstrations that those speculations are reasonable is less easy. It is in the nature of psychological investigation that laboratory-based studies distort and may even destroy the phenomena about which information is sought, and many a perfectly reasonable theory has foundered upon the rocks of translation into experimental terms. In those areas of psychology which have implications for psychiatry and the conceptualisation of psychopathological states, this danger is particularly evident: psychiatric syndromes are complex, variable, and have social referrents, but laboratory experiments are limited in their capacity to reflect all these attributes, and consequently they may never provide really adequate tests of a theory about a psychiatric state. We have to try to come to terms with this apparent impasse--in the first place by being circumspect in translating psychiatric concepts into experimental terms, and secondly by exercising caution in interpreting the results to which the experiments give rise. More importantly, however, we have to accept the essential inadequacy of the majority of experimental paradigms in psychiatric research and to regard theorizing--even when it is not linked to explicitly testable hypotheses--as having inherent value.