Isolation and characterization of a nuclear depressive syndrome

We investigated the nosology of endogenous depression by numerical taxonomy. Five hundred and sixty-nine patients diagnosed as having unipolar major depressive disorder in the NIMH Clinical Research Branch Program on the Psychobiology of Depression-Clinical were studied. Thirty-six symptoms which might distinguish endogenous from non-endogenous depressions were chosen from the literature. Patients' symptom profiles assessed by structured interview were grouped by two methods: a K-means improvement of Ward's method of cluster analysis, and a latent class algorithm. The methods produced very similar groups and several internal validity criteria suggested that the groups were not spurious. Cluster 1, 'nuclear depression,' included a nucleus of patients common to multiple definitions of endogenous depression. The non-nuclear group scored as less neurotic than the nuclear group on personality tests administered during the index episode. The groups do not differ in frequency, number or severity of reported life events prior to onset of the index episode. The nuclear group shows a poor prognosis on two-year prospective follow-up, greater disturbance on personality inventories, and increased heritability of depression in siblings.

The concepts of mild depression

The term 'depression' is now used to cover a wider range of emotional disturbances than was the case when psychiatrists confined their attention to patients referred to psychiatric hospitals. There is considerable confusion about the variety of meanings and the loose terminology leads to claims and counter-claims about aetiology and treatment. The current classificatory systems and the variety of rating scales do not clarify issues concerning appropriate management. The guidelines for a clearer definition of a biogenic form of the concept of depression, which is likely to respond to antidepressant drug therapy, would be of considerable value to psychiatrists, non-psychiatric physicians and others who try to treat or help people in states of disordered emotion. Such guidelines are proposed.

An American validation study of the Newcastle diagnostic scale. I. Relationship with the dexamethasone suppression test

The Newcastle diagnostic index was completed on 159 depressed in-patients, who received the dexamethasone suppression test during their first week in hospital. Patients suffering from endogenous depression had a significantly higher rate of DST non-suppression, were older, were more frequently psychotic, and more frequently lost weight; even after controlling for these variables, DST non-suppression was significantly more frequent in the endogenous group. The relationship between Newcastle scores and the frequency of DST non-suppression was non-linear.

Bimodality and the nature of depression

Arguments concerning the nature of depressive disorders have involved as a central issue the question of the bimodality or otherwise of the distribution of some variable expressing variation in symptomatology. The implications of a particular type of frequency distribution along this dimension, whether uni- or bi-modal, have been misunderstood by a number of workers, and an attempt is made to clarify the situation.

Classification of depressive states

A uniform classification of depressive states is still far from being complete and generally accepted, although improved and expanding treatment modalities today require valid homogeneous groupings more urgently than ever before. Semantic clarification is needed regarding many terms, for instance that of psychotic depression which is used by many as being synonymous with endogenous. Many attempts of establishing solid categories of depression by sophisticated statistical analysis have failed to yield definitive results, although several independent studies of this kind have produced suggestive evidence for the existence of a type of depression that may be equated with the classic endogenous depression. However, most efforts to demonstrate a clear bimodal distribution of depressive states and establish a category of neurotic depression have failed. These difficulties have prompted such compromise diagnostic labels as endoreactive or endogenomorphous. Genetic research has contributed to the only unequivocal diagnosis in this field: that of bipolar depression. A distinction between necessary and sufficient depressive symptoms is being proposed in this paper; and Foulds and Bedford's category of dysthymic disorders, which includes anxiety and depression, opens an interesting new perspective. The time-honoured diagnosis of involutional melancholia will no longer be included in the new editions of DSM III and ICD9 which are now being prepared. Current active research into the pathophysiology of depression and the biochemical disorders associated with it are likely to produce in the near future biological criteria for diagnosis and prognosis of depression that will be more operational than the traditional clinical features.