False-positive diagnosis with primary-affective-disorder criteria

Does melancholia predict response in major depression?

We examined the value of the melancholic distinction for predicting response to 1 week of hospitalization without antidepressant drugs and to a 4-week fixed plasma level desipramine (DMI) trial in patients with unipolar non-psychotic major depression. Both DSM-III and III-R criteria were tested. Response to hospitalization (HDRS less than or equal to 12) was much less common in DSM-III melancholic than in non-melancholic patients (1 of 19 vs. 18 of 37, chi 2 = 8.69, df = 1, P less than 0.001) and severity did not account for this association. DSM-III-R melancholia criteria were also associated with poor hospital response but slightly less predictive. Melancholic patients, however, diagnosed with either set of criteria, were not more likely to respond to drug treatment on any of the measures examined.

The GH response to clonidine in endogenous as compared with reactive depression

The growth hormone (GH) response to clonidine was measured in 10 patients meeting standardized criteria for 'endogenous' depression and in 10 patients individually matched for age and sex but meeting the corresponding criteria for 'reactive' depression. In a paired comparison of patients with reactive and endogenous depression (matched for age and sex), the GH response to clonidine was less in the endogenous member of the pair in 8 out of 10 cases. These findings are interpreted as evidence of a defect at alpha 2 adrenoceptors in neuroendocrine systems in endogenous as compared with reactive depression.

Diagnosis of endogenous depression. Comparison of clinical, research and neuroendocrine criteria

Eighty-nine depressed outpatients were studied by clinical criteria, Research Diagnostic Criteria (RDC), and the dexamethasone suppression test (DST) of neuroendocrine regulation. A simple outpatient version of the DST, requiring only one blood sample, correctly identified 40% of patients diagnosed clinically as endogenous depression (ED), with a specificity of 98% and a diagnostic confidence of 95%. Differences in age, sex, or severity of symptoms between endogenous and non-endogenous depressives did not account for these results. By comparison, the diagnostic performance of the DST was weaker for the RDC categories Major Depressive Disorder (MDD) and primary MDD. These were less selective and more heterogeneous than the clinical category ED. The clinical diagnoses of ED were supported in 98% of cases by the RDC, but 22% of RDC endogenous MDD diagnoses were not supported by the clinical diagnoses. Abnormal DST results were found only in patients with both the clinical diagnosis of ED and the RDC diagnosis of endogenous MDD. Patients with definite endogenous MDD had a significantly higher frequency of abnormal DST results (42%) than those with probable endogenous MDD (14%), or those with other RDC diagnoses (3%). A significant association was found between positive DST results and a positive family history of depression. These results support other evidence for use of a positive DST result as an external validating criterion for ED. The category MDD contained all cases diagnosed clinically as ED, but was diluted by cases diagnosed clinically as non-endogenous depression who had no neuroendocrine disturbance. The results also confirmed that the endogenous/non-endogenous and primary/secondary classifications of depression are not identical. We conclude: (1) that the DST can be used in the differential diagnosis of depressed outpatients as well as inpatients; (2) that the RDC category primary MDD and the Washington University category primary depression are more heterogeneous and probably less valid than the clinical category ED; (3) that the RDC for endogenous MDD have only moderate validity; (4) that RDC diagnoses cannot substitute for careful clinical diagnoses in research studies; (5) that the best use of the RDC is to support clinical diagnoses, but not to generate diagnoses independently as a free-standing system; (6) that the concept of endogenous or endogenomorphic depression has validity and should be retained in research studies of depression.

Reassessing the bipolar-unipolar dichotomy

This paper is a critical review of the literature on the dichotomous classification of affective disorders into unipolar and bipolar types. The majority of genetic studies show significant overlap in the liability to develop two forms of illness, and the majority of lithium studies show a similar clinical responsiveness of both groups to both acute and maintenance treatment. Biological studies comparing the two groups are difficult to interpret as most have compared manics to depressives without controlling for motor activity, excitement, and other state-dependent clinical variables. Viewed in light of our research findings in a recent genetic study of affective states, we believe these data suggest that the separation of affective disorders by polarity may have been premature, and that the search for heterogeneity should now be carried out using alternative strategies.

The WHO Depression Scale. Relationship to the Newcastle Scales

The WHO (World Health Organization) Depression Scale is a new rating scale developed to evaluate the complete clinical history and description of depression. Items of the WHO scale were transformed to cover the items of the two Newcastle scales that are designed to differentiate between endogenous and non-endogenous depressions. In 98 depressed inpatients examined prior to antidepressive therapy only moderate agreement between scores transformed to the two Newcastle scales was found. Also the distribution patterns of the scores on the two scales were different. In patients classified as endogenous on one or both scales a significant relationship between plasma levels of imipramine or clomipramine and antidepressive effect was found. In patients classified on both scales as doubtful - or non-endogenous depressions - no such correlation could be identified. The initial severity of depression, as defined by the Hamilton Depression Scale, was the same in endogenous, doubtful and non-endogenous depression according to the scores transformed to the two Newcastle scales.