The research diagnostic criteria for endogenous depression and the dexamethasone suppression test: a discriminant function analysis

The facets of melancholia

OBJECTIVE

To clarify the role of 'melancholia' in psychiatric nomenclature. Most clinicians and researchers are convinced that the syndrome currently termed major depressive disorder encompasses multiple subgroups that differ meaningfully in phenomenology, natural history, treatment response, and pathophysiology. Delusional depression and melancholia have attracted the most empirical work, but efforts to define the latter condition have declined in recent years following a number of failures to show the validity of the melancholic/nonmelancholic distinction.

METHOD

Review of experience.

RESULTS

Beyond the DSM-IV symptom profile, melancholia has been associated with greater overall severity, a low likelihood of placebo response, an episodic course, a family history of depression without alcoholism, a relatively healthy personality, and hypothalamic-pituitary-adrenal axis hyperactivity. Evidence for the validity of the melancholia concept lies in the fact that the presence of each of these characteristics has been shown to increase the likelihood of one or more of the others.

CONCLUSION

A diagnosis of melancholia may eventually prove valuable in treatment selection, but the necessary evidence will not be forthcoming until a widely accepted definition exists that is both inherently valid and that can be applied consistently across research sites.

Validity of the PAS-ADD for detecting psychiatric symptoms in adults with learning disability (mental retardation)

The Psychiatric Assessment Schedule for Adults with Developmental Disability (PAS-ADD) is a semi-structured interview for use with respondents who have learning disability and for key informants. This report investigates the ability of the instrument to detect symptoms that had been found to exist during routine clinical assessment of the patients. Field trials involved 95 referred patients with learning disability and a key informant for each sample member. Clinical opinions of the referring psychiatrists were sought using a symptom checklist. Referrer checklist symptoms and PAS-ADD data were both factor analysed. Validity testing involved (a) computation of correlations between PAS-ADD factors and checklist data and (b) comparison of PAS-ADD and referrers' diagnoses. Results indicated good validity for the PAS-ADD in relation to psychotic symptoms and depressive symptoms. Anxiety symptom identification was not well validated, probably due to small numbers. Expansive mood identified by the referrers was not detected by the PAS-ADD because there is currently no corresponding section in the interview. Where the PAS-ADD produced a diagnosis (in 58 members of the sample), 44 were in agreement with the referrer. Probability of diagnosis by PAS-ADD increased with the number of relevant active symptoms identified by the referrer. The PAS-ADD has been shown in a previous report to have the sensitivity to detect mental disorders not known to psychiatric services. For psychotic and depressive conditions, our results showed that symptom detection was in good agreement with the information provided by the referring psychiatrists on their patients. The PAS-ADD needs a section on hypomania and further investigation of its detection of anxiety disorders.

DSM-III-R and persons with dual diagnoses: conceptual issues and strategies for future research

Diagnosis of mental health needs in people with mental retardation using the DSM-III-R manual was critically reviewed. Conceptual issues included the interaction of different diagnosis categories; the cognitive and linguistic competencies often required for diagnosis; the potential mismatch between psychopathology in people with mental retardation and the DSM-III-R nosology; and issues relating to multi-axial classification. Strategies identified to explore and resolve these issues include better documentation of the frequency and nature of these problems when using unmodified DSM-III-R criteria, better empirical piloting of modified diagnostic criteria with people with severe and profound mental retardation, and the use of social validity data to identify potential mismatches between psychopathology in people with mental retardation and DSM-III-R diagnoses.

Maintenance treatment and psychobiologic correlates of endogenous subtypes

Although the endogenous subtype in depression has long been thought to have prognostic significance, to date no long-term maintenance treatment trial has examined the relative risk of recurrence in patients meeting criteria for this subtype. Following our analysis of the primary hypotheses regarding the relationship between treatment assignment and outcome [Frank et al. (1990) Arch. Gen. Psychiatry 47, 1093-1099], we now examine psychobiologic and maintenance treatment correlates for these recurrent unipolar patients grouped according to melancholic, endogenous but not melancholic, and non-endogenous subtype at index presentation. No differences were observed among the three groups in overall survival time; however, in the 52 patients who received psychotherapy without active medication during the maintenance phase, length of survival was inversely related to endogeneity. Interestingly, no differences were found among the three groups in EEG sleep parameters when studied either at baseline or following recovery.

Clinical subtypes of unipolar depression: Part III. Quantitative differences in various biological markers between the cluster-analytically generated nonvital and vital depression classes

The hypothalamic-pituitary-adrenal (HPA) axis, the hypothalamic-pituitary-thyroid (HPT) axis, and the availability of L-tryptophan (L-TRP) to the brain were studied in their relationships to (1) 14 depressive symptoms measured by the Structured Clinical Interview for DSM-III-R--Patient Version (SCID) and (2) the cluster-analytically generated vital/nonvital classes. The following biological parameters were measured in 100 depressed females: free thyroxine (FT4), baseline thyroid stimulating hormone (TSH), predexamethasone and postdexamethasone cortisol and adrenocorticotropic hormone (ACTH) values, the circulating levels of total L-TRP, and the L-TRP/sum of competing amino acids ratio. We found that the psychopathological correlates of disorders in the HPA/HPT axis and of a decreased availability of L-TRP were vital symptoms, i.e., distinct quality of mood, nonreactivity, early morning awakening, anorexia-weight loss, and psychomotor disorders. There was no significant relationship between those biological markers and the nonvital symptoms of the SCID inventory for depressive symptoms. However, we did not validate our SCID clustering in vital and nonvital classes by qualitative differences in the biological variables. It was concluded that our nonvital/vital clusters should be regarded as continuous categories with regard to the biological markers studied; these clusters constitute relevant stages in the continuum of progressing biological dysfunction.

Past loss as a symptom formation factor in depression

We examined the relationship between past loss and endogenous subtyping of depressed patients. In a sample of 124 female depressed inpatients there was no association between past loss and RDC endogenous or DSM-III melancholic subtyping. We thus failed to replicate Brown and colleagues' finding that past loss is a symptom formation factor.

Neuroendocrine aspects of primary endogenous depression. III. Cortisol secretion in relation to diagnosis and symptom patterns

In order to ascertain the extent of hypothalamo-pituitary-adrenal cortical (HPA) hyperactivity in endogenous depression, we determined circadian serum cortisol patterns, cortisol responses to dexamethasone (DEX) administration, and urine free cortisol excretion before and after DEX administration in 40 definite endogenous depressives diagnosed with the Research Diagnostic Criteria. The cortisol measures ranged from normal to clearly elevated. To elucidate the clinical correlates of these hormone measures in the patients, we examined the relationships of the pre- and post-DEX cortisol measures to the diagnosis of endogenous/melancholic depression by different systems and to the overall severity and specific dimensions of depressive symptomatology. In this group of endogenous depressives, none of the diagnostic schemes for endogenous/melancholic depression which we studied was significantly related to the pre- or post-DEX cortisol measures. Of the other subject and symptom variables, only age and the agitation/anxiety factor of the Hamilton depression scale shown consistent relationships with the cortisol measures. Both were positively correlated, to a moderate degree, with the hormone measures, and they were not correlated with each other. Together they explained approximately 20% of the variance in the cortisol measures. Thus, within a group of moderately to severely ill endogenous depressives, the older and the more agitated anxious patients have a significantly greater likelihood of showing increased HPA activity. These findings indicate that age should be controlled in studies of the HPA axis and that the subjective experience of anxiety may contribute to HPA hyperactivity in endogenous depression.

HPA-axis abnormalities in psychiatrically well controls

The considerable divergence in the literature describing dexamethasone suppression test (DST) nonsuppression rates among psychiatrically well controls led the authors to explore screening procedures as a possible source of variance. Using what they judged to be a typical screening procedure, the authors eliminated 69 of 128 subjects responding to an advertisement seeking psychiatrically and physically healthy subjects. Structured interviews for Axis I and II disorders then revealed that 36% of the remaining 59 subjects nevertheless had historical evidence of psychiatric illness; the 38 who passed all phases of screening underwent three monthly DSTs, which demonstrated the stability over time of both normal and abnormal results. Moreover, a family study revealed that relatives of nonsuppressors had a significantly higher morbid risk of affective disorder (20.5% vs. 8.8%), particularly mania and hypomania.

Iowa Discriminant Index for endogenous depression: family history correlates

We examined the risk of psychiatric illness in the first-degree relatives of the 257 depressed inpatients upon whom we constructed the Iowa Discriminant Index (IDI) for endogenous depression. Nonendogenous depressives had a higher rate of alcoholism and antisocial personality in their families. IDI endogenous subtyping was not associated with a family history of depression. These results provide additional support for the validity of the empirically derived IDI.