Endogenous depression as a construct: a quantitative analysis of the literature and a study of clinician judgements

Melancholia: An Attempt at Definition Based on a Review of Empirical Data

We sought to identify clinical features that best discriminate melancholia from nonmelancholic depressive conditions. An extensive review of studies using latent factor models that identified a melancholic depression dimension/factor was undertaken. Clinical variables extracted from these studies were analyzed in terms of their contribution to a diagnosis of melancholia and their consistency across studies. Psychomotor retardation and mood nonreactivity were the most relevant clinical features for the identification of melancholic depressions. Other clinical features commonly described as weighted to melancholia, such as anhedonia, psychomotor agitation, late insomnia, or appetite/weight loss, seemed less useful in distinguishing these subtypes of depression. Study results are considered in relation to the potential limitations of current operational definitions of melancholia, and how symptom sets could be modified.

The role played by depression associated with somatic symptomatology in accounting for the gender difference in the prevalence of depression

PURPOSE

A variety of studies suggest the existence of a distinct phenotype of somatic depression, i.e., depression accompanied by significant somatic symptomatology. Previous research suggests that the gender difference in the prevalence of depression is primarily due to a difference in somatic depression. The aim of this study was to compare the gender difference in the prevalence of somatic depression and of depression not accompanied by significant somatic symptomatology (labelled "pure" depression) in two representative samples, the National Comorbidity Survey-Replication (NCS-R) and the Zurich Study.

METHOD

The gender difference in lifetime somatic depression was compared to that of pure depression based on analyses weighted back to the general population in two representative samples. The NCS-R analyses involved a narrow definition of somatic depression with items from the DSM criteria for depression--appetite, sleep, and fatigue. The analysis of the Zurich study added headaches, body image issues, and breathing difficulties to the criteria and comparison to atypical depression.

RESULTS

In both samples, the gender difference in depressive prevalence was due to a large difference in somatic depression with other phenotypes showing little or no gender difference. The gender differences were found to be due to the somatic symptoms rather than the number of symptoms and were much larger for somatic than for atypical depression.

CONCLUSION

The gender difference in the prevalence of depression results from the higher prevalence among women of a specific phenotype, somatic depression.

Does dopamine dysfunction drive depression?

OBJECTIVE

To examine the evidence that dopamine (DA) dysfunction contributes to melancholic depression.

METHOD

Database (EMBASE, PsychLit and MEDLINE) searches using relevant key words were conducted and citations were scrutinized.

RESULTS

In this paper, we assume that the definition of melancholia is contingent upon the presence of psychomotor disturbance (PMD). In melancholic depression PMD comprises both a cognitive and motor component and DA is found to be important in both. DA neurotransmission modulates cognition in particular in attention, adaptation and motivational processes and has a pivotal role in motor function.

CONCLUSION

DA is a credible aetiological candidate for the PMD in melancholic depression. However, melancholia needs first to be characterized both clinically and in terms of its pathophysiology. In this regard, illnesses such as bipolar depression and Parkinson's disease warrant consideration as they provide suitable models of both the cognitive and motor aspects of PMD, and hold the necessary markers to better define melancholia.

Ocular motor differences between melancholic and non-melancholic depression

BACKGROUND

Major depressive disorder may be a heterogeneous disorder, yet melancholic depression is the most consistently described subtype, regarded as qualitatively different to non-melancholic depression in terms of cognitive and motor impairments. Eye movement studies in depression are infrequent and findings are inconclusive.

METHODS

This study employed a battery of saccadic eye movement tasks to explore reflexive saccades, as well as higher order cognitive aspects of saccades including inhibitory control and spatial working memory. Nineteen patients with major depressive disorder (9 melancholic; 10 non-melancholic) and 15 healthy controls participated.

RESULTS

Differences were revealed between melancholic and non-melancholic patients. Melancholia was associated with longer latencies, difficulty increasing peak velocities as target amplitudes increased, and hypometric primary saccades during the predictable protocol. In contrast, the non-melancholic depression group performed similarly to controls on most tasks, but saccadic peak velocity was increased for reflexive saccades at larger amplitudes.

LIMITATIONS

Most patients were taking antidepressant medication.

CONCLUSIONS

The latency increases, reduced peak velocity and primary saccade hypometria with more severe melancholia may be explained by functional changes in the fronto-striatal-collicular networks, related to dopamine dysfunction. In contrast, the serotonergic system plays a greater role in non-melancholic symptoms and this may underpin the observed increases in saccadic peak velocity. These findings provide neurophysiological support for functional differences between depression subgroups that are consistent with previous motor and cognitive findings.

Taxonicity of adolescent melancholia: a categorical or dimensional construct?

A taxometric analysis was conducted to test the hypothesis that the latent structure of melancholia in adolescents is categorical. Two taxometric procedures were used: Mean Above Minus Below a Cut (MAMBAC) and Maximum Covariance (MAXCOV) analyses. Participants were 378 adolescents presenting for a depression evaluation. Indicators of melancholia were constructed using items from the Schedule for Affective Disorders and Schizophrenia for School Aged Children (K-SADS) and the Beck Depression Inventory (BDI). The indicators of melancholia were consistent with a categorical latent variable. The findings suggest that the latent structure of melancholia in adolescents is similar to its previously identified categorical structure in adults. Implications for clinical research are discussed.

Is psychotherapy an effective treatment for melancholia and other severe depressive states?

The treatment of severe depression with psychotherapy, alone, is controversial. In this paper, we review the historical, conceptual, and empirical contexts of this controversy. In addition to work by others, we review recent work from our institute which has examined the psychobiological substrates of response to treatment in depressive subtypes. We examine the traditional categories that describe severe depressions. The features and psychobiological correlates of melancholia are discussed, as is the relationship between melancholia and aging. Research on treatment of melancholia and other severe depressive states with psychotherapies such as cognitive behavior therapy (CBT) and interpersonal psychotherapy (IPT) is reviewed in detail. We conclude that although some melancholic patients are responsive to IPT or CBT, there is not yet compelling evidence that melancholic patients respond to psychotherapy as well as they do to medications. The potentially mediating effects of hypercortisolism, alterations of sleep neurophysiology, and disturbances of information processing and regional cerebral metabolism represent fertile grounds for future investigation. We discuss the practical implications of the literature reviewed.

Performance of the Hamilton Depression Rating Scale in depressed patients in the United Arab Emirates

Cross-cultural variation in the frequencies and modes of expression of depressive symptoms may influence the validity of depression rating scales. The most widely used instrument for this purpose, namely Hamilton's Depression Rating Scale (HDRS), has not been systematically evaluated in Arab countries. This study evaluates the face validity of the HDRS-21 by studying symptom frequencies, factor structure and symptom clusters in 100 UAE depressed patients. Concurrent validity is tested by comparing total HDRS scores with global estimates of severity made by clinicians, admission status, impairment of social and occupational functioning, and the endogenicity score of the Newcastle (NC) Diagnostic Index. Total HDRS scores show highly significant agreement with three independent measures of severity of depression. Rank orders of the most and least frequent symptoms are consistent with studies of similar design. Marked differences lie in more retardation and somatization and fewer cognitive components in the present study. Principal-component analysis confirmed the heterogeneous structure of the scale, separating a group of core depressive symptoms, and endogenous, somatization, anxiety and psychotic symptom components. The internal consistency (reliability) of the whole scale is moderate, and improves in the core symptom factor. The main conclusion is that the HDRS is sensitive to severity of depression in the UAE culture. However, it measures heterogeneous aspects, and its internal consistency suffers as a result. High levels of retardation and somatization contribute significantly to the total score in socially developing communities.

Problems in validating endogenous depression in the Arab culture by contemporary diagnostic criteria

This study highlights the difficulties that may be encountered in attempting to apply the clinical construct of endogenous depression derived from western studies to depressed Arab patients. The agreement between 4 operational systems on the diagnosis of endogenous (melancholic) depression is explored in 100 patients with primary depressive disorder in Al-Ain, United Arab Emirates. The symptom characteristics of the 61 patients in whom all diagnostic systems agreed are then described quantitatively and qualitatively. Subjects were evaluated by the Newcastle scale, Hamilton's 21 item depression scale, global assessment of functioning scale, and the operational criteria of the diagnostic systems used. Diagnosis of endogenicity was derived by computer according to the respective criteria. The agreement between DSM-IV, ICD-10, and RDC criteria is moderately high (0.72). When the Newcastle Index is included, it is only moderate (0.58). Disagreements are related to differences in diagnostic criteria. Small differences affect concordance appreciably. DSM-IV agreed with a majority of external validators, differentiating a more homogeneous groups of patients. In the present study, endogenous depression identified by western criteria, was less likely to manifest by guilt feelings, a distinct quality of mood, and loss of libido. The descriptions of patients reveal that the mood component of depression is expressed differently, somatic metaphors are used frequently to express distress, religious elements influence the expression of symptoms, and depression may manifest in behaviours not directly indicative of the disorder. Endogenous depression may be identified in the Arab culture, but considerable variation in its component symptom frequencies and mode of expression needs to be taken in consideration for defining it in terms appropriate to the culture.

The tyramine test is not a marker for postnatal depression: early postpartum euphoria may be

Abnormally low tyramine test values are known to be markers for vulnerability to unipolar, but not bipolar, endogenous depression. In the present study, 37 women with recent postnatal depression (25 major, 12 minor) and 22 puerperal controls with no depressive disorder, all assessed by Schedule for Affective Disorder and Schizophrenia (SADS-L) interview, together with 17 other controls, underwent the test. No significant differences in tyramine sulfate output were demonstrated between the different groups. Those subjects with endogenous features according to Newcastle score (n = 7) or Research Diagnostic Criteria (RDC) (n = 6) also had normal output. Thus, the tyramine test does not appear to be a useful marker for vulnerability to postnatal depression. Over half the subjects recalled that their postnatal depression had started in the first 2 weeks postpartum. Of the total of 62 postpartum subjects interviewed with the SADS-L, ten recalled a period of euphoria in the first postpartum week, which met RDC for hypomania and eight of them went on to become depressed postnatally. An additional patient from the total group was hospitalized with mania.

Specificity of interpersonal sensitivity to non-melancholic depression

Scores of 69 remitted depressed patients were compared to control subjects on the Interpersonal Sensitivity Measure (IPSM). The patients were categorised into melancholic and non-melancholic sub-groups according to DSM-III criteria. Differences between the depressives and controls were detected but were principally the result of high IPSM scores being returned by the non-melancholic depressives. Melancholic depressives did not differ from the controls in their IPSM scores, supporting the proposition that this depressive sub-type is not associated with a vulnerable personality style.

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.

Distinguishing psychotic and non-psychotic melancholia

To examine the necessary and sufficient status of delusions and hallucinations as clinical features of psychotic (delusional) depression, we studied a consecutive sample of 137 patients meeting DSM-III, RDC and our clinical criteria for endogenous depression/melancholia, of whom 35 had delusions and/or hallucinations, and represented our putative 'psychotic depressives' (PDs). The PDs were contrasted with the remaining 'endogenous depressives' (the EDs), and an age- and sex-matched subsample of the latter, the MEDs. Univariate and multivariate analyses of clinical features established that, in addition to the presence of delusions and/or hallucinations, the PDs could be distinguished in particular by severe psychomotor disturbance, as well as by sustained and unvarying depressive content, the absence of any diurnal mood variation and by constipation. Latent class analyses suggested that overt psychotic features (such as delusions and hallucinations) were sufficient but not necessary for a subject to be assigned to the 'psychotic' latent class, and a subsequent chart review suggested that, in some PDs actual psychotic features may not be able to be elicited because of severe psychomotor change, suggesting that clinical reliance on eliciting delusions or hallucinations may result in a number of 'masked psychotic depressives' escaping valid diagnosis.