Study of the unidimensionality of the Bech-Rafaelsen Melancholia Scale using Rasch analysis in a French sample of major depressive disorders

Clinical target syndromes in psychiatry: latent structure analysis versus factor analysis

The algorithms for the demonstration of shared phenomenology of psychiatric syndromes in DSM-III are resistant to quantification. In contrast, the rating scale approach quantifies clinical target syndromes in psychiatry. The two most useful statistical models for quantifying shared phenomenology by symptom rating scales have been reviewed; namely factor analysis and latent structure analysis. Results have shown that factor analysis has demonstrated dimensions of dementia, delirium, schizophrenia, mania, outward aggression, depression and anxiety. Latent structure analysis has confirmed that the items of brief rating scales (such as the Melancholia Scale) are additively related implying that their total scores are sufficient statistics for the measurement of these factors or dimensions. Latent structure analysis should be considered as a psychometric “glasnost” compared to algorithm-resistant logic of quantification in DSM-III.

The Major Depressive Disorder Hierarchy: Rasch Analysis of 6 items of the Hamilton Depression Scale Covering the Continuum of Depressive Syndrome

OBJECTIVES

Melancholic features of depression (MFD) seem to be a unidimensional group of signs and symptoms. However, little importance has been given to the evaluation of what features are related to a more severe disorder. That is, what are the MFD that appear only in the most depressed patients. We aim to demonstrate how each MFD is related to the severity of the major depressive disorder.

METHODS

We evaluated both the Hamilton depression rating scale (HDRS-17) and its 6-item melancholic subscale (HAM-D6) in 291 depressed inpatients using Rasch analysis, which computes the severity of each MFD. Overall measures of model fit were mean (±SD) of items and persons residual = 0 (±1); low χ2 value; p>0.01.

RESULTS

For the HDRS-17 model fit, mean (±SD) of item residuals = 0.35 (±1.4); mean (±SD) of person residuals = -0.15 (±1.09); χ2 = 309.74; p<0.00001. For the HAM-D6 model fit, mean (±SD) of item residuals = 0.5 (±0.86); mean (±SD) of person residuals = 0.15 (±0.91); χ2 = 56.13; p = 0.196. MFD ordered by crescent severity were depressed mood, work and activities, somatic symptoms, psychic anxiety, guilt feelings, and psychomotor retardation.

CONCLUSIONS

Depressed mood is less severe, while guilt feelings and psychomotor retardation are more severe MFD in a psychiatric hospitalization. Understanding depression as a continuum of symptoms can improve the understanding of the disorder and may improve its perspective of treatment.

Validation of the Bech-Rafaelsen Melancholia Scale and the Hamilton Depression Scale in patients with major depression; is the total score a valid measure of illness severity?

OBJECTIVE

Evaluation of antidepressant drug efficacy requires adequate rating scales for measuring the severity of depression. However, to measure the illness severity by such a total score, the scale needs to fulfil criteria of unidimensionality. On this background, we aimed at comparing the unidimensionality of the Bech-Rafaelsen Melancholia Scale (MES) and the 17-item Hamilton Depression Rating Scale (HAM-D(17)).

METHOD

A total of 1629 patients aged between 18 and 65 years with a major depressive episode were treated openly with sertraline at a fixed oral dose of 50 mg daily during 4 weeks. The HAM-D(17) and the MES were applied at baseline and at weeks 2 and 4. Unidimensionality was tested with Mokken and Rasch analysis.

RESULTS

Unidimensionality of the HAM-D(17) could not be confirmed. However, the 6-item Hamilton Depression Subscale (HAM-D(6)), was accepted by the Rasch analysis both at baseline and after 2 and 4 weeks of therapy. For the MES (as well as for the HAM-D(6)), a Loevinger coefficient of homogeneity above 0.40 (suggesting acceptance) was found at week 4.

CONCLUSION

The HAM-D(6) and the MES did fulfil criteria for unidimensionality while the HAM-D(17) did not. Therefore, the extended use of the HAM-D(17) in drug trials may be questioned.

The Bech-Rafaelsen Melancholia Scale (MES) in clinical trials of therapies in depressive disorders: a 20-year review of its use as outcome measure

OBJECTIVE

To evaluate the psychometric properties of the Bech-Rafaelsen Melancholia Scale (MES) by reviewing clinical trials in which it has been used as outcome measure.

METHOD

The psychometric analysis included internal validity (total scores being a sufficient statistic), interobserver reliability, and external validity (responsiveness in short-term trials and relapse prevention in long-term trials).

RESULTS

The results showed that the MES is a unidimensional scale, indicating that the total score is a sufficient statistic. The interobserver reliability of the MES has been found adequate both in unipolar and bipolar depression. External validity including both relapse, response and recurrence indicated that the MES has a high responsiveness and sensitivity.

CONCLUSION

The MES has been found a valid and reliable scale for the measurement of changes in depressive states during short-term as well as long-term treatment.

Three dimensions of depression in patients with acute psychotic disorders: a replication study

Depressive symptoms in psychotic disorders are of high relevance but seem to be heterogeneous when assessed with a standard rating scale. The present analysis is a replication study on the dimensionality of the Bech-Rafaelsen Melancholia Scale (BRMES) in acutely psychotic patients with substantial depression defined according to a functional approach across the nosological borders of schizophrenia with major affective symptoms, schizoaffective disorder, depressed subtype, and major depression with psychotic features. The baseline data of 123 patients participating in a multicenter pharmacological trial were evaluated with structural equation models. A previously reported three-dimensional model of the BRMES comprising the facets retardation, depressive core symptoms, and accessory depressive symptoms was cross-validated by confirmatory factor analysis (CFA). The three-dimensional model proved to be superior to one-, two-, or four-factor models with respect to goodness-of-fit (goodness-of-fit index [GFI] = 0.91 and comparative fit index [CFI] = 0.89) and parsimony (adjusted GFI [AGFI] = 0.85). When comparing the present model with the previously reported model, a highly satisfactory correspondence emerged (CFI = 0.87). The results corroborate our previous findings that depression-like symptoms in acutely psychotic patients assessed by the BRMES can best be represented by a three-dimensional model and should not be treated as a homogeneous syndrome.

On the validity of the Bech-Rafaelsen Melancholia Scale (BRMS)

BACKGROUND

The findings published to date on convergent validity of the BRMS are mainly concerned with the correlation with other observer-rating scales for depression. In many studies on the evaluation of therapeutic interventions self-rating scales are used in connection with observer-rating scales. Therefore, findings on the relations among instruments of both groups are necessary in order to justify the combination of a particular observer-rating scale with a particular self-rating scale. In the ICD-10 three different degrees of severity of depressive episodes are distinguished. No data on the discriminant validity of the BRMS with respect to this new diagnostic classification are available till now.

METHODS

45 depressed inpatients were assessed with two observer-rating scales (BRMS and DEPRES of the AMDP system) and two self-rating scales (BDI and DS).

RESULTS

The discriminant validity with reference to the three degrees of severity of depressive episodes as defined in ICD-10 is at r = 0.80 very high. The convergent validity of the BRMS is high at r = 0.70, related to the DEPRES. The correlations between the BRMS and the BDI as well as the DS were clearly lower, at 0.53 and 0.32 each.

CONCLUSIONS

The only moderate convergent validity between self-rating and observer-rating scales is a strong argument for a multi-methodological approach in the context of therapy evaluation.

The Cronholm-Ottosson Depression Scale: the first depression scale designed to rate changes during treatment

In 1960 Ottosson published the first specific depression rating scale (the Cronholm-Ottosson Depression Scale) designed to be sensitive in measuring change during antidepressive therapy. Ottosson and his group have never used factor analysis to validate the scale, as the items of the scale were used factor analysis to validate the scale, as the items of the scale were selected on a preconceived idea for homogeneity, i.e. having a monotonic correspondence to the underlying dimension of severity of depression. The most appropriate method of testing the construct validity of the Cronholm-Ottosson Depression Scale is latent structure analysis. Using the original Ottosson data, a latent structure analysis has been made showing that the 8 items of the scale are homogeneously related, i.e. can be ordered on one dimension of severity of depression. The descriptive statistic of a 50% reduction of pretreatment score (or more) equaled the global clinical score of moderate to excellent improvement. Both scales showed that, already after 4 electroconvulsive treatments, about 80% of depressed patients who received adequate fits had moderate to excellent improvement, whereas only around 40% of depressed patients who received inadequate fits improved moderately or excellently.

Diagnostic and classification systems with special emphasis on the Minicompendium

With the introduction of major tranquillizers more than three decades ago symptom rating scales were soon accepted as the method of evaluating their clinical effects. The Mini-compendium is a collection of rating scales for measuring outcome of antianxiety drugs, antidepressants, antimanics, and anti-psychotics. The scales have been selected by their "cash values", i.e. the scales most frequently used for the respective dimensions. These scales have been further developed in terms of strict item definitions. The simple sum of the individual scale items has been considered as a sufficient statistic if they fulfilled latent structure analysis of shared phenomenology.