articleAtypical depression is more common than melancholic in fibromyalgia : an observational cohort study

Background: It has been postulated that atypical and melancholic depression subtypes exist in depressed fibromyalgia (FM) patients, yet no study has empirically tested this hypothesis. The purpose of this study is to determine whether major depressive disorder (MDD) with atypical features and MDD with melancholic features occurs in a FM sample and to describe their demographic, clinical and diagnostic characteristics. Methods: An observational cohort study using a descriptive cross-sectional design recruited a convenience sample of 76 outpatients with FM from an academic Rheumatology clinic and a community mental health practice. Diagnoses of FM were confirmed using the 1990 ACR classification guidelines. Diagnoses of MDD and diagnostic subtypes were determined using the DSM-IV-TR criteria. Clinical characteristics were measured using the Fibromyalgia Impact Questionnaire, Structured Interview Guide for the Hamilton Depression Rating Scale with Atypical Depression Supplement and other standardized instruments. Odds ratios were computed on subtype-specific diagnostic criteria. Correlations assessed associations between subtype diagnoses and diagnostic criteria. Results: Of the 76 subjects with FM, 11.8% (n = 9) were euthymic, 52.6% (n = 40) met diagnostic criteria for MDD with atypical features and 35.6% (n = 27) for MDD with melancholic features. Groups did not differ on demographic characteristics except for gender (p = 0.01). The non-depressed and atypical groups trended toward having a longer duration of FM symptoms (18.05 yrs. ± 12.83; 20.36 yrs. ± 15.07) compared to the melancholic group (14.11 yrs. ± 8.82; p = 0.09). The two depressed groups experienced greater severity on all clinical features compared to the non-depressed group. The atypical group did not differ clinically from the melancholic group except the latter experienced greater depression severity (p = 0.001). The atypical group demonstrated the highest prevalence and correlations with atypical-specific diagnostic criteria: (e.g., weight gain/ increased appetite: OR = 3.5, p = 0.02), as did the melancholic group for melancholic-specific criteria: (e.g., anhedonia: OR = 20, p < 0.001). Conclusion: Depressed fibromyalgia patients commonly experience both atypical and melancholic depressive features; however, in this study, atypical depression was 1.5 times more common than melancholic depression. This finding may have significant research and clinical implications. Background Fibromyalgia (FM) is a common, chronic and often debilitating rheumatologic disorder which presents in 7% of all primary care visits [1]. FM is characterized by widespread musculoskeletal pain (100%), specified tender points (100%), fatigue (96-100%), sleep disturbances (86%-98%), and co-morbid mood disorders (29%) [2]. While the lifetime prevalence rate of major depressive disorders in the general population is 10% to 25% for women and from 5% to 12% for men [3], 74% of FM patients report at least one major depressive disorder (MDD) episode in their lifetime [4]. Depression is known to worsen FM symptom severity including pain, functional impairment, sleep quality and quality of life [5-7]. Of grave concern is suicide is the leading cause of premature mortality in those with FM. People with FM have been reported to have a * Correspondence: rossre@ohsu.edu 1 Oregon Health & Science University, School of Nursing, 3455 SW US Veterans Hospital Road, Portland, Oregon, 97239, USA † Contributed equally Full list of author information is available at the end of the article © 2010 Ross et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Ross et al. BMC Musculoskeletal Disorders 2010, 11:120 http://www.biomedcentral. com/1471-2474/11/120 Page 2 of 13 nine-fold increased risk of death from suicide during depressive episodes [8]. It is important to further elucidate the biological and psychological underpinnings of depression in FM, as the successful treatment of depression has been shown to significantly improve FM symptomatology [9]. While several subtypes of MDD have been discussed in the literature, only three have specific diagnostic criteria defined in the Diagnostic and Statistical Manual, 4 th edition, Text Revised (DSM-IV-TR) [10]: MDD with psychotic features, MDD with atypical features and MDD with melancholic features. Full diagnostic criteria can be viewed in an additional file (#1). Combined, the atypical and melancholic subtypes represent approximately 60% of all MDD cases [11] and have been postulated to represent the two main subtypes of depression in FM [12], thus are the focus of this study. Major depressive disorder, with atypical and melancholic features, has been methodically investigated in depressed populations: yet there is still some debate as to the validity of the subtype-specific criteria, especially for atypical depression [13]. While several researchers have critiqued the current DSM-IV-TR criteria, as yet a viable alternative has not been agreed upon [14]. Therefore, for the purpose of this study, the current prevailing criteria as per the DSM-IV-TR were used. Gold and Chrousos [15] postulated that atypical depression would be more prevalent in FM patients compared to melancholic depression due to the shared biological underpinnings of atypical depression and FM. Specifically, there is a blunting of hypothalamic-pituitary-adrenal (HPA) axis functioning as evidenced by low to normal levels of plasma cortisol following dexamethasone suppression testing. This blunting is secondary to glucocorticoid receptor desensitization as a result of chronic over secretion of cortisol. However, there are no studies to date that have evaluated Gold and Chrousos' assertions. Thus the first aim of this study was to test the hypotheses that atypical depressive episodes (ADE) and melancholic depressive episodes (MDE) occur in FM patients with ADE being the predominant subgroup. A secondary aim was to describe the demographic and clinical characteristics and diagnostic features of depression subgroups in people with FM to determine if they exhibited the same symptom clusters as those in depressed, non-FM samples.