- Email: [email protected]
Is chronic pain a variant of depressive disease? The case of primary fibromyalgia syndrome
105
Pain, 29 (1987) 105-111 Elsevier
PAI 01013
Is chronic pain a variant of depressive disease? The case of primary fibromyalgia syndrome Tim A. Ahles
*, Muhammad
B. Yunus
* * and Alfonse
T. Masi
**
Departments of * Psychiutry and Behaviorai Medicine and * * Medicine, ~nive~siiy of Illinois Coliege oj~ed~~in~ Peoria, IL (U.S.A.) (Received 21 February 1986, revised received 12 August 1986, accepted 19 August 1986)
The responses of 45 primary fibromyalgia syndrome (PFS) patients, 29 rheumatoid arthritis (RA) patients and 31 healthy non-pain controls (NC) on the Zung Self-Rating Depression scale were compared. No difference between the PFS and RA groups was found, although the former has no known organic pathology, unlike the latter. Therefore, the hypothesis that the presentation of chronic pain in the absence of a known organic pathology is a variant of ‘depressive disease’ was not supported in the case of PFS. However, a subgroup of PFS (28.6%) and RA (31.0%) patients appeared to be experiencing significant depressive symptomatology.
fJ-
Key words: Primary fibromyalgia syndrome; Rheumatoid arthritis; Chronic pain; Depression
Introduction Blumer and Heilbrorm [5] have recently proposed that the presentation of chronic pain in the absence of an identifiable organic pathology is a variant of ‘depressive disease,’ the ‘pain-prone disorder.’ The authors describe 4 clinical features of the pain-prone disorder: (1) somatic complaint (continuous pain of obscure origin, h~~hond~ac~ preoccupation, desire for surgery); (2) ‘solid citizen’ style (denial of conflicts, idealization of self and family relations, ergomania [prepain]); (3) depression (anergia [post pain], anhedonia, insomnia, depressive mood and despair); and (4) history (family and personal history of depression and alcoholism, past abuse by spouse, crippled relative, relative with chronic pain). In addition to their theoretical formulation, Blumer and Heilbromr present empirical support for their theory. A higher frequency of depressive symptoms was
Correspondence to: Tim A. Ahles, Ph.D., Dartmouth Hitchcoek Medical Center, Behavioral Medicine Section, 704 Remsen, Dartmouth Medical School, Hanover, NH 03756, U.S.A. 0304-3959/87/$03.50
0 1987 Elsevier Science Publishers B.V. (Biomedical Division)
106
found in patients with pain which ‘by well accepted clinical standards had been found without somatic basis’ than in a rheumatoid arthritis (RA) group. Although the validity of the diagnosis of pain-prone disorder has gained some acceptance, others have criticized their conceptualization and the validity of the empirical support of the concept [17]. First, the investigators do not employ objective, standardized psychological measures of depressive symptoms. Second, the authors do not describe specific inclusion and exclusion criteria used to define the pain-prone disorder group. Therefore, this group may have been quite heterogeneous. An alternate approach would be to study patients who have no identifiable organic basis for their pain and who present with a well-defined clinical entity. Primary fibromyalgia syndrome (PFS) is a clinical syndrome, frequently seen by rheumatologists, defined by specific inclusion and exclusion criteria [20]. The condition is characterized by the presence of diffuse aches and pains in the absence of an identifiable organic pathology. Therefore, patients with PFS may present with symptoms similar to those of patients conforming to Blumer and Heilbronn’s description of the pain-prone disorder. Indeed, several authors have proposed that many PFS patients in fact have a variant of depression or psychogenic pain [3,8]. The purpose of the present paper is to review the literature examining the relationship between PFS and depression. Additionally, new data examining the extent to which PFS and RA patients differ in the reporting of depressive symptoms (pain-prone disorder clinical feature number 3 above) will be presented from a study similar in design to the one presented by Blumer and Heilbronn [5].
Review of the literature Several recent studies have utilized the Minnesota Multiphasic Personality Inventory (MMPI) to study psychological factors associated with PFS. Payne et al. [13] reported that PFS patients scored significantly higher on 6 of the clinical scales (Hs, Hy, Pd, Pa, SC, Ma) when compared to a RA group. These authors also noted a significant degree of variability of the MMPI scores of the PFS patients suggesting the presence of subgroups. Ahles et al. [2] found that PFS patients could be classified into 3 subgroups based on MMPI profiles: (1) normal profile (35.6%); (2) typical pain profile (33.3%); and (3) psychological disturbance profile (31.1%). Further, the use of contemporary MMPI norms [6] to score the data reduced the number of patients classified as ‘psychologically disturbed’ by nearly half [l]. Similar results (using the original MMPI norms) have been presented by Wolfe et al.
u91. In general, these studies support the hypothesis that psychological factors may play a significant role in a subgroup of patients with PFS. However, the method of classifying patients described above provides an indication of the level of psychopathology but does not supply specific diagnoses. Interestingly, a close examination of the studies cited above [2,13,19] revealed that in no study were the scores on the depression scale for the PFS patients significantly higher than the RA comparison
107
groups. Therefore, these data do not directly support the hypothesis that PFS is a variant of depression. Clark et al. [6] compared a ‘fibrositis’ group with a control group recruited from a general medical population using the Beck Depression Inventory (BDI) and the Symptom Checklist-90 (SCL-90-R). No group differences were found on the BDI or the depression subscale of the SCL-90-R. However, as the authors point out, the ‘fibrositis’ patients were selected from a general medical population and were not being specifically evaluated for ‘fibrositis.’ Therefore, the symptoms were probably quite mild which may have obscured group differences. Finally, Hudson et al. [9] found that significantly more fibromyalgia patients conformed to the DSM-III criteria of current (26%) or past history (45%) of depression when compared to an RA group. Additionally, the fibromyalgia group had significantly higher scores on the Hamilton Rating Scale for Depression. Unfortunately, several problems hinder the interpretation of the results: (1) all interviews were conducted by a single clinician; therefore, data necessary for calculating the reliability of the diagnosis of depression were not collected [14]; (2) the RA comparison group was quite small (N = 14); and (3) joint deformities were obvious in 3 RA patients, thereby revealing the diagnosis. Therefore, because of the small RA sample size, the interviewer was not blind to the medical diagnosis of a fairly large proportion (21.5%) of the sample. Further, caution must be taken in interpreting data concerning the past history of depression. The occurrence of a depressive episode may generally predispose an individual to medical/psychiatric problems, rather than the development of pain specifically, since an increased frequency of depression has been found in other disorders such as bulimia [l l] and alcoholism (121. Additionally, depression tends to be cyclical in nature whereas PFS is typically a continuous problem from its onset. Therefore, despite the resolution of the depression, the symptoms of PFS persist
WI. In summary, the studies reviewed provide mixed support for the hypothesis that PFS is a variant of depression. However, the frequency of ‘psychological disturbance’ profiles in PFS patients reported by Ahles et al. (31%) and Wolfe et al. (37%) is quite similar to the 26% frequency of current depression reported in the Hudson et al. study. Therefore, a subgroup of PFS patients may exist who have significant psychological problems, primarily depression. As part of a larger study [2], PFS, RA and healthy non-pain participants completed the Zung Self-Rating Depression scale [21]; a standardized measure of depression which, a recent study has suggested, is superior to the BDI or the MMPI D-scale as a measure of depressive symptomatology 1161. Therefore, the purpose of the present study was to evaluate whether the PFS patients had higher Zung scores than the RA and non-pain groups. A second purpose of the study was to evaluate the hypothesis that the subgroup of PFS patients, classified as ‘psychologically disturbed’ in the original study [2], exhibited significantly higher depression scores than the other subgroups.
108
Methods Forty-five PFS, 29 RA and 31 healthy non-pain controls (NC). from a larger study [2] completed the Zung Depression Inventory. The PFS patients had chronic, diffuse aches and pains and multiple soft tissue tender points in the absence of an underlying or associated condition such as rheumatoid arthritis, hypothyroidism, significant osteoarthritis or a history of trauma. Roentgenograms showed minor osteophytes in 4 patients, but in none could any symptoms be attributed to these findings. Results of laboratory tests, including complete blood count, Westergren erythrocyte sedimentation rate, blood chemistry profile, including muscle enzymes, as well as rheumatoid factor and antinuclear antibodies were normal or negative. Forty-three of the PFS patients were female with ages ranging from 17 to 54 (mean = 34 years) and with a mean symptom duration of 7 years. The RA patients (27 female, 2 male; aged 16-55 years, mean = 37 years) satisfied the American Rheumatism Association criteria for classical or definite rheumatoid arthritis [15]. Finally, 31 age-matched (k2 years) female controls (aged 17-53, mean = 35 years) with no significant illness, aches, or pains were recruited from friends, neighbors, or relatives of the PFS patients. This procedure was used to minimize differences in social status. All participants signed an informed consent form prior to participation. In order to examine the hypothesis that patients classified as ‘psychologically disturbed’ were experiencing higher levels of depression, the MMPI subgroups of the PFS patients from the original study [2] were utilized: (1) Normal Profile (no T scores > 70, N = 16); (2) Typical Pain Profile (T scores > 70 on HS, D and/or HY, N = 15); and (3) Psychological Disturbance Profile (4 or more T scores > 70, N = 14). Using this procedure, 90% of the subjects fell within these 3 categories. The remaining subjects had fewer than 4 T score elevations > 70, but at least one was on a scale other than HS, D or HY. For purposes of this analysis, these subjects were placed in the Typical Pain Profile group.
Results A one-way ANOVA was done with patient group as the independent variable and Zung SDS scores as the dependent variable. This analysis revealed a significant difference among the groups, F (2, 102) = 10.6, P < 0.001. Post-hoc analyses using the Newman-Keuls Multiple Range test revealed that the PFS and RA groups differed significantly from the NC group (P < 0.05) but did not differ from each other (Table I). Another one-way ANOVA was conducted among the PFS patients with MMPI subgroup as the independent variable. This analysis also produced a significant main effect, F (2, 42) = 18.8, P < 0.001. Newman-Keuls post-hoc analysis revealed that all 3 subgroups of PFS patients differed significantly (P < 0.05) on mean Zung SDS scores (Table II).
109
TABLE
1
MEAN ZUNG
SDS SCORES FOR THE PFS, R4 AND NC GROUPS
The PFS and RA groups differ significantly (P ,< 0.05) fmm the NC
Group
Zung SDS score
PFS f,N = 45) RA (N = 29) NC (N - 31)
49.Y& 11.2 47Zi+ 10.1
TABLE
3s.9+
group but do not differ
fOm
each
,,1,,1.-
9.8
II
MEAN ZUNG
SDS SCORES FUR THE 3 MMPI SUBGROUPS
All groups differ significantly
OF PFS PATIENTS
(U < 0.05) from each other. SDS score
GPJUD
Zung
Normal Profile (N = 16) Typical Rain Profile (N = 15) Fsychalugicaf Jkturbance Profile (N = 14)
41.8 + 8.7 4x.9+6.7 60.4 4 9.4
Finally, an SDS cutoff score of greater than 55 was used to divide patients into depressed and non-depressed groups 141. A &i-square analysis revealed that significantly more PFS (28.9%) and FLA (31%) patients scored within the depressed range when compared to the NC (6.5%) group (P < 0.05). However, the PFS and RA groups did not differ from each other. Further, a chi-square anaIysis revealed that significantly more (P < O.OS>PFS patients in the i psychckgically disturbed’ MMPI subgroup were classified as depressed (IO of 14) as compared to the ‘normal’ (7 of 16) or ‘typical pain’ (2 of 15) subgroups which did not differ from each other.
Discussion The data from this study, which is similar in design to that of Blumer and Heilbrorm, do not support the hypothesis that depressive symptoms are more common among PFS patients who have no known organic basis for their pain, than RA patients who have a ckar organic etiology for their pain. The PFS and RA patients do not differ in terms of either mean Zung SDS scores or the percentage of patients classified as depressed using a clinically relevant cutoff scare. The Zung appears to be a particularly relevant measure of major depressive symptoms since it systematically assesses those items evaluated in Btumer and Heilbronn’s original study (e.g., sleep disturbance, anhedonia, etc.). Of course, these data do not preclude the possibility that other groups of chronic pain patients e,xist who more closely conform to the clinical picture of the pain-prone disorder.
110
Additionally, Blumer and Heilbronn describe the pain-prone disorder as a variant of depressive ‘disease’ with clinical features, family history, biological markers and treatments similar to the DSM-III category of major affective disorder. The present data examined only the clinical symptoms of depression. However. other aspects of the depressive syndrome may predo~nate if one hypothesizes that PFS is a form of masked depression. Interestingly, Hudson et al. [IO] found non-suppression in only 1 of 23 fibromyalgia patients who were administered the dexamethasone suppression test (DST). Therefore, the DST results did not demonstrate a clear association between this biological marker of depression and fibromyalgia. Nonetheless, a study comparing the proportion of PFS and RA patients who fulfill established diagnostic criteria of masked depression would be important. However, these data do support the hypothesis that a subgroup of PFS and RA patients experience significant depressive symptomatology. In PFS patients, those classified as ‘psychologically disturbed’ had significantly higher depression scores than the other two groups. Further, the majority of PFS patients classified as depressed on the Zung exhibited the Psychological Disturbance profile on the MMPI. These results are not surprising given that there is a depression scale on the MMPI which is utilized to classify patients (although this is not a problem when comparing the ‘typical pain’ and ‘psycholo~cally disturbed’ subgroups). However. since definite diagnoses cannot be established using this MMPI coding system, these data support the notion that depressive symptoms are a significant factor in the ‘psychologically disturbed’ group. Additionally, the percentage of PFS patients classified as depressed in the present study (28.9%) is strikingly similar to the percentage of patients currently experiencing a depressive episode as reported by Hudson et al. (26%). Therefore, among the subgroup of PFS patients who experience ‘psychological disturbances.’ depression may be the most common type of psychopathology. Importantly, however, the question of whether the depression which is present is primary or secondary to living with chronic pain remains largely unresolved. Hudson et al. [9] reported that the depression developed prior to the PFS in 64% of their patients. However, a chi-square analysis using their data reveals that this percentage is not significantly different from chance (a reasonable prediction is that when comparing two relatively common disorders that have a similar age of onset that one (e.g., depression) will occur before the other (e.g., PFS) approximately 50% of the time). Additionally, as Hudson et al. are aware, the retrospective nature of their data make them somewhat inconclusive. Clearly, prospective studies are necessary to completely understand the relationship between PFS and depression.
References 1 Ahles, T.A., Yunus, M.B., Gaudier, B., Riley, SD. and Masi, A.T., The use of contemporary MMPI norms in the study of chronic pain patients, Pain, 24 (1986) 159-163. 2 Ahles, T.A.. Yunus, M.B., Riley, SD., Bradley, J.M. and Masi, A.T., Psychological factors associated with primary fibromyalgia syndrome. Arthr. Rheum., 27 (1984) 1101-1106.
111 3 Beetham, Jr., W.P., Diagnosis and management of fibrositis syndrome and psychogenic Med. Clin. N. Amer., 63 (1979) 433-439. 4 Blumenthal, M.D. and Dielman, T.E., Depressive symptomatology and role function population, Arch. gen. Psychiat., 32 (1975) 985-991. 5 Blumer, D. and Heilbronn, M., Chronic pain as a variant 6
7 8 9
10 11
12 13 14 15 16
17 18
19
20 21
of depressive
disease:
rheumatism, in a general the pain-prone
disorder, J. nerv. ment. Dis., 170 (1982) 381-406. Clark, S., Campbell, S.M., Forehand, M.E., Tindall, E.A. and Bennett, R.M., Clinical characteristics of fibrositis. II. A ‘blinded,’ controlled study using standard psychological tests, Arthr. Rheum., 28 (1985) 132-137. Colligan, R.C., Osboume, D., Swenson, W.M. and Offord, K.P., The aging MMPI: development of contemporary norms, Mayo Chn. Proc., 59 (1984) 377-390. Diamond, H.S., Psychogenic rheumatism, Clin. Rheumatol. Pratt., 2 (1984) 131-133. Hudson, J.I., Hudson, M.S., Pliner, L.F., Goldenberg, D.L. and Pope, Jr., H.G., Fibromyalgia and major affective disorder: a controlled phenomenology and family history study, Amer. J. Psychiat., 142 (1985) 44-446. Hudson, J.I., Pliner, L.F., Hudson, M.S., Goldenberg, D.L. and Melby, J.C., The dexamethasone suppression test in fibrositis, Biol. Psychiat., 19 (1984) 1489-1493. Hudson, J.I., Pope, H.G. and Jonas, J.M., Treatment of bulimia with antidepressants: theoretical considerations and clinical findings. In: A.J. Stunkard and E. Stellar (Eds.), Eating and its Disorders, Raven Press, New York, 1984, pp. 259-273. Keeler, M.H., Alcoholism and affective disorder. In: E.M. Pattison and E. Kaufman (Eds.), Encyclopedia Handbook of Alcoholism, Gardner Press, New York, 1982, pp. 618-627. Payne, T.C., Lea&t, F., Garron, D.C., Katz, R.S., Golden, H.E., Glickman, P.B. and Vanderplate, C. Fibrositis and psychological disturbance, Arthr. Rheum., 25 (1982) 213-217. Romano, J.M. and Turner, J.A., Chronic pain and depression: does the evidence support a relationship?, Psychol. Bull., 97 (1985) 18-34. Ropes, M.W., Bennett, G.A., Cobb, S., Jucox, R. and Jessar, R.A., 1958 revision of diagnostic criteria for rheumatoid arthritis, BuIl. rheum. Dis., 9 (1958) 175-176. Schaefer, A., Brown, J., Watson, C.G., Plemel, D., DeMotts, J., Howard, M.T., Pet& N., Balleweg, B.J. and Anderson, D., Comparison of the validities of the Beck, Zung and MMPI depression scales, J. consult. clin. Psychol., 50 (1985) 113-124. Turk, D.C. and Salovey, P., ‘Chronic pain as a variant of depressive disease’: a critical reappraisal, J. nerv. ment. Dis., 172 (1984) 3988404. Williams, J.B.W. and Spitzer, R.L., Idiopathic pain disorder: a critique of pain-prone disorder and a proposal for a revision of the DSM-III category psychogenic pain disorder, J. nerv. ment. Dis., 170 (1982) 415-419. Wolfe, F., Cathey, M.A., Kleineksel, S.M., Amos, S.P., Hoffman, R.G., Young, D.Y. and Hawky, D.J., Psychological status in primary fibrositis and fibrositis associated with rheumatoid arthritis, J. Rheumatol., 11 (1984) 500-506. Yunus, M.B., Masi, A.T., Calabro, J.J. and Miller, K.A., Primary fibromyalgia (fibrositis): clinical study of 50 patients with matched normal controls, Sem. Arthr. Rheum., 11 (1981) 151-171. Zung, W.W., A self-rating depression scale, Arch. gen. Psychiat., 12 (1965) 63-70.
Pain, 29 (1987) 105-111 Elsevier
PAI 01013
Is chronic pain a variant of depressive disease? The case of primary fibromyalgia syndrome Tim A. Ahles
*, Muhammad
B. Yunus
* * and Alfonse
T. Masi
**
Departments of * Psychiutry and Behaviorai Medicine and * * Medicine, ~nive~siiy of Illinois Coliege oj~ed~~in~ Peoria, IL (U.S.A.) (Received 21 February 1986, revised received 12 August 1986, accepted 19 August 1986)
The responses of 45 primary fibromyalgia syndrome (PFS) patients, 29 rheumatoid arthritis (RA) patients and 31 healthy non-pain controls (NC) on the Zung Self-Rating Depression scale were compared. No difference between the PFS and RA groups was found, although the former has no known organic pathology, unlike the latter. Therefore, the hypothesis that the presentation of chronic pain in the absence of a known organic pathology is a variant of ‘depressive disease’ was not supported in the case of PFS. However, a subgroup of PFS (28.6%) and RA (31.0%) patients appeared to be experiencing significant depressive symptomatology.
fJ-
Key words: Primary fibromyalgia syndrome; Rheumatoid arthritis; Chronic pain; Depression
Introduction Blumer and Heilbrorm [5] have recently proposed that the presentation of chronic pain in the absence of an identifiable organic pathology is a variant of ‘depressive disease,’ the ‘pain-prone disorder.’ The authors describe 4 clinical features of the pain-prone disorder: (1) somatic complaint (continuous pain of obscure origin, h~~hond~ac~ preoccupation, desire for surgery); (2) ‘solid citizen’ style (denial of conflicts, idealization of self and family relations, ergomania [prepain]); (3) depression (anergia [post pain], anhedonia, insomnia, depressive mood and despair); and (4) history (family and personal history of depression and alcoholism, past abuse by spouse, crippled relative, relative with chronic pain). In addition to their theoretical formulation, Blumer and Heilbromr present empirical support for their theory. A higher frequency of depressive symptoms was
Correspondence to: Tim A. Ahles, Ph.D., Dartmouth Hitchcoek Medical Center, Behavioral Medicine Section, 704 Remsen, Dartmouth Medical School, Hanover, NH 03756, U.S.A. 0304-3959/87/$03.50
0 1987 Elsevier Science Publishers B.V. (Biomedical Division)
106
found in patients with pain which ‘by well accepted clinical standards had been found without somatic basis’ than in a rheumatoid arthritis (RA) group. Although the validity of the diagnosis of pain-prone disorder has gained some acceptance, others have criticized their conceptualization and the validity of the empirical support of the concept [17]. First, the investigators do not employ objective, standardized psychological measures of depressive symptoms. Second, the authors do not describe specific inclusion and exclusion criteria used to define the pain-prone disorder group. Therefore, this group may have been quite heterogeneous. An alternate approach would be to study patients who have no identifiable organic basis for their pain and who present with a well-defined clinical entity. Primary fibromyalgia syndrome (PFS) is a clinical syndrome, frequently seen by rheumatologists, defined by specific inclusion and exclusion criteria [20]. The condition is characterized by the presence of diffuse aches and pains in the absence of an identifiable organic pathology. Therefore, patients with PFS may present with symptoms similar to those of patients conforming to Blumer and Heilbronn’s description of the pain-prone disorder. Indeed, several authors have proposed that many PFS patients in fact have a variant of depression or psychogenic pain [3,8]. The purpose of the present paper is to review the literature examining the relationship between PFS and depression. Additionally, new data examining the extent to which PFS and RA patients differ in the reporting of depressive symptoms (pain-prone disorder clinical feature number 3 above) will be presented from a study similar in design to the one presented by Blumer and Heilbronn [5].
Review of the literature Several recent studies have utilized the Minnesota Multiphasic Personality Inventory (MMPI) to study psychological factors associated with PFS. Payne et al. [13] reported that PFS patients scored significantly higher on 6 of the clinical scales (Hs, Hy, Pd, Pa, SC, Ma) when compared to a RA group. These authors also noted a significant degree of variability of the MMPI scores of the PFS patients suggesting the presence of subgroups. Ahles et al. [2] found that PFS patients could be classified into 3 subgroups based on MMPI profiles: (1) normal profile (35.6%); (2) typical pain profile (33.3%); and (3) psychological disturbance profile (31.1%). Further, the use of contemporary MMPI norms [6] to score the data reduced the number of patients classified as ‘psychologically disturbed’ by nearly half [l]. Similar results (using the original MMPI norms) have been presented by Wolfe et al.
u91. In general, these studies support the hypothesis that psychological factors may play a significant role in a subgroup of patients with PFS. However, the method of classifying patients described above provides an indication of the level of psychopathology but does not supply specific diagnoses. Interestingly, a close examination of the studies cited above [2,13,19] revealed that in no study were the scores on the depression scale for the PFS patients significantly higher than the RA comparison
107
groups. Therefore, these data do not directly support the hypothesis that PFS is a variant of depression. Clark et al. [6] compared a ‘fibrositis’ group with a control group recruited from a general medical population using the Beck Depression Inventory (BDI) and the Symptom Checklist-90 (SCL-90-R). No group differences were found on the BDI or the depression subscale of the SCL-90-R. However, as the authors point out, the ‘fibrositis’ patients were selected from a general medical population and were not being specifically evaluated for ‘fibrositis.’ Therefore, the symptoms were probably quite mild which may have obscured group differences. Finally, Hudson et al. [9] found that significantly more fibromyalgia patients conformed to the DSM-III criteria of current (26%) or past history (45%) of depression when compared to an RA group. Additionally, the fibromyalgia group had significantly higher scores on the Hamilton Rating Scale for Depression. Unfortunately, several problems hinder the interpretation of the results: (1) all interviews were conducted by a single clinician; therefore, data necessary for calculating the reliability of the diagnosis of depression were not collected [14]; (2) the RA comparison group was quite small (N = 14); and (3) joint deformities were obvious in 3 RA patients, thereby revealing the diagnosis. Therefore, because of the small RA sample size, the interviewer was not blind to the medical diagnosis of a fairly large proportion (21.5%) of the sample. Further, caution must be taken in interpreting data concerning the past history of depression. The occurrence of a depressive episode may generally predispose an individual to medical/psychiatric problems, rather than the development of pain specifically, since an increased frequency of depression has been found in other disorders such as bulimia [l l] and alcoholism (121. Additionally, depression tends to be cyclical in nature whereas PFS is typically a continuous problem from its onset. Therefore, despite the resolution of the depression, the symptoms of PFS persist
WI. In summary, the studies reviewed provide mixed support for the hypothesis that PFS is a variant of depression. However, the frequency of ‘psychological disturbance’ profiles in PFS patients reported by Ahles et al. (31%) and Wolfe et al. (37%) is quite similar to the 26% frequency of current depression reported in the Hudson et al. study. Therefore, a subgroup of PFS patients may exist who have significant psychological problems, primarily depression. As part of a larger study [2], PFS, RA and healthy non-pain participants completed the Zung Self-Rating Depression scale [21]; a standardized measure of depression which, a recent study has suggested, is superior to the BDI or the MMPI D-scale as a measure of depressive symptomatology 1161. Therefore, the purpose of the present study was to evaluate whether the PFS patients had higher Zung scores than the RA and non-pain groups. A second purpose of the study was to evaluate the hypothesis that the subgroup of PFS patients, classified as ‘psychologically disturbed’ in the original study [2], exhibited significantly higher depression scores than the other subgroups.
108
Methods Forty-five PFS, 29 RA and 31 healthy non-pain controls (NC). from a larger study [2] completed the Zung Depression Inventory. The PFS patients had chronic, diffuse aches and pains and multiple soft tissue tender points in the absence of an underlying or associated condition such as rheumatoid arthritis, hypothyroidism, significant osteoarthritis or a history of trauma. Roentgenograms showed minor osteophytes in 4 patients, but in none could any symptoms be attributed to these findings. Results of laboratory tests, including complete blood count, Westergren erythrocyte sedimentation rate, blood chemistry profile, including muscle enzymes, as well as rheumatoid factor and antinuclear antibodies were normal or negative. Forty-three of the PFS patients were female with ages ranging from 17 to 54 (mean = 34 years) and with a mean symptom duration of 7 years. The RA patients (27 female, 2 male; aged 16-55 years, mean = 37 years) satisfied the American Rheumatism Association criteria for classical or definite rheumatoid arthritis [15]. Finally, 31 age-matched (k2 years) female controls (aged 17-53, mean = 35 years) with no significant illness, aches, or pains were recruited from friends, neighbors, or relatives of the PFS patients. This procedure was used to minimize differences in social status. All participants signed an informed consent form prior to participation. In order to examine the hypothesis that patients classified as ‘psychologically disturbed’ were experiencing higher levels of depression, the MMPI subgroups of the PFS patients from the original study [2] were utilized: (1) Normal Profile (no T scores > 70, N = 16); (2) Typical Pain Profile (T scores > 70 on HS, D and/or HY, N = 15); and (3) Psychological Disturbance Profile (4 or more T scores > 70, N = 14). Using this procedure, 90% of the subjects fell within these 3 categories. The remaining subjects had fewer than 4 T score elevations > 70, but at least one was on a scale other than HS, D or HY. For purposes of this analysis, these subjects were placed in the Typical Pain Profile group.
Results A one-way ANOVA was done with patient group as the independent variable and Zung SDS scores as the dependent variable. This analysis revealed a significant difference among the groups, F (2, 102) = 10.6, P < 0.001. Post-hoc analyses using the Newman-Keuls Multiple Range test revealed that the PFS and RA groups differed significantly from the NC group (P < 0.05) but did not differ from each other (Table I). Another one-way ANOVA was conducted among the PFS patients with MMPI subgroup as the independent variable. This analysis also produced a significant main effect, F (2, 42) = 18.8, P < 0.001. Newman-Keuls post-hoc analysis revealed that all 3 subgroups of PFS patients differed significantly (P < 0.05) on mean Zung SDS scores (Table II).
109
TABLE
1
MEAN ZUNG
SDS SCORES FOR THE PFS, R4 AND NC GROUPS
The PFS and RA groups differ significantly (P ,< 0.05) fmm the NC
Group
Zung SDS score
PFS f,N = 45) RA (N = 29) NC (N - 31)
49.Y& 11.2 47Zi+ 10.1
TABLE
3s.9+
group but do not differ
fOm
each
,,1,,1.-
9.8
II
MEAN ZUNG
SDS SCORES FUR THE 3 MMPI SUBGROUPS
All groups differ significantly
OF PFS PATIENTS
(U < 0.05) from each other. SDS score
GPJUD
Zung
Normal Profile (N = 16) Typical Rain Profile (N = 15) Fsychalugicaf Jkturbance Profile (N = 14)
41.8 + 8.7 4x.9+6.7 60.4 4 9.4
Finally, an SDS cutoff score of greater than 55 was used to divide patients into depressed and non-depressed groups 141. A &i-square analysis revealed that significantly more PFS (28.9%) and FLA (31%) patients scored within the depressed range when compared to the NC (6.5%) group (P < 0.05). However, the PFS and RA groups did not differ from each other. Further, a chi-square anaIysis revealed that significantly more (P < O.OS>PFS patients in the i psychckgically disturbed’ MMPI subgroup were classified as depressed (IO of 14) as compared to the ‘normal’ (7 of 16) or ‘typical pain’ (2 of 15) subgroups which did not differ from each other.
Discussion The data from this study, which is similar in design to that of Blumer and Heilbrorm, do not support the hypothesis that depressive symptoms are more common among PFS patients who have no known organic basis for their pain, than RA patients who have a ckar organic etiology for their pain. The PFS and RA patients do not differ in terms of either mean Zung SDS scores or the percentage of patients classified as depressed using a clinically relevant cutoff scare. The Zung appears to be a particularly relevant measure of major depressive symptoms since it systematically assesses those items evaluated in Btumer and Heilbronn’s original study (e.g., sleep disturbance, anhedonia, etc.). Of course, these data do not preclude the possibility that other groups of chronic pain patients e,xist who more closely conform to the clinical picture of the pain-prone disorder.
110
Additionally, Blumer and Heilbronn describe the pain-prone disorder as a variant of depressive ‘disease’ with clinical features, family history, biological markers and treatments similar to the DSM-III category of major affective disorder. The present data examined only the clinical symptoms of depression. However. other aspects of the depressive syndrome may predo~nate if one hypothesizes that PFS is a form of masked depression. Interestingly, Hudson et al. [IO] found non-suppression in only 1 of 23 fibromyalgia patients who were administered the dexamethasone suppression test (DST). Therefore, the DST results did not demonstrate a clear association between this biological marker of depression and fibromyalgia. Nonetheless, a study comparing the proportion of PFS and RA patients who fulfill established diagnostic criteria of masked depression would be important. However, these data do support the hypothesis that a subgroup of PFS and RA patients experience significant depressive symptomatology. In PFS patients, those classified as ‘psychologically disturbed’ had significantly higher depression scores than the other two groups. Further, the majority of PFS patients classified as depressed on the Zung exhibited the Psychological Disturbance profile on the MMPI. These results are not surprising given that there is a depression scale on the MMPI which is utilized to classify patients (although this is not a problem when comparing the ‘typical pain’ and ‘psycholo~cally disturbed’ subgroups). However. since definite diagnoses cannot be established using this MMPI coding system, these data support the notion that depressive symptoms are a significant factor in the ‘psychologically disturbed’ group. Additionally, the percentage of PFS patients classified as depressed in the present study (28.9%) is strikingly similar to the percentage of patients currently experiencing a depressive episode as reported by Hudson et al. (26%). Therefore, among the subgroup of PFS patients who experience ‘psychological disturbances.’ depression may be the most common type of psychopathology. Importantly, however, the question of whether the depression which is present is primary or secondary to living with chronic pain remains largely unresolved. Hudson et al. [9] reported that the depression developed prior to the PFS in 64% of their patients. However, a chi-square analysis using their data reveals that this percentage is not significantly different from chance (a reasonable prediction is that when comparing two relatively common disorders that have a similar age of onset that one (e.g., depression) will occur before the other (e.g., PFS) approximately 50% of the time). Additionally, as Hudson et al. are aware, the retrospective nature of their data make them somewhat inconclusive. Clearly, prospective studies are necessary to completely understand the relationship between PFS and depression.
References 1 Ahles, T.A., Yunus, M.B., Gaudier, B., Riley, SD. and Masi, A.T., The use of contemporary MMPI norms in the study of chronic pain patients, Pain, 24 (1986) 159-163. 2 Ahles, T.A.. Yunus, M.B., Riley, SD., Bradley, J.M. and Masi, A.T., Psychological factors associated with primary fibromyalgia syndrome. Arthr. Rheum., 27 (1984) 1101-1106.
111 3 Beetham, Jr., W.P., Diagnosis and management of fibrositis syndrome and psychogenic Med. Clin. N. Amer., 63 (1979) 433-439. 4 Blumenthal, M.D. and Dielman, T.E., Depressive symptomatology and role function population, Arch. gen. Psychiat., 32 (1975) 985-991. 5 Blumer, D. and Heilbronn, M., Chronic pain as a variant 6
7 8 9
10 11
12 13 14 15 16
17 18
19
20 21
of depressive
disease:
rheumatism, in a general the pain-prone
disorder, J. nerv. ment. Dis., 170 (1982) 381-406. Clark, S., Campbell, S.M., Forehand, M.E., Tindall, E.A. and Bennett, R.M., Clinical characteristics of fibrositis. II. A ‘blinded,’ controlled study using standard psychological tests, Arthr. Rheum., 28 (1985) 132-137. Colligan, R.C., Osboume, D., Swenson, W.M. and Offord, K.P., The aging MMPI: development of contemporary norms, Mayo Chn. Proc., 59 (1984) 377-390. Diamond, H.S., Psychogenic rheumatism, Clin. Rheumatol. Pratt., 2 (1984) 131-133. Hudson, J.I., Hudson, M.S., Pliner, L.F., Goldenberg, D.L. and Pope, Jr., H.G., Fibromyalgia and major affective disorder: a controlled phenomenology and family history study, Amer. J. Psychiat., 142 (1985) 44-446. Hudson, J.I., Pliner, L.F., Hudson, M.S., Goldenberg, D.L. and Melby, J.C., The dexamethasone suppression test in fibrositis, Biol. Psychiat., 19 (1984) 1489-1493. Hudson, J.I., Pope, H.G. and Jonas, J.M., Treatment of bulimia with antidepressants: theoretical considerations and clinical findings. In: A.J. Stunkard and E. Stellar (Eds.), Eating and its Disorders, Raven Press, New York, 1984, pp. 259-273. Keeler, M.H., Alcoholism and affective disorder. In: E.M. Pattison and E. Kaufman (Eds.), Encyclopedia Handbook of Alcoholism, Gardner Press, New York, 1982, pp. 618-627. Payne, T.C., Lea&t, F., Garron, D.C., Katz, R.S., Golden, H.E., Glickman, P.B. and Vanderplate, C. Fibrositis and psychological disturbance, Arthr. Rheum., 25 (1982) 213-217. Romano, J.M. and Turner, J.A., Chronic pain and depression: does the evidence support a relationship?, Psychol. Bull., 97 (1985) 18-34. Ropes, M.W., Bennett, G.A., Cobb, S., Jucox, R. and Jessar, R.A., 1958 revision of diagnostic criteria for rheumatoid arthritis, BuIl. rheum. Dis., 9 (1958) 175-176. Schaefer, A., Brown, J., Watson, C.G., Plemel, D., DeMotts, J., Howard, M.T., Pet& N., Balleweg, B.J. and Anderson, D., Comparison of the validities of the Beck, Zung and MMPI depression scales, J. consult. clin. Psychol., 50 (1985) 113-124. Turk, D.C. and Salovey, P., ‘Chronic pain as a variant of depressive disease’: a critical reappraisal, J. nerv. ment. Dis., 172 (1984) 3988404. Williams, J.B.W. and Spitzer, R.L., Idiopathic pain disorder: a critique of pain-prone disorder and a proposal for a revision of the DSM-III category psychogenic pain disorder, J. nerv. ment. Dis., 170 (1982) 415-419. Wolfe, F., Cathey, M.A., Kleineksel, S.M., Amos, S.P., Hoffman, R.G., Young, D.Y. and Hawky, D.J., Psychological status in primary fibrositis and fibrositis associated with rheumatoid arthritis, J. Rheumatol., 11 (1984) 500-506. Yunus, M.B., Masi, A.T., Calabro, J.J. and Miller, K.A., Primary fibromyalgia (fibrositis): clinical study of 50 patients with matched normal controls, Sem. Arthr. Rheum., 11 (1981) 151-171. Zung, W.W., A self-rating depression scale, Arch. gen. Psychiat., 12 (1965) 63-70.