chronic low back pain and depression
TRANSCRIPT
K. RANOA RAMA KRISHNAN. M.B.
RANDAL D. FRANCE. M.D.
JEFFREY L. HOUPT. M.D. '
Chronic low back painand depression
Dr. Krishnan and Dr. France are both assistant professors at Duke University MedicalCenter. Dr. Houpt is choirman ofthe depanment ofpsychiatry at Emory University, andatthe time ofthis study he was prOfessor ofpsychiatry at Duke University Medical Center.Reprint requests to Dr. France, Department ofPsychiatry, Duke University MedicalCenter, Box 3903, Durhom. NC 27710.
ABSTRACT: In an attempt to clarify the relationship between chroniclow back pain and depression, the authors studied the incidence ofdepression, alcoholism, and chronic back pain in first-degreerelatives of chronic pain patients with and without depression. Ahigher incidence of recurrent unipolar depression was found in thoserelatives of patients with depression than without depression. Thesefindings raise questions about the concept of chronic low back painsimply as a variant of depression and they suggest that theoccurrence of major depression together with chronic back painmight relate to genetic vulnerability to depression.
Chronic pain syndrome is often associated with depression.' but the exactnature of this association remains unclear. Some2have considered chronicpain a variant of depression; others'have conceptualized it as maskeddepression. These hypotheses havebeen based on the assumption that patients with chronic pain share manyfeatures with depressed patients. suchas anhedonia, appetite and sleep disturbances. ,,2 response to tricyclic
drugs,· neuroendocrine abnonnalities,> and increased familial incidenceof alcoholism and depression. 2.•However. as Williams and Spitzer'have pointed out, the evidence forchronic pain as a variant ofdepressionis not compelling.
Pilowsky and associates' examinedthe characteristics of depression inpain clinic patients and found thatabout 10% of them had a depressivesyndrome. In a later study. Pilowsky
and Bassett" noted a number ofdifferences between patients with chronicpain and those with depression in demographic characteristics, abnormalillness behavior patterns, and recall ofchildhood events. Maruta and associates lO also found similar differencesbetween chronic pain patients and patients with depression.
In a recent review" we noted that atpresent insufficient evidence is available for the efficacy of tricyclic antidepressants in the treatment of pain.without depression. In a study'2 of thedexamethasone suppression test inchronic low back pain patients, wefound a 40% incidence of abnormalsuppression ofcortisol in patients withmajor depression, but normal suppression in patients without it. Thesestudies clearly raise questions aboutchronic pain being regarded simply asa variant of depression or as maskeddepression.
In this paper we describe a preliminary study undertaken to further clarify the relationship between chroniclow back pain and depression by comparing the frequency of depression,alcoholism, and chronic low backpain in first-degree relatives of
APRIL 1985 • VOL 26 • NO 4 199
~ 1-Demographlc and Clinical Characteristics ofChronic Pain Patients WIth and WIthout Major
II Depression
"alor Nomelordep.....lon depresalon
(N = 34) (N=16) Significance
Mean age ± SO (yr) 49.82±3.30 46.18±4.31 NS'
SexMale 18 9 NSFemale 16 7
Mean duration of pain 3.36± 1.70 4.93±2.20 NS'± SO (yr)
Mean number of siblings 4.52 4.56 NS'
Number currently married 33 15 NS
History of operations: Yes 20 10 NStNo 14 6
Organic pathology present:Yes 28 14 NSNo 6 2
'Student/tesltChi·square tesl
Pain and depression
chronic low back pain patients withand without major depression.
ProcedureThe 50 consecutive chronic low backpain patients involved in this studyhad been admitted to a pain management unit after initial screening at anoutpatient pain clinic. The structureand functioning of the clinic and unithave been described elsewhere. 13 Allpatients admitted to the unit were thoroughly investigated for somatic pathology that might be contributing tothe pain. These investigations included orthopedic and neurosurgical evaluations, electromyography (EMG),computed tomography, and myelography.
The inclusion criterion for the studywas the presence of daily low backpain for more than six months, with
300
that pain being the major complaintfor which help was soug~t. Based onthe above evaluations, none of the patients had a somatic basis for the pain.Although 84% (42) of them had abnormal EMG or physical findings,these findings often related to priorsurgery or injury and were not thoughtby neurosurgical and orthopedic consultants to be sufficient to account forthe chronic pain. Each patient was interviewed by one of the authors (RF orRK), and a lifetime diagnosis utilizingResearch Diagnostic Criteria (ROC)was formed as to whether or not thepatient had major depression, basedon medical records as well as on thatinterview. The proband was then interviewed by the other of the two authors, using the family history-ROCmethod." This interviewer for familyhistory was blind to the proband diag-
nosis made by the first interviewer.Family history data were obtainedonly for first-degree relatives.
Prior to initiation of the study, thetwo interviewers had obtained high interrater agreement (K = 1.0),using theROC, regarding the presence or absence of major depression in six patients. With regard to the family history-ROC method, good interrateragreement (K=0.9) was achieved forthe major diagnosis, such as alcoholdependence, bipolar disorder. or recurrent unipolar depression. Interrateragreement was poor (K=0.3) forchronic depression. This group wasnot included in the data analysis.
Morbidity risk was calculated usingan abridged Weinberg formula,
a
b - bo - bm
"2
in which a is the number of affectedindividuals. b is the total number of individuals examined, bo the number ofindividuals who have not passed intothe risk period, and bm the number ofindividuals who are within the risk period. In addition to psychiatric disorders, a family history of back disorders was also obtained. No familymembers were interviewed. The agerange used for risk of alcoholism was20 to 40 years and for depression, ISto 60 years.
ResultsDemographic and clinical differencesbetween the two groups of chronicpain patients are shown in Table I.Thirty-four patients had major depression, six of whom had it before the onset of chronic back pain. The other 16patients did not have a history of majordepression or other psychiatric disorders. Sixteen of the patients with major depression satisfied criteria for endogenous depression, ROC type. According to the probands, no family
PSYCHOSOMATICS
Table 2-Morbidlty Risk (MR) for Affective Disordersand Alcoholism in Patients and Siblings of Chronic
Pain Patients With and Without Depression
Major depression No major depression
MR,% MR,% MR,% MR,%Family hi tory Parents Siblings Parents Siblingsdiagnosis-ROC (N=68) (N = 154) (N=32) (N=73)
Alcohol dependence 8.89 531 625 0
Remitting depression 0 2.56 667" 0
Recurrent unipolar 6.67 2.56 a 0depression
Bipolar disorder 1,67 128 0 0'The two parents who showed remitting depreSSion were both paren so the sameproband
history of psychopathology existed in27 (54%) of the families.
Table 2 shows the morbidity risk fordepression and alcoholism in parentsand siblings of chronic pain patientswith and without depression. Morbidity risk for recurrent unipolar depression was higher in families of chronicpain patients with than withoutdepression. The risk for alcohol dependence in the parents of both groupswas not greatly dissimilar, but risk foralcohol dependence was higher in thesiblings of patients with depression.Four (12%) of the 34 probands withmajor depression had first-degree relatives with back problems suggestiveof disk pathology and two (13%) ofthe 16 probands without majordepression had first-degree relatives withback problems. One proband with ahistory of major depression had a parent who had committed suicide. Onesibling of a patient with depressionhad schizoaffective disorder. None ofthe children of probands, both withand without depression, had any history of psychiatric disorders or alcoholism. However. the significance ofthe results is limited because of thesmall sample size.
DiscussionThe findings indicate that chronicback pain patients with a lifetime history of major depression differed fromsuch patients without major depression in that a higher percentage offirst-degree relatives of probands withdepression had a history of affectivedisorders. Blumer and Heilbronn' reported in their study of chronic pain ahigher incidence of mental disorderssuch as depression in the families ofchronic pain patients. The fact thatthey did not separate out patients withand without major depression precludes comparison of their findingswith our results. The higher incidencein their study might be a reflection of
APRIL 1985· VOL 26· NO 4
the incidence of major depression intheir population. A study· of 20chronic pain patients found that 73%of chronic pain patients with depression and 40% of such patients withoutdepression had a family history ofdepressive spectrum disorder. However, they did not provide sufficientdata to assess the morbidity risk ofdepression or alcoholism and thismakes it difficult to compare our results with theirs.
The morbidity risk reported by usfor recurrent unipolar depression inthe families of chronic pain patientswith major depression is lower thanthat found in other studies. 15.11 Thisprobably is a consequence of themethod used. The family historyROC method has limitations in termsof sensitivity. and this might have ledto underreporting of psychopathology. Increased sensitivity could havebeen obtained if family members hadbeen interviewed. The method doesproduce more false negatives thanfalse positives. I. Overreporting ofdepression in the relatives of depressed probands may occur. but thishas not been documented.
The morbidity risk for alcohol dependence in families of chronic painpatients is similar to that reported elsewhere" for families of probands withunipolar depression. probably indicating that affective illness is transmittedin these families without regard towhether or not alcoholism is present.
Our findings indicate that the ideathat pain is a variant of depressionmight be an oversimplification of theissue. In some cases major depressioncould be a concomitant feature ofchronic back pain. This raises the possibility that in some chronic pain patients the occurrence of major depression may relate to a genetic vulnerability to depression. The study must beregarded as preliminary in view of thelimited number of subjects. A familystudy ofchronic pain patients with andwithout depression may further clarifythe relationship between chronic painsyndromes and depression. 0
REFERENCES1 Sternbach RA: Pam Patients. Traits and Treat·
ment New York, Academic Press, 1974.2. Blumer D, Heilbronn M: Chronic pain as a var·
iant of depressive disease. The pain-pronedisorderJNervMentDis 170:381-406, 1979.
(continued)
301
Pain and depression
3. Lopez-lbor J: Masked depression. Br J Psychiatry 120:245-258,1972.
4. Ward GN. Bloom VL, Friedel RO: The effecti·veness of tricyclic antidepressants in thetreatment of coexisting pain and depression.Pain 7:331-341, 1979.
5. Blumer D. Zorick F, Heilbronn M: Biologicalmarkers for depression in chronic pain. JNeN Ment Dis 170:425-428, 1982.
6. Schaffer CB, Donlan PT, Billie RM: Chronicpain and depression: A clinical and familyhistory survey. Am J Psychiatry 137: 118-120.1980
7. Williams JBW, Spitzer RL: Idiopathic pain disorder. A critique of pain-prone disorder and aproposal for revision of the DSM-III categorypsychogenic pain disorders. J NeN Ment Dis170:415-419,1982.
8. Pilowsky I. Chapman CR, Bonica JJ: Pain,
CORRECTIONThe last three items were inadvertently omitted from the Table in the recently published article, "Referral formedically unexplained somatic complaints: The role of histrionic traits,"by Phillip R. Slavney, Mark L. Teitel-
depression and illness behavior in a pain clinic population. Pain 4: 183-192, 1977.
9. Pilowsky I, Bassett DL: Pain and depression.Br JPsychiatry 14130-36,1982.
10 Maruta T, Swanson OW. Swenson WM Painas a psychiatric symptom Comparisonbetween low back pain and depression. Psychosomatics 17:123-127, 1976.
11 France RD, Houpt JL, Ellinwood EH: Therapeutic effects of antidepressants in chronicpain. Gen Hosp Psychiatry 6:55·63, 1984
12. France RD, Krishnan KRR. Houpt JL. et al Differentiation of depression from chronic painwith the dexamethasone suppression testand DSM-1I1 AmJPsychiatry 141 :1577·1579,1984
13. Houpt JL, Keefe FJ. Snipes M The ClinicalSpecialty Unit: The use of the psychiatric inpatient unit to treat chronic pain syndromes.
baum, and Gary A. Chase (Psychosomatics 26: 103-109, 1985). The paragraph referring to these lines concluded: "The items least frequently ratedindicate that the referring physiciansdid not believe many patients to have
Gen Hosp Psychiatry 665-70. 198414. Andreasen NC. Endicott J, Spitzer RL: The
family history method using diagnostic criteria Reliability and validity. Arch Gen Psychiatry 341229-1235. 1977
15 Perris C Genetic transmission of depressivepsychoses Acta Psychiatr Scand203(suppl) 15-44. 1966
16 Smeraldi E. Negri F. Melica AM: A geneticstudy of affective disorder. Acta PsychiatrScand 56382-393. 1977
17. Gershon ES. Hamovlt J. Guroff JJ, et al: A family study of schizoaffective, bipolar I. bipolarII, unipolar and normal control probands.Arch Gen Psychiatry 391157-1167, 1982
18 Thompson WB. Orvaschel H, Prusoff BA, et al:Evaluation of family history method for ascertaining psyChiatric disorder Arch Gen Psychiatry 3953-58. 1982
been malingerers (item 13), to havehad factitious illnesses (item 3), or tohave been motivated by secondarygain (items 14 and 15)." The correctTable appears below. We sincerely regret this error.
302
Table-Frequency With Which Checklist Items WereIndicated for 100 Patients by Referring Physicians
Item No.
2. The symptoms appear to be excessive for the physical findings.
1. The symptoms cannot be explained by the physical findings
5 The symptoms seem primarily emotional In nature rather than physical
7. The patient is self-dramatizing.
9. The patient is dependent.
8. The patient is attention-seeking.
12. The patient is demanding.
6. The patient cannot be reassured about his/her health.
11. The patient is suggestible about his/her symptoms.
14. The patient is using his/her symptoms to avoid responsibility.
10. The patient is vague about his/her symptoms.
4. The patient is indifferent to his/her disability.
15. The patient is using his/her symptoms for financial gain
13. The patient is lying about his/her symptoms.
3. The patient has injured himself/herself so as to produce symptoms
Frequency
69
65
48
43
41
33
32
30
21
19
18
11
8
6
5
PSYCHOSOMATICS