Comments on Sullivan et al., PAIN, 50 (1992) 5–13

249 It would be self-indulgent to attribute our results to a superior methodology. This would mean that numerous clinicians and investigators were misguided by their results and that we obtained the final objective answer: antidepressant-induced analgesia is a myth. A more safer conclusion would be that the antidepressant-induced analgesic effect is far from well established under all conditions. The antidepressant chosen, the pain patients involved and the type of pain assessment all seem powerful determinants of the outcome and need further investigation. In our study, for example, we used mianserin and, as the meta-analysis indicates, this might be a drug that has no analgesic properties for non-headache pain. To return to the letter of Richardson and Williams, it is clear that we share their scepticism and that we look out for further confirming or disconfirming evidence. We think the conclusions and provisional guidelines we formulated in our meta-analytic review give a balanced appraisal of past research, but it is true that science develops not only through summarizing the past but also by learning from it and trying to systematically replicate studies with a refined methodology. Finally, we want to thank Richardson and Williams for their inspiring letter and for the interesting references. Their attention to the methodological subtleties and alternative explanations in drug trials strengthens our conviction that there is a lot of work still to be done in this area.

Gracely, R.H., Dubner, R., Deeter, W.R. and Wolskee, P.J., Clinicians’ expectations influence placebo analgesia, Lancet, Jan. (1985) 43. Onghena, P. and Van Houdenhove, B., Antidepressant-induced analgesia in chronic non-malignant pain: a meta-analysis of 39 placebo-controlled studies, Pain, 49 (1992) 205-219. Pilowsky, I. and Barrow, CC., A controlled study of psychotherapy and amitriptyline used individually and in combination in the treatment of chronic intractable, ‘psychogenic’ pain, Pain, 40 (1990) 3-19. Rosenthal, R., Meta-analysis: a review, Psychosom. Med., 53 (1991) 247-271. Thomson, R., Side effects and placebo amplification, Br. J. Psychiat., 140 (1982) 64-68. Van Houdenhove, B., Verstraeten, D., Onghena, P. and De Cuyper, H., Chronic idiopathic pain, mianserin and ‘masked’ depression, Psychother. Psychosom., in press. Wheatley, D., Antidepressants in elderly arthritics, Practitioner, 230 (1986) 477-481.

Patrick Onghena Boudewijn Van Houdenhove

References Dept. of Psychology and Faculty of Medicine

Glass, G.V., Primary, secondary, Educ. Res., 5 (1976) 3-8.

and meta-analysis

of research,

Katholieke Uniuersiteit Leuoen B-3000 Leuuen, Belgium

PAIN 02229

Comments

on Sullivan et al., PAIN, 50 (1992) 5-13

Sullivan and his colleagues’ article “The treatment of depression in chronic low back pain: review and recommendations” is a useful examination of an important subject. However, I must take issue with their statement that “Depressed chronic pain patients show a greater tendency to drop out of treatment prematurely, and may be more likely to relapse following treatment.” Although they do note “that research in this area has not been unequivocal in showing a relation between depression and poor rehabilitation outcome,” I do not believe that their comments, even with the addition of this somewhat tepid qualifier, accurately reflect the current literature. In support of their view regarding the negative impact of depression, the authors acknowledge studies by Kerns and Haythornthwaite (1988) and Painter et al. (1980). The former reported that depressed patients were. more likely to drop out of an interdisciplinary outpatient pain rehabilitation program. In contrast, in our study of patients who were discharged from or left a 21-day inpatient multidisciplinary pain program prior to completion, we found that, on pre-admission testing, they admitted to less psychopathology including depression than those who completed the program (King and Snow 1989). Furthermore, Painter et al. (1980) reported that the patients who were the most successful in maintaining the benefits from a chronic pain treatment program considered themselves to have been more depressed at the time of admission to the program than those who were less successful. Similarly, Kleinke and Spangler (1988) reported that an elevation in the MMPI depression scale predicted treatment success in terms of admission-to-discharge improvement. The effect of the psychological state of chronic pain patients on treatment outcome is an unresolved issue that requires more study.

Clearly, any final conclusions are premature and unsubstantiated by the current literature. Unfortunately, comments such as those made by Sullivan et al., especially when included in a comprehensive review article, may lead clinicians to inappropriately exclude from treatment patients who might benefit.

References Kerns, R.D. and Haythornthwaite, J.A., Depression among chronic pain patients: cognitive-behavioral analysis and effect on rehabilitation outcome, J. Consult. Clin. Psychol., 56 (1988) 870-876. King, S.A. and Snow, B.R., Factors for predicting premature termination from a multidisciplinary inpatient chronic pain program, Pain, 39 (1989) 281-287. Kleinke, CL. and Spangler, A.S., Predicting treatment outcome of chronic back pain patients in a multidisciplinary pain clinic: methodological issues and treatment implications, Pain, 33 (1988) 41-48. Painter, J.R., Seres, J.L. and Newman, RI., Assessing benefits of pain centers: why some patients regress, Pain, 8 (1980) 101-113. Sullivan, M.J.L., Reesor, K., Mikail, S. and Fisher R., The treatment of depression in chronic low back pain: review and recommendations, Pain, 50 (1992) 5-13. Steven A. King Pain Center Jefferson Medical College Philadelphia, PA 19107, USA