Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-02T18:44:00.713Z Has data issue: false hasContentIssue false

Which treatments are effective: an epidemiological perspective1

Published online by Cambridge University Press:  11 October 2011

Michael G. Gelder*
Affiliation:
Department of Psychiatry, Warneford Hospital, Oxford
*
Indirizzo per la corrispondenza: Professor M. G. Gelder, University Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX (England). Fax +44 - 1-865.793.101

Summary

Objective – To consider some of the problems that may arise when the results of clinical trials are applied uncritically to everyday clinical practice. To show how an epidemiological perspective makes it easier to identify these problems. Method – A review of clinical trials to illustrate problems of: (a) covert selection bias in individual trials, (b) bias in the selection of trials included in reviews and meta-analyses. Results – Several kinds of selection bias are known to exist. In particular, trials with negative results are less likely to be published in widely read journals than are trials of similar scientific quality reporting positive results. Conclusions – There are dangers in applying the results of trials to clinical practice in an uncritical way. These dangers can be avoided by adopting and epidemiological perspective, seeking for clinical trials that are representative of the whole population of trials. The Cochrane Collaboration has been established to minimize biases in reviews and meta-analysis. The first Cochrane Centre on Schizophrenia has been established in Oxford and others are planned.

Riassunto

Scopo - Descrivere alcuni problemi che possono emergere quando i risultati degli studi clinici controllati sono utilizzati acriticamente nella pratica clinica quotidiana e mostrare come una prospettiva epidemiologica faciliti l'identificazione di questi problemi. Metodo - Una rassegna degli studi clinici controllati per illustrare i problemi di: a) nascosta distorsione nella selezione dei casi, nei singoli trial; b) distorsione nella selezione degli studi inclusi nelle rassegne e nelle meta analisi. Risultati - È nota l'esistenza di molti tipi di distorsione nella selezione. In particolare, gli studi clinici con risultati negativi, a paritá di qualita scientifica, hanno minori probability di essere pubblicati su riviste a larga diffusione rispetto agli studi con risultati positivi. Conclusioni - Ci sono dei rischi nell'applicare, in modo acritico, i risultati dei trial alia pratica clinica. Tali rischi sono evitabili adottando una prospettiva epidemiologica e cercando trial clinici che siano rappresentativi dell'intera popolazione dei trial stessi. Il Cochrane Collaboration è stato fondato per minimizzare le deviazioni nelle rassegne e nelle meta analisi. Il primo Cochrane Centre on Schizophrenia è stato istituito ad Oxford ed altri sono previsti.

Type
Articles
Copyright
Copyright © Cambridge University Press 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

1

Testo della lettura magistrale tenuta al Secondo Congresso Nazionale della Società Italiana di Epidemiologia Psichiatrica (Bologna 12-14 ottobre 1994)

References

Adams, C.E., Power, A., Frederick, K. & Lefebvre, C. (1994). An investigation into the adequacy of MEDLINE searches for trials of the effects of mental health care. Psychological Medicine 24, 741748.CrossRefGoogle ScholarPubMed
Balestrieri, M., Ruggeri, M. & Bellantuono, C. (1989). Drug treatment of panic disorder - a critical review of controlled clinical trials. Psychiatric Developments 4, 337350.Google Scholar
Chalmers, T.C., Celano, P., Sacks, H. S. & Smith, H. (1983). Bias in treatment assignment in controlled clinical trials. New England Journal of Medicine 309, 13581361.CrossRefGoogle ScholarPubMed
Clark, D.M., Salkovskis, P.M., Hackmann, A., Middleton, H., Anastasiades, P. & Gelder, M.G. (1994). A comparison of cognitive therapy, applied relaxation and imipramine in the treatment of panic disorder. British Journal of Psychiatry 164 759769.CrossRefGoogle ScholarPubMed
Dickersin, K., Hewitt, P., Mutch, L., Chalmers, I. & Chalmers, T.C. (1985). Controlled Clinical Trials 6, 306317.Google Scholar
Durham, R.C., Murphy, T., Allan, T., Richard, K., Treliving, L. R. & Fenton, G.W. (1994). Cognitive therapy, analytic psychotherapy and anxiety management training for generalized anxiety disorder. British Journal of Psychiatry 165, 315324.CrossRefGoogle Scholar
Elkin, I., Shea, T., Watkins, J.T., Imber, S.D., Sotsky, S.M., Collins, J.F., Glass, D.R., Pilkonis, P.A., Leber, W.R., Docherty, J.P., Fiester, S. J. & Parloff, M.B. (1989). National Institute of Mental Health treatment of depression collaborative research program. Archives of General Psychiatry 46, 971980.CrossRefGoogle ScholarPubMed
Fairburn, C.G.Norman, P.A., Welch, S.L., O'Connor, M.E., Doll, H. A. & Peveler, R.C. (1995). A prospective study of the outcome in bulimia nervosa and the long-term effects of three psychological treatments. Archives of General Psychiatry 52, 304312.CrossRefGoogle ScholarPubMed
Klein, D.F. (1994) Cognitive therapy. British Journal of Psychiatry 165, 838Google Scholar
Lau, J., Antman, E.M., Jimerez-Silva, J., Kupelnick, B., Mosteller, F. & Chalmers, T.C. (1992). Cumulative meta-analysis of therapeutic trials of myocardial infarction. New England Journal of Medicine 327, 248254CrossRefGoogle Scholar
Piccinelli, M., Pini, S., Bellantuono, C. & Wilkinson, G. (1995). Efficacy of drug treatment in obsessive-compulsive disorder. A meta-analytic review. British Journal of Psychiatry 166, 424443.Google Scholar
Schulz, K.F., Chalmers, I., Grimes, D. A. & Altaian, D.G. (1994). Assessing the quality of randomization from reports of controlled trials published in obstetrics and gynacology journals. Journal of the American Medical Association 272, 125128.Google Scholar
Scherer, R.W., Dickersin, K. & Langenberg, P. (1994). Full publication of results initially presented in abstracts: a meta-analysis. Journal of the American Medical Association 272, 158162.Google Scholar
Smith, M.L. & Glass, G.V. (1977). Meta-analysis of psychotherapy outcome studies. American Psychologist 32 752760.Google Scholar
Wittchen, H.U., Zhao, S., Kessler, R. C. & Eaton, W.W. (1994). DSM-III-R Generalized anxiety disorder in tie national comorbidity survey. Archives of General Psychiatry 343, 355364.Google Scholar
Xiong, W., Phillips, M.R., Hu, X., Wang, R., Dai, Q., Kleinman, A. (1994). Family-based intervention for schizophrenic patients in China: a randomised controlled trial. British Journal of Psychiatry 165, 239247.Google Scholar
Zhang, M., Wang, M., Li, J. & Phillips, M.R. (1994). Randomized-control trial of family intervention for 78 first-episode male schizophrenic patients: an 18 month study in Suzhou, Jiangsu. British Journal of Psychiatry 165 (Suppl.), 96102.CrossRefGoogle Scholar