Skip to main content
    • Aa
    • Aa

Which treatments are effective: an epidemiological perspective1

  • Michael G. Gelder (a1)

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.


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.

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

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

Hide All
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.
Balestrieri M., Ruggeri M. & Bellantuono C. (1989). Drug treatment of panic disorder - a critical review of controlled clinical trials. Psychiatric Developments 4, 337350.
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.
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.
Dickersin K., Hewitt P., Mutch L., Chalmers I. & Chalmers T.C. (1985). Controlled Clinical Trials 6, 306317.
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.
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.
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.
Klein D.F. (1994) Cognitive therapy. British Journal of Psychiatry 165, 838
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, 248254
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.
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.
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.
Smith M.L. & Glass G.V. (1977). Meta-analysis of psychotherapy outcome studies. American Psychologist 32 752760.
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.
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.
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.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Epidemiology and Psychiatric Sciences
  • ISSN: 2045-7960
  • EISSN: 2045-7979
  • URL: /core/journals/epidemiology-and-psychiatric-sciences
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 1 *
Loading metrics...

Abstract views

Total abstract views: 16 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 20th October 2017. This data will be updated every 24 hours.