Drug Safety 2005; 28 (9): 825-833 ORIGINAL RESEARCH ARTICLE 0114-5916/05/0009-0825/$34.95/0  2005 Adis Data Information BV. All rights reserved. Physicians’ Attitudes and Adverse Drug Reaction Reporting A Case-Control Study in Portugal Maria T. Herdeiro, 1,2 Adolfo Figueiras, 1 Jorge Pol´ onia 3 and Juan Jesus Gestal-Otero 1,4 1 Department of Preventive Medicine and Public Health, University of Santiago de Compostela, Santiago de Compostela, Spain 2 Northern Polytechnic Health Institute (Cooperativa de Ensino Superior Polit´ ecnico e Universit´ ario – CESPU), Gandra, Porto, Portugal 3 Northern Pharmacovigilance Unit, Faculty of Medicine, University of Porto, Porto, Portugal 4 Preventive Medicine Service, University Hospital of Santiago de Compostela, Spain Objectives: Voluntary adverse drug reaction (ADR) reporting is fundamental to Abstract medical drug safety surveillance; however, substantial under-reporting exists and is the main limitation of the system. This study sought to identify the knowledge- and attitude-related factors associated with ADR reporting by physicians in Northern Portugal. Methods: Case-control study covering a population of National Health Service medical practitioners. The 88 cases comprised physicians who had reported at least one ADR to the drug surveillance unit from the year 2000 to the date of enrolment in the study. The 771 controls were randomly selected from among the remaining physicians. All interviews were conducted using a self-administered questionnaire. Knowledge and attitudes regarding spontaneous ADR reporting were based on Inman’s ‘seven deadly sins’. Agreement with the questions included in the questionnaire was measured using a horizontal, continuous visual analogue scale, which was unnumbered. Recorded answers were read in a range from zero (total disagreement) to ten (total agreement). We used logistic regres- sion to determine the ADR reporting adjusted odds ratio (ORadj) for a change in exposure corresponding to the interquartile range for each attitude. Results: A total of 397 questionnaires were received from 731 eligible practition- ers (54.3%). Physicians who worked in primary versus hospital care (ORadj 7.74 [95% CI 1.85, 32.30]) and in general medicine (ORadj 1.05 [95% CI 0.30, 3.69]) versus medical specialities were more likely to report ADRs. In contrast, physi- cians working in the medical-surgical/surgical fields were significantly less likely to report ADRs compared with medical specialists (ORadj 0.10 [95% CI 0.02, 0.46]). Attitudes to ADRs were strongly associated with reporting probability. Hence, an interquartile decrease in any of the following attitudes increased the probability of reporting by: (i) 87% (p < 0.05) for complacency (the belief that really serious ADRs are well documented by the time a drug is marketed); (ii) 109% (p < 0.01) for insecurity (the belief that it is nearly impossible to determine whether a drug is responsible for a particular adverse reaction); (iii) 143% (p < 0.001) for diffidence (the belief that one would only report an ADR if one were sure that it was related to the use of a particular drug); (iv) 220% (p < 0.001) for indifference (the belief that the one case an individual doctor might see could not