Psychometrics of the Instrument Measuring Beliefs Related to Drug Abuse among Iranian College Students

Abstract

Background: Researchers in the field of drug abuse need standard instruments in order to investigate the underlying factors behind the inclination to use drugs in different groups of society so that they could be able to design preventive interventions based on those instruments. The aim of this study is psychometrics of the questionnaire of the beliefs related to drug abuse among Iranian male medical college students. Methods: This cross-sectional study was done on 425 male students who were randomly selected to participate voluntarily in the study conducted in two medical universities in Iran. The studied constructs included attitude, outcome expectation, outcome expectancies, self-control and subjective norms. Data were analyzed by SPSS software (ver. 21.0) and Amos software (ver. 21.0). Results: All of the loads of the exploratory factorial analysis were larger than 0.4. The calculated Kaiser–Meyer–Olkin (KMO) value was 0.906. Overall, five factors under investigation accounted for 61.15 per cent of the variance in the hypothesized model. Cronbach’s alpha for the measured constructs including attitude, outcome expectation, outcome expectancies, self-control and subjective norms were 0.92, 0.90, 0.91, 0.81 and 0.73, respectively. Conclusion: The investigated questionnaire is adequately reliable and valid for measurement of the constructs of attitude, outcome expectation, outcome expectancies, self-control and subjective norms for prediction of drug abuse among Iranian male medical college students.