Validation study of the extended theory of reasoned action questionnaire for drug abuse prevention in adolescents

The aim of this study was to design and assess the validity and reliability of the theory of reasoned action extended version questionnaire for drug abuse avoidance in Iranian male adolescents. Validity and reliability of a measure consisting of TRA and self efficacy construct for substance abuse avoidance was assessed by scientific methods. Cross-sectional data was collected via self-administered surveys from adolescents sample (n = 433). A questionnaire was designed based on two guidance for TRA/TPB developing. The instrument was validated using content validity and construct validity (Exploratory & confirmatory factor analysis). The reliability of scale was assess by inter consistency. The reliability coefficients were calculated by two different methods: Cranach alpha and test-retest. Results of exploratory & confirmatory factor analysis showed that extended version of TRA model consisted of 29 questions and 4 components (attitude toward behavior, subjective norms, intention and self efficacy), was a good fitness. Results showed the total test-retest reliability and internal consistency to be 0.72 and 0.85, respectively, too. The validity and reliability of the Persian extended version of TRA scale were suitable for use in future intervention.