Self-efficacy is the belief or personal confidence related to the own ability to perform a specific action necessary to obtain a certain result. Its use refers to the application of validated instruments.

Describe the process of cross-cultural adaptation of the drug-taking confidence Questionnaire (DTCQ-8) drugs’ version and to verify its content validity and reliability.

It's a methodological study accomplished by nine experts to the process of adaptation and validation and had a sample of 40 drug users in treatment in the Center of Psycho-Social Attention for alcohol and other drugs, Recife, Pernambuco, Brazil.

The mean index semantics’ agreement (0.989; 0.989; 1.00), idiomatic (0.967), experiential (0.956), conceptual (0.978) and content validation on the clarity of language (0.972), practical relevance (0.958), the theoretical importance (0.958) and theoretical dimension (1.00) demonstrated a satisfactory process. The clinical validation showed that 57.5% of users were classified as moderate on the self-efficacy item to resist the urge to use drugs in high-risk situations, and the Cronbach's alpha coefficient was 0.889 for the complete instrument, ranging from 0.863 to 0.890 among its items.

DTCQ-8 drugs proved to be easy to apply and understand. Its adaptation process was satisfactory for the application in the Brazilian context. The results showed that in this sample, this instrument was suitable to measure the Brazilian user's self-efficacy to resist the urge to consume these substances in high-risk situations.

The authors have not supplied their declaration of competing interest.