Effects of identification and usefulness of the Lie Scale of the Drug Use Screening Inventory (DUSI-R) in the assessment of adolescent drug use

Abstract

Objectives: The main objectives of this study were to evaluate the effects of subject identification versus anonymity on adolescents’ drug use assessment using the Drug Use Screening Inventory-R and to assess the usefulness of the “Lie Scale” of that instrument. Methods: Six hundred and fifty-five Brazilian students (5th to 11th graders) from a public school of São Paulo participated in the study. One third of them were instructed to put their names on the questionnaire, one third answered it anonymously and the remaining ones were partially identified according to a code list that was kept by one student who represented his classmates. The answers of the identified groups of students were compared with those from the anonymous group. According to their scores in the Lie Scale, the students were divided into two groups: low and high score groups. Results and conclusions: No significant differences were found among anonymous, identified and partially identified groups regarding alcohol or drug consumption report, or in the density of problems in all drug use screening inventory (DUSI) areas. Regarding the Lie Scale, the high score group reported lower alcohol or drug consumption and fewer alcohol or drug related problems in all DUSI areas when compared to the low score group. The results suggest that identification or anonymity does not affect the students’ answers to the DUSI and point out the usefulness of the Lie Scale of DUSI-R.