Psychometric validation of the POSIT for screening alcohol and other drugs risk consumption among adolescents.

Early detection of alcohol and drug abuse among adolescents is decisive not only for rapid referral and intervention in cases of risk, but also as an indicator for use in the evaluation of prevention programs and public policies to reduce consumption. One of the most widely-used screening instruments in the world is the Problem Oriented Screening Instrument for Teenagers (POSIT) (Rahdert, 1991), whose substance use and abuse subscale (POSITUAS) is a brief tool of enormous applied potential. However, there is still no empirical validation study that would ensure its good psychometric performance in Spain. The aim of this paper is to analyse the psychometric properties of POSITUAS among Spanish adolescents. For this purpose, 569 students aged between 12 and 18 years (M = 14.71; SD = 1.79) were personally interviewed. The study sample was selected through two-stage sampling. The results obtained, using the Adolescent Diagnostic Interview (Winters & Henly, 1993) as the gold criterion, allow us to inform that the Spanish version of the POSITUAS has excellent psychometric behaviour, both at the level of internal consistency (a  = .82) as well as regards sensitivity (94.3%) and specificity (83.9%), with an area under the ROC curve of .953. Also, the realisation of a Confirmatory Factor Analysis allows for verifying the one-dimensional character of the scale. As a result, POSITUAS is made available to researchers and professionals in the field of addictive behaviours for use with a minimum of psychometric guarantees.