Construcción de un cuestionario para la Valoración de los Efectos Subjetivos de Sustancias con Potencial de Abuso (VESSPA): Evaluación del éxtasis

Abstract

The objective of this study was to construct an instrument capable of measuring the subjective effects produced by 3.4- methyilenedioxymethamphetamine (MDMA). After the construction of a bank of items, subsequent reductions and a factorial analysis, a 36-item questionnaire was obtained with a five-point Likert response. This questionnaire was called VESSPA- SEE (Evaluation of Subjective Effects of Substances with Abuse Potential) and contains 6 scales: Sedation, Physical Anxiety, Changes in Perception, Pleasure and Social Contact, Activity and Energy, and Psychotic Symptoms. For these scales, the coefficients of alpha ranged from 0.67 to 0.86, and the coefficients of test-retest reliability ranged from 0.79 to 0.91. The validity of the scale was investigated by the application of three tests: correlations with VESSPA and ARCI scales (Addiction Research Center Inventory-49 item short form), scores of the different scales in other simulated conditions (alcohol, cannabis, cocaine and LSD), and response of the questionnaire in an experimental situation in a clinical trial in where MDMA and alcohol were administered. The results showed that the VESSPA questionnaire is an instrument with an acceptable validity and reliability for measuring the pharmacological effects of the MDMA and other psychopharmacos. In addition, the questionnaire seems apropiate for use in a clinical trial context.