Psychometric assessment of the Hallucinogen Rating Scale

Reliability and convergent-discriminant validity of a Spanish version of th e Hallucinogen Raring Scale (HRS) were assessed in two differentiated popul ations of hallucinogen users involving the retrospective assessment of drug effects. In Study 1 (immediate assessment), 75 European users of the South American hallucinogenic drink ayahuasca answered the HRS 4 h after drug in take in their habitual setting. In Study 2 (delayed assessment), 56 adult p olydrug users answered the HRS and a short form of the Addiction Research C enter Inventory (ARCI) recalling the effects they experienced when they las t took a hallucinogen, in order to test the convergent-discriminant validit y of HRS with the scales of the standard questionnaire used in most studies involving psychoactive drugs. The HRS scales showed increases after both t he immediate and delayed retrospective assessment of drug effects. Reliabil ity data indicated that four of the six scales show an acceptable level of internal consistency. Significant but limited correlations were found betwe en the Perception and Somaesthesia scales and the ARCI LSD scale, pointing out the questionnaire's construct validity. Thus, the HRS was sensitive to hallucinogenic drug effects other than those elicited by intravenous N,N-di methyltryptamine (DMT), for which it was originally designed, and showed re asonable reliability and convergent validity. Results suggest its usefulnes s in the evaluation of subjective effects elicited by psychoactive drugs wi th hallucinogenic properties, and constitute a preliminary approach to the effects of ayahuasca in European subjects. (C) 2001 Elsevier Science Irelan d Ltd. All rights reserved.