The Tobacco and Alcohol Questionnaire (TAQ) and the Cannabis Experience Questionnaire (CEQ) are two instruments employed in the evaluation of substance use. The First Episode Psychosis (FEP) study in Athens employed two versions of those questionnaires, as part of a battery of psychometric tools, detecting environmental and genetic factors associated with FEP and addressed specifically to the distinctive characteristics of patients with FEP. The goal of the present study is to present those two versions, regarding their content, their use in international research, their translation in Greek, and their test-retest reliability. The two questionnaires were translated by two independent translators and administered to 32 subjects with FEP twice, in order to be tested for test-retest reliability. Cohen's kappa was used to measure agreement between qualitative variables and ICC between quantitative variables. Significant agreement was found between the two measurements in all items of the TAQ version and almost all items of the CEQ version. Our study is an indication that both translations are reliable, although a more thorough test of their psychometric properties is needed. Both might be used in the Greek research field as part of a broad package of psychometric tools, specifically addressed to patients with FEP.
Keywords: Alcohol; Cannabis; Psychosis; Tobacco; reliability; translation.