Only limited information is available with respect to personality traits and the psychopathological characteristics of Ecstasy users. To shed some light on the issue, we compared a group of 43 Ecstasy consumers (made up of both 'experimenters', those who took less than or equal to 27.5 tablets in their lifetime, and 'abusers', those who took larger amounts of the drug) with a composite control group of 77 subjects (made up of drug-free people, cannabis users and users of illicit drugs other than Ecstasy). Three instruments were used: the Questionnaire for the Assessment of the Use of Entactogenic Drugs (to assess modalities and characteristics of Ecstasy use); the Cloninger Tridimensional Personality Questionnaire (which measures harm avoidance, reward dependence and novelty seeking) and the SCL-90 (which measures 10 different psychiatric variables). The Ecstasy consumer group subjects showed higher novelty seeking scores than the controls (p < 0.001), and Ecstasy experimenters showed lower harm avoidance scores than the abusers (p = 0.029), but values of both reward dependence and harm avoidance dimensions were associated with sex. On the SCL-90, Ecstasy users showed higher scores than the controls on the obsession-compulsion (p = 0.004), phobic anxiety (p = 0.037), psychoticism (p = 0.005) and sleep disturbances (p = 0.046) subscales. However, many of the SCL-90 subscale results were associated with sex, and only the psychoticism values seemed to suggest a clinical condition. The main finding of this study is that high novelty seeking scores are characteristic of Ecstasy consumers: The propensity to look selectively for novelties could possibly act as a predisposing factor for Ecstasy abuse itself. Copyright (C) 2001 John Wiley & Sons, Ltd.