Demographic characteristics, EPQ-R scores, and use of other recreational drugs.

Standard deviation in parentheses. Ns, Non-significant difference; Raven IQ, IQ measured by means of the Raven Progressive Matrices; Monthly drinks, monthly number of standard alcoholic drinks; Monthly cigarettes, monthly standard cigarettes smoked; Lifetime exposure cannabis, lifetime consumption of joints; Lifetime exposure MDMA, lifetime consumption of MDMA (ecstasy) tablets; Personality traits measured by means of the Eysenck Personality Questionnaire Revised Short Scale.
**p<0.01.