Positive and negative affective states were assessed with the (Positive and Negative Affect Schedule) PANAS [25] and personality traits were studied with the (Zuckerman-Kuhlman Personality Questionnaire) ZKPQ [26]. To confirm self-reported drug-use information, urine samples were screened for cannabis, along with other illicit drugs; all subjects also underwent a breathalyzer. None of the subjects screened positive for alcohol or any other drug than cannabis. 86.0% of the cannabis dependent individuals were positive for cannabis.
