Each assessment battery consisted of subjective-effects questionnaires and performance tasks. Participants were instructed to answer the subjective-effects questions based on how they felt at that time. The Beck Depression Inventory (BDI-II; Beck et al., 1996) and the State component of the State-Trait Anxiety Inventory (Spielberger et al., 1970) were completed at baseline, 2 and 4 h after dosing. The 72-item Profile of Mood States questionnaire (POMS; McNair et al., 1971) and a 50-item Visual Analog Scale (VAS) were completed at baseline, 0.5, 1, 2, 3 and 4 hr after dosing. For the POMS questionnaire, 10 scales were analyzed (see Evans et al., 2000 for details). To have all scales on a similar 5-point scale, total scores for each of the 8 major scales were divided by the number of items used to determine the scale score. The VAS was subjected to a cluster analysis that resulted in five clusters comprising 41 of the 50 items (see Evans and Levin, 2002). The “Personality Traits” cluster consisted of 8 items related to personality traits (e.g. “I feel friendly”), the “Physical Symptoms” cluster
