Subsequent investigations have examined a range of clinical measures related to marijuana use, however, these are not direct assessments of affective perception and processing. Hart and colleagues compared the effects of smoked marijuana (3.1% THC) and oral THC (20 mg) administered to the same chronic marijuana smoking individuals over an 18 day period in a double-blind fashion, with four days of placebo administration separating each of the active drug conditions (Hart et al., 2002). Psychomotor performance, food intake and subjective effects of the drug were measured at several points for each condition for a period of three days. Results demonstrated that relative to the placebo baseline, both orally ingested THC and smoked marijuana produced similar subjective ratings on a visual analog scale (VAS) which included levels of feeling “high” or “mellow”. While no specific measures of mood or affective perception were acquired, subjects reported more negative subjective effects, including ratings of “irritable” or “miserable” during the days following the smoking but not oral THC administration. The authors concluded that results were consistent with previous comparison studies of oral THC vs.
