Most published studies have been human laboratory studies of short duration (typically 3–4 days), using an inpatient human laboratory model developed at Columbia University (New York, US) [35]. Participants were non-treatment-seeking volunteers who smoked cannabis many times a day. They smoked cannabis (active or placebo) and received oral medication (active or placebo) each day under double-blind conditions. The protocols used a within-subjects crossover design so that each participant received each active and placebo combination of cannabis and medication [38].
