Background: The two main constituents of cannabis, cannabidiol and D9 -tetrahydrocannabinol (THC), have opposing effects both pharmacologically and behaviourally when administered in the laboratory. Street cannabis is known to contain varying levels of each cannabinoid. Aims To study how the varying levels of cannabidiol and THC have an impact on the acute effects of the drug in naturalistic settings. Method: Cannabis users (n = 134) were tested 7 days apart on measures of memory and psychotomimetic symptoms, once while they were drug free and once while acutely intoxicated by their own chosen smoked cannabis. Using an unprecedented methodology, a sample of cannabis (as well...
