The good, the bad, and the intoxicated
January 1, 2021 Natasha Leigh Mason
Cannabis, the most commonly used illicit drug, alters consciousness and impairs cognitive function. In a double-blind, placebo-controlled study, 20 occasional cannabis users received acute doses of cannabis (300 μg/kg THC) or placebo in one of two dose regimes. THC increased striatal glutamate concentrations and reduced functional connectivity between the nucleus accumbens and cortical areas, indicating increased dopamine activity. These effects were dose-dependent, evident when THC serum concentrations exceeded 2 ng/ml. Changes in glutamate and functional connectivity correlated strongly, and connectivity changes correlated with subjective high and decreased attention performance. THC likely produces subjective and cognitive effects through increased striatal dopamine and loss of corticostriatal connectivity, linked to increased striatal glutamate.