Delay- and Dose-Dependent Effects of Δ9-Tetrahydrocannabinol Administration on Spatial and Object Working Memory Tasks in Adolescent Rhesus Monkeys

Among adolescents, the perception that cannabis can cause harm has decreased and use has increased. However, in rodents, cannabinoid administration during adolescence induces working memory (WM) deficits that are more severe than if the same exposure occurs during adulthood. As both object and spatial WM mature in a protracted manner, although apparently along different trajectories, adolescent cannabis users may be more susceptible to impairments in one type of WM. Here, we evaluate the acute effects of a range of doses (30-240 mu g/kg) of intravenous Delta(9)-tetrahydrocannabinol (THC) administration on the performance of spatial and object WM tasks in adolescent rhesus monkeys. Accuracy on the object WM task was not significantly affected by any dose of THC. In contrast, THC administration impaired accuracy on the spatial WM task in a delay-and dose-dependent manner. Importantly, the THC-induced spatial WM deficits were not because of motor or motivational impairments. These data support the idea that immature cognitive functions are more sensitive to the acute effects of THC. Neuropsychopharmacology (2012) 37, 1357-1366; doi: 10.1038/npp.2011.321; published online 4 January 2012