Additional studies from our laboratory (e.g., 54 compared young adult marijuana users (ages 16–18) after one month of abstinence to matched controls on the same SWM task described in the previous studies. Although there were no differences in task performance between the marijuana users and controls, the marijuana users exhibited increased activation in parietal, temporal, and frontal (including insula) brain regions. The marijuana users also showed less activation in cerebellum and occipital cortices than controls. Findings remained significant after controlling for alcohol and other drug use, and also suggest compensatory and possibly inefficient SWM-related neural response associated with marijuana use.
