The medical use of cannabis improves performance of tasks testing cognition. This is the result of research by scientists of the McLean Hospital in Belmont, USA. Participants were tested before starting the intake of cannabis and 3 months later. Patients completed the Multi-Source Interference Test (MSIT) while undergoing functional magnetic resonance imaging (fMRI). The MSIT was designed to study normal human cognition and psychiatric pathophysiology.
Following 3 months of treatment, cannabis patients demonstrated improved task performance accompanied by changes in brain activation patterns within certain brain regions (cingulate cortex and frontal regions). Authors wrote that after cannabis treatment, “brain activation patterns appeared more similar to those exhibited by healthy controls from previous studies than at pre-treatment, suggestive of a potential normalization of brain function relative to baseline.” They concluded that their findings suggest that the medical use of cannabis “may result in different effects relative to recreational marijuana (MJ) use, as recreational consumers have been shown to exhibit decrements in task performance accompanied by altered brain activation.” Patients also reported improvements in clinical state and health-related measures.
Gruber SA, Sagar KA, Dahlgren MK, Gonenc A, Smith RT, Lambros AM, Cabrera KB, Lukas SE. The Grass Might Be Greener: Medical Marijuana Patients Exhibit Altered Brain Activity and Improved Executive Function after 3 Months of Treatment. Front Pharmacol. 2018;8:983.