According to a study published recently in JAMA Network Open, there was no significant impact on brain activation in individuals using medical marijuana over the course of a year.
Titled Year-Long Cannabis Use for Medical Symptoms and Brain Activation During Cognitive Processes and conducted by researchers from Universitas Mercatorum, University of Foggia, University of Bari, and The Allergist in Italy, along with researchers from Asnières-sur-Seine in France, the study explores the cognitive effects of long-term medical cannabis use.
The objective of the study was to assess whether one year of cannabis use for conditions like anxiety, depression, pain, or insomnia would influence brain activity during tasks related to working memory, reward, and inhibitory control—cognitive processes known to be affected by cannabis. The study focused on individuals who obtained medical cannabis cards and were monitored for brain activation before and after a year of use.
Participants, aged 18 to 65, were recruited from the greater Boston area between July 2017 and July 2020. Exclusion criteria included daily cannabis use and cannabis use disorder at baseline. Brain imaging was collected from 57 participants at the start and 54 participants after one year of cannabis use. Additionally, 32 healthy control participants were imaged at baseline for comparison.
Results showed no significant changes in brain activation between baseline and the one-year mark, with no associations found between the frequency of cannabis use and brain activation over time. The cognitive tasks consistently activated the expected brain areas, but the one-year use of medical cannabis did not alter this activation.
The study concludes:
In this cohort study of adults obtaining medical cannabis cards for medical symptoms, no significant association between brain activation in the areas of cognition of working memory, reward, and inhibitory control and 1 year of cannabis use was observed. The results warrant further studies that probe the association of cannabis at higher doses, with greater frequency, in younger age groups, and with larger, more diverse cohorts.
You can find the full text of the study by clicking here.
