At some point in the past you may have heard people describe cannabis as ‘heady’, and according to new research they may have been more spot-on than they knew. A study published earlier this year in the medical journal Neuropsychopharmacology found a direct correlation between THC blood content and the brain’s ability to harvest oxygen from its blood supply, as well as the rate at which oxygen is metabolized by the brain.
The study, conducted at the Center for BrainHealth at the University of Texas at Dallas, analyzed brain blood oxygenation and metabolism in 175 participants—101 nonusers and 74 regular users, the latter of which had used cannabis at least 5,000 times in their lifetimes, and at least once every day in the 60 days that preceded the study. After a 72-hour period without consuming cannabis, participants were scanned with magnetic resonance imaging, and THC metabolite levels were measured using urinalysis.
Led by Dr. Francesca Filbey, director of Cognitive Neuroscience Research in Addictive Disorders at the Center for BrainHealth, the study sought to understand the possible neurophysiological mechanisms that may drive cognitive changes associated with long-term cannabis use.
What they found was that participants with a history of cannabis use showed increased blood flow within the brain, higher rates of oxygen extraction from that blood, and higher cerebral metabolic rates for oxygen than in non-using participants. This could indicate that THC helps the brain dilate existing blood vessels, or that it aids in the development of additional circulatory pathways.
The study’s authors are careful to emphasize that these correlations don’t necessarily establish a causal link between cannabis and the observed changes. But this increase in oxygen uptake could be one of the reasons cannabis users have higher rates of surviving intensive care hospitalization, as observed by another recent study conducted at the University of Arizona.
In an ahead-of-print data summary, the research team at U of A has announced their findings from a nine year study that analyzed adult trauma patients admitted into the Arizona State Trauma Registry over a five year period. The study found a strong correlation between patients who screened positive for cannabis and decreased mortality rates compared to ICU patients who screened negative for cannabis.
The Arizona study focused on 2,678 patients—1,339 cannabis-positive and 1,339 cannabis-negative, matched for age, severity of injury, and length of stay in hospital or ICU. The study found that overall, “patients with a positive marijuana screen had a lower mortality rate (5.3 percent versus 8.9 percent) compared to patients with a negative marijuana screen.”
The authors also noted that among patients who received mechanical ventilation, the cannabis-positive group experienced a mortality rate that was less than half that of the cannabis-negative group, at 7.3 percent versus 16.1 percent.
These new findings also serve to bolster previous research, such as the 2014 study conducted at UCLA linking cannabis-positive patients with an increased survival rate among brain injury hospitalizations.
While the data presented in these studies is compelling, the authors of all three studies cited in this article call for further research into the physiological effects of regular cannabis use.
Featured image by Wikipedia user Calleamanecer.