Cannabis protects against stroke and improves oxygen uptake in the brain
Consuming cannabis regularly causes an increase in oxygen levels in the brain and increases blood flow to the brain, according to a new study. Unlike past studies, there was no difference in effect between men and women and no association was found between cannabis use and IQ levels. While several larger studies have found an increased risk of stroke, other studies have found no risk. Adding to the debate, a new study, published in the Neurology® Clinical Practice, states that cannabis use does not affect the risk of ischemic stroke (stroke caused by a blockage in a blood vessel, such as a blood clot).
Cannabis improves oxygen in the brain
New research at the Center for Brain Health at the University of Texas, Dallas and published in the Journal of Neuropharmacology states: THC, psychoactive component of cannabis, leads to major changes in the way the human brain uses it. oxygen from the blood.
Study director Dr. Francesca Filbey found that cannabis users had higher blood flow rates than those who did not, and cannabis users were more likely to use more oxygen than they did. 'they don't usually consume without cannabis.
“The results show structural and functional changes in the behavior of oxygen in the brain and blood oxygenation due to cannabis use,” she explained, “but more studies are needed to determine how these changes affect behavior ”.
There was a positive association between cannabis use and THC levels for higher blood flow rates in the frontal cortex (from study)
The researchers recruited 175 people:
74 reported cannabis users, who used cannabis at least 5 times in their lifetime, in addition to regular daily use in the last 000 days prior to the study.
And 101 people who have never used cannabis, which are a perfect match for their average age and IQ.
Before testing, cannabis users were told to stop using cannabis for 72 hours. Those who could not comply with the abstinence requirement were excluded from this study. The levels of THC in their bodies were examined by urinalysis. The psychoactive components remaining in their bodies were examined using brain MRI scans.
The researchers sought to examine three main parameters:
- Blood flow imaging (cerebral blood flow (CBF)), which examines the amount of blood reaching the brain.
- (OEF), which represents the amount of oxygen that actually reached the brain compared to the amount of oxygen inhaled.
- Brain Oxygen Metabolism Rate (CMRO2), which is the rate at which oxygen is absorbed and used in the brain.
Researchers found that regular cannabis users had higher OEF and CMRO2 than those who did not use cannabis in general. Which means that the brains of cannabis users take in more oxygen from the blood and have higher blood flow.
Another interesting finding brought to light that regular cannabis users had a higher blood flow to the brain area, called Putamen; It is one of the basal ganglia that is responsible for, among other things, the reward system and habit formation, as evidenced by another interesting study.
“Our results suggest that THC dilates blood vessels, increases brain oxygen uptake, blood flow, and the formation of new blood vessels,” the authors conclude.
Other results in the study showed that, unlike previous studies, there was no difference between men and women on the effects of cannabis. But the authors note that this finding may be due to a disproportion of men and women in the sample population in this study.
As in previous studies who refuted claims that cannabis lowers IQ, the researchers concluded that “although we have found that CBF (cerebral blood flow) can be altered with THC, no other association has been found on it. cannabis use and its impact on IQ ”.
These neurophysiological alterations should be better examined in the future in research and clinical applications that could prevent the risk of stroke.
Another recent study claims cannabis does not increase the risk of stroke
Previous studies that looked at cannabis use and stroke risk have had conflicting results, some showing a decreased risk and others a large increase in risk, the study author said. Carmela V. San Luis, MD, of the University of Mississippi at Jackson and fellow of the American Academy of Neurology.
“Our observational study looked specifically at recent cannabis use by examining data from drug tests among people admitted to hospital. While more research is needed with more people, our study supports studies showing that cannabis use does not increase the risk of stroke".
The study involved 9350 people aged 18 and over who had been admitted to hospital and given a urine test for drug use. People who tested positive for drugs other than marijuana were excluded from the study. A total of 1643 people, or 18%, tested positive for marijuana. Those who tested positive were more often males, young people and current smokers than those who tested negative.
San Luis noted that the study did not take into account whether people had been drinking recently. She did not collect information on the amount consumed or their history of use. Among the other limitations of the study, it should be noted that information on synthetic drugs was not available and that the researchers could not take into account risk factors such as physical inactivity and the blood pressure index. body mass.
Of those who tested positive, 130 out of 1643, or 8%, had ischemic stroke. Of those who tested negative, 16% had an ischemic stroke, or 1 out of 207 people. But after researchers took into account other factors that influence stroke risk, such as age, hypertension, high cholesterol, sickle cell anemia, obesity, diabetes, smoking and heart problems, there was no link between recent cannabis use and an increased or decreased risk stroke.
The study being observation-based, the results do not 100% prove that recent consumption has no effect on a person's risk of stroke, but only show that the researchers found an association. going in this direction.
“Our research adds to the list of studies with conflicting results, so it is important to continue to study the risks of stroke and cannabis use,” Mr. San Luis said. “There is now a need for further studies on larger groups of people, which include not only data from synthetic drug screens, but also dose amounts as well as a person's history of cannabis use. ”.