Marijuana has a powerful psychoactive effect and many people have assumed that prolonged use can hurt the brain, similarly to alcohol. The effects of alcohol on the brain have been thoroughly documented, however, the same is not true for marijuana.
The legalization of recreational and medical marijuana has prompted new research over the past decade. So far, there are a multitude of contradictory findings. One thing that is certain: if long-term use of marijuana poses a risk to the brain, it is not anywhere near as harmful as alcohol. This is according to researchers at the University of Colorado Boulder and the CU Change Lab.
Tetrahaydrocannabinol, or THC, is the psychoactive compound that causes the high, however, there are more than 60 cannabinoids, and most of them are not psychoactive. Cannabidiol (CBD) is the second most famous compound found in marijuana, and it is a nonpsychoactive compound that actually blocks the high from THC.
Other well-studied cannabinoids, such as Cannabigerol (CBG) that has anti-inflammatory properties, Cannabichromene (CBC) with ant-depressant and anti-inflammatory effects, and Tetrahydrocannabivarin (THCV) promotes appetite.
These cannabinoids interact with receptors in the brain. They keep neurons firing and affect dopamine levels. This is similar to the effects of alcohol, sugar, and caffeine. The short-term effects of marijuana can be so intense, it has caused a valid concern that long-term use can cause physical changes in the brain.
Alcohol, is known to damage the brain. According to alcohol studies, it can cause brain shrinkage, which is a common indicator of brain damage, causing memory and learning problems.
UCB researchers examined the brains of more than 1,000 people: 853 adults, 18 to 55 and 439 teenagers, ages 14 to 18. All participants varied their use of marijuana and alcohol. The results were compared to alcohol drinkers. Scientists focused on the gray matter and the white matter of the brain to look for differences.
The gray matter, which is a pinkish-gray color in a living brain, contains cell bodies, the axon terminals of neurons, and dendrites.
White matter includes axons that connect different parts of gray matter to each other. Both gray and white matter are important for cognition. Loss of size in either area is a sign of brain damage or an indication the brain is not functioning properly.
When the researchers reviewed previous studies, one reported that marijuana use contributes to volume reduction in the hippocampus. Then, the next study says the use of marijuana causes changes in the cerebellum. Co-author Kent Hutchison says the point is the research is not consistent in terms of brain structure. Hutchinson is a professor of behavioral neuroscience at CU Boulder and the co-director of the CU Change Lab.
MRI scans showed significant reduction in gray matter and the integrity of white matter in those who drink alcohol, especially those who drank for many years. The longer the exposure, the more significant the effects.
The long-term effects of marijuana, however, does not impact the size of the brain’s white or gray matter. Nonetheless, there still may be some undesirable physical changes in the brain with long-term use of marijuana, they are nowhere near as harmful as the long-term effects of alcohol. However, Hutchinson says this research is only the tip of the iceberg.
An estimated 22.2 million people in the Unites States have used marijuana in the last 30 days, making it “the most commonly used illicit drug.”
As a result of changing legislation concerning marijuana across the nation, researchers are working to learn more about the health benefits and the damage it could cause.
Last year, Medical News Today reported on a study that linked teenage marijuana use to a higher risk of psychosis. Another study reported that the drug is worse than cigarette on cardiovascular health. However, researchers have found that the drug helps prevent migraines and another study linked it to an increased sex drive.
By Jeanette Smith
ZME Science: Marijuna is nowhere near as dangerous to the brain as alcohol
Medical News Today: Alcohol ‘more damaging to brain health than marijuana’
Daily News: Study: Alcohol more harmful to the brain than marijuana
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