by Kayt Sukel December 6, 2016
California’s Proposition 64, or the Adult Use of Marijuana Act, passed on Nov. 8, 2016, making it legal for people 21 and older in that state to use marijuana recreationally. California is just the latest—more than 20 states have now legalized some manner of Cannabis sativa use and it is expected that more will follow. At Neuroscience 2016, the annual meeting of the Society for Neuroscience, Nora Volkow, director of the National Institute of Drug Abuse, said these changes in legislation are cause for concern…“With the changes in legislation, we are already seeing an increase in consumption of marijuana across the population of the United States,” said Volkow…
That impact appears to be significant. In a talk entitled, “Translational Neuroepigenetic Insights of Addiction Vulnerability,” Hurd discussed how her research is demonstrating that both adolescent marijuana use, as well as exposure to THC in utero, makes epigenetic changes to the brain, priming it for greater susceptibility for later addiction to opiate drugs.
“We see specific morphological changes in the brain to important neurotransmitter systems, and individuals who are exposed to THC early in life show greater sensitivity to opiates than others do,” she said. “We know that the brain definitely adapts to marijuana. It is profoundly changing the receptors and receptor signaling that impact gene expression. And the changes it makes last through adulthood and even into the next generation.
Written by Honor Whiteman, 29 November 2016
A new study warns that marijuana use may increase susceptibility to Alzheimer's disease, after finding the drug severely reduces blood flow in an area of the brain affected by the illness.
[A man smoking marijuana]
Researchers suggest marijuana use may increase susceptibility to Alzheimer's by reducing blood flow in the hippocampus.
Published in the Journal of Alzheimer's Disease, the study reveals that individuals with a marijuana use disorder showed reduced blood flow in nearly all areas of the brain, compared with healthy controls.
What is more, the research team - including co-author Dr. Elisabeth Jorandby of Amen Clinics Inc. in California - found that the hippocampus saw the largest reduction in blood flow with marijuana use.
The hippocampus is the brain region associated with learning and memory, and it is the first region to be affected in patients with Alzheimer's disease.
In the United States, marijuana is becoming increasingly legalized for recreational and/or medicinal use.With this in mind, researchers are in agreement that it is more important than ever to understand the possible harms of marijuana use, and Dr. Jorandby and colleagues caution that reduced brain blood flow may be one such effect.
Almost every brain region affected by marijuana use. When blood flow in the brain is reduced, this causes a reduction in the amount of oxygen that reaches brain cells, which can cause brain tissue damage and death.
According to the authors, few previous studies have assessed the effects of marijuana use on blood flow in the brain.
To address this research gap, the team used single photon emission computed tomography (SPECT) to measure the blood flow and brain activity of 982 individuals who had been diagnosed with a marijuana use disorder, alongside 92 healthy controls. SPECT was used to measure participants' brain blood flow and activity during a mental concentration task and when at rest.
Compared with the healthy controls, the researchers found that subjects with marijuana use disorders showed significantly reduced blood flow in almost all brain regions, but the hippocampus fared worst. In particular, the team identified abnormally low blood flow in the right hippocampus of subjects with marijuana use disorders as they completed the concentration task.
Written by Honor Whiteman
Published:12 November 2016
Researchers have long suggested marijuana can cause memory loss. Now, a new study provides insight on this association, revealing how cannabinoids in the drug activate receptors in the mitochondria of the brain's memory center to cause amnesia.
Researchers have shed light on how cannabinoids affect the brain to cause memory loss.
Study leader Dr. Giovanni Marsicano, of the University of Bordeaux in France, and team believe their findings - published in the journal Nature - may lead to the development of new therapeutics that target cannabinoid receptors, without the side effect of memory loss.
Cannabinoids are chemicals present in marijuana, as well as synthetic forms of the drug. According to the National Institute on Drug Abuse (NIDA), there are more than 100 cannabinoids in marijuana, including the main psychoactive compound delta-9-tetrahydrocannabinol (THC). These cannabinoids are similar in structure to cannabinoids that occur in the body naturally, such as anandamide. Naturally occurring cannabinoids function as neurotransmitters; they send signals between nerve cells, or neurons, affecting various brain regions, including those responsible for emotion, movement, coordination, sensory perception, and memory and thinking.
Because THC and other cannabinoids present in marijuana and synthetic forms are similar to naturally occurring cannabinoids, they are able to bind to cannabinoid receptors situated on neurons and activate certain brain regions.
Impact of cannabis on the neurocognitive performance of Jamaican adolescents
Conclusion: Findings support the fact that cannabis use impairs learning, attention and memory. These results support the need for public health policies aimed at targeting early prevention strategies, demand reduction and the identification and treatment of adolescent cannabis users in Jamaica.