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Marijuana Found to Engender Both a Therapeutic or Damaging Effect on the Brain, Depending on Age & Other Factors

Marijuana is the most used illicit substance in the country; experts anticipate that its use will continue to increase, as the substance becomes legalized in more and more states.

Interestingly, marijuana is also the most commonly used illegal substance by women who are pregnant—regardless of the fact that marijuana has been found to cause long-term effects to a person who is exposed to the drug before birth.

Those who start using marijuana during the teenage years may be exposing their brain to damaging effects that last a lifetime.  The brain is vulnerable and still developing during adolescents, which puts it at higher risks for impairment from exposure to substances—such as marijuana.

At the same time, many adults are using marijuana for relief from the symptoms of long-term illnesses, such as multiple sclerosis and epilepsy.  But what are the long-term effects of marijuana on adults?  Let’s look at what the recent research tells us.

The New Research

A new study released by the Society for Neuroscience, discovered that compounds in marijuana, called cannabis, may engender both a therapeutic, as well as a damaging effect to the brain—depending on age and other circumstances.

The researchers discovered that when a fetus was exposed to marijuana in utero (during pregnancy), the result was damaging, long-term effects in the brain.  The scientists also discovered that marijuana use during adolescence may disrupt learning and memory, adversely impact communication between regions of the brain, and disrupt key neurotransmitters.  Neurotransmitters are chemicals that are released at the end of a nerve fiber that enable the transfer of impulses from one to another nerve fiber. 

But, in older adults with Alzheimer’s disease, the psychoactive compound called THC—found in marijuana—was found to improve memory and help alleviate some of the symptoms of the disease. 

Study Findings

The research findings revealed:
• Prenatal exposure to THC in rat studies,  produced long-term effect on metabolites (small molecules that are the end-products of metabolism) in the brain (making the animals more susceptible to stress in later life).
•Rats that were exposed to compounds similar to THC, during fetal development, were found to have impaired formation of neural (nerve) circuits.
•Adolescent rats exposed to marijuana were found to have an increase in activity in pathways of the brain that are involved in addiction.
•Cannabinoids in adolescent rats were found to disrupt protein development in the area of the brain involved in decision making, planning and self-control.
•In adult mice, long-term cannabinoid use alters metabolism and connectivity in the areas of the brain involved in memory and learning.
•In mice with Alzheimer’s disease, treatment with the psychoactive compound found in marijuana improved memory and reduced the loss of nerve cells.

In a press release, Michael Taffe, PhD, of Scripps Research Institute and an expert in substance abuse research, stated,  “Today’s findings lend new understanding of the complex effects that cannabis has on the brain.  While it may have therapeutic potential in some situations, it is important to get a better understanding of the negative aspects as well, particularly for pregnant women, teens, and chronic users.”

The research findings were presented at this year’s meeting of the Society for Neuroscience—the largest source of information and current news about brain science and health.

Learn more about innovative research on new treatment for Alzheimer’s disease by CLICKING HERE to access the Alzheimer’s Drug Discovery Foundation’s website, Cognitive Vitality.

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