How cannabis and cannabis-based drugs harm your brain

How cannabis and cannabis-based drugs harm your brain
The cannabis plant. Credit: Lancaster University

Long-term use of either cannabis or cannabis-based drugs impairs memory say researchers. The study has implications for both recreational users and people who use the drug to combat epilepsy, multiple sclerosis and chronic pain.

They found that mice exposed to the long-term had "significant ... memory impairments" and could not even discriminate between a familiar and novel object.

There is little understanding of the potential negative side effects of long-term exposure, though it is already known that heavy, regular cannabis use increases the risk of developing problems including psychosis and schizophrenia.

More and more people are using the drug long-term due to its legalisation in several countries, while more potent varieties are available for recreational users.

Researchers from Lancaster and Lisbon Universities studied the effects of the cannabinoid drug WIN 55,212-2 in mice and found that:

  • Long-term exposure impairs learning and memory in the animals
  • Brain imaging studies showed that the drug impairs function in key brain regions involved in learning and memory
  • Long-term exposure to the drug impairs the ability of brain regions involved in learning and memory to communicate with each other, suggesting that this underlies the negative effects of the drug on memory

Dr. Neil Dawson, the lead researcher from Lancaster University said "This work offers valuable new insight into the way in which long-term cannabinoid exposure negatively impacts on the brain. Understanding these mechanisms is central to understanding how long-term cannabinoid exposure increases the risk of developing mental health issues and memory problems."

He also highlighted the relevance of the work to those using cannabinoid-based therapies to treat medical conditions.

"Cannabis-based therapies can be very effective at treating the symptoms of chronic diseases such as epilepsy and , and dramatically increase the quality of life for people living with these conditions. We need to understand the side effects that these people may experience so that we can develop new interventions to minimise these side effects".

Professor Ana Sebastiao, lead researcher at the University of Lisbon, said: "Importantly, our work clearly shows that prolonged cannabinoid intake, when not used for medical reasons, does have a negative impact in brain function and memory. It is important to understand that the same medicine may re-establish an equilibrium under certain diseased conditions, such as in epilepsy or MS, but could cause marked imbalances in healthy individuals."As for all medicines, cannabinoid based therapies have not only beneficial disease-related actions, but also . It is for the medical doctor to weight the advantages of the therapy, taking into consideration quality of life and diseases progression, against the potential side effects."


Explore further

Questions remain about the benefits and harms of cannabis

More information: Francisco M Mouro et al, Chronic, intermittent treatment with a cannabinoid receptor agonist impairs recognition memory and brain network functional connectivity, Journal of Neurochemistry (2018). DOI: 10.1111/jnc.14549
Provided by Lancaster University
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Jul 23, 2018
Pick your poison.

Another research in February 2018, which was published in the journal Addiction, examined the brains of more than 1,000 participants of varying ages, and found that long-term alcohol use is much more damaging to the brain than marijuana, contradicting years of research into the effects of marijuana and other cannabinoid products on the brain.
https://medicalxp...oze.html

Jul 25, 2018
Geez I thought pot was a wonder-drug

Jul 29, 2018
So the article's headline is "How cannabis ... harms your brain". But humans weren't even tested, just mice. Also it's not stated how much THC they were given, which makes the study impossible to comprehend. Clear is one thing: That study has not proven that weed is harmful for your brain. At all. Just that if you give mice (!!) an unknown amount of cannabinoids (which one?) for an unknown amount of time they get memory-trouble.

Seems like propaganda to me, but whatever.

Sep 20, 2018
Medical Cannabis helps patients who combats with epilepsy a lot. Those researches tested the effects of cannabinoid on mice. Human brain and Animal brain are different.

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