How cannabis and cannabis-based drugs harm your brain
July 23, 2018
Science Daily/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 drug 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 cannabinoid exposure, though it is already known that heavy, regular cannabis use increases the risk of developing mental health 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 multiple sclerosis, 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 negative side effects. 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."
The research was published in the Journal of Neurochemistry and was conducted as part of the European Commission Horizon 2020 funded SynaNET project.
https://www.sciencedaily.com/releases/2018/07/180723132251.htm
Cannabis extract helps reset brain function in psychosis
August 29, 2018
Science Daily/King's College London
Research from King's College London has found that a single dose of the cannabis extract cannabidiol can help reduce brain function abnormalities seen in people with psychosis. Results from a new MRC-funded trial, published in JAMA Psychiatry, provide the first evidence of how cannabidiol acts in the brain to reduce psychotic symptoms.
Cannabidiol, also referred to as CBD, is a non-intoxicating compound found in cannabis. A purified form of cannabidiol has recently been licensed in the USA as a treatment for rare childhood epilepsies, and a 2017 King's College London trial has demonstrated cannabidiol has anti-psychotic properties.
However, exactly how cannabidiol may work in the brain to alleviate psychosis has remained a mystery.
"The mainstay of current treatment for people with psychosis are drugs that were first discovered in the 1950s and unfortunately do not work for everyone," says Dr Sagnik Bhattacharyya, from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN). "Our results have started unravelling the brain mechanisms of a new drug that works in a completely different way to traditional anti-psychotics."
The researchers studied a group of 33 young people who had not yet been diagnosed with psychosis but who were experiencing distressing psychotic symptoms, along with 19 healthy controls. A single dose of cannabidiol was given to 16 participants while the other 17 received a placebo.
All participants were studied in an MRI scanner while performing a memory task which engages three regions of the brain known to be involved in psychosis.
As expected, the brain activity in the participants at risk of psychosis was abnormal compared to the healthy participants. However, among those who had cannabidiol, the abnormal brain activity was less severe than for those who received a placebo, suggesting cannabidiol can help re-adjust brain activity to normal levels.
The influence of cannabidiol on these three brain regions could underlie its therapeutic effects on psychotic symptoms.
Intriguingly, previous research from King's College London shows cannabidiol appears to work in opposition to tetrahydrocannabinol (THC); the ingredient in cannabis responsible for getting users high which has been strongly linked to the development of psychosis. THC can be thought of as mimicking some of the effects of psychosis, while cannabidiol has broadly opposite neurological and behavioural effects.
Dr Bhattacharyya and colleagues at IoPPN are now launching the first large scale, multi-centre trial to investigate whether cannabidiol can be used to treat young people at high risk of developing psychosis. The trial is supported by a £1.85 million grant from an NIHR and MRC partnership.
Some estimates suggest that in England alone, over 15,000 people present with early symptoms of psychosis every year. Despite symptoms that can be extremely severe, there are currently no treatments that can be offered to patients at high risk of psychosis because current anti-psychotic drugs can have serious side-effects.
"There is an urgent need for a safe treatment for young people at risk of psychosis," says Dr Bhattacharyya. "One of the main advantages of cannabidiol is that it is safe and seems to be very well tolerated, making it in some ways an ideal treatment. If successful, this trial will provide definitive proof of cannabidiol's role as an antipsychotic treatment and pave the way for use in the clinic."
https://www.sciencedaily.com/releases/2018/08/180829115228.htm