How Does Cannabis Affect The Brain?

For decades, people have been ingrained with the idea (and still believe) that using cannabis is harmful to brain health, but new research is challenging that idea. Recent studies — even some a few decades old — suggest that THC, the main psychoactive compound in marijuana, can actually protect and enhance brain function, especially as we age. 

A fascinating study published in the American Chemical Society journal Pharmacology and Translational Science shows that long-term, low-dose THC treatment improved brain health in older mice, restoring cognitive abilities and helping prevent age-related decline. So, just how did scientists arrive at this conclusion? 

To find out more, this article will take a close look at the findings and debunk the myth that marijuana is bad for your brain by examining the latest study that shows how THC might be used as an anti-aging and brain-boosting treatment.

Study Design and Key Findings

In the study, researchers designed an experiment using male mice divided into two age groups: younger mice (4 months old) and older mice (18 months old). The mice were treated with either low doses of THC or a placebo over 28 days. This approach allowed scientists to observe how THC impacts brain function, metabolism, and aging across different stages of life.

To measure the impact of THC, researchers conducted various tests on the mice. These included cognitive tests to assess learning and memory capabilities, as well as biochemical analyses. The analyses focused on proteins and fatty acids involved in metabolism, memory, and aging processes, which help determine how THC influences the brain’s biological functions.

What The Study Found About The Role of mTOR and THC in Aging and Brain Performance

Since mTOR is the most significant factor in this process, it may be helpful to define it before getting into the remarkable results of this study. 

The protein mTOR is primarily responsible for vital bodily functions, including: 

• Aging
• Metabolism
• Immunity
• Autophagy
• New cell growth and migration
• Survival
• Body homeostasis

In essence, mTOR acts as a central regulator for many cellular processes, and its activity determines not only how our cells grow and function but also how they age. In the brain, mTOR is especially important for cognitive performance because it helps maintain synaptic plasticity, the ability of brain cells to form and strengthen connections, which is essential for learning and memory. mTOR also regulates neural stem cells, development, and circuit formation.

During the study, it was discovered that THC was found to activate mTOR in the brains of older mice by way of the endocannabinoid system (ECS). Interestingly, this corroborates similar findings published by the journal Nature in 2017 by the same research group. The new study is a supportive follow-up to that one. 

This activation boosted the formation and repair of synapses, allowing brain cells to communicate more effectively. By promoting synaptic growth, increased mTOR activity helped enhance the mice’s learning and memory functions, explaining the cognitive improvements observed during the experiment. Essentially, THC’s activation of mTOR helped rejuvenate the aging brain by stimulating processes critical for memory retention and mental clarity.

However, THC’s effect on mTOR was not uniform across all tissues. While it activated mTOR in the brain, THC actually inhibited mTOR activity in adipose (fat) tissue. This reduction in mTOR activity in fat cells brought several benefits, including decreased metabolic stress. 

Lower mTOR activity in fat tissue is associated with improved metabolic health and may slow down certain aging processes related to fat accumulation and energy expenditure. This dual effect, which boosts mTOR in the brain while reducing it in fat, implies that THC may offer systemic anti-aging benefits, working on multiple fronts to slow aging.

The timing of these effects was noteworthy as well. Significant changes in brain activity were observed around two weeks into the study, while the anti-aging effects in fat tissue became more pronounced toward the end of the 28-day period. Based on this, it might be concluded that the benefits of THC might unfold in phases, first affecting brain function and later impacting other aspects of aging.

What Science Actually Shows About Cannabis for Brain Health

Beyond the recent study on THC’s anti-aging potential, a growing body of research challenges the belief that cannabis is harmful to the brain. In fact, several studies suggest that cannabis may actually help improve cognitive health in certain contexts. 

For example, 2024 research published in the journal Current Alzheimer Research showed that cannabis use may reduce symptoms of subjective cognitive decline (SCD), which is an early indicator of potential dementia. Adults aged 45 and older who used weed for recreation reported fewer memory issues and less confusion at a decreased rate of 96% compared to non-users. These findings suggest that weed may offer some protection against cognitive decline, at least in certain populations.

In addition, another 2023 study released by the journal CNS Drugs, focusing on medical marijuana users, found minimal acute impact on cognitive function. 

Also in 2023, Exploration in Medicine, a peer-reviewed journal, reports that patients using weed for cancer reported no significant decrease in cognitive abilities after treatment. In fact, many medical cannabis users have reported an improved quality of life, with benefits including better pain management, reduced anxiety, and greater mental clarity during treatment.

In young people, studies show that regular cannabis use did not trigger psychosis in youth who were considered at risk of developing mental health disorders. Instead, these individuals often saw improvements in their cognitive functioning and reduced use of other medications. As such, this landmark finding possibly refutes the long-held belief that cannabis inevitably worsens mental health and suggests that its impact on the brain may be more multifaceted than previously thought.

Finally, some of the most persistent myths about cannabis involve its impact on intelligence and brain structure. Claims that marijuana causes a loss of IQ points or changes the brain’s structure apply mainly to adolescents who use cannabis chronically or frequently, while adults who start cannabis could show a slight ~2 IQ point reduction. 

Implications for Future Research and Human Applications

The findings from this new study open up exciting possibilities for developing anti-aging supplements that could help combat age-related cognitive decline. Low-dose THC, terpenes like pinene, flavonoids like quercetin, and more could be explored as possible ways to support brain health as we age, perhaps offering a new avenue for treating conditions like dementia or Alzheimer’s disease.

However, before we can consider THC for anti-aging purposes in humans, more research is needed, particularly in the form of human clinical trials. While animal studies offer valuable insights, human biology is a bit more complex. Therefore, before we draw a hard line and translate these findings into human treatments, more rigorous testing is needed.

Final Thoughts

The myth that cannabis is harmful to brain health is increasingly being debunked by new research, including this most recent study. From restoring cognitive abilities in aging mice to its potential in combating subjective cognitive decline, cannabis shows promise as a tool for improving brain health throughout life. While more research, particularly in humans, is needed to fully understand its benefits, these findings effectively challenge outdated misconceptions.

For those continuing to tout “Reefer Madness” style misinformation by claiming that weed has no real role in modern medicine, it’s important to rethink that stance. The conversation should be approached with an open mind, exploring not only the possible risks but also its potential benefits.

Note: The content on this page is for informational purposes only and is not intended to be professional medical advice. Do not attempt to self-diagnose or prescribe treatment based on the information provided. Always consult a physician before making any decision on the treatment of a medical condition.