How Does Cannabis Affect Brain Health? — BrainPost | Easy-to-read summaries of the latest neuroscience publications

What are cannabinoids?

Cannabinoids are a broad class of biological compounds found primarily in the cannabis plant. They are known for their interaction with the endogenous cannabinoid system in the human body and have various physiological and psychoactive effects. The two most well-known, used and understood classes of cannabinoids are tetrahydrocannabinol (THC) and cannabidiol (CBD) (Atakan et al., 2012).

Cannabinoids affect the human body and brain by interacting with endogenous cannabinoid receptors. These receptors are highly expressed in brain regions that control cognitive functions, including the neocortex, hippocampus, basal ganglia, and cerebellum (Marsicano and Kuner, 2008). Thus, endogenous cannabinoid signaling can contribute to crucial brain functions like memory, motivation, and motor coordination.

What are cannabinoids used for?

Cannabinoids are used for both clinical and recreational purposes. In clinical settings, cannabinoids are used to manage pain, alleviate chemotherapy-induced nausea, and treat epilepsy (Allan et al., 2018). Recreational use primarily involves the consumption or inhalation of cannabis. Notably, cannabinoids, particularly THC, can induce sensations of euphoria, heighten pleasure response, and stimulate increased appetite (Mahler et al., 2007).

Cannabis use has also shown promise as a therapeutic option in both HIV treatment and opioid use management. In HIV treatment, some studies suggest that cannabis may help alleviate symptoms associated with the virus, such as pain, nausea, and loss of appetite (Ellis et al., 2021). Additionally, it may have potential anti-inflammatory and neuroprotective properties that could benefit those with HIV-related neurological complications. In the context of opioid withdrawal, cannabis may assist individuals in managing withdrawal symptoms and reducing opioid cravings (Lucas et al., 2021).

How do cannabinoids affect brain health?

Cannabis use has notable effects on brain function in the short term and over prolonged periods. In the short term, immediate cognitive impairment is a common consequence, affecting memory, attention, and problem-solving abilities. These effects are typically temporary and subside as the drug is metabolized. Users may also experience altered sensory perception, impacting their perception of time, colors, and sounds. Some users encounter heightened anxiety or paranoia, particularly when consuming high doses or strains with high levels of THC (Wainberg et al., 2021).

In the long term, chronic and heavy cannabis use can have profound implications for brain health. Persistent use, particularly during adolescence when the brain is still developing, may lead to cognitive impairments, including memory deficits, and reduced attention span (Crean et al., 2011). Additionally, there is evidence of an increased risk of mental health issues, such as anxiety disorders and depression (Jefsen et al., 2023). These long-term effects underscore the importance of responsible cannabis use and consideration of individual susceptibility, as the impact on brain health can vary depending on factors like usage patterns, potency, and personal vulnerabilities.

Our understanding of the precise mechanisms by which cannabis affects brain health remains incomplete. We do know that cannabis use can influence sleep patterns, a fundamental contributor to mental and brain well-being. The impact of cannabis on sleep is multifaceted and can be influenced by factors such as the specific cannabinoids present, the method of consumption, the dosage, and individual variations in drug response (Kaul et al., 2021). In some cases, cannabinoids have been reported to have a positive influence on sleep. Many users claim that it helps them fall asleep more easily and can improve the overall quality of their sleep. However, it's important to note that the relationship between cannabis use and sleep is complex, and the effects can be highly variable. While some people experience improved sleep, others may encounter negative effects. For instance, cannabis use can disrupt the sleep cycle by reducing the amount of rapid eye movement (REM) sleep, which is associated with dreams and overall sleep quality (Vaillancourt et al., 2022).

The takeaway

The relationship between cannabis use and brain health is complex and multifaceted. Cannabis can have both short- and long-term effects on cognitive function and mental well-being, but these effects can vary significantly among individuals and depend on factors such as frequency of use, potency, and age of use initiation. It is essential for individuals to be well-informed about the potential risks associated with cannabis use, particularly heavy and prolonged use, which may be linked to cognitive impairments and mental health issues, especially when use begins before the brain is fully developed (typically the mid-to-late twenties). Responsible and moderate use, as well as considering individual vulnerability, remains key in minimizing potential harm. Further research is also needed to uncover the full potential of cannabis in clinical settings to mitigate or improve certain conditions or disease symptoms.

References +

Atakan Z. (2012). Cannabis, a complex plant: different compounds and different effects on individuals. Therapeutic advances in psychopharmacology, 2(6), 241–254.

Marsicano, G., and Kuner, R. (2008). Anatomical distribution of receptors, ligands and enzymes in the brain and in the spinal cord: circuitries and neurochemistry. Cannabinoids and The Brain, ed. A. Köfalvi, 161–201.

Allan, G. M., Finley, C. R., Ton, J., Perry, D., Ramji, J., Crawford, K., Lindblad, A. J., Korownyk, C., & Kolber, M. R. (2018). Systematic review of systematic reviews for medical cannabinoids: Pain, nausea and vomiting, spasticity, and harms. Canadian family physician Medecin de famille canadien, 64(2), e78–e94.

Mahler, S. V., Smith, K. S., & Berridge, K. C. (2007). Endocannabinoid hedonic hotspot for sensory pleasure: anandamide in nucleus accumbens shell enhances 'liking' of a sweet reward. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 32(11), 2267–2278.

Ellis, R. J., Wilson, N., & Peterson, S. (2021). Cannabis and Inflammation in HIV: A Review of Human and Animal Studies. Viruses, 13(8), 1521

Lucas, P., Boyd, S., Milloy, M. J., & Walsh, Z. (2021). Cannabis Significantly Reduces the Use of Prescription Opioids and Improves Quality of Life in Authorized Patients: Results of a Large Prospective Study. Pain medicine (Malden, Mass.), 22(3), 727–739.

Wainberg, M., Jacobs, G. R., di Forti, M., & Tripathy, S. J. (2021). Cannabis, schizophrenia genetic risk, and psychotic experiences: a cross-sectional study of 109,308 participants from the UK Biobank. Translational psychiatry, 11(1), 211.

Crean, R. D., Crane, N. A., & Mason, B. J. (2011). An evidence based review of acute and long-term effects of cannabis use on executive cognitive functions. Journal of addiction medicine, 5(1), 1–8.

Jefsen, O. H., Erlangsen, A., Nordentoft, M., & Hjorthøj, C. (2023). Cannabis Use Disorder and Subsequent Risk of Psychotic and Nonpsychotic Unipolar Depression and Bipolar Disorder. JAMA psychiatry, 80(8), 803–810.

Kaul, M., Zee, P. C., & Sahni, A. S. (2021). Effects of Cannabinoids on Sleep and their Therapeutic Potential for Sleep Disorders. Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics, 18(1), 217–227.

Vaillancourt, R., Gallagher, S., Cameron, J. D., & Dhalla, R. (2022). Cannabis use in patients with insomnia and sleep disorders: Retrospective chart review. Canadian pharmacists journal : CPJ = Revue des pharmaciens du Canada : RPC, 155(3), 175–180.