As marijuana continues to gain acceptance in society, with recreational use legalized in several states and medical help widely acknowledged, it is crucial to understand the potential effects of cannabis on the mind and body. While some people firmly believe in the benefits of marijuana, others raise concerns about its potential risks, particularly its impact on the brain.
One question that has long been debated is does weed permanently damage your brain? Or does marijuana kill brain cells? While this subject remains controversial, various studies have attempted to shed light on the relationship between marijuana use and cognitive health. Staying informed about the latest research and making informed decisions about your consumption habits is essential.
We will delve into the science behind marijuana’s effects on the brain, exploring its impact on cognition, memory, and intelligence. We will also compare the results of smoking weed versus consuming THC edibles and discuss the short and long-term consequences of marijuana use. Our goal is to provide accurate, non-judgmental information to help you become more informed about your health and well-being.
Understanding the impact of marijuana on the brain
How cannabinoids, specifically THC, interact with the brain
Cannabinoids, such as delta-9-tetrahydrocannabinol (THC), are the active compounds found in marijuana that interact with the brain’s cannabinoid receptors . THC, marijuana’s primary psychoactive ingredient, is responsible for the “high” experienced by users. When THC enters the bloodstream, it reaches the brain. It binds to the cannabinoid receptors, primarily the CB1 receptor, influencing the release of neurotransmitters and altering brain chemistry . This process affects various cognitive functions, including memory, learning, and attention.
The endocannabinoid system and its role in regulating brain function
The endocannabinoid system (ECS) is a complex cell-signaling system within the human brain and body that plays a crucial role in maintaining homeostasis, the state of internal balance necessary for optimal health . The ECS comprises three primary components: endocannabinoids, receptors, and enzymes. The main endocannabinoids are anandamide and 2-arachidonoylglycerol (2-AG), which bind to the CB1 and CB2 receptors, respectively .
The ECS involves various physiological processes, such as pain regulation, mood, appetite, and sleep. When cannabis is consumed, THC and other cannabinoids interact with the ECS, affecting these functions. While the short-term effects of marijuana use can be pleasurable, prolonged exposure to THC may lead to changes in the brain’s structure and function, potentially resulting in adverse consequences for cognitive health .
Ways that marijuana affects cognition
Memory and learning
Marijuana use can impair memory and learning, particularly when used frequently or in high doses. THC affects the hippocampus, a brain region critical for forming new memories, leading to difficulties in acquiring, encoding, and recalling information. This cognitive impairment can be short-lived or persist after marijuana use has ceased, depending on the frequency and duration of use.
Attention and focus
Cannabis use can negatively impact attention and focus. Studies have found that marijuana users may experience difficulties maintaining concentration and increased distractibility. These effects may be more pronounced in heavy or chronic users.
Decision-making and problem-solving
Marijuana can impair executive function, responsible for decision-making, problem-solving, and impulse control. This impairment can result in difficulties in planning, organizing, and completing tasks and increased risk-taking behavior. Prolonged marijuana use may lead to long-lasting changes in executive function. Some studies suggest a potential for cognitive decline.
Reaction time and motor coordination
THC affects motor coordination and reaction time, leading to slower and less accurate responses. This impact can be especially troubling for activities that necessitate rapid reflexes and accurate movements, such as operating machinery, sports, or driving. The impairment in motor skills can temporarily subside after marijuana use has ceased.
Do THC edibles kill more or fewer brain cells than weed? Do they have the same impact on the brain?
Differences in the absorption and metabolism of THC between smoking and ingesting edibles
The primary difference between smoking marijuana and consuming edibles lies in how THC is absorbed and metabolized in the body. When smoked, THC is rapidly absorbed into the bloodstream through the lungs, reaching the brain within minutes. In contrast, edibles are ingested, and THC is absorbed more slowly through the gastrointestinal tract, leading to a delayed onset of effects, usually within 30 minutes to 2 hours.
Comparing the effects of edibles and smoked weed on the brain
Both methods of consuming marijuana can lead to cognitive impairment; however, the intensity and duration of the effects may vary. Edibles tend to produce a more prolonged and potent high due to the slow absorption and metabolism of THC in the liver, which converts it into 11-hydroxy-THC, a more potent psychoactive compound. This can produce more pronounced cognitive effects, particularly in inexperienced users or those who consume high doses.
Key factors influencing the impact of THC on brain cells
The impact of THC on brain cells depends on several factors, including dosage, frequency of use, individual tolerance, and the method of consumption. While smoking and ingesting edibles can lead to cognitive impairment, the severity and duration of the effects may differ. However, there is currently no conclusive evidence indicating that one method of consumption leads to more significant brain cell damage than the other.
Effect of Marijuana Use on IQ
Several studies have explored the relationship between marijuana use and IQ. Some findings suggest long-term cannabis use might be associated with decreased cognitive abilities and lost IQ points . For instance, a Meier et al. (2012) study demonstrated that persistent cannabis users experienced a neuropsychological decline from childhood to middle age . However, the relationship between marijuana use and IQ is complex and not fully understood.
Limitations and Controversies Surrounding These Studies
Although some studies suggested a link between marijuana use and decreased IQ, these findings have significant limitations. Many studies lack control for confounding variables, such as socioeconomic status, other substance use, or mental health issues . Additionally, the methods used to measure cognitive abilities may not always be consistent, leading to discrepancies in the results. Moreover, some research has shown that IQ can recover with prolonged abstinence from marijuana use .
Potential Factors That May Contribute to Changes in IQ
Several factors may contribute to the observed changes in IQ among marijuana users. First, marijuana has been shown to impact verbal memory , an essential component of IQ tests. Second, heavy marijuana use at a young age, when the brain is still developing, might significantly affect cognitive abilities more significantly than use during adulthood . Third, other substances or drugs combined with marijuana may exacerbate its impact on IQ .
In conclusion, while some studies suggested a link between marijuana use and decreased IQ, this relationship is complex and not fully understood. Factors such as verbal memory, young age, and other substance use may contribute to the observed changes in IQ. Additional research is required to enhance our comprehension of the long-term impacts of marijuana usage on cognitive abilities.
Short and Long-term Effects of Marijuana Use on the Brain
Immediate and Short-term Effects
Altered Perception and Mood
Marijuana use can lead to altered perceptions and changes in mood . Users may experience an increased sense of relaxation, euphoria, and heightened sensory experiences. However, some may also experience anxiety, paranoia, and panic.
Impaired Memory and Cognition
Cannabis use can temporarily impair memory and cognitive function, making it difficult to focus, learn, and remember information . These effects can last for several hours after consumption and may persist longer in heavy users.
Potential for Acute Psychosis in High Doses
In rare cases, high doses of marijuana can lead to acute psychosis, characterized by hallucinations, delusions, and disorganized thinking . This risk is generally higher in individuals predisposed to mental health disorders.
Long-term Effects and Potential Risks
Neuroplastic Changes and Cognitive Decline
Prolonged marijuana use may lead to neuroplastic changes and cognitive decline . Heavy users may experience a decline in IQ points and impaired memory, particularly if they began using at a young age . However, the extent of this decline and its permanence are still under debate.
The Relationship between Marijuana Use and Mental Health Disorders
Prolonged cannabis usage has been linked to an elevated likelihood of developing mental health ailments like depression, anxiety, and psychosis . Nevertheless, it is critical to bear in mind that correlation does not imply causation, and more studies are necessary to comprehend this connection.
The Impact of Heavy and Chronic Use on Brain Structure and Function
Heavy and chronic marijuana use has been linked to changes in brain structure and function . Such changes may involve modifications in the prefrontal cortex, which plays a role in higher cognitive functions like impulse control, planning, and decision-making. Nevertheless, it remains uncertain whether these changes lead to irreversible brain damage or whether they can be restored with abstinence.
In summary, marijuana can have both short and long-term effects on the brain. Short-term effects include altered perception and mood, impaired memory and cognition, and potential for acute psychosis in high doses. Marijuana’s long term effects and potential risks involve neuroplastic changes, cognitive decline, and associations with mental health disorders. Heavy marijuana use can also impact brain structure and function, particularly during adolescent brain development.
It is essential to approach cannabis use responsibly and be aware of the potential risks to your brain and overall health. If you are concerned about your marijuana use, consider seeking help from a healthcare professional or support group. Remember that more research is needed to fully understand the complexities of marijuana’s effects on the brain, but the information presented in this blog can serve as a starting point for those looking to make informed decisions about their cannabis use.
For more active help, we recommend the app Grounded, which is available for both iOS and Android. Grounded offers useful features and support for those looking to quit or reduce their cannabis consumption. So, why wait? Download Grounded today and start your journey towards a healthier lifestyle.
 National Institute on Drug Abuse. (2021). Marijuana DrugFacts. https://www.drugabuse.gov/publications/drugfacts/marijuana
 Russo, E. B. (2016). Beyond Cannabis: Plants and the Endocannabinoid System. Trends in Pharmacological Sciences, 37(7), 594–605. https://doi.org/10.1016/j.tips.2016.04.005
 Aizpurua-Olaizola, O., Elezgarai, I., Rico-Barrio, I., Zarandona, I., Etxebarria, N., & Usobiaga, A. (2017). Targeting the endocannabinoid system: future therapeutic strategies. Drug Discovery Today, 22(1), 105–110. https://doi.org/10.1016/j.drudis.2016.08.005
 Lu, H. C., & Mackie, K. (2016). An Introduction to the Endogenous Cannabinoid System. Biological Psychiatry, 79(7), 516–525. https://doi.org/10.1016/j.biopsych.2015.07.028
 VVolkow, N. D., Swanson, J. M., Evins, A. E., DeLisi, L. E., Meier, M. H., Gonzalez, R., Bloomfield, M. A., Curran, H. V., and Baler, R. (2016). A comprehensive review of the impacts of cannabis use on human behavior, encompassing areas such as motivation, cognition, and psychosis. JAMA Psychiatry, 73(3), 292–297. https://doi.org/10.1001/jamapsychiatry.2015.3278.
 Schreiner, A. M., & Dunn, M. E. (2012). A meta-analysis of residual effects of cannabis use on neurocognitive performance after extended abstinence. Experimental and Clinical Psychopharmacology, 20(5), 420–429. https://doi.org/10.1037/a0029117.
 Ranganathan, M., & D’Souza, D. C. (2006). A review of the immediate effects of cannabinoids on human memory. Psychopharmacology, 188(4), 425–444. https://doi.org/10.1007/s00213-006-0508-y.
 Solowij, N., & Battisti, R. (2008). A comprehensive review of the long-term effects of cannabis use on human memory. Current Drug Abuse Reviews, 1(1), 81–98. https://doi.org/10.2174/1874473710801010081.
 In their article published in the Journal of Addiction Medicine, Crean, Crane, and Mason (2011) conducted a systematic review of the available evidence regarding the acute and long-term effects of cannabis use on executive cognitive functions. Their work is available at the following DOI: https://doi.org/10.1097/ADM.0b013e31820c23fa.
 McDonald, K., Ward, A., Poulton, R., & Moffitt, T. E. (2012). Neuropsychological decline in persistent cannabis users from childhood to midlife: a longitudinal study based on available evidence. Proceedings of the National Academy of Sciences, 109(40), E2657–E2664. https://doi.org/10.1073/pnas.1206820109.https://doi.org/10.1073/pnas.1206820109.
 Sewell, R. A., Poling, J., & Sofuoglu, M. (2009). The effect of cannabis compared
 Grotenhermen, F. (2003). Pharmacokinetics and pharmacodynamics of cannabinoids. Clinical Pharmacokinetics, 42(4), 327–360. https://doi.org/10.2165/00003088-200342040-00003
 Lachenmeier and Rehm (2015) utilized the margin of exposure approach to conduct a risk assessment comparing alcohol, tobacco, cannabis, and other illicit drugs. They shared their results in a publication called Scientific Reports (volume 5, article number 8126), and the information is accessible via this DOI: https://doi.org/10.1038/srep08126.
 Huestis, M. A. (2007). Human cannabinoid pharmacokinetics. Chemistry & Biodiversity, 4(8), 1770–1804. https://doi.org/10.1002/cbdv.200790152