In the expanding landscape of public health discourse, few topics generate as much intrigue and misinformation as psychedelic substances. As research into their potential applications cautiously advances, popular understanding often outpaces the scientific evidence, leading to a proliferation of myths and exaggerated claims. Unusual physiological responses and complex neuroscience concepts, in particular, are frequently stripped of their context and presented in misleading ways. This article aims to bring clarity to this complex area, acting as a scientific editor to separate established fact from popular fiction.
This analysis will focus on two specific, commonly misunderstood phenomena associated with psychedelic mushrooms: the act of yawning during psychedelic experiences and the persistent, inaccurate claim that these substances can “regrow brain tissue.” Our goal is to provide a detailed, evidence-based explanation grounded in physiology and neuroscience. We will explore the established science behind yawning, clarify the crucial differences between neuroplasticity and neurogenesis, and examine how preliminary scientific findings can be distorted by media and public discourse. It is essential to state clearly that this article is for informational and educational purposes only. It does not provide medical advice, advocate for any substance use, or describe subjective experiences. Our sole purpose is to promote scientific literacy and correct misinformation.
What Is Yawning From a Neuroscience Perspective?
Yawning is a universally recognized yet surprisingly complex behavior. Far from being a simple sign of boredom, it is an involuntary reflex managed by the autonomic nervous system—the same system that controls heart rate, digestion, and respiratory rate. From a neuroscience standpoint, yawning is understood as a sophisticated behavior involving a precise sequence of muscle movements and physiological changes, including a deep inhalation, a brief pause (apnea), and a slow exhalation [1]. This phylogenetically ancient behavior, observed across all five classes of vertebrates, suggests it serves a fundamental adaptive function [1].
For decades, the prevailing folk theory was that yawning helps to increase low oxygen levels or decrease high carbon dioxide levels in the blood. However, rigorous scientific investigation has largely debunked this idea. A landmark 1987 study by Provine and colleagues demonstrated that manipulating the levels of oxygen and carbon dioxide in the air subjects breathed had no effect on their yawning frequency [2]. Furthermore, while physical exercise significantly increases the body’s demand for oxygen, it does not increase the rate of yawning, further disconnecting the behavior from simple respiratory needs [2].
Modern research has shifted focus to two more promising hypotheses: arousal regulation and thermoregulation. The arousal hypothesis posits that yawning serves to increase alertness during periods of transition, such as waking up or before an important event [3]. The thermoregulatory hypothesis, which has gained considerable support, proposes that yawning is a mechanism for cooling the brain [4]. Research has shown a direct link between brain temperature and yawning in animal models. For instance, a study on rats found a significant increase in cortical temperature just before a yawn, followed by a significant decrease back to baseline temperature after the yawn occurred [5]. The deep inhalation of cool air and the stretching of jaw muscles during a yawn are thought to facilitate the flow of cooler blood to the brain, thus helping to maintain thermal homeostasis [1] [4].
The initiation and control of yawning involve a complex interplay of neurotransmitters within the brainstem and hypothalamus. Dopamine is considered a primary activator of this behavior. The stimulation of dopamine receptors can induce yawning, and this effect is often mediated through the activation of other neurochemical pathways. Oxytocin, a neuropeptide, is also a key facilitator, often released following dopamine activation to produce the yawning response [6]. Serotonin, another major neurotransmitter, has a more modulatory role; its stimulation can also elicit yawning, sometimes independently of the oxytocin pathway [6]. Finally, acetylcholine is involved in the process, particularly through its muscarinic receptors [1]. This intricate neurochemical cascade underscores that yawning is not a random occurrence but a tightly regulated physiological event.
Why Yawning Has Been Observed in Psychedelic Research
Given the complex neurochemical underpinnings of yawning, it is not surprising that substances affecting these neurotransmitter systems might influence its frequency. Observations of increased yawning have been noted in some clinical and research settings involving psilocybin, the primary psychoactive compound in psychedelic mushrooms. This phenomenon can be understood by examining psilocybin’s primary mechanism of action in the brain.
Psilocybin and its active metabolite, psilocin, exert their main effects by acting on the serotonin system. Specifically, they are potent agonists of the serotonin 2A receptor (5-HT2A) [7] [8]. As discussed, serotonin is one of the key neurotransmitters involved in the regulation of yawning [6]. By stimulating these receptors, psilocybin can trigger a cascade of downstream neurochemical events that may include the induction of yawning. Some research has directly linked the stimulation of central serotonin receptors to drug-induced yawning in humans [9].
However, it is absolutely critical to interpret these observations with scientific caution. The following points must be emphasized:
1.Observational Nature: Reports of yawning are primarily observational and have been noted as a side effect in controlled research environments. They are not a universal or guaranteed effect, nor are they the focus of the research itself.
2.Lack of Established Causality: While the link to the serotonergic system provides a plausible hypothesis, a direct causal mechanism proving that psilocybin-induced 5-HT2A activation causes yawning for a specific functional purpose has not been established. The observation is an association, not a proven functional relationship.
3.Observation Does Not Imply Benefit: The mere occurrence of yawning in this context does not imply any therapeutic benefit or unique physiological advantage. It is a physiological side effect of a substance interacting with the brain’s complex neurochemistry.
In summary, the yawning sometimes observed in psychedelic research is best understood as a plausible, non-specific side effect of potent serotonergic stimulation. It is a direct consequence of the drug’s pharmacology, similar to how other substances that affect dopamine or serotonin systems can also induce yawning [9]. This observation highlights the profound impact these compounds have on the brain’s regulatory systems but should not be misinterpreted as evidence of a unique or therapeutic mechanism.
Do Psychedelic Mushrooms “Regrow Brain Tissue”?
One of the most pervasive and scientifically inaccurate myths surrounding psychedelic mushrooms is the claim that they can “regrow brain tissue” or regenerate lost neurons. This assertion is a significant misrepresentation of the available scientific evidence. To be unequivocally clear: there is no scientific evidence that psychedelic mushrooms, or their active compound psilocybin, can cause the regeneration of lost neurons or regrow damaged brain tissue in humans.
This myth persists due to a fundamental misunderstanding of complex neuroscience concepts, particularly the conflation of “neuroplasticity” with “neurogenesis” or “regeneration.” Preliminary findings from animal studies are often amplified and distorted by online forums, social media, and sensationalist media headlines. Metaphors like “rewiring the brain” are taken literally, leading to the false conclusion that the brain is physically rebuilding itself in a way that is not supported by research. To correct this misinformation, it is essential to define these terms precisely and review what the science actually shows.
Neuroplasticity vs. Brain Regeneration
The distinction between neuroplasticity and brain regeneration (neurogenesis) is crucial for an accurate understanding of this topic. They are not interchangeable terms; they describe fundamentally different processes.
Term | Definition | Relevance to Psychedelics | Example |
Neuroplasticity | The brain’s ability to reorganize itself by forming new neural connections and adjusting the strength of existing ones. It is an adaptive process of change. | Research suggests psychedelics can promote structural and functional neuroplasticity, primarily in animal models. | Learning a new language, which strengthens synaptic connections in language centers of the brain. |
Synaptic Remodeling | A form of neuroplasticity involving the formation, elimination, or alteration of synapses (the junctions between neurons). | Studies in rodents show that psychedelics can increase the density of dendritic spines, which are related to synaptic connections [10]. | A memory being consolidated, which involves strengthening specific synaptic pathways. |
Neurogenesis | The process by which new neurons are formed in the brain. | There is no evidence that psychedelics induce neurogenesis in humans. | The formation of new neurons in the hippocampus during early development. |
Brain Regeneration | The repair of damaged brain tissue, often involving the creation of new neurons to replace lost ones. This is extremely limited in the adult human brain. | This claim is unsupported by evidence in the context of psychedelics. | The regrowth of tissue after a severe brain injury, which does not occur to any significant degree in humans. |
Neuroplasticity, also known as neural plasticity, is a lifelong process that allows the brain to adapt to new experiences, learn new information, and recover from injury [11]. It involves changes in the structure and function of existing neurons and their connections. This can include structural plasticity, such as the growth of new dendritic spines (small protrusions on neurons that receive synaptic input), and functional plasticity, which refers to changes in the strength of communication between neurons.
In contrast, neurogenesis is the birth of entirely new neurons. While robust during embryonic development, its occurrence in the adult human brain is a subject of intense scientific controversy. For many years, it was believed that the adult brain could not generate new neurons. More recent evidence suggests that a very limited form of neurogenesis may persist in specific, isolated regions, most notably the dentate gyrus of the hippocampus [12]. However, even this is heavily debated. A highly cited 2018 study in Nature concluded that neurogenesis in the human hippocampus drops to “undetectable levels” by childhood [13], while other studies suggest it continues at a very low rate [12]. Even proponents of adult neurogenesis agree that it is an exceptionally rare event in humans compared to other mammals and is not a mechanism for widespread brain repair or regeneration [14].
The claim that psychedelics “regrow brain tissue” incorrectly equates the evidence for neuroplasticity with the unsupported idea of large-scale neurogenesis.
How Scientific Language Gets Misinterpreted
The journey from a nuanced scientific finding to a viral public myth is often paved with simplification and exaggeration. The journey from a nuanced scientific finding to a viral public myth is often paved with simplification and exaggeration. This process is particularly common in neuroscience, where the brain’s complexity makes it ripe for misunderstanding. Several factors contribute to this distortion:
•Media Simplification and Headline Exaggeration: News headlines are designed to grab attention. A complex finding like “psilocybin promotes dendritic spine growth in rodent cortical neurons” might be shortened to “Psychedelics Rewire the Brain” or, even more inaccurately, “Mushrooms Regrow Brain Cells.” While technically related, the headline loses all critical nuance regarding the specific mechanism, the animal model, and the limitations of the study.
•Misleading Metaphors: Terms like “rewiring” or “resetting” the brain are powerful metaphors, but they are not literal descriptions of the underlying biology. These metaphors can create a false impression of a computer-like process where old circuits are removed and new ones are installed. In reality, neuroplasticity is a far more subtle and complex biological process of adaptation.
•Social Media Amplification: Misinformation spreads rapidly on social media, where context is often lost and sensational claims are rewarded with engagement. A single exaggerated headline can be shared thousands of times, cementing the myth in the public consciousness long after the original, more nuanced article is forgotten.
The importance of precise terminology in neuroscience cannot be overstated. The difference between promoting synaptic plasticity and regenerating entire neurons is immense. The former is a well-established process of learning and adaptation; the latter is a biological event that is extremely limited, if not absent, in the adult human brain. Conflating the two creates false hope and fundamentally misrepresents the state of scientific knowledge.
What Research Actually Supports
So, what does the credible scientific evidence actually suggest about psilocybin’s effects on brain structure and function? The research, primarily from animal studies, points toward the promotion of neuroplasticity, not neurogenesis.
A 2022 review in Neuropsychopharmacology analyzing psychedelic-induced neuroplasticity noted that studies in rats have shown that compounds like LSD and psilocybin can promote the growth of new dendritic spines and synapses in the prefrontal cortex [10]. These structural changes are considered a key part of neuroplasticity. The idea is that by increasing the potential for new connections, these substances may help the brain break out of rigid patterns of thought and activity that are associated with conditions like depression. This is what is meant by promoting “functional flexibility.”
However, it is crucial to reinforce the limitations of this research:
•Reversibility: The changes in neural connectivity observed are not necessarily permanent. Plasticity is, by its nature, a dynamic process. Synapses are constantly being formed and pruned throughout life.
•Lack of Long-Term Structural Proof in Humans: The direct, physical evidence for these structural changes comes almost exclusively from animal models. It is not currently possible to observe these microscopic changes in living human brains with the same level of detail. Human research relies on indirect measures, such as brain imaging (fMRI) that shows changes in functional connectivity (how different brain regions communicate), not the underlying physical structure of synapses.
•Ongoing Research Limitations: The field is still in its early stages. Much of the research involves small sample sizes, and the long-term effects and clinical relevance of these plastic changes are still under active investigation [15].
[Internal link: Psychedelic Mushrooms: A Science-First Overview] [Internal link: How Psychedelic Mushrooms Affect the Brain]
Conclusion
Navigating the complex world of neuroscience requires a commitment to evidence-based understanding and a critical eye for sensationalism. The phenomena of yawning and the myth of brain regeneration in the context of psychedelic mushrooms serve as powerful case studies in the importance of scientific literacy. Yawning, a behavior rooted in the brain’s ancient systems for arousal and thermoregulation, can be influenced by any substance that interacts with its controlling neurotransmitter pathways, including the serotonergic system targeted by psilocybin. This observation is a testament to the drug’s potent pharmacological effects, not evidence of a unique therapeutic action.
More importantly, the claim that psychedelic mushrooms “regrow brain tissue” is a fundamental misinterpretation of scientific research. The evidence points towards the promotion of neuroplasticity—the brain’s natural ability to adapt and remodel its connections—primarily in animal studies. It does not support the idea of neurogenesis, or the creation of new neurons, in humans. This distinction is not merely academic; it is central to fostering an honest and accurate public discourse.
As research continues, it is vital for the public, journalists, and health communicators to interpret emerging findings with caution and precision. We must learn to distinguish between established evidence, emerging hypotheses, and unsupported speculation. By encouraging a critical reading of neuroscience claims and resisting the allure of simplified, exaggerated narratives, we can foster a more informed and responsible conversation about these powerful and complex substances.
[Internal link: Brain Regions Glossary] [Internal link: Neuroplasticity Explained]
Sources & Further Reading
1.Corey, T. P., Shoup-Knox, M. L., Gordis, E. B., & Gallup, G. G., Jr. (2012). Changes in physiology before, during, and after yawning. Frontiers in Evolutionary Neuroscience, 3, 7. (source)
2.Provine, R. R., Tate, B. C., & Geldmacher, L. L. (1987). Yawning: no effect of 3-5% CO2 and 100% O2 in humans. Ethology, 76(2), 151-155. (source)
3.Baenninger, R. (1997). On yawning and its functions. Psychonomic Bulletin & Review, 4(2), 198-207. (source)
4.Gallup, A. C., & Gallup, G. G., Jr. (2007). Yawning as a brain cooling mechanism. Neuroscience & Biobehavioral Reviews, 31(6), 799-805. (source)
5.Shoup-Knox, M. L., Gallup, A. C., Gallup, G. G., Jr., & McNay, E. C. (2010). Yawning and stretching predict brain temperature changes in rats: support for the thermoregulatory hypothesis. Frontiers in Evolutionary Neuroscience, 2, 108. (source)
6.Argiolas, A., & Melis, M. R. (1998). The neuropharmacology of yawning. European Journal of Pharmacology, 343(1), 1-16. (source)
7.López-Giménez, J. F., & González-Maeso, J. (2018). Hallucinogens and Serotonin 5-HT2A Receptor-Mediated Signaling Pathways. Current Topics in Behavioral Neurosciences, 36, 45–73. (source)
8.Vargas, M. V., Dunlap, L. E., Dong, C., Carter, S. J., Tombari, R. J., Jami, S. A., … & Olson, D. E. (2023). Psychedelics promote neuroplasticity through the activation of intracellular 5-HT2A receptors. Science, 379(6633), 700-706. (source)
9.Sommet, A., Desplas, M., Lapeyre-Mestre, M., & Montastruc, J. L. (2007). Drug-induced yawning: a review of the French pharmacovigilance database. Drug Safety, 30(4), 327-331. (source)
10.Calder, A. E., & Hasler, G. (2023). Towards an understanding of psychedelic-induced neuroplasticity. Neuropsychopharmacology, 48(1), 104-112. (source)
11.Puderbaugh, M., & Emmady, P. D. (2023). Neuroplasticity. In StatPearls. StatPearls Publishing. (source)
12.Moreno-Jiménez, E. P., Flor-García, M., Terreros-Roncal, J., Rábano, A., Cafini, F., Pallas-Bazarra, N., … & Llorens-Martín, M. (2019). Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer’s disease. Nature Medicine, 25(4), 554-560. (source)
13.Sorrells, S. F., Paredes, M. F., Cebrian-Silla, A., Sandoval, K., Qi, D., Kelley, K. W., … & Alvarez-Buylla, A. (2018). Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults. Nature, 555(7696), 377-381. (source)
14.Nano, P. R., & Fariñas, I. (2022). Mounting evidence suggests human adult neurogenesis is an exceptionally rare event. Cell Stem Cell, 29(2), 178-180. (source)
15.Weiss, F., Magnesa, A., Gambini, M., Gurrieri, R., Annuzzi, E., Elefante, C., … & Marazziti, D. (2025). Psychedelic-Induced Neural Plasticity: A Comprehensive Review and a Discussion of Clinical Implications. Brain Sciences, 15(2), 117. (source)
Educational Disclaimer
This article is for educational and informational purposes only and does not constitute medical, psychological, or legal advice. The information presented is based on scientific research and is intended to promote science literacy. The discussion of any substance does not imply endorsement, promotion, or recommendation for its use. The legality and availability of psychedelic substances vary by jurisdiction, and this article does not provide any information on these matters. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment. The scientific discussion of these compounds does not imply therapeutic use or benefit. Readers should approach the topic with a critical and discerning perspective.“`))