Ayahuasca does not appear to cause permanent brain damage or lasting cognitive decline based on current evidence. The primary psychoactive compound, DMT, has limited neurotoxicity, and long-term ritual users show no signs of cognitive impairment. That said, ayahuasca is not without serious risks. In rare cases, it can trigger prolonged psychotic episodes, dangerous interactions with common medications, and acute cardiovascular stress that could harm someone with an underlying condition.
What the Brain Looks Like After Years of Use
One of the strongest pieces of evidence comes from a 2024 cross-sectional study comparing long-term ayahuasca users (more than 20 years of ritual use) to beginners and non-users. Researchers tested intelligence, verbal working memory, visuospatial memory, visual perception, and executive function. They found no evidence of cognitive decline in any ayahuasca group. In fact, the experienced users scored higher than beginners on tests of working verbal and visuospatial memory.
Brain imaging studies tell a more nuanced story. Long-term users do show measurable structural differences in their brains compared to non-users, particularly in the thickness of certain cortical regions. A 2023 study found a distributed pattern of structural changes across sensory and higher-order brain areas. But these differences don’t appear to be damage. They look more like the kind of neuroplastic remodeling the brain undergoes in response to repeated experience, similar in concept to how meditation or intensive learning reshapes brain structure over time. Researchers have noted that DMT may actually be neuroprotective rather than neurotoxic.
The Risk of Prolonged Psychosis
The most concerning potential for lasting harm involves psychotic episodes. A systematic review of published case reports found multiple instances of psychosis lasting beyond the expected duration of the drug’s effects. One Brazilian ayahuasca church documented 29 psychotic disorders among its members over a 13-year period, including cases of schizophrenia, acute psychotic disorders, bipolar episodes with psychotic features, and substance-induced psychosis.
The overall rate, however, is extremely low. Data from that same church estimated the incidence of psychotic episodes at somewhere between 0.003% and 0.096% of all servings, depending on the dataset used. Importantly, no prolonged psychotic reactions have been reported in controlled clinical settings where participants are screened beforehand. The people most vulnerable are those with a personal or family history of schizophrenia, bipolar disorder, or other psychotic conditions. Clinical trial guidelines universally exclude these individuals from participating.
This is the area where “permanent damage” is most plausible. A psychotic break triggered by ayahuasca could, in someone genetically predisposed, mark the onset of a chronic psychiatric condition. Whether ayahuasca caused the condition or simply accelerated something that would have emerged anyway is impossible to disentangle in individual cases.
Hallucinogen Persisting Perception Disorder
HPPD is a condition where visual disturbances from a psychedelic experience continue long after the drug has worn off. Symptoms include geometric patterns, trails behind moving objects, halos around lights, flashes of color, and objects appearing larger or smaller than they are. The DSM-5 estimates that roughly 4.2% of all hallucinogen users experience HPPD-like symptoms, though reliable prevalence data is limited.
Ayahuasca has been reported as a cause of HPPD, but it accounts for a small fraction of documented cases. The vast majority of HPPD reports involve LSD. In a systematic review of HPPD cases, ayahuasca was grouped with several other substances that together made up only 13.4% of all cases. For most people who develop mild HPPD symptoms, they fade over weeks to months. Severe, truly persistent cases exist but are rare.
Serotonin Syndrome From Drug Interactions
One of the most dangerous and preventable risks of ayahuasca involves its interaction with common antidepressants. Ayahuasca contains potent compounds that block the enzyme responsible for breaking down serotonin in the brain. SSRI antidepressants also increase serotonin levels. Combining the two can flood the brain and body with serotonin, causing a potentially life-threatening condition called serotonin syndrome.
Symptoms range from agitation, rapid heart rate, and muscle twitching to dangerously high body temperature, seizures, and organ failure. This is not a theoretical concern. The interaction is well-documented pharmacologically, and the outcome can be fatal. Anyone taking SSRIs, SNRIs, or other serotonergic medications faces serious risk if they drink ayahuasca without a sufficient washout period. This category of harm is entirely avoidable with proper screening but represents the clearest path to permanent injury or death.
Cardiovascular Stress During the Experience
Ayahuasca causes significant short-term cardiovascular changes. Studies have measured blood pressure increases of up to 35 mmHg (both systolic and diastolic) and heart rate spikes of 26 beats per minute within just two minutes of ingestion. For a healthy person, this is temporary and manageable. For someone with undiagnosed high blood pressure, a heart condition, or vascular fragility, a sudden spike like that could trigger a cardiac event or stroke.
These effects diminish with repeated use, and they resolve completely once the drug wears off. There is no evidence that ayahuasca causes lasting cardiovascular damage in healthy individuals. The concern is entirely about what happens if someone with a pre-existing vulnerability experiences that acute spike without medical support nearby.
Common Side Effects vs. Lasting Harm
A large survey of more than 10,800 ayahuasca users across 50 countries found that 55.9% reported some kind of adverse mental health effect in the weeks or months following use, including emotional or cognitive changes (42%) and altered perception (38.3%). Those numbers sound alarming in isolation, but the researchers noted these effects were generally mild and transient. Most participants described them as part of a positive process of psychological integration.
Acute physical side effects are even more common. Nearly 70% of users reported nausea and vomiting, which practitioners of traditional ayahuasca ceremonies often frame as an expected part of the experience rather than a complication. These gastrointestinal effects resolve within hours and leave no lasting physical trace.
The gap between common side effects and permanent damage is wide. The typical ayahuasca experience involves temporary discomfort, intense psychological content, and measurable but short-lived physiological stress. Permanent harm is concentrated in a narrow set of scenarios: pre-existing psychiatric vulnerability, dangerous drug interactions, or unmanaged cardiovascular risk. For people outside those categories, the current evidence does not support a risk of lasting damage.