Occasional use of classic psychedelic drugs, such as LSD and psilocybin, may actually be associated with increased mental adjustment, rather than associated with decreased cognitive function. A recent evaluation in young adults found that sporadic users performed similarly to non-users on a variety of brain function tests and showed a clear advantage in changing problem-solving strategies. This study Advances in neuropsychopharmacology and biological psychiatry.
Classic psychedelics alter perception and mood by interacting with specific brain receptors. Examples include psilocybin and LSD, which are the active compounds in magic mushrooms. Clinical trials are testing these substances as treatments for mental health conditions, and public interest is growing. At the same time, the recreational use of these compounds is increasing around the world.
Previous studies on the long-term cognitive effects of psychedelics have yielded conflicting results. Early studies investigating LSD and mescaline in the mid-20th century raised alarms about the potential for brain damage. However, these older studies often had small sample sizes or did not take into account external factors that could skew test results.
A recent study examining the frequent ritual consumption of peyote and ayahuasca, an Amazonian beer, noted neutral results. Some studies suggest a small effect on memory and problem solving. Ritual use typically takes place within a well-defined cultural framework that strictly regulates the amount and context of psychedelic experiences.
Lead author Simon Reiche, a researcher at Charité in Berlin, Germany, and colleagues identified a gap in the literature. Most people around the world who take psychedelics do so sporadically in unstructured, naturalistic settings. The research team wanted to investigate whether these mild to moderate usage patterns leave a lasting mark on cognitive health.
To find out, researchers recruited 136 participants between the ages of 18 and 50. The study group included 84 people who had used psychedelics at least once in their lives and 52 control subjects who had never tried psychedelics. Participants underwent a structured psychiatric assessment and screening to ensure they had abstained from all psychoactive substances for two weeks prior to testing.
The researchers conducted a comprehensive battery of neuropsychological tests. These assessments measured multiple areas of brain function. Specific areas include attention, memory, visuospatial abilities, and executive function.
Executive function is a broad term that refers to advanced mental skills that help people plan, focus attention, remember instructions, and juggle multiple tasks. Working memory and impulse control fall under this operational umbrella. These skills are necessary to overcome day-to-day challenges and achieve long-term goals.
Recognizing that people who take psychedelic drugs also take other substances on a daily basis, the researchers allowed participants who were mild users of other recreational drugs to participate in the study. To make the groups as comparable as possible, control subjects were required to have a history of cannabis use. This rule was established because cannabis consumption was common among psychedelic users.
The research team also used a statistical method called matched-pair analysis to perform a more precise comparison. They isolated 30 participants in a psychedelic group who had used drugs at least 10 times in their lives. These people were then paired with 30 control subjects who shared similar age, gender, education level, and cannabis habits.
When researchers looked at the entire study population, they observed that overall cognitive ability was roughly equivalent between the two groups. People who used psychedelics showed no signs of overall cognitive decline. Across basic tests such as memory, processing speed, and attention, their scores were similar to those of non-users.
Matched pair analysis revealed significant differences in specific areas of executive function. Psychedelic users showed a clear advantage in the Wisconsin Card Sorting Test. This particular assessment measures cognitive flexibility, which is the brain’s ability to adapt its behavior and thinking in response to changing circumstances.
In the Wisconsin Card Sorting Test, participants are asked to sort cards based on hidden rules that change without warning as the test progresses. Subjects must discover new rules through trial and error. Psychedelic users made fewer repetitive errors than control subjects. Once an old sorting strategy stopped working, people were less likely to stick with it.
The researchers also looked at dose-response relationships across groups of psychedelic users. They analyzed whether lifetime psychedelic use correlated with test performance. They found a link between a higher number of past psychedelic experiences and fewer errors on card sorting tests.
Other analyzes within the study also support these observations. After controlling for variables such as education and alcohol use, the researchers found that lifetime psychedelic use was associated with faster visual reaction times during divided attention tasks. This task required participants to simultaneously monitor visual and auditory signals. This suggests that there is an overlap between problem-solving adaptability and the ability to allocate attention effectively in dynamic environments.
Cognitive flexibility plays a central role in complex decision-making and is the ability to devise fresh strategies when faced with unfamiliar scenarios. Mental rigidity, an ambivalent trait, is a hallmark of several mental illnesses. These inflexible thinking patterns greatly contribute to substance abuse, eating disorders, and severe depression.
The observed association with mental flexibility is consistent with emerging theories about how psychedelics affect the physical brain. Recent biological studies suggest that these compounds promote structural changes in neurons. They are thought to chemically induce a temporary window of increased neuroplasticity.
Neuroplasticity refers to the ability of the central nervous system to reorganize its structure, function, or connections in response to internal or external stimuli. Psychedelics exert their effects by activating specific serotonin receptors distributed throughout the cerebral cortex. This activation triggers a chemical cascade within the cell that can lead to subtle structural changes.
Scientists observed that these compounds promoted dendrite branching in animal models. Dendrites act as communication antennas on nerve cells. Psychedelics may promote an unconstrained cognitive state by encouraging the growth of new connections between brain cells.
This study has several limitations that prevent researchers from declaring that psychedelics directly cause increased cognitive flexibility. Because this study relied on a cross-sectional design, we only captured a snapshot in time. People who have high levels of mental flexibility to begin with may be more drawn to psychedelic experimentation.
The study also relied on self-reported data on past substance use. Asking participants to recall specific past drug incidents can lead to memory bias and inaccurate reporting. Additionally, psychedelic users in the matched group had higher rates of lifetime use of other illicit drugs, which may have influenced their test scores.
Despite the statistical matching process, the study population was largely comprised of highly educated urban youth. This demographic profile reflects broad trends in non-clinical psychedelic use, but limits how well the findings apply to different populations. The researchers noted that they could not independently verify the chemical purity or dosage of the street drugs taken by the participants.
The researchers also assessed multiple variables without making targeted statistical adjustments that penalize multiple comparisons. This mathematical approach increases the risk that some favorable test results occurred by chance. To confirm these initial observations, future studies should employ focused longitudinal cognitive assessments.
Advancing the scientific understanding of these substances will require extensive research that follows individuals before and after using psychedelics. The researchers hope their work will inform realistic risk profiles to evolve public health efforts. By investigating the use of non-medical drugs in realistic settings, scientists can better understand the true biological effects of these powerful compounds.
The study, “Sporadic use and neuropsychological performance of classic psychedelics: A cross-sectional analysis,” was co-authored by Simon Reiche, Tim Hirschfeld, Anna Lena Gröticke, Marie Traub, Nicklas Jakob Hafiz, Rico Haas, Lara Sedlaczek, Linda Ortlieb, Georg Leistenschneider, Lukas A. Basedow, Andrea Lohse, Felix Written by Bermpohl. Thomas Günter Riemer and Tomislav Majic.
