How Psychedelics Affect Memory: Can They Help or Harm Recall?

From ancient rituals to cutting-edge clinical trials, psychedelics have long fascinated humanity for their mind-expanding effects. But as interest in substances like psilocybin, LSD, and MDMA surges — especially in therapeutic settings — so does the question: What do psychedelics actually do to your memory?

These substances can unlock vivid recollections and offer new insights into past traumas. However, they may temporarily cloud short-term memory or even distort familiar narratives. So, do psychedelics boost memory, harm it, or do a little of both?

“Psychedelics appear to augment the subjective experience of autobiographical memory recall — that is, people often feel like they are remembering past events with more vividness, emotional intensity, and realism.”

— Katharine Chan, MSc, BSc, PMP

In this article, we’ll explore how different types of psychedelics affect memory formation, recall, and emotional processing. Drawing on the latest neuroscience research and clinical findings, we’ll look at whether psychIn this article, we’ll explore how different types of psychedelics affect memory formation, recall, and emotional processing. Drawing on the latest neuroscience research and clinical findings, we’ll look at whether psychedelics can support memory-based therapies or introduce new risks when it comes to how we remember.

Acute Effects of Psychedelics on Memory

A 2021 review looked at how classic psychedelics affect memory in the short term (i.e., during or shortly after a psychedelic experience). The researchers used two major scientific databases, PubMed and PsycInfo, to find relevant studies. The review only included human studies and excluded animal research and isolated case reports.

Lower Doses Versus Higher Doses

The review showed a complex, dose-dependent relationship between psychedelics and memory. At lower doses, psychedelics generally do not affect memory performance. 

However, at higher doses, people tend to perform worse on tasks that assessed the following:

• Spatial and verbal working memory: holding and using information briefly, like remembering a phone number.
• Semantic memory: recalling facts or general knowledge.
• Episodic memory: remembering specific events that do not relate to the person’s own life history.

The review showed that autobiographical memories, especially emotionally charged ones that people may have suppressed or long forgotten, often become more vivid, detailed, and emotionally powerful. Users frequently report spontaneously remembering and emotionally re-experiencing these personal moments. Interestingly, people who have previous experience with psychedelics may show less cognitive impairment than first-time users.

The authors concluded that “[c]lassic psychedelics dose-dependently impair memory task performance but may enhance autobiographical memory. These findings are relevant to the understanding of psychological mechanisms of action of psychedelic-assisted psychotherapy.”

Psychedelics and Autobiographical Memory

Autobiographical memory refers to our ability to remember personal information and experiences that shape our sense of self. Autobiographical memory combines episodic and semantic memory. Episodic memory helps us mentally revisit specific events from our past, like a birthday party or a difficult conversation. These memories are rich in detail and include information about where and when something happened. Semantic memory includes general facts about our lives, like knowing your hometown or your profession, without needing to recall the exact moment you learned them.

Together, these two systems make up autobiographical memory, which plays a vital role in how we understand who we are. It connects our past to our present and helps us create a continuous narrative of our lives — a foundation for identity, meaning-making, and self-awareness.

Do Psychedelics Improve Autobiographical Recall?

A 2025 commentary delved into whether psychedelics enhance autobiographical memory. The authors state that psychedelics appear to augment the subjective experience of autobiographical memory recall — that is, people often feel like they are remembering past events with more vividness, emotional intensity, and realism. Researchers have noted this intense recall effect since the early days of LSD research when some users described reliving childhood or even repressed memories. However, current evidence does not support these claims, especially around repressed memories, which researchers now see as unlikely.

Recent qualitative studies continue to report that psychedelics like LSD and psilocybin can provoke emotionally rich and vivid recollections, particularly in therapeutic settings. For example, participants in clinical trials often describe reliving significant life events with exceptional clarity and feeling.

Yet, when it comes to objective evidence, such as more accurate, detailed, or reliable recall, psychedelics do not seem to improve autobiographical memory. In fact, high doses often reduce general memory function and can even disrupt the sense of self or induce temporary amnesia. So far, no solid research has demonstrated that psychedelics increase the accuracy or accessibility of real autobiographical memories.

The dose likely matters: lower doses, used in older psycholytic therapy models, may support clearer memory experiences without overwhelming cognitive function. Contextual factors such as the environment, therapeutic support, and memory cues can influence how memory unfolds during a psychedelic experience.

Ultimately, psychedelics can intensify how people experience memories; however, it remains scientifically unproven whether they actually enhance true recall.

Comparing MDMA and Classic Psychedelics on Memory

A 2024 systematic review and meta-analysis investigated the acute and subacute (“afterglow”) effects of MDMA and classic psychedelics on cognitive functioning. The researchers found strong evidence that psychedelics immediately reduce attention and temporarily worsen memory and executive functioning.

In contrast, the review showed that MDMA mainly impacts memory during the acute phase, while attention and executive functions seem less affected. Interestingly, after the immediate effects of psychedelics wear off during the “afterglow” period, people may experience improvements in executive functioning. However, researchers did not observe any similar afterglow benefits with MDMA.

These authors conclude that the results suggest that psychedelics and MDMA should be used differently in therapy. 

“Given deteriorations of attention under psychedelics, psychotherapeutic interventions might be less fruitful during acute effects of the substance when compared to the subacute “afterglow” period. In contrast, given the specifics of acute effects of MDMA on cognition, psychotherapeutic techniques may be more fruitful during the acute experience when compared to psychedelics, whereas therapy during the subacute window might be somewhat less effective.”

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Psychedelics and Posttraumatic Stress Disorder (PTSD)

Posttraumatic stress disorder (PTSD) affects how people process and remember past events, especially those related to trauma. Recent research suggests that psychedelics could offer a promising new approach to treating PTSD because they influence several memory systems in the brain.

Studies on PTSD and psychedelics have focused on fear conditioning and extinction. Fear conditioning is when someone learns to associate a harmless situation with fear (like a soldier feeling fear when hearing fireworks after combat). Extinction is the process of unlearning that fear once the threat is no longer present. 

A 2024 review looked at 25 studies examining how psychedelics affect fear-related memory for those with PTSD. The strongest finding so far is that psychedelics can improve extinction learning — the ability to “unlearn” fear, which is often limited in people with PTSD. However, there’s also evidence that psychedelics can strengthen fear learning during the acute effects of psychedelics.

The review found that PTSD and psychedelics both seem to temporarily disrupt the formation of new episodic memories, which rely on the hippocampus. At the same time, psychedelics might enhance semantic learning, which depends more on the brain’s cortex. Strengthening semantic memory could help trauma survivors better integrate their painful memories and challenge harmful beliefs about themselves.

The researchers conclude that “ targeting multiple memory mechanisms could improve upon the current psychedelic therapy paradigm for PTSD, thereby necessitating a greater emphasis on assessing diverse measures of memory in translational PTSD and psychedelic research.”

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LSD and Memory

A 2022 randomized, double-blind, placebo-controlled crossover study looked at LSD on episodic memory, verbal fluency, and cognitive flexibility. The study included 24 healthy participants. Each person received either a 50 μg dose of LSD or a placebo. The team measured cognitive performance and the effects on memory and thinking 24 hours after dosing.

They evaluated multiple areas of cognition using standardized tests, including:

• Memory (Rey-Osterrieth Complex Figure, Object-Location Memory, Auditory-Verbal Learning)
• Verbal and design fluency (creative word and pattern generation)
• Cognitive flexibility (ability to shift thinking, assessed by the Wisconsin Card Sorting Test)
• Attention, inhibition, and perceptual reasoning (Stroop Task, Trail Making Test, Block Design Test)

Compared to the placebo group, the LSD group had better cognitive functions. Participants performed better on visuospatial memory tasks and showed improved phonological verbal fluency. However, LSD also negatively impacted cognitive flexibility, as reflected in increased errors and reduced performance on tasks requiring mental switching and adaptation.

The researchers conclude that “the low dose of LSD moderately induced both “afterglow” and “hangover.” The improvements in visuospatial memory and phonological fluency suggest that researchers should explore LSD-assisted therapy as a novel treatment perspective in conditions involving memory and language declines, such as brain injury, stroke, or dementia.”

Psilocybin and Episodic Memory

Recollection and familiarity are key processes that help us retrieve episodic memories. Recollection involves mentally “reliving” an event with vivid detail and a sense of going back to the past. You might remember the sounds, smells, or exact words spoken during the event. Familiarity is more of a gut feeling that something happened, but you can’t recall the details. For example, you might read a passage in a book and feel certain you’ve seen it before but don’t remember when or where.

A 2024 double-blind, placebo-controlled, within-participants study investigated the effect of psilocybin and 2C-B on episodic memory. The researchers included 24 participants and three different conditions: placebo, 15 mg of psilocybin, and 20 mg of 2C-B. During the experience, the researchers showed participants negative, neutral, and positive images. The day after, the subjects completed memory tests about the pictures.

Psychedelics May Enhance Familiarity, Which Can Lead to False Memories

The results showed that the psilocybin and 2C-B groups had poorer recollection, especially for positive and neutral pictures, compared to the placebo group. The psychedelic group had significantly more familiarity-based false recognition effects (i.e., saying you saw something when you didn’t actually see it).

One of the study authors, Manoj K. Doss, a research fellow at The University of Texas at Austin Dell Medical School, shared with PsyPost that psychedelics enhanced familiarity, which led to increased false recognition. Doss explained that researchers think that feelings of familiarity involve the fluency (i.e., the ease of information processing) with which information is processed through the cortex, resulting in fewer neural resources to process repeated or related information:

“In addition to fluency producing false memories, fluency (by presenting a stimulus several times) can also result in other illusory phenomena such as liking a stimulus more (i.e., the mere exposure effect) or increasing the plausibility of a statement (i.e., the illusory truth effect). One idea might be that psychedelics enhance fluency, which could explain why people taking psychedelics together may like each other more (despite having little conversation) or think the ideas they conjure up during a psychedelic experience are true.”

Therefore, psychedelics have a complex relationship with memory. They temporarily impair some types of memory during the acute experience while potentially enhancing the emotional vividness of personal memories. While early research offers fascinating insights, there is still much we don’t fully understand, especially about how psychedelics affect memory over the long term and how therapists can best harness these effects in therapy. 

Future studies will uncover how different doses, settings, and individual experiences shape memory outcomes. If you’re curious to dive deeper into this rapidly evolving field, be sure to explore our other articles that break down the latest research and emerging discoveries about psychedelics, mental health, and memory.

References

Basedow, L. A., Majić, T., Hafiz, N. J., Algharably E. A. E., Kreutz, R., & Riemer, T. G. (2024). Cognitive Functioning Associated with Acute and Subacute Effects of Classic Psychedelics and MDMA – a Systematic Review and Meta-Analysis. Scientific Reports, 14(1). https://doi.org/10.1038/s41598-024-65391-9.

Dolan, E. W. (2024, August 9). Scientists Reveal a Weird Effect of Psychedelics on Memory. PsyPost . https://www.psypost.org/scientists-reveal-a-weird-effect-of-psychedelics-on-memory/.

Doss, M. K., DeMarco, A., Dunsmoor, J. E., Cisler, J. M., Fonzo, G. A., & Nemeroff, C. B. (2024). How Psychedelics Modulate Multiple Memory Mechanisms in Posttraumatic Stress Disorder. Drugs, 84(11), 1419–1443. https://doi.org/10.1007/s40265-024-02106-4.

Doss, M. K., Mallaroni, P., Mason, N. L., & Ramaekers, J. G. (2024). Psilocybin and 2C-B at Encoding Distort Episodic Familiarity. Biological Psychiatry Cognitive Neuroscience and Neuroimaging, 9(10), 1048–1057. https://doi.org/10.1016/j.bpsc.2024.06.008.

Healy, C. J. (2021). The Acute Effects of Classic Psychedelics on Memory in Humans. Psychopharmacology, 238(3), 639–653. https://doi.org/10.1007/s00213-020-05756-w.

Kangaslampi, S., & Lietz, M. (2025). Psychedelics and Autobiographical Memory – Six Open Questions. Psychopharmacology. https://doi.org/10.1007/s00213-025-06771-5.

Wießner, I., Olivieri, R., Falchi, M., Palhano-Fontes, F., Maia, L. O., Feilding, A., Araujo, D. B., Ribeiro, S., & Tófoli, L. F. (2022). LSD, Afterglow and Hangover: Increased Episodic Memory and Verbal Fluency, Decreased Cognitive Flexibility. European Neuropsychopharmacology, 58, 7–19. https://doi.org/10.1016/j.euroneuro.2022.01.114.