What Did the Study Investigate?

The central aim of this study was to explore how small doses of LSD affect cognitive processes like arousal, attention, and memory, particularly focusing on how an individual’s baseline cognitive state (e.g., their attention or memory abilities before taking the drug) might influence their response to LSD. The study utilized a rigorous placebo-controlled, double-blind design, where participants either received repeated doses of LSD or a placebo over two weeks.

The researchers employed neurophysiological measurements, such as resting-state EEG (electroencephalogram) to track changes in brainwave patterns and specific tasks designed to assess pre-attentive processing (how the brain processes stimuli before we consciously pay attention to them) and memory-related learning. These measures were taken before, during, and after the dosing period to track both immediate and longer-term effects of LSD.

Key Findings

The study yielded some compelling results that highlight the variability in how different individuals respond to low doses of LSD. These findings can be broken down into a few key areas:

• 🧠 Arousal and Brain Activity: One of the most significant findings was that low doses of LSD had stimulatory effects on brain activity. This was evident from reductions in low-frequency EEG brainwave power (delta, theta, and alpha waves), which are typically associated with relaxed, drowsy, or meditative states. In contrast, increased arousal or alertness is linked to reductions in these wave patterns. This effect was most pronounced in individuals who had lower arousal and attention levels at baseline, meaning that people who were less alert to begin with experienced the greatest increase in brain arousal from LSD. Notably, these effects persisted even a week after the final dose, suggesting lasting changes in brain activity.

• 👀 Attention and Pre-attentive Processing: The study also found that LSD improved pre-attentive processing, which refers to the brain’s ability to detect changes in the environment before consciously attending to them. This was measured using an “oddball task” where participants were presented with repetitive stimuli, followed by an unexpected deviation. In people who had poorer attention at baseline, LSD sped up the brain’s response to these unexpected stimuli and increased the magnitude of the brain’s automatic, unconscious response (called the P3a component). These improvements suggest that LSD enhances how efficiently the brain processes sensory information, but this effect again was dependent on the individual’s baseline cognitive state.

• 🧮 Memory and Perceptual Learning: On the flip side, LSD appeared to impair a specific form of memory-related neural activity called long-term potentiation (LTP). LTP is a process that strengthens the connections between neurons, making it critical for learning and memory. In this study, LSD blunted LTP, particularly in individuals who had high memory performance at baseline. This suggests that while LSD may enhance attention and arousal, it may simultaneously impair certain memory processes, especially in individuals with already strong memory capabilities.

• 👥 Inter-individual Variability: One of the most interesting aspects of the study was the way individuals’ responses to LSD varied based on their initial cognitive state. For example, the drug’s stimulatory effects were strongest in participants who were more relaxed or had lower attention at baseline, while the impairing effects on memory were most pronounced in individuals who started with stronger memory performance. This highlights the importance of individual differences in understanding how psychedelics work, even at low doses.

Long-lasting Neural Effects

Perhaps one of the most intriguing findings from the study is the evidence of long-lasting effects from LSD microdosing. Even a week after the final dose, participants in the LSD group showed persistent changes in brainwave patterns (specifically, reductions in delta power) and enhanced pre-attentive processing in the oddball task. This suggests that low doses of LSD may produce durable changes in brain function, potentially through mechanisms related to neuroplasticity—the brain’s ability to reorganize and form new neural connections.

How Do These Findings Fit into the Larger Picture of Psychedelic Research?

While this study provides valuable insights into how low doses of LSD affect brain function, it also highlights the complexity of psychedelic effects and the variability of individual responses. Previous research on psychedelics has produced mixed results regarding the benefits of microdosing. Some studies have reported improvements in mood, cognition, and creativity, while others have found little to no benefit compared to placebo. This study adds nuance to that conversation by suggesting that the effects of microdosing may depend heavily on an individual’s baseline cognitive state, genetic factors, and perhaps even their environment or mindset.

Moreover, the lasting changes in brain activity observed in this study align with other research suggesting that psychedelics may promote long-term neuroplasticity. Studies on higher doses of psychedelics have shown that substances like psilocybin and LSD can increase the production of brain-derived neurotrophic factor (BDNF), a protein that supports the growth and maintenance of neurons. This could explain why some cognitive effects persist long after the drug has left the system, although more research is needed to fully understand the mechanisms behind these changes.

Implications for Mental Health Treatments

The findings from this study have potential implications for using low-dose psychedelics in clinical settings. For instance, the stimulatory effects of LSD on arousal and attention could be useful for treating conditions like Attention Deficit Hyperactivity Disorder (ADHD), which is characterized by excessive low-frequency brain activity (particularly in the theta range) and difficulty maintaining attention. Similarly, individuals with mood disorders like depression, which are often associated with low arousal states, might also benefit from the arousal-boosting effects of low-dose psychedelics.

On the other hand, the impairing effects of LSD on memory processes suggest caution when considering microdosing for individuals who rely heavily on memory and learning in their daily lives. These findings also underscore the need for personalized approaches in psychedelic therapy, as not everyone responds to these substances in the same way.

Conclusion: Microdosing’s Benefits Depend on the Individual

This study provides strong evidence that microdosing LSD produces measurable changes in brain function, but it also reveals that these effects are highly dependent on individual differences. Low doses of LSD can enhance attention and arousal in those who need it but may impair memory in individuals who start with strong cognitive performance. Furthermore, the lasting neural effects observed in this study suggest that even small doses of psychedelics can induce long-term changes in brain function, potentially through mechanisms related to neuroplasticity.

As interest in microdosing continues to grow, this study highlights the importance of understanding how individual baseline states, genetics, and cognitive abilities influence the effects of psychedelics. It also opens the door to further research into how these substances might be used in targeted therapies for mental health conditions like ADHD, depression, and anxiety. However, it also calls for caution, especially for those with strong memory capabilities or in cognitive-demanding professions.

In the end, while microdosing psychedelics may offer benefits, this study reminds us that, like any substance, its effects are not one-size-fits-all.