Psychedelic drugs and perception: a narrative review of the first era of research

Predictors of Psychedelic Experience: A Thematic Analysis

Research on the therapeutic potential of psychedelic substances is expanding. A limitation within this field is the unpredictability of individual responses to psychedelics. Better understanding of factors predicting psychedelic experience is essential to clinical progress and wider harm reduction frameworks. Ketamine, MDMA, LSD and psilocybin were selected for comparison due to their promising therapeutic effects and different mechanisms of action. This study aimed to (a) identify factors that produce positive and adverse psychedelic experience, and (b) compare these potential predictors across four psychedelic substances. A thematic analysis was conducted on twenty-two first-person reports of psychedelic use (six per substance), sourced from the Erowid database. This revealed three external predictors (nature, music, and preparation) and three internal predictors (understanding, mind-set, and motivation). Each factor identified contained two sub-themes that further elucidated meaning and impact. Nature and music emerged as potential tools for de-escalating adverse reactions to psychedelics. Substance-specific perceptual and sensorial effects were also examined. Finally, the importance of, and interrelationship between, preparation, mind-set, understanding, and motivation was examined as common themes that emerged. The broader clinical and sociological implications are discussed, with reference to developing harm reduction frameworks. These findings constitute an early step in developing a more nuanced understanding of factors shaping psychedelic experience.

Effect of LSD and music on the time-varying brain dynamics

RATIONALE

Psychedelics are getting closer to being widely used in clinical treatment. Music is known as a key element of psychedelic-assisted therapy due to its psychological effects, specifically on the emotion, meaning-making, and sensory processing. However, there is still a lack of understanding in how psychedelics influence brain activity in experimental settings involving music listening.

OBJECTIVES

The main goal of our research was to investigate the effect of music, as a part of "setting," on the brain states dynamics after lysergic acid diethylamide (LSD) intake.

METHODS

We used an open dataset, where a group of 15 participants underwent two functional MRI scanning sessions under LSD and placebo influence. Every scanning session contained three runs: two resting-state runs separated by one run with music listening. We applied K-Means clustering to identify the repetitive patterns of brain activity, so-called brain states. For further analysis, we calculated states' dwell time, fractional occupancy and transition probability.

RESULTS

The interaction effect of music and psychedelics led to change in the time-varying brain activity of the task-positive state. LSD, regardless of the music, affected the dynamics of the state of combined activity of DMN, SOM, and VIS networks. Crucially, we observed that the music itself could potentially have a long-term influence on the resting-state, in particular on states involving task-positive networks.

CONCLUSIONS

This study indicates that music, as a crucial element of "setting," can potentially have an influence on the subject's resting-state during psychedelic experience. Further studies should replicate these results on a larger sample size.