Summary: As psychedelics gain traction in mental health treatment, questions remain about their long-term effects. A new study followed individuals self-administering psychedelics and found that while some experienced lingering visual aftereffects, most were not distressed by them.
Surprisingly, delusional ideation slightly decreased a month after use, suggesting that psychedelics may not heighten psychotic traits as once feared. Traits like high sensory absorption and younger age were most associated with persistent visual effects, reinforcing the need for careful screening in clinical and recreational contexts.
Key Facts:
- Visual Aftereffects: About one-third reported lingering visuals like afterimages, but few found them distressing.
- Reduced Delusions: Delusional ideation slightly decreased one month after psychedelic use.
- Risk Factors: High sensory absorption and younger age were strongest predictors of HPPD-like symptoms.
Source: PNAS Nexus
Psychedelic drugs are seeing a surge of interest from mainstream medicine, and initial results suggest that psychedelic-therapy can be a safe and effective treatment for some mental health conditions.
However, the side-effect profile is still incompletely understood.
In particular, the use of psychedelics has been posited to carry a risk of triggering latent psychotic disorders or persistent visual hallucination, known as Hallucinogen Persisting Perception Disorder (HPPD).
In order to better understand the prevalence and risk factors of such side-effects, Katie Zhou and colleagues surveyed 654 people online who were planning to take psychedelics through their own initiative.
Of those, 315 people were resurveyed two weeks after their experience and 212 people were resurveyed again four weeks after their experience.
The sample was 74% male, and 77% university educated. About one third had been diagnosed with at least one psychiatric condition.
The authors found a weak correlation between lifetime psychedelic use and both delusional ideation and magical thinking.
However, on average, delusional ideation was slightly reduced one month after psychedelic use.
These results suggest that schizotypal traits may not be caused by taking LSD or magic mushrooms, in keeping with the principle that correlation does not imply causation.
About a third of individuals surveyed at the four-week mark did have some lingering hallucinatory sensory experiences, such as intensified colors and afterimages. However, the majority of those who experienced this did not report being distressed by it.
The strongest predictors of persistent visual aftereffects were the personality trait absorption—the tendency to be easily immersed in sensory or imaginative experiences—and younger age.
This corroborates previous findings showing that young people and adolescents may be at a particular risk of HPPD.
According to the authors, empirical scrutiny of the potential risks of psychedelics should accompany changes in policy and access to psychedelic drugs.
About this psychedelics and visual neuroscience research news
Author: Katie Zhou
Source: PNAS Nexus
Contact: Katie Zhou – PNAS Nexus
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Prediction of hallucinogen persisting perception disorder and thought disturbance symptoms following psychedelic use” by Katie Zhou et al. PNAS Nexus
Abstract
Prediction of hallucinogen persisting perception disorder and thought disturbance symptoms following psychedelic use
Interest in using psychedelic drugs to treat psychiatric disorders is growing rapidly.
While modern controlled clinical trials show a favorable safety and efficacy profile, it remains unclear if the risk of side effects would increase with broader use in more heterogeneous populations.
To address this, we investigated the frequency and baseline predictors of delusional ideation, magical thinking, and “hallucinogen persisting perception disorder” (HPPD)-related symptoms following psychedelic use in a self-selected naturalistic sample.
Using a prospective cohort study, symptoms were assessed in (N=654) participants at one week before a planned psychedelic experience, and at two and four weeks afterward.
Across the sample, delusional ideation was found to be reduced one month after psychedelic use (P<0.001) with no changes detected in magical thinking.
These findings were in seeming opposition to positive correlations between lifetime psychedelic use at baseline with magical thinking (rs=0.12, P=0.003) and delusional ideation (rs=0.11, P=0.01), suggesting that schizotypal traits, instead of being caused by, may merely correlate with psychedelic use.
Importantly, over 30% of the sample reported HPPD-type effects at the 4-week endpoint, although rarely perceived as distressing (< 1% of the population).
Younger age, female gender, history of a psychiatric diagnosis and baseline trait absorption predicted the occurrence of HPPD-like effects.
This is in line with prior studies showing a high prevalence of HPPD-like symptoms in psychedelic users, which, however, appear to remain at a subclinical severity in most cases, explaining the comparatively lower prevalence of HPPD diagnoses.
