Predictors Of Hallucinogen Persisting Perception Disorder Symptoms, Delusional Ideation And Magical Thinking Following Naturalistic Psychedelic Use

Abstract

OBJECTIVE: Psychedelics have over recent years been subject to a fast-paced growth in scientific research, clinical applications, commercial investment, and substance use trends by the general public. Yet, concerningly little is known about the frequency of adverse side effects of psychedelic use, despite a breadth of anecdotal reports and largely untested assumptions that inform the screening criteria in modern controlled research. This study aimed to evaluate the frequency and predictive factors of specific, enduring, and potentially undesirable, cognitive and perceptual changes, including symptoms related to delusional ideation, magical thinking and hallucinogen persisting perception disorder (HPPD), following real-world psychedelic use in naturalistic settings.METHOD: In this prospective online cohort study, participants were assessed at 3 timepoints: 1 week before (N = 654) a planned psychedelic experience, and at 2 weeks (N = 305) and 4 weeks afterwards (N = 212). Correlational analyses were performed between lifetime psychedelic use, delusional ideation and magical thinking reported at baseline. Additionally, longitudinal changes in these variables were investigated using Friedman’s test, differentiating between novice (≤ 5 times psychedelic use) and experienced users (> 5 times psychedelic use). Further exploratory analyses of longitudinal increases in delusional and magical ideation were performed using logistic regression to identify predictors of change. The frequency of enduring visuo-perceptual effects indicative of HPPD was assessed at the 4 week endpoint. Predictor variables for the occurrence of such effects were determined via logistic regression.RESULTS: Frequency of lifetime psychedelic use was positively, albeit negligibly, correlated with higher baseline levels of delusional ideation rs = .11, p = .01), and magical ideation (rs = .12, p = .003). Contradictorily, delusional ideation was significantly reduced 4 weeks after the reported psychedelic experience. Baseline personality trait absorption was found to be a predictor of persistent increases in magical thinking at 4 weeks after the acute psychedelic experience. Approximately a third (32.7%) of participants, reported symptoms related to HPPD, with ‘intensified colours’ reported most frequently. However, in line with previous findings, only 2.94% (n = 2) of these respondents perceived these symptoms as distressing. Younger age, female gender, absorption, less non-psychedelic substance use in the last 6 months and non-retreat setting were found to be significant predictors of HPPD-like symptoms.CONCLUSION: The present study found an association between the measured cognitive thinking styles and lifetime psychedelic use at baseline. However, observed longitudinal reductions in delusional ideation from before to after the assessed psychedelic experience suggest that this relationship may not be causative, and that the observed correlation with psychedelic use might be driven by other underlying factors. Although HPPD-like symptoms were more common than expected, the absence of associated distress might explain the relatively low incidence of HPPD diagnoses. Predictors of HPPD have been identified, which may help to inform an at-risk profile. Nevertheless, these results warrant further controlled research on the frequency of enduring, yet subtle, adverse side-effects in clinical and non-clinical populations, being limited by the observational nature of the current study.

Focusing on the negative: cases of long-term negative psychological responses to psychedelics

“…Relatively high prevalence of occasional HPPD symptoms, but very low prevalence of HPPD diagnosis as well as low prevalence of perceived negative impact of the experienced symptoms, is also consistent with the findings from previous studies [52] including a recent one by our group, where 68 of 212 respondents (32%) reported at least one HPPD symptom. However, only one of these 68 (i.e., 3% of those reporting any HPPD symptom) expressed that they experienced the symptoms as distressing [60]. This is also consistent with previous research, where very few of those reporting HPPD-like symptoms found them unpleasant or harmful [52].…”

“…One could attempt to simplify the 'individual vulnerability' factor by referring to an individual's biologically based disposition (e.g., as influenced by genetic factors) but even this cannot be extricated from environmental influence [e.g., 59]. Moreover, according to this study's data and currently unpublished findings [60] we would argue that young age should be included as a vulnerability factor.…”

Case analysis of long-term negative psychological responses to psychedelics

“…One could attempt to simplify the ‘individual vulnerability’ factor by referring to an individual’s biologically based disposition (e.g., as influenced by genetic factors) but even this cannot be extricated from environmental influence [e.g., 58 ]. Moreover, according to this study’s data and currently unpublished findings 59 we would argue that young age should be included as a vulnerability factor.…”

“…Relatively high prevalence of occasional HPPD symptoms, but very low prevalence of HPPD diagnosis and perceived negative impact of the experienced symptoms, is also consistent with the findings from previous studies 51 including a recent one by our group, where 68 of 212 respondents (32%) reported at least one HPPD symptom. However, only one of these 68 (i.e., 3% of those reporting any HPPD symptom) experienced the symptoms as distressing 59 .…”

Psychological effects of psychedelics in adolescents

“…When visual effects such as "trailing", intensification of colour, or "visual snow" persist after psychedelic use and are either perceived as distressing or lead to functional impairment, they are clinically recognised as "hallucinogen persisting perceptual disorder" (85). Survey studies indicate that while the occurrence of persisting visual aberrations might be as high as in 40% of users (86), they are in most cases sufficiently mild or transient to not be perceived as distressing, thus keeping the estimated prevalence of HPPD low at <1% (86)(87)(88)(89). While the pathophysiological mechanisms underlying HPPD are yet to be uncovered (90), it is plausible that elevated neuroplastic changes in adolescence combined with the likely neuroplastic effects of psychedelics may put adolescents at special risk of developing the disorder.…”