Psychedelic drug use and schizotypy in young adults

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 ( r s = 0.12 , P = 0.003 ) and delusional ideation ( r s = 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.

Delusion-proneness predicts COVID-19 vaccination behavior

Introduction

Vaccination-related conspiracy ideation is related to reduced compliance with public health advice globally. Such beliefs have previously been linked to the delusion-proneness trait. However, it is not known how this extends to getting vaccinated.

Methods

Here, we examined how delusion-proneness, as assessed by Peters et al. Delusions Inventory (PDI), is associated with COVID-19 vaccination in a sample of 273 subjects. We also examined whether delusion-proneness predicted the time to get vaccinated, after the vaccine became available.

Results

Unvaccinated subjects were more delusion-prone than vaccinated subjects (W=2225.5, p<0.001, effect-size=0.27). Among vaccinated subjects, higher delusion-proneness was related to longer time to get vaccinated (r s =0.27, p<0.001). These effects remained after adjusting for anxiety, ADHD, and ASD (Autism Spectrum Disorder) traits as well as for psychiatric diagnoses and sex. Path analyses indicated that the effect of delusion-proneness on vaccination rate was strongly mediated through COVID-19 conspiracy ideation, suggesting that delusion prone individuals first develop specific delusion-like ideas regarding vaccination, which then delays vaccination. An exploratory analysis of written text by subjects instructed to explain why they had vaccinated or not, revealed a difference in reasoning between the groups. Unvaccinated individuals were primarily motivated by concerns about personal safety and potential side effects, while vaccinated individuals stated a desire to protect themselves and others as the primary reasons to get vaccinated.

Discussion

Our results suggest that delusion-proneness is a key factor for attaining conspiracy beliefs, at least in relation to COVID-19 pandemic, and associated with lower vaccination rates as well as longer time to get vaccinated.

Longitudinal associations between psychedelic use and psychotic symptoms in the United States and the United Kingdom

It has long been speculated that psychedelic use could provoke the onset of psychosis, but there is little evidence to support this conjecture. Using a longitudinal research design with samples representative of the US and UK adult populations with regard to sex, age, and ethnicity (n = 9732), we investigated associations between psychedelic use and change in the number of psychotic symptoms during the two-month study period. In covariate-adjusted regression models, psychedelic use during the study period was not associated with a change in the number of psychotic symptoms unless it interacted with a personal or family history of bipolar disorder, in which case the number of symptoms increased, or with a personal (but not family) history of psychotic disorders, in which case the number of symptoms decreased. Taken together, these findings indicate that psychedelic use may affect psychotic symptoms in individuals with a personal or family history of certain disorders characterized by psychotic symptomatology.

Prevalence and risk factors for psychotic symptoms in young, first-episode and drug-naïve patients with major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is a common psychiatric disorder worldwide. Psychotic depression has been reported to be frequently under-diagnosed due to poor recognition of psychotic features. Therefore, the purpose of this study was to reveal the rate and risk factors of psychotic symptoms in young, drug-naïve patients with major depressive disorder at the time of their first episode.

METHODS

A total of 917 patients were recruited and divided into psychotic and non-psychotic subgroups based on the Positive and Negative Syndrome Scale (PANSS) positive subscale score. Anxiety symptoms and depressive symptoms were measured by the Hamilton Anxiety Rating Scale (HAMA) and the 17-item Hamilton Depression Rating Scale (HAMD-17), respectively. Several biochemical indicators such as total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting blood glucose (FBG), thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were also measured.

RESULTS

The rate of psychotic symptoms among young adult MDD patients was 9.1%. There were significant differences in TSH (p<0.001), FBG (p<0.001), TC (p<0.0001), TG (p = 0.001), HDL-C (p = 0.049), LDL-C (p = 0.010), diastolic blood pressure (DP) (p<0.001), systolic blood pressure (SP) (p<0.001), and HAMD total score (p<0.001) between young MDD patients with and without psychotic depression. HAMD, TSH, TC, and severe anxiety were independently associated with psychotic symptoms in young adult MDD patients. In addition, among young MDD patients, the rate of suicide attempts in the psychotic subgroup was much higher than in the non-psychotic subgroup (45.8% vs. 16.9%).

CONCLUSIONS

Our findings suggest that psychotic symptoms are common in young MDD patients. Several clinical variables and biochemical indicators are associated with the occurrence of psychotic symptoms in young MDD patients.

Psychedelic use and psychiatric risks

RATIONALE

Research on psychedelics has recently shown promising results in the treatment of various psychiatric disorders, but relatively little remains known about the psychiatric risks associated with naturalistic use of psychedelics.

OBJECTIVE

The objective of the current study was to investigate associations between naturalistic psychedelic use and psychiatric risks.

METHODS

Using a sample representative of the US adult population with regard to sex, age, and ethnicity (N=2822), this study investigated associations between lifetime naturalistic psychedelic use, lifetime unusual visual experiences, and past 2-week psychotic symptoms.

RESULTS

Among respondents who reported lifetime psychedelic use (n=613), 1.3% reported having been told by a doctor or other medical professional that they had hallucinogen persisting perception disorder. In covariate-adjusted linear regression models, lifetime psychedelic use was associated with more unusual visual experiences at any point across the lifetime, but no association was observed between lifetime psychedelic use and past 2-week psychotic symptoms. There was an interaction between lifetime psychedelic use and family (but not personal) history of psychotic or bipolar disorders on past 2-week psychotic symptoms such that psychotic symptoms were highest among respondents who reported lifetime psychedelic use and a family history of psychotic or bipolar disorders and lowest among those who reported lifetime psychedelic use and no family history of psychotic or bipolar disorders.

CONCLUSIONS

Although the results in this study should be interpreted with caution, the findings suggest that lifetime naturalistic use of psychedelics might be associated with more unusual visual experiences across the lifetime, as well as more psychotic symptoms in the past 2 weeks for individuals with a family history of psychotic or bipolar disorders and the reverse for those without such a family history. Future research should distinguish between different psychotic and bipolar disorders and should also utilize other research designs (e.g., longitudinal) and variables (e.g., polygenic risk scores) to better understand potential cause-and-effect relationships.

Extended difficulties following the use of psychedelic drugs: A mixed methods study

Long-term adverse experiences following psychedelic use can persist for weeks, months, or even years, and are relatively unexplored in psychedelic research. Our convergent mixed-method study gained quantitative and qualitative data from 608 participants who reported extended difficulties following psychedelic experiences. Data was gathered on the context of use, the nature and duration of the challenges they experienced (including a written description of these), plus a range of possible risk factors and perceived causes. The most common forms of extended difficulty were feelings of anxiety and fear, existential struggle, social disconnection, depersonalization and derealization. For approximately one-third of the participants, problems persisted for over a year, and for a sixth, they endured for more than three years. It was found that a shorter duration of difficulties was predicted by knowledge of dose, drug type and lower levels of difficulty reported during the psychoactive experience, while a narrower range of difficulties was predicted by taking the drug in a guided setting. Implications for psychedelic harm reduction are discussed.

Alternative beliefs in psychedelic drug users

Previous research has suggested that classical psychedelics can foster significant and enduring changes in personality traits and subjective wellbeing. Despite the lack of evidence for adverse effects on mental health stemming from psychedelic use, concerns persist regarding the capacity of these substances to modulate information processing and attitudes towards factual data. The aim of the present study was to investigate the propensity for accepting alternative facts and the general treatment of knowledge within a sample of 392 participants, 233 of whom reported at least a single incidence of psychedelic use in their lifetime. To do this, we leveraged step-wise methods of linear modelling investigating effects of demographics, psychiatric conditions and concomitant drug use. Our findings revealed a moderate positive association between psychedelic use and beliefs in alternative facts, as well as the specific belief that facts are politically influenced. However, no links were found for favouring intuition over evidence when confirming facts. Among other investigated drugs, only alcohol was negatively associated with beliefs in alternative facts. Taken together, our results support the link between psychedelic use and non-conformist thinking styles, which can be attributed to the psychological effects of the drugs themselves, but may also mirror a common trait related to unconventional beliefs and illicit substance use.