The "Endless Trip" among the NPS Users: Psychopathology and Psychopharmacology in the Hallucinogen-Persisting Perception Disorder. A Systematic Review

Psychedelic research, assisted therapy and the role of the anaesthetist: A review and insights for experimental and clinical practices

Recent years have witnessed an unprecedented increase in the search for the use of psychedelics in improving physical and mental health. Anaesthesia has evolved since very early times, born from the need to eliminate pain and reduce suffering and there are reports of the use of anaesthetics to achieve mystical states since the nineteenth century. Nowadays, the renaissance of psychedelics in anaesthesia has been inspired by their potential in the treatment of chronic pain syndromes, palliative care and in the emergency department and pre-hospital care with the administration of psychedelics in cases of ischaemia, given their potential in neuroprotection. Although there are already some published protocols for the administration of psychedelics in patients with mental illness, little has been addressed concerning non-mental medical applications. In this sense, in patients with multiple comorbidities, functional limitations and polymedicated, the anaesthetist may play a fundamental role, not only in clinical practice, but also in translational research. This article focuses on the description of psychedelics, with a particular focus on dimethyltryptamine (DMT) and ayahuasca pharmacology, effects, safety and toxicity. A detailed description of the role of the anaesthetist in clinical and experimental research is provided, from participant's screening to preparation and dosing session, expected adverse effects and how to manage them, based on the protocol and standard procedures of a current study with neuroimaging during the psychedelic experience. Specific considerations regarding the management of psychedelic toxicity are also provided as well as future directions for safe psychedelic use in clinical practice.

Efficacy and safety of psychedelics for the treatment of mental disorders: A systematic review and meta-analysis

We aim to systematically review and meta-analyze the effectiveness and safety of psychedelics [psilocybin, ayahuasca (active component DMT), LSD and MDMA] in treating symptoms of various mental disorders. Web of Science, Embase, EBSCO, and PubMed were searched up to February 2024 and 126 articles were finally included. Results showed that psilocybin has the largest number of articles on treating mood disorders (N = 28), followed by ayahuasca (N = 7) and LSD (N = 6). Overall, psychedelics have therapeutic effects on mental disorders such as depression and anxiety. Specifically, psilocybin (Hedges' g = -1.49, 95% CI [-1.67, -1.30]) showed the strongest therapeutic effect among four psychedelics, followed by ayahuasca (Hedges' g = -1.34, 95% CI [-1.86, -0.82]), MDMA (Hedges' g = -0.83, 95% CI [-1.33, -0.32]), and LSD (Hedges' g = -0.65, 95% CI [-1.03, -0.27]). A small amount of evidence also supports psychedelics improving tobacco addiction, eating disorders, sleep disorders, borderline personality disorder, obsessive-compulsive disorder, and body dysmorphic disorder. The most common adverse event with psychedelics was headache. Nearly a third of the articles reported that no participants reported lasting adverse effects. Our analyses suggest that psychedelics reduce negative mood, and have potential efficacy in other mental disorders, such as substance-use disorders and PTSD.

Uncovering transcriptomic biomarkers for enhanced diagnosis of methamphetamine use disorder: a comprehensive review

Introduction

Methamphetamine use disorder (MUD) is a chronic relapsing disorder characterized by compulsive Methamphetamine (MA) use despite its detrimental effects on physical, psychological, and social well-being. The development of MUD is a complex process that involves the interplay of genetic, epigenetic, and environmental factors. The treatment of MUD remains a significant challenge, with no FDA-approved pharmacotherapies currently available. Current diagnostic criteria for MUD rely primarily on self-reporting and behavioral assessments, which have inherent limitations owing to their subjective nature. This lack of objective biomarkers and unidimensional approaches may not fully capture the unique features and consequences of MA addiction.

Methods

We performed a literature search for this review using the Boolean search in the PubMed database.

Results

This review explores existing technologies for identifying transcriptomic biomarkers for MUD diagnosis. We examined non-invasive tissues and scrutinized transcriptomic biomarkers relevant to MUD. Additionally, we investigated transcriptomic biomarkers identified for diagnosing, predicting, and monitoring MUD in non-invasive tissues.

Discussion

Developing and validating non-invasive MUD biomarkers could address these limitations, foster more precise and reliable diagnostic approaches, and ultimately enhance the quality of care for individuals with MA addiction.

Neuropsychiatric Disorders: Bridging the Gap Between Neurology and Psychiatry

Given the ongoing difficulties faced by clinicians and researchers in dealing with neuropsychiatric illnesses, it is becoming more and more evident that there is a need to go beyond traditional disciplinary boundaries. This research consolidates existing material, examining changes in history, the fundamental neurobiological aspects, and the shared clinical manifestations between neurology and psychiatry. This inquiry examines the historical development of neuropsychiatry, focusing on the relationship between early understandings of mental illness and the later division of neurology and psychiatry. The focus is on recent advancements in comprehending the common neurobiological pathways and genetic factors that highlight the merging of these fields. The research highlights the complexities of clinical presentations in neuropsychiatric illnesses by analyzing the overlapping cognitive, affective, and behavioral symptoms. The text critiques the diagnostic issues in traditional frameworks, emphasizing the limitations in differentiating between neurological and psychiatric origins. This has ramifications for achieving correct diagnosis and arranging appropriate treatment. The paper explores developing multidisciplinary care approaches, highlighting successful collaborations between neurologists and psychiatrists. This study examines the difficulties in carrying out a plan and the process of identifying obstacles to combining different elements. It also highlights the urgent need for improved instruction and learning for smooth cooperation. The paper examines the therapeutic implications by investigating pharmacological therapies focusing on shared pathways. It also discusses the difficulties involved in managing neurological and psychiatric diseases that occur together. The study also explores non-pharmacological therapies, such as psychotherapy and rehabilitation methods, as part of a comprehensive treatment approach. Anticipating the future, the report identifies areas where the study could be improved and forecasts the influence of technological improvements on the subject. Suggestions are put out to encourage additional exploration, cooperation, and originality to narrow the divide between neurology and psychiatry, ultimately augmenting our comprehension and treatment of neuropsychiatric illnesses. This real-time synthesis adds to the ongoing discussion, providing valuable insights that align with the ever-changing field of contemporary neuropsychiatric research and therapy.

Epidemiology of classic psychedelic substances: results from a Norwegian internet convenience sample

Objective

In recent years, there has been a renewed interest in investigating the use of classic psychedelics such as psilocybin and lysergic acid diethylamide (LSD) in the treatment of mental disorders and substance use disorders. However, knowledge about the epidemiology of classic psychedelics in the Nordic countries is limited.

Methods

We recruited adult, Norwegian participants who have had a memorable experience after taking a classic psychedelic substance. They filled in an anonymous internet survey with 119 items covering matters related to recreational use of psychedelics using a secure, web-based application. Data are presented by using descriptive statistics (frequencies, means, and standard deviations).

Results

We recruited 841 participants, 770 (72% male; 88% 45 years or younger) of which were included in the data analysis. The intentions behind taking the psychedelic substance were mainly recreational (46.1%) or therapeutic (42.3%). Most participants reported that their most memorable experience was with psilocybin. As in modern era clinical trials, most participants were well-prepared before, did processing during, and did integration work after the experience, whereas only a minority were supported by a therapist. Self-perceived symptoms of various mental disorders and substance use disorders were prevalent in the sample. Most subjects reported improvements in their condition. Although adverse reactions were usually mild and short-lived, 4.2% lasted for 1 year or more. Persisting flashbacks were present for a year or more among 2.9% of the participants.

Conclusion

In this cross-sectional sample of Norwegian, self-selecting adults, we shed light on what characterizes the most memorable experience with a classic psychedelic substance, including short- and long-term risks and benefits. For the most part, the psychedelic experience led to improvements in self-perceived symptoms of mental disorders and substance use disorders. However, a small subset experienced persisting adverse reactions.

Hallucinogen-Induced Persisting Perception Disorder: A Case Report

Hallucinogen-persisting perception disorder (HPPD), also known as acute hallucinogen-induced psychosis or informally known as "flashbacks," is an unusual condition experienced by patients due to the use of different hallucinogenic substances. Hallucinogen-persisting perception disorder causes many symptoms, predominantly persistent visual perception distortion instead of intermittent distortion. Although different hallucinogens could cause HPPD, lysergic acid diethylamide (LSD) and LSD-like properties seem to be the most common hallucinogens causing the symptoms. In our case report, the patient is a 28-year-old Caucasian male with a long psychiatric and social history of polysubstance use using LSD and cannabis. He started experiencing many of the classic symptoms of HPPD seven months after stopping LSD. The diagnosis is suspected by ruling out all other possible underlying causes with the help of several laboratory and imaging tests. Despite having an extensive psychiatric history of illnesses, the patient's symptoms failed to improve with antipsychotics, confirming that the symptoms were not only due to mental illness. Although supposedly the first-line treatment for HPPD is the use of alpha-2 adrenergic drugs such as clonidine and benzodiazepines, we started to witness improvement in patient's symptoms with the use of lamotrigine, which is the gold standard in treating perceptual disturbance in time and space.

Prevalence of psilocybin use in vaping and associated factors: a study among amphetamine-type stimulants (ATS) use disorder in Malaysia

BACKGROUND

The emergence of New Psychoactive Substances (NPS), including synthetic psilocybin, has raised concern among health experts due to the numerous health and socioeconomic consequences. The current trend is shifting to the hazardous use of synthetic psilocybin in vaping, and little is known about the prevalence of use, specifically among amphetamine-type stimulants (ATS) users.

METHODS

Interviewer-administered questionnaires were conducted in drug detention centers between March and October 2022. The study was conducted using ASSIST 3.0 and obtained information on the respondents' socio-demographic characteristics and clinical profiles. N = 355 ATS users were enrolled in this study.

RESULTS

The results show a high prevalence of psilocybin vaping among ATS users (182/355, 53.1%). Most of the respondents were males (85.1%) and unmarried (69.3%), with a mean age of 29.2 (SD = 7.3). Across all respondents, five factors were associated with psilocybin vaping: tobacco smoking, aOR =5.790 (95% CI: 1.723, 8.183); cannabis uses, aOR= 9.152 (95% CI: 2.693, 10.396); and alcohol use, aOR= 3.137 (95% CI: 1.461, 5.817). Respondents of the Malay race had higher odds of being involved in psilocybin vaping compared to other races, with aOR= 1.638 (0.043, 2.459). Meanwhile, a reduction in age by 1.9 will increase the likelihood of involvement in psilocybin vaping with aOR = 1.897 (95% CI: 0.857, 1.938).

CONCLUSION

Psilocybin in vaping is growing among ATS users and across all populations. Unfortunately, knowledge regarding the long-term effects on health is limited. Further studies should highlight the harmful effects of psilocybin and the potential risk of psilocybin vaping among the younger population.

Stimulant and hallucinogenic novel psychoactive substances; an update

INTRODUCTION

The renewed interest in considering a range of stimulants, psychedelics and dissociatives as therapeutics emphasizes the need to draft an updated overview of these drugs' clinical and pharmacological issues.

AREAS COVERED

The focus here was on: stimulants (e.g. amphetamines, methamphetamine, and pseudoephedrine; phenethylamines; synthetic cathinones; benzofurans; piperazines; aminoindanes; aminorex derivatives; phenmetrazine derivatives; phenidates); classical (e.g. ergolines; tryptamines; psychedelic phenethylamines), and atypical (e.g. PCP/ketamine-like dissociatives) psychedelics.Stimulant and psychedelics are associated with: a) increased central DA levels (psychedelic phenethylamines, synthetic cathinones and stimulants); b) 5-HT receptor subtypes' activation (psychedelic phenethylamines; recent tryptamine and lysergamide derivatives); and c) antagonist activity at NMDA receptors, (phencyclidine-like dissociatives).

EXPERT OPINION

Clinicians should be regularly informed about the range of NPS and their medical, psychobiological and psychopathological risks both in the acute and long term. Future research should focus on an integrative model in which pro-drug websites' analyses are combined with advanced research approaches, including computational chemistry studies so that in vitro and in vivo preclinical studies of index novel psychoactives can be organized. The future of psychedelic research should focus on identifying robust study designs to convincingly assess the potential therapeutic benefits of psychedelics, molecules likely to present with limited dependence liability levels.

Psilocybin for Depression: From Credibility to Feasibility, What's Missing?

Psilocybin has been suggested as a promising transdiagnostic treatment strategy for a wide range of psychiatric disorders. Recent findings showed that psychedelic-assisted/"psycholitic" psychotherapy should provide significant and sustained alleviation of depressive symptoms. However, to date, there have been several study limitations (e.g., small sample sizes, blinding, limited follow-up, highly screened treatment populations) and some health/political issues, including practitioners' experience, lack of standardized protocols, psychedelics' legal status, ethical concerns, and potential psychological/psychopathological/medical untoward effects. The focus here is on a range of clinical and methodological issues, also aiming at outlining some possible suggestions. We are confident that newer evidence, more precise protocols, and eventual reclassification policies may allow a better understanding of the real potential of psilocybin as a transdiagnostic therapeutic molecule.

Drogeninduzierte Psychosen

Substanzkonsumstörungen und Psychosen stehen häufig in einem kausalen Zusammenhang. Dieser kann uni- oder bidirektional sein – oder beide Störungen beruhen auf gemeinsamen ätiopathogenetischen Faktoren. Substanzen wie Cannabinoide, Stimulanzien oder Halluzinogene scheinen wichtige Ko-Faktoren für die Entwicklung einer (sekundären) Psychose darzustellen. Der Beitrag gibt einen Überblick über die Substanzgruppen, Diagnostik und Therapie.

Apophenia, absorption and anxiety: Evidence for individual differences in positive and negative experiences of Hallucinogen Persisting Perceptual Disorder

Background and Aims

Little is known about individual differences in Hallucinogen Persisting Perceptual Disorder (HPPD). This study investigated visual processing style and personality across two HPPD types (HPPD I and HPPD II) and a Non-HPPD group.

Methods

An online survey was delivered to participants sourced from online HPPD and psychedelic user groups and forums (N = 117). Using one-way ANOVA, respondents were compared across four measures of individual difference. Using logistic regression, a range of visual symptoms and experiences were investigated as potential predictors of group categorisation.

Results

The HPPD I group had higher absorption and visual apophenia scores than the other groups and was predicted by higher drug use. The HPPD II group showed significantly higher trait anxiety than both other groups. Across the HPPD groups, HPPD II categorisation was also predicted by increased negative precipitating experiences, lack of prior knowledge and pre-existing anxiety diagnoses.

Conclusions

Anxiety, negative precipitating experiences and lack of prior knowledge are associated with negative experiences of persistent visual symptoms following hallucinogen use, whilst higher absorption and visual apophenia are associated with positive or neutral experiences. Together these findings indicate that differences in personality may play a role in determining an individual's experience of HPPD, highlighting the role of individual difference research in expanding knowledge around HPPD.

Use of plant-based hallucinogens and dissociative agents: U.S. Time Trends, 2002-2019

Aims

Information on time trends in use of different plant-based hallucinogens is lacking. The current study used nationally representative U.S. data to assess overall and age-specific time trends in the prevalence of lifetime and 12-month use of plant-based hallucinogens and dissociative agents.

Methods

Participants were respondents aged ≥ 12 years (N = 1,006,051) from the National Survey on Drug Use and Health, 2002-2019. Predictors were continuous years. Outcomes included illicit use of peyote, mescaline, psilocybin, ketamine, salvia, and tryptamine. Sociodemographic variables (gender; age; race/ethnicity; educational level; family income) were modeled as covariates. Trends were estimated overall and by age (12-17, 18-25, 26+). Prevalence differences [PDs] were obtained for each category, along with 95 % confidence intervals [CI].

Results

Increases in lifetime use were observed for psilocybin (2002-2019 PD=+1.61), tryptamine (2006-2014 PD=+0.55; 2015-2019 PD=+0.44), and ketamine (2006-2014 PD=+0.27; 2015-2019 PD=+0.21). Mescaline use decreased (PD = -0.89). While overall lifetime salvia use increased between 2006 and 2014 (PD=+1.81), prevalence did not change between 2015 and 2019. Twelve-month use of tryptamine and ketamine increased between 2006 and 2014 (PD=+0.14; +0.03, respectively). Twelve-month ketamine use also increased from 2015 to 2019 (PD=+0.03). By age, participants aged 12-17 and 18-25 showed decreases in use of most types of hallucinogens, but those age 26+ generally showed increases.

Conclusions

While use of plant-based hallucinogens and dissociative agents remains rare, lifetime use of ketamine, tryptamine, and psilocybin is increasing in adults. Considering these increases alongside concerns about unsupervised use of illicit products whose dose and composition is uncertain, clinicians and policymakers should remain mindful of the rising rates of illicit use in the general population.

Psilocybin in neuropsychiatry: a review of its pharmacology, safety, and efficacy

Psilocybin is a tryptamine alkaloid found in some mushrooms, especially those of the genus Psilocybe. Psilocybin has four metabolites including the pharmacologically active primary metabolite psilocin, which readily enters the systemic circulation. The psychoactive effects of psilocin are believed to arise due to the partial agonist effects at the 5HT2A receptor. Psilocin also binds to various other receptor subtypes although the actions of psilocin at other receptors are not fully explored. Psilocybin administered at doses sufficient to cause hallucinogenic experiences has been trialed for addictive disorders, anxiety and depression. This review investigates studies of psilocybin and psilocin and assesses the potential for use of psilocybin and a treatment agent in neuropsychiatry. The potential for harm is also assessed, which may limit the use of psilocybin as a pharmacotherapy. Careful evaluation of the number needed to harm vs the number needed to treat will ultimately justify the potential clinical use of psilocybin. This field needs a responsible pathway forward.

Visual hallucinations in Lewy body disease: pathophysiological insights from phenomenology

Visual hallucinations (VH) in Lewy body disease (LBD) have a heterogenous phenomenology classified into minor phenomena (MVH) and complex hallucinations (CVH). Mechanisms underpinning VH and their temporal aspects are largely unknown. According to the hodotopic model, we investigated whether changes in distinct cognitive domains and neural networks in the hallucination trait underpin temporal aspects of MVH and CVH in the hallucination state. 35 LBD patients with VH underwent a complete neuropsychological evaluation and resting-state fMRI. North-East-Visual-Hallucinations-Interview was used to assess their typical VH content, duration, and frequency. We found that MVH was not associated with cognitive impairment, while CVH was associated with impairments in visuoperceptual processes, attention and visual abstract reasoning. In seed-to-seed functional connectivity (FC) analysis we identified functional couplings associated with MVH and CVH temporal severity (duration x frequency), duration and frequency. MVH severity was negatively associated with FC between early visual areas (EVA) and ventral-visual-stream regions, and negatively associated with FC between brainstem and EVA, which may be linked to LBD brainstem neuropathology. CVH duration was positively associated with FC between ventral-visual stream and salience network (SN). CVH frequency was negatively associated with FC between DMN and SN. Functional alterations in distinct visual and attentional networks and their dynamic interaction in trait LBD hallucinators are linked to both the phenomenology of state content and its temporal characteristics. Within a network, VH frequency and duration may be linked to different types of functional alterations: increased connectivity leading to sustained activity prolonging VH (duration) and decreased connectivity increasing dysregulated, spontaneous activity (frequency). These findings support the hodotopic hypothesis of VH and may reflect a link between VH phenomenology, LBD neuropathological progression and the involvement of specific neurotransmitter systems.

Three Naturally-Occurring Psychedelics and Their Significance in the Treatment of Mental Health Disorders

Classical psychedelics represent a family of psychoactive substances with structural similarities to serotonin and affinity for serotonin receptors. A growing number of studies have found that psychedelics can be effective in treating various psychiatric conditions, including post-traumatic stress disorder, major depressive disorder, anxiety, and substance use disorders. Mental health disorders are extremely prevalent in the general population constituting a major problem for the public health. There are a wide variety of interventions for mental health disorders, including pharmacological therapies and psychotherapies, however, treatment resistance still remains a particular challenge in this field, and relapse rates are also quite high. In recent years, psychedelics have become one of the promising new tools for the treatment of mental health disorders. In this review, we will discuss the three classic serotonergic naturally occurring psychedelics, psilocybin, ibogaine, and N, N-dimethyltryptamine, focusing on their pharmacological properties and clinical potential. The purpose of this article is to provide a focused review of the most relevant research into the therapeutic potential of these substances and their possible integration as alternative or adjuvant options to existing pharmacological and psychological therapies.

Comparison of LC-MS and LC-DAD Methods of Detecting Abused Piperazine Designer Drugs

Recreational use of piperazine designer drugs is a serious threat to human health. These compounds act on the body in a similar fashion to illegal drugs. They induce psychostimulatory effects as well as visual and auditory hallucinations to varying degrees. In many cases of poisoning and deaths, the presence of two or even several psychoactive substances have been demonstrated. Piperazine derivatives are often found in such mixtures and pose a great analytical problem during their identification. Additionally, some piperazine derivatives can be detected in biological material as a result of metabolic changes to related drugs. Therefore, it is necessary to correctly identify these compounds and ensure repeatability of determinations. This article presents a comparison of the methods used to detect abused piperazine designer drugs using liquid chromatography in combination with a diode-array detector (LC-DAD) or mass spectrometer (LC-MS). Each of methods can be used independently for determinations, obtaining reliable results in a short time of analysis. These methods can also complement each other, providing qualitative and quantitative confirmation of results. The proposed methods provide analytical confirmation of poisoning and may be helpful in toxicological diagnostics.

A retrospective analysis of the "Neverending Trip" after administration of a potent full agonist of 5-HT2A receptor - 25I-NBOMe

BACKGROUND

5-HT2A receptor (e.g. 25I-NBOMe) agonists not only pose risks of acute intoxication but also long-term effects and significant adverse reactions, e.g. hallucinogen persisting perception disorder (HPPD), derealization, and depersonalization.

AIMS

We evaluated the risk associated with single and repeated use of 25I-NBOMe. We aimed to identify factors that may increase the risk of HPPD, increase its severity and determine the time when the first symptoms appear. Herein, we report the first extensive evaluation of 25I-NBOMe-induced HPPD.

METHOD

We assessed all reports (58) collected by The Pomeranian Pharmacovigilance Centre (PPC) from 2013 to 2020.

RESULTS

The study included a total of 58 reports of adverse reactions caused by 25I-NBOMe. In the case of 15 reports (in patients aged 19-26 years), symptoms persisted many months after the discontinuation of 25I-NBOMe. The most common were: pseudohallucinations, bizarre delusions, derealizations and in some cases development or worsening of depression has been diagnosed. HPPD-like symptoms were most common in patients who took the drug regularly (i.e., several times a month). The risk of HPPD-like symptoms is higher in patients who have severe visual pseudohallucinations, severe bizarre delusions, derealization and/or depersonalization onset immediately after taking the drug. Recurrence of HPPD symptoms may be provoked by many factors, however, there is some cases there is no apparent reason. HPPD after 25I-NBOMe use can last from 2 months up to 2 years. In some patients, pharmacological treatment was necessary due to 25I-NBOMe-induced HPPD and depression.

CONCLUSIONS

The study showed long-lasting effects after 25I-NBOMe administration and allowed for the determination of HPPD risk factors.

Flashback phenomena after administration of LSD and psilocybin in controlled studies with healthy participants

BACKGROUND

LSD and psilocybin are increasingly used in phase I trials and evaluated as therapeutic agents for mental disorders. The phenomenon of reoccurring drug-like experiences after the acute substance effects have worn off was described for both substances and especially attributed to LSD. According to the DSM-V, the persisting and distressing manifestation of these experiences is called hallucinogen-persisting perception disorder (HPPD). Data on both conditions is very limited.

OBJECTIVE

This study aims to provide descriptive data on reoccurring drug-like experiences after the administration of LSD and psilocybin in controlled studies with healthy participants.

METHODS AND MATERIALS

Data from 142 healthy subjects enrolled in six double-blinded, placebo-controlled, randomized cross-over studies were analyzed. In total, 60 subjects received LSD; 27 subjects received LSD, MDMA, and D-amphetamine; 31 subjects received LSD and psilocybin; and 25 subjects received psilocybin and escitalopram. At the end-of-study visit (mean 39.8 days after last study session, SD 37.2), subjects were asked for any reoccurring drug effects since the initial substance effects had worn off. Those reporting reoccurring perception changes more than 24 h after administration were contacted for follow-up (mean follow-up duration: 31.2 months, SD 28.6).

RESULTS

Thirteen out of 142 subjects reported reoccurring drug-like experiences (LSD: seven, psilocybin: two, both: four). The reported phenomena were predominantly mild and perceived as neutral to pleasant. Flashbacks were mostly of visual nature, lasted for seconds to minutes, and occurred within a week after the last drug administration. Two subjects reported distressing experiences that subsided spontaneously. One subject reported brief and pleasant visual perception changes which reoccurred for 7 months. None of the subjects reported impairment in their daily lives. None of the cases met DSM-V criteria for HPPD.

CONCLUSION

Reoccurring drug-like experiences after the administration of LSD and psilocybin are a common phenomenon occurring in up to 9.2% of healthy subjects (7.8% for LSD, 8.3% for psilocybin and 14.3% if both substances are administered). Additionally, our work suggests that flashback phenomena are not a clinically relevant problem in controlled studies with healthy participants.

Psychedelic Therapy's Transdiagnostic Effects: A Research Domain Criteria (RDoC) Perspective

Accumulating clinical evidence shows that psychedelic therapy, by synergistically combining psychopharmacology and psychological support, offers a promising transdiagnostic treatment strategy for a range of disorders with restricted and/or maladaptive habitual patterns of emotion, cognition and behavior, notably, depression (MDD), treatment resistant depression (TRD) and addiction disorders, but perhaps also anxiety disorders, obsessive-compulsive disorder (OCD), Post-Traumatic Stress Disorder (PTSD) and eating disorders. Despite the emergent transdiagnostic evidence, the specific clinical dimensions that psychedelics are efficacious for, and associated underlying neurobiological pathways, remain to be well-characterized. To this end, this review focuses on pre-clinical and clinical evidence of the acute and sustained therapeutic potential of psychedelic therapy in the context of a transdiagnostic dimensional systems framework. Focusing on the Research Domain Criteria (RDoC) as a template, we will describe the multimodal mechanisms underlying the transdiagnostic therapeutic effects of psychedelic therapy, traversing molecular, cellular and network levels. These levels will be mapped to the RDoC constructs of negative and positive valence systems, arousal regulation, social processing, cognitive and sensorimotor systems. In summarizing this literature and framing it transdiagnostically, we hope we can assist the field in moving toward a mechanistic understanding of how psychedelics work for patients and eventually toward a precise-personalized psychedelic therapy paradigm.

Rapid Targeted Method of Detecting Abused Piperazine Designer Drugs

Piperazine derivatives belong to the popular psychostimulating compounds from the group of designer drugs. They are an alternative to illegal drugs such as ecstasy and amphetamines. They are being searched by consumers for recreational use due to their stimulating and hallucinogenic effects. Many NPS-related poisonings and deaths have been reported where piperazines have been found. However, a major problem is the potential lack of laboratory confirmation of the involvement of piperazine derivatives in the occurrence of poisoning. Although many methods have been published, piperazine derivatives are not always included in a routine analytical approach or targeted toxicological analysis. There is an increasing need to provide qualitative evidence for the presence of piperazine derivatives and to ensure reproducible quantification. This article describes a new rapid method of detecting piperazine derivatives in biological material, using LC-MS. All target analytes were separated in a 15 min run time and identified based on the precursor ion, at least two product ions, and the retention time. Stable isotopically labeled (SIL) internal standards: BZP-D7, mCPP-D8 and TFMPP-D4 were used for analysis, obtaining the highest level of confidence in the results. The proposed detection method provides the analytical confirmation of poisoning with piperazine designer drugs.

On Perception and Consciousness in HPPD: A Systematic Review

Hallucinogen-persisting perception disorder (HPPD) features as a diagnostic category in the DSM-5, ICD-11, and other major classifications, but our knowledge of the phenomenology of the perceptual symptoms involved and the changes in consciousness during the characteristic “flashbacks” is limited. We systematically evaluated original case reports and case series on HPPD to define its phenomenology, associated (psycho)pathology, and course. Our search of PubMed and Embase yielded 66 relevant publications that described 97 people who, together, experienced 64 unique symptoms of HPPD. Of these, 76% concerned symptoms characteristic of Alice in Wonderland syndrome, over 50% non-visual symptoms, and 38% perceptual symptoms not clearly linked to prior intoxication states. This is in contrast with the DSM-5 diagnostic criteria for HPPD. Even though less than half of the patients showed a protracted disease course of over a year, a third achieved remission. However, in patients with co-occurring depression (with or without anxiety) HPPD symptoms persisted longer and treatment outcomes were more often negative. Thus, unlike the acute stages of psychedelic drug intoxication, which may be accompanied by altered states of consciousness, HPPD is rather characterized by changes in the content of consciousness and an attentional shift from exogenous to endogenous phenomena. Since HPPD is a more encompassing nosological entity than suggested in the DSM-5, we recommend expanding its diagnostic criteria. In addition, we make recommendations for clinical practice and future research.

Molecular and Functional Imaging Studies of Psychedelic Drug Action in Animals and Humans

Hallucinogens are a loosely defined group of compounds including LSD, N,N-dimethyltryptamines, mescaline, psilocybin/psilocin, and 2,5-dimethoxy-4-methamphetamine (DOM), which can evoke intense visual and emotional experiences. We are witnessing a renaissance of research interest in hallucinogens, driven by increasing awareness of their psychotherapeutic potential. As such, we now present a narrative review of the literature on hallucinogen binding in vitro and ex vivo, and the various molecular imaging studies with positron emission tomography (PET) or single photon emission computer tomography (SPECT). In general, molecular imaging can depict the uptake and binding distribution of labelled hallucinogenic compounds or their congeners in the brain, as was shown in an early PET study with N1-([11C]-methyl)-2-bromo-LSD ([11C]-MBL); displacement with the non-radioactive competitor ketanserin confirmed that the majority of [11C]-MBL specific binding was to serotonin 5-HT2A receptors. However, interactions at serotonin 5HT1A and other classes of receptors and pleotropic effects on second messenger pathways may contribute to the particular experiential phenomenologies of LSD and other hallucinogenic compounds. Other salient aspects of hallucinogen action include permeability to the blood-brain barrier, the rates of metabolism and elimination, and the formation of active metabolites. Despite the maturation of radiochemistry and molecular imaging in recent years, there has been only a handful of PET or SPECT studies of radiolabeled hallucinogens, most recently using the 5-HT2A/2C agonist N-(2[11CH3O]-methoxybenzyl)-2,5-dimethoxy- 4-bromophenethylamine ([11C]Cimbi-36). In addition to PET studies of target engagement at neuroreceptors and transporters, there is a small number of studies on the effects of hallucinogenic compounds on cerebral perfusion ([15O]-water) or metabolism ([18F]-fluorodeoxyglucose/FDG). There remains considerable scope for basic imaging research on the sites of interaction of hallucinogens and their cerebrometabolic effects; we expect that hybrid imaging with PET in conjunction with functional magnetic resonance imaging (fMRI) should provide especially useful for the next phase of this research.

The e-psychonaut drugs' psychopharmacology

The focus here was on the pharmacological and clinical pharmacological issues pertaining to the vast range of drugs (e.g. synthetic cannabimimetics, synthetic opioids, novel stimulants, novel psychedelics, PCP/ketamine-like compounds, prescribed medicinal compounds and popular psychotropic herbs/plants) discussed by Internet-based enthusiasts of new/novel psychoactive substances (NPS), 'e-psychonauts'. Currently ongoing related in silico studies, followed by further in vitro and in vivo/preclinical studies, will hopefully provide important findings in terms of which molecules within each given NPS class may present with higher levels of receptor affinities, and hence clinical potency. Understanding the pharmacological characteristics/potency of those novel recreational molecules will hopefully help in predicting related NPS diffusion, morbidity and possible lethality data.

Improving the measurement of alexithymia in autistic adults: a psychometric investigation and refinement of the twenty-item Toronto Alexithymia Scale

BACKGROUND

Alexithymia, a personality trait characterized by difficulties interpreting one's own emotional states, is commonly elevated in autistic adults, and a growing body of literature suggests that this trait underlies a number of cognitive and emotional differences previously attributed to autism, such as difficulties in facial emotion recognition and reduced empathy. Although questionnaires such as the twenty-item Toronto Alexithymia Scale (TAS-20) are frequently used to measure alexithymia in the autistic population, few studies have attempted to determine the psychometric properties of these questionnaires in autistic adults, including whether differential item functioning (I-DIF) exists between autistic and general population adults.

METHODS

We conducted an in-depth psychometric analysis of the TAS-20 in a large sample of 743 verbal autistic adults recruited from the Simons Foundation SPARK participant pool and 721 general population controls enrolled in a large international psychological study (the Human Penguin Project). The factor structure of the TAS-20 was examined using confirmatory factor analysis, and item response theory was used to further refine the scale based on local model misfit and I-DIF between the groups. Correlations between alexithymia and other clinical outcomes such as autistic traits, anxiety, and quality-of-life were used to assess the nomological validity of the revised alexithymia scale in the SPARK sample.

RESULTS

The TAS-20 did not exhibit adequate global model fit in either the autistic or general population samples. Empirically driven item reduction was undertaken, resulting in an eight-item unidimensional scale (TAS-8) with sound psychometric properties and practically ignorable I-DIF between diagnostic groups. Correlational analyses indicated that TAS-8 scores meaningfully predict autistic trait levels, anxiety and depression symptoms, and quality of life, even after controlling for trait neuroticism.

LIMITATIONS

Limitations of the current study include a sample of autistic adults that was overwhelmingly female, later-diagnosed, and well-educated; clinical and control groups drawn from different studies with variable measures; and an inability to test several other important psychometric characteristics of the TAS-8, including sensitivity to change and I-DIF across multiple administrations.

CONCLUSIONS

These results indicate the potential of the TAS-8 as a psychometrically robust tool to measure alexithymia in both autistic and non-autistic adults. A free online score calculator has been created to facilitate the use of norm-referenced TAS-8 latent trait scores in research applications (available at http://asdmeasures.shinyapps.io/TAS8_Score ).

Neurotoxicology Syndromes Associated with Drugs of Abuse

Substance use disorders-and their associated neurologic complications-are frequently encountered by neurologists as well as emergency room physicians, internists, psychiatrists, and medical intensivists. Prominent neurologic sequelae of drug abuse, such as seizure and stroke, are common and often result in patients receiving medical attention. However, less overt neurologic manifestations, such as dysautonomia and perceptual disturbances, may be initially misattributed to primary medical or psychiatric illness, respectively. This article focuses on the epidemiology, pharmacology, and complications associated with commonly used recreational drugs, including opioids, alcohol, marijuana, cocaine, and hallucinogens.

Psychomotor Agitation Non-responsive to Treatment: A Case Report of Phenibut Withdrawal Syndrome

Background and Objectives: Phenibut (4-amino-3-phenyl-butyric acid), acting as a GABA-B receptor agonist, has a beneficial effect on anxiety. Although its medical use is not approved in western countries, it can be easily obtained worldwide via the Internet, so it spread as a substance of abuse. In recent years, some case reports have, therefore, highlighted episodes of acute toxicity or withdrawal, but it is still a largely unknown phenomenon. Methods: In this case report, a 50-year-old woman was admitted to the emergency room with psychomotor agitation, psychotic symptoms, and insomnia, and was non-responsive to treatment. She was hospitalized at the psychiatry ward for 25 days and gave her consent for the publication of the present case report. Results: The suspicion of phenibut withdrawal allowed to establish the appropriate management, leading to the restitutio ad integrum of the psychopathological case. Conclusions: In the face of an incoercible psychomotor agitation case, the knowledge of the so-called novel psychoactive substances allows for more appropriate clinical management of intoxication and withdrawal syndromes. This is a scientifically significant report as it provides therapeutic and outcome data concerning a syndrome that is still quite unfamiliar.

Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms

Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT_2A and 5-HT_1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.

Piperazine derivatives as dangerous abused compounds

Piperazine derivatives are a group of compounds with a psychostimulant effect. They are an alternative to illegal drugs. They are being searched for recreational use due to their psychoactive and hallucinogenic effects. The high popularity of these compounds can be noticed all over the world due to easy purchase, lack of legal regulations and incorrect assessment of the safety of use. The recreational use of piperazine derivatives can often result in chronic and acute health problems and additionally with unpredictable remote effects. It is also common to take mixtures of psychoactive compounds. This hinders the correct diagnosis and treatment of patients with poisoning. The presented work is an illustration of the wide problem of piperazine derivatives abuse. The health effects and the possibility of identifying these compounds in preparations and biological material are described.

Hallucinations: diagnosis, neurobiology and clinical management

Hallucinations are important diagnostic symptoms in schizophrenia, but also occur in other medical and neuropsychiatric conditions. Not all patients with hallucinations are psychotic. There has been a surge of interest in the topic of hallucinations, as new research data have begun to reveal their neurobiology. Hallucinogenic molecules may also serve as new scaffolds for the development of new psychotropic drugs. We searched and reviewed recent literature, focusing on the refinement of clinical management, which was inspired by new data regarding the neurobiology of hallucination subtypes. We concluded that the successful management of hallucinations depends on accurate differential diagnosis to identify subtypes, which would then determine the most appropriate treatment.

Psychedelic science in post-COVID-19 psychiatry

The medium- to long-term consequences of COVID-19 are not yet known, though an increase in mental health problems are predicted. Multidisciplinary strategies across socio-economic and psychological levels may be needed to mitigate the mental health burden of COVID-19. Preliminary evidence from the rapidly progressing field of psychedelic science shows that psilocybin therapy offers a promising transdiagnostic treatment strategy for a range of disorders with restricted and maladaptive habitual patterns of cognition and behaviour, notably depression, addiction and obsessive compulsive disorder. The COMPASS Pathways (COMPASS) phase 2b double-blind trial of psilocybin therapy in antidepressant-free, treatment-resistant depression (TRD) is underway to determine the safety, efficacy and optimal dose of psilocybin. Results from the Imperial College London Psilodep-RCT comparing the efficacy and mechanisms of action of psilocybin therapy to the selective serotonin reuptake inhibitor (SSRI) escitalopram will soon be published. However, the efficacy and safety of psilocybin therapy in conjunction with SSRIs in TRD is not yet known. An additional COMPASS study, with a centre in Dublin, will begin to address this question, with potential implications for the future delivery of psilocybin therapy. While at a relatively early stage of clinical development, and notwithstanding the immense challenges of COVID-19, psilocybin therapy has the potential to play an important therapeutic role for various psychiatric disorders in post-COVID-19 clinical psychiatry.

Designer drugs: mechanism of action and adverse effects

Psychoactive substances with chemical structures or pharmacological profiles that are similar to traditional drugs of abuse continue to emerge on the recreational drug market. Internet vendors may at least temporarily sell these so-called designer drugs without adhering to legal statutes or facing legal consequences. Overall, the mechanism of action and adverse effects of designer drugs are similar to traditional drugs of abuse. Stimulants, such as amphetamines and cathinones, primarily interact with monoamine transporters and mostly induce sympathomimetic adverse effects. Agonism at μ-opioid receptors and γ-aminobutyric acid-A (GABAA) or GABAB receptors mediates the pharmacological effects of sedatives, which may induce cardiorespiratory depression. Dissociative designer drugs primarily act as N-methyl-D-aspartate receptor antagonists and pose similar health risks as the medically approved dissociative anesthetic ketamine. The cannabinoid type 1 (CB1) receptor is thought to drive the psychoactive effects of synthetic cannabinoids, which are associated with a less desirable effect profile and more severe adverse effects compared with cannabis. Serotonergic 5-hydroxytryptamine-2A (5-HT2A) receptors mediate alterations of perception and cognition that are induced by serotonergic psychedelics. Because of their novelty, designer drugs may remain undetected by routine drug screening, thus hampering evaluations of adverse effects. Intoxication reports suggest that several designer drugs are used concurrently, posing a high risk for severe adverse effects and even death.

[Visual snow in hallucinogen-persisting perception disorder]

This article presents the case of a 24-year-old female patient who was referred to this department due to permanent flickering in front of both eyes. This flickering, described as being like visual snow in television, had started 1.5 years ago and was perceived to be very disturbing. Visual acuity, visual field and morphology of the anterior and posterior segment were bilaterally inconspicuous. A neurological examination including a magnetic resonance imaging of the cranium (cMRI) and visual evoked potentials (pattern-VEP) also showed no abnormalities. Furthermore, the patient suffered from schizophrenia. This also first occurred 1.5 years ago directly after consumption of a "narcotic cocktail" consisting of amphetamines, hallucinogens and alcohol. In a synopsis of the findings the patient was diagnosed with type II hallucinogen-persisting perception disorder. Treatment options for this disease are limited and the symptoms often remain permanently.

Substance-Induced Psychosis in Youth

Youth experiencing psychosis also frequently misuse substances, making it clinically challenging to differentiate substance-induced psychosis (SIP) from a primary psychotic disorder (PPD), which has important implications for management and prognosis. This article presents practical considerations related to differentiating SIP from PPD, including information on substances associated with symptoms of psychosis. Recommendations for management of SIP are also reviewed, including screening for and treating comorbid substance use disorders and using evidence-based medication and psychosocial interventions.

The Bridge Between Classical and "Synthetic"/Chemical Psychoses: Towards a Clinical, Psychopathological, and Therapeutic Perspective

The critical spread and dissemination of novel psychoactive substances (NPS), particularly among the most vulnerable youngsters, may pose a further concern about the psychotic trajectories related to the intake of new synthetic drugs. The psychopathological pattern of the "new psychoses" appears to be extremely different from the classical presentation. Therefore, clinicians need more data on these new synthetic psychoses and recommendations on how to manage them. The present mini-review aims at deepening both the clinical, psychopathological features of synthetic/chemical NPS-induced psychoses and their therapeutic strategies, according to the different NPS classes implicated, by underlining the main differences with the "classical" psychoses. A comprehensive review was conducted using the PubMed/Medline database by combining the search strategy of free-text terms and exploding a range of MESH headings relating to the topics of novel psychoactive substances and synthetic/chemical psychoses as follows: {(Novel Psychoactive Substances[Title/Abstract]) AND Psychosis[Title/Abstract])} and for each NPS categories as well, focusing on synthetic cannabinoids and cathinones, without time and/or language restrictions. Finally, an overview of the main clinical and psychopathological features between classical versus NPS-induced chemical/synthetic psychoses is provided for clinicians working with dual disorders and addiction psychiatry. Further insight is given here on therapeutic strategies and practical guidelines for managing patients affected with synthetic/chemical NPS-induced psychoses.

Hallucinogen persisting perception disorder: A literature review and three case reports

The paper describes diagnostic criteria, clinical presentation and types of hallucinogen persisting perception disorder (HPPD), as well as current approaches to the treatment of this phenomenon using available scientific sources. Three case reports are also presented to demonstrate different types of this disorder. The first case report describes a 23-year old patient with a previous history of cannabis consumption who reported HPDD type I after the use of psilocybin mushrooms with small amounts of alcohol and hash. A month later, after cannabis use, the same visual and auditory distortions appeared again. During the following year, hallucinations recurred with the consumption of natural cannabinoids but not with alcohol intake. The symptoms have reduced within a year. Surprisingly, both other cases belonging to HPDD type II appeared in patients who consumed ecstasy, although MDMA is generally not considered a hallucinogen and hallucinations are not frequently reported after MDMA consumption. In both cases of HPPD type II after the use of ecstasy, the condition was very stressful and frightening. Both patients sought medical help and received tofisopam, lamotrigine and sertraline. After that, in both cases visual impairments have smoothed, but have not passed completely. Scientific sources suggest that HPPD may affect more than 50% of hallucinogen users and this disorder is often underdiagnosed. Therefore, patients suffering from HPPD can present in various clinical settings, and clinicians should be aware of this condition.

Hallucinogen-persisting Perception Disorder in a 21-year-old Man

This is a case report of hallucinogen-persisting perception disorder in a 21-year-old man. Hallucinogen-persisting perception disorder, or acute hallucinogen-induced psychosis, is a rare disorder characterized by the presence of flashbacks of visual hallucinations as a result of previous hallucinogenic drug use. There is no standard of treatment, and management involves a combination of pharmaceuticals and lifestyle modifications. The combination of the rarity of the disorder along with the drastic impact this disorder has on a person's life makes this condition unique as compared to other substance-induced conditions.

Does getting high hurt? Characterization of cases of LSD and psilocybin-containing mushroom exposures to national poison centers between 2000 and 2016

BACKGROUND

Lysergic acid diethylamide (LSD) and psilocybin are serotonergic hallucinogens that are used primarily for recreational abuse. Small studies evaluated the efficacy of LSD and psilocybin for several psychiatric conditions. There are limited safety or toxicity data for either of these substances, especially in large populations.

METHODS

This was a retrospective analysis of single-substance exposures of LSD or psilocybin-containing mushrooms (PcMs) reported to United States poison centers from 1 January 2000 to 31 December 2016. The study describes the most frequent toxicities, management sites, and medical outcomes.

RESULTS

A total of 5883 PcM and 3554 LSD exposures were included. Most patients were between 13 and 29 years of age (83.9% PcM, 88.9% LSD) and primarily male (77.9% PcM, 74.1% LSD). Most common clinical effects were hallucinations (45.8% PcM, 37.4% LSD), agitation (24.1% PcM, 42.4% LSD), and tachycardia (18.0% PcM, 38.6% LSD). Serious clinical effects were infrequent, but included hyperthermia, seizures, coma, increased serum creatinine, and cardiac arrest. Most patients were treated and released from the emergency department. More LSD patients were admitted to critical care and non-critical care units than PcM patients. Moderate effect was the most frequent outcome for both substances (61.0% PcM, 62.3% LSD).

CONCLUSION

These data find that LSD and PcM use occurs primarily in adolescents and young adults, who experience mild to moderate adverse effects. Serious effects are infrequent but can occur. While most LSD and PcM users require only emergency department management, LSD use is more likely to require medical admission.

DARK Classics in Chemical Neuroscience: Psilocybin

Psilocybin is found in a family of mushrooms commonly known as "magic mushrooms" that have been used throughout history to induce hallucinations. In the late 1950s Albert Hofmann, of Sandoz Laboratories, identified and synthesized the psychoactive compounds psilocybin and psilocin which are found in psilocybe mushrooms. Psilocybin was marketed by Sandoz as Indocybin for basic psychopharmacological and therapeutic clinical research. Psilocybin saw a rapid rise in popularity during the 1960s and was classed as a Schedule I drug in 1970. This led to a significant decrease in psilocybin research. Recently, however, preliminary studies with psilocybin have shown promise as potential for the treatment of obsessive compulsive disorder, alcohol addiction, tobacco addiction, and major depressive disorder, and the treatment of depression in terminally ill cancer patients. This review describes in detail the synthesis, metabolism, pharmacology, adverse drug reactions, and importance of psilocybin to neuroscience in the past and present.

Efficacy, tolerability, and safety of serotonergic psychedelics for the management of mood, anxiety, and substance-use disorders: a systematic review of systematic reviews

INTRODUCTION

Mood, anxiety, and substance-use disorders are among the most prevalent psychiatric disorders in the population. Although several pharmacological treatments are available, they are not effective for a significant proportion of patients and are associated with several adverse reactions. Therefore, new treatments should be explored. Recent studies suggest that serotonergic hallucinogens/psychedelics including ayahuasca, psilocybin, and lysergic acid diethylamide (LSD) have anxiolytic, antidepressive, and antiaddictive effects. Areas Covered: A systematic review of systematic reviews assessing the efficacy, safety, and tolerability of serotonergic hallucinogens/psychedelic was performed using the PubMed data base until 11 April 2018. Systematic reviews with or without meta-analysis were analyzed, but only reviews that described at least one randomized controlled trial (RCT) were included. Expert Commentary: Psilocybin and LSD reduced anxiety and depression in cancer patients and symptoms of alcohol and tobacco dependence, and ayahuasca reduced depression symptoms in treatment-resistant depression. Although the results are promising, several studies were open label, and only few were RCTs, and most had small sample sizes and a short duration. Single or few doses of these drugs seem to be well tolerated, but long-term studies are lacking. New RCTs with bigger samples and longer duration are needed to replicate these findings.

Hallucinogen Persisting Perception Disorder: Etiology, Clinical Features, and Therapeutic Perspectives

Hallucinogen Persisting Perception Disorder (HPPD) is a rare, and therefore, poorly understood condition linked to hallucinogenic drugs consumption. The prevalence of this disorder is low; the condition is more often diagnosed in individuals with a history of previous psychological issues or substance misuse, but it can arise in anyone, even after a single exposure to triggering drugs. The aims of the present study are to review all the original studies about HPPD in order to evaluate the following: (1) the possible suggested etiologies; (2) the possible hallucinogens involved in HPPD induction; (3) the clinical features of both HPPD I and II; (4) the possible psychiatric comorbidities; and (5) the available and potential therapeutic strategies. We searched PubMed to identify original studies about psychedelics and Hallucinogen Persisting Perception Disorder (HPPD). Our research yielded a total of 45 papers, which have been analyzed and tabled to provide readers with the most updated and comprehensive literature review about the clinical features and treatment options for HPPD.