Hallucinogen-persisting perception disorder

Content analysis of Reddit posts about coadministration of selective serotonin reuptake inhibitors and psilocybin mushrooms

RATIONALE

Treatments with the serotonergic psychedelic psilocybin are being investigated for multiple neuropsychiatric disorders. Because many patients with these disorders use selective serotonin reuptake inhibitors (SSRIs), understanding interactions between psilocybin and SSRIs is critical for evaluating the safety, efficacy, and scalability of psilocybin-based treatments. Current knowledge about these interactions is limited, as most clinical psilocybin research has prohibited concomittant SSRI use.

OBJECTIVES

We aimed to explore potential interactions between psilocybin and SSRIs by characterizing peoples' real-world experiences using psilocybin mushrooms and SSRIs together.

METHODS

We conducted a systematic search of Reddit for posts describing psilocybin mushroom and SSRI coadministration. We identified 443 eligible posts and applied qualitative content analysis to each.

RESULTS

8% of posts reported negative physical or psychological effects resulting from coadministration. These included 13 reports that may reflect serotonin toxicity, and 1 concerning for a psychotic/manic episode. 54% of posts described reduced intensity of the acute psilocybin experience, but 39% reported unchanged intensity with SSRI coadministration.

CONCLUSIONS

Psilocybin's interactions with SSRIs are likely complex and may depend on multiple factors. Prospective studies are needed to evaluate whether psilocybin treatments are reliably safe and effective in the setting of SSRI use.

Visual snow syndrome and its relationship with migraine

INTRODUCTION

Visual snow syndrome (VSS) is a central nervous system disorder that consists of the constant perception of small black and white dots throughout the entire visual field.

DEVELOPMENT

VSS can present from infancy to old age, with greater prevalence in the young population, and shows no difference between sexes. The diagnostic criteria include the presence of visual snow and such other visual phenomena as palinopsia, photophobia, nyctalopia, and other persistent visual phenomena. The pathophysiology of VSS is unknown, but hyperexcitability of the visual cortex and a dysfunction in higher-order visual processing are postulated as potential mechanisms. The prevalence of migraine among patients with VSS is high, compared to the general population, and symptoms are more severe in patients presenting both conditions. No effective treatment is available, but the drug with the best results is lamotrigine, which is recommended only in selected cases with severe functional limitation.

CONCLUSIONS

VSS is a little-known and underdiagnosed entity, but the increasing number of studies in recent years has made it possible to establish diagnostic criteria and begin studying its pathophysiology. This entity is closely related to migraine, with overlapping symptoms and probably shared pathophysiological mechanisms.

Use of Lysergic Acid Diethylamide by Major Depression Status

Importance

Renewed interest in the clinical potential of hallucinogens may lead people with depression to a generally more positive view of the use of lysergic acid diethylamide (LSD). Therefore, past-year LSD use among people with depression may be increasing in prevalence.

Objective

To assess time trends in the prevalence of past-year nonmedical LSD use by past-year major depression status and the variation in this association by sociodemographic characteristics.

Design, Setting, and Participants

This survey study used pooled publicly available data from 478 492 adults aged 18 years or older who were administered the National Survey on Drug Use and Health from 2008 through 2019. Statistical analysis was conducted from December 2022 to June 2023.

Main Outcome and Measures

Past-year major depression diagnoses per criteria from the DSM-IV were analyzed. Logistic regression models examined whether time trends in past-year nonmedical LSD use differed between adults with vs without past-year depression, adjusting for sociodemographic characteristics. Secondary analyses examined whether the trends in LSD use by depression status differed between sociodemographic subgroups.

Results

The analytic sample included 478 492 adults, of whom 51.8% were female, 56.1% were younger than 50 years, 11.7% were Black, 15.1% were Hispanic, 65.8% were White, and 7.5% were another race. Weighted interview response rates ranged from 64.9% to 75.6% during the study time frame. From 2008 to 2019, past-year use of LSD increased significantly more among adults with major depression (2008 prevalence, 0.5%; 2019 prevalence, 1.8%; prevalence difference [PD], 1.3% [95% CI, 1.0%-1.6%]) compared with adults without major depression (2008 prevalence, 0.2%; 2019 prevalence, 0.8%; PD, 0.6% [95% CI, 0.5%-0.7%]) (difference in difference, 0.8% [95% CI, 0.5%-1.1%]). This difference was particularly pronounced among young adults aged 34 years or younger (PD among those aged 18-25 years with depression, 3.3% [95% CI, 2.5%-4.2%]; PD among those aged 26-34 years with depression, 2.7% [95% CI, 1.6%-3.8%]) and individuals with incomes less than $75 000 per year (PD among those with income <$20 000, 1.9% [95% CI, 1.3%-2.6%]; PD among those with income $20 000-$49 999, 1.5% [95% CI, 1.0%-2.1%]; PD among those with income $50 000-$74 999, 1.3% [95% CI, 0.7%-2.0%]).

Conclusions and Relevance

This study suggests that, from 2008 to 2019, there was a disproportionate increase in the prevalence of past-year LSD use among US adults with past-year depression. Among those with depression, this increase was particularly strong among younger adults and those with lower household incomes. Among individuals with depression who also report LSD use, clinicians should discuss potential strategies for mitigating harm and maximizing benefits in medically unsupervised settings.

Psychedelic renaissance: Revitalized potential therapies for psychiatric disorders

Psychiatric disorders represent the largest cause of disability worldwide. Global interests in psychedelic substances as potentially therapeutic agents for psychiatric disorders has recently re-emerged. Here, we review progress in the development of psychedelic compounds that have potential therapeutic effects as well as the safety concerns. We include psilocybin, N,N-dimethyltryptamine (DMT), lysergic acid diethylamide (LSD), and the entactogen 3,4-methyl-enedioxy-methamphetamine (MDMA). We also review the potential interactive effects these compounds can have with psychotherapeutic approaches. We provide a cutting-edge review of active and recently completed clinical trials based on the published literature (from MEDLINE), published abstracts at citable conferences, clinical trials from the US Clinical Trials registry (clinicaltrials.gov) and media press releases.

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.

[Attitudes of Mental Health Experts Towards Psilocybin]

OBJECTIVE

In recent years, studies investigating the use of psilocybin to treat mental disorders have shown promising results. In this context, this online survey investigated attitudes of trained psychiatrists and psychotherapists towards psilocybin and psilocybin-assisted therapies.

MATERIALS AND METHODS

A total of 530 valid responses from individuals with suitable job profiles were collected in this online survey. Statistical analysis was used to identify relevant predictors of attitude measures.

RESULTS

The opinions of experts in the treatment of mental disorders with psilocybin and psilocybin-assisted therapies varied widely, and the level of knowledge of the participants to some extent was low. A large number of participants considered treatment of mental disorders with psilocybin to be promising and treatment of depression with psilocybin was seen as promising by the majority of the participants. The results of this study suggest that a higher level of knowledge about psilocybin is associated with more optimistic views about its use in a therapeutic setting. Having additional scientific information led in some cases to more optimistic attitudes towards psilocybin and the use of psilocybin in the treatment of mental disorders.

CONCLUSION

If the scientific and public discourse on psilocybin continues to grow in the future, changes in the attitudes of psychotherapists and psychiatrists can be expected.

The Canadian Network for Mood and Anxiety Treatments (CANMAT) Task Force Report: Serotonergic Psychedelic Treatments for Major Depressive Disorder

OBJECTIVE

Serotonergic psychedelics are re-emerging as potential novel treatments for several psychiatric disorders including major depressive disorder. The Canadian Network for Mood and Anxiety Treatments (CANMAT) convened a task force to review the evidence and provide a consensus recommendation for the clinical use of psychedelic treatments for major depressive disorder.

METHODS

A systematic review was conducted to identify contemporary clinical trials of serotonergic psychedelics for the treatment of major depressive disorder and cancer-related depression. Studies published between January 1990 and July 2021 were identified using combinations of search terms, inspection of bibliographies and review of other psychedelic reviews and consensus statements. The levels of evidence for efficacy were graded according to the Canadian Network for Mood and Anxiety Treatments criteria.

RESULTS

Only psilocybin and ayahuasca have contemporary clinical trials evaluating antidepressant effects. Two pilot studies showed preliminary positive effects of single-dose ayahuasca for treatment-resistant depression (Level 3 evidence). Small randomized controlled trials of psilocybin combined with psychotherapy showed superiority to waitlist controls and comparable efficacy and safety to an active comparator (escitalopram with supportive psychotherapy) in major depressive disorder, with additional randomized controlled trials showing efficacy specifically in cancer-related depression (Level 3 evidence). There was only one open-label trial of psilocybin in treatment-resistant unipolar depression (Level 4 evidence). Small sample sizes and functional unblinding were major limitations in all studies. Adverse events associated with psychedelics, including psychological (e.g., psychotomimetic effects) and physical (e.g., nausea, emesis and headaches) effects, were generally transient.

CONCLUSIONS

There is currently only low-level evidence to support the efficacy and safety of psychedelics for major depressive disorder. In Canada, as of 2022, psilocybin remains an experimental option that is only available through clinical trials or the special access program. As such, Canadian Network for Mood and Anxiety Treatments considers psilocybin an experimental treatment and recommends its use primarily within clinical trials, or, less commonly, through the special access program in rare, special circumstances.

Hallucinogenic Persisting Perception Disorder: A Case Series and Review of the Literature

Background

Hallucinogen persisting perception disorder (HPPD) is characterized by the re-emergence of perceptual symptoms experienced during acute hallucinogen intoxication following drug cessation. The underlying pathophysiology is poorly understood. We report the clinical characteristics and investigation findings of a series of HPPD cases with a literature review of previous case reports. We draw parallels between the features of HPPD and Visual Snow Syndrome (VSS).

Methods

Retrospective case series of 13 patients referred from neuro-ophthalmologists. Literature review with 24 HPPD case reports were identified through database search using the terms “hallucinogenic persisting perception disorder” OR “hallucinogen persisting perception disorder.”

Results

Lysergic acid diethylamide (LSD), 3,4-Methyl enedioxy methamphetamine (MDMA) and cannabinoid use was common. Cannabinoids and MDMA were mostly used in association with classical hallucinogens. The most frequent symptoms in our patients were visual snow, floaters, palinopsia, photophobia and nyctalopia. In the literature other symptoms included visual hallucinations altered motion perception, palinopsia, tracers and color enhancement. Ophthalmic and neurologic investigations were mostly normal. The majority of patients had ongoing symptoms. Two of our patients fully recovered—one after treatment with benzodiazepine and one without treatment. Twenty-five percent of cases from the literature fully recovered.

Conclusions

HPPD presents with heterogeneous visual phenomena on a background of previous classic and non-classic hallucinogen use. Ophthalmic investigations are typically normal. The symptoms of HPPD in our case series overlap with the typical features of Visual Snow Syndrome (VSS). Patients presenting with VSS should be screened for past recreational drug use. The DSM-5 description of HPPD does not include visual snow, nyctalopia, photophobia or floaters. A revision of the diagnostic criteria to include these symptoms may better reflect the typical clinical phenotype. Increased awareness of HPPD as a secondary cause of VSS can avoid extensive investigations. Controlled trials comparing primary and secondary VSS patients are needed to understand the pathophysiology better and optimize treatment for HPPD.

Malingering of Psychotic Symptoms in Psychiatric Settings: Theoretical Aspects and Clinical Considerations

Malingering is the intentional production of false or grossly exaggerated physical or psychological symptoms motivated by external incentives. Although the Diagnostic and Statistical Manual of Mental Disorders (DSM–5) does not list malingering in its diagnostic section and therefore does not identify it as a formal mental disorder, malingering and verified mental illness commonly coexist. Some subtypes of feigning behaviors, such as partial or pure malingering, dissimulation, and false imputation, can be suspected when patients have marked discrepancies between reported stressors and objective findings. The article discusses these three theoretical concepts with their possible clinical aspects, illustrating each phenomenon by clinical case with self-reported and/or observed psychotic symptoms. We summarized relevant findings and provided a review of clinical considerations that physicians can use to aid in the evaluation of psychotic symptoms in the context of those three concepts.

Visual Snow: Updates on Pathology

Purpose of Review

Until the last 5 years, there was very little in the literature about the phenomenon now known as visual snow syndrome. This review will examine the current thinking on the pathology of visual snow and how that thinking has evolved.

Recent Findings

While migraine is a common comorbidity to visual snow syndrome, evidence points to these conditions being distinct clinical entities, with some overlapping pathophysiological processes. There is increasing structural and functional evidence that visual snow syndrome is due to a widespread cortical dysfunction. Cortical hyperexcitability coupled with changes in thalamocortical pathways and higher-level salience network controls have all shown differences in patients with visual snow syndrome compared to controls.

Summary

Further work is needed to clarify the exact mechanisms of visual snow syndrome. Until that time, treatment options will remain limited. Clinicians having a clearer understanding of the basis for visual snow syndrome can appropriately discuss the diagnosis with their patients and steer them towards appropriate management options.

New Insights Into the Clinical and Nonclinical Effects of Psychedelic Substances

Abstract. After decades of stagnation, research on psychedelic substances (such as lysergic acid diethylamide [LSD], psilocybin, or N,N-dimethyltryptamine [DMT]) has experienced a renaissance over the last 10 years, with various major research programs being conducted across Europe and the United States. This research primarily investigates the potential of psychedelics in the treatment of mental health disorders, their short- and long-term effects on recreational users, and the neurological and cognitive processes responsible for their effects. The present review provides a concise summary of the most recent insights gained from this research. We briefly outline the history of psychedelic research, the objective and subjective effects caused by these substances, the prevalence and socio-psychological correlates of their use, as well as their potential for harm. Subsequently, we review empirical research on the beneficial effects of psychedelics in clinical samples, focusing on their efficacy in the treatment of major depression, anxiety, and substance use disorders, and discuss research on the proposed neural and cognitive mechanisms behind these effects. We then review research on their effects on healthy subjects, focusing on psychological well-being as well as changes in personality, nature-relatedness, and creativity. Finally, we review empirical evidence regarding the long-term effects of single experiences with psychedelics and conclude with a summary and outlook.

Visual snow syndrome and its relationship with migraine

INTRODUCTION

Visual snow syndrome (VSS) is a central nervous system disorder that consists of the constant perception of small black and white dots throughout the entire visual field.

DEVELOPMENT

VSS can present from infancy to old age, with greater prevalence in the young population, and shows no difference between sexes. The diagnostic criteria include the presence of visual snow and such other visual phenomena as palinopsia, photophobia, nyctalopia, and other persistent visual phenomena. The pathophysiology of VSS is unknown, but hyperexcitability of the visual cortex and a dysfunction in higher-order visual processing are postulated as potential mechanisms. The prevalence of migraine among patients with VSS is high, compared to the general population, and symptoms are more severe in patients presenting both conditions. No effective treatment is available, but the drug with the best results is lamotrigine, which is recommended only in selected cases with severe functional limitation.

CONCLUSIONS

VSS is a little-known and underdiagnosed entity, but the increasing number of studies in recent years has made it possible to establish diagnostic criteria and begin studying its pathophysiology. This entity is closely related to migraine, with overlapping symptoms and probably shared pathophysiological mechanisms.

Illusions, hallucinations, and visual snow

Illusions and hallucinations are commonly encountered in both daily life and clinical practice. In this chapter, we review definitions and possible underlying mechanisms of these phenomena and then review what is known about specific conditions that are associated with them, including ophthalmic causes, migraine, epilepsy, Parkinson's disease, and schizophrenia. We then discuss specific syndromes including the Charles Bonnet syndrome, visual snow syndrome, Alice in Wonderland syndrome, and peduncular hallucinosis. The scientific study of illusions and hallucinations has contributed significantly to our understanding of how eye and brain process vision and contribute to perception. Important concepts are the distinction between topologic and hodologic mechanisms underlying hallucinations and the involvement of attentional networks. This chapter examines the various ways in which pathological illusions and hallucinations might arise in relation to the phenomenology and known pathology of the various conditions associated with them.

Psilocybin as a New Approach to Treat Depression and Anxiety in the Context of Life-Threatening Diseases-A Systematic Review and Meta-Analysis of Clinical Trials

Psilocybin is a naturally occurring tryptamine known for its psychedelic properties. Recent research indicates that psilocybin may constitute a valid approach to treat depression and anxiety associated to life-threatening diseases. The aim of this work was to perform a systematic review with meta-analysis of clinical trials to assess the therapeutic effects and safety of psilocybin on those medical conditions. The Beck Depression Inventory (BDI) was used to measure the effects in depression and the State-Trait Anxiety Inventory (STAI) was used to measure the effects in anxiety. For BDI, 11 effect sizes were considered (92 patients) and the intervention group was significantly favored (WMD = −4.589; 95% CI = −4.207 to −0.971; p-value = 0.002). For STAI-Trait, 11 effect sizes were considered (92 patients), being the intervention group significantly favored when compared to the control group (WMD = −5.906; 95% CI = −7.852 to −3.960; p-value ˂ 0.001). For STAI-State, 9 effect sizes were considered (41 patients) and the intervention group was significantly favored (WMD = −6.032; 95% CI = −8.900 to −3.164; p-value ˂ 0.001). The obtained results are promising and emphasize the importance of psilocybin translational research in the management of symptoms of depression and anxiety, since the compound may be effective in reducing symptoms of depression and anxiety in conditions that are either resistant to conventional pharmacotherapy or for which pharmacologic treatment is not yet approved. Moreover, it may be also relevant for first-line treatment, given its safety.

Long-term effects of psychedelic drugs: A systematic review

Research into the basic effects and therapeutic applications of psychedelic drugs has grown considerably in recent years. Yet, pressing questions remain regarding the substances' lasting effects. Although individual studies have begun monitoring sustained changes, no study to-date has synthesized this information. Therefore, this systematic review aims to fill this important gap in the literature by synthesizing results from 34 contemporary experimental studies which included classic psychedelics, human subjects, and follow-up latencies of at least two weeks. The bulk of this work was published in the last five years, with psilocybin being the most frequently administered drug. Enduring changes in personality/attitudes, depression, spirituality, anxiety, wellbeing, substance misuse, meditative practices, and mindfulness were documented. Mystical experiences, connectedness, emotional breakthrough, and increased neural entropy were related to these long-term changes in psychological functioning. Finally, with proper screening, preparation, supervision, and integration, limited aversive side effects were noted by study participants. Future researchers should focus on including larger and more diverse samples, lengthier longitudinal designs, stronger control conditions, and standardized dosages.

Lamotrigine Uses in Psychiatric Practice

BACKGROUND

Lamotrigine (LAM), an antiepileptic, with panoply of indications and uses in neurology, is FDA approved, in psychiatry, for bipolar prophylaxis. Apart from this indication, trend of its use in psychiatry is on the rise addressing a multitude of disorders.

STUDY QUESTION

LAM remains one of only few psychotropic drugs with antiglutamate activity. This might render LAM a potential therapeutic option in treatment-resistant major psychiatric disorders. We reviewed LAM pharmacology and its diverse indications while examining the extant evidence.

METHODS

EMBASE, Ovid MEDLINE, PubMed, Scopus, Web of Science, and Cochrane Database of Systemic Reviews were searched for all relevant studies up to date of June 2016.

RESULTS

Sound evidence supports use of LAM for acute bipolar depression and prophylaxis, treatment-resistant schizophrenia, treatment-resistant obsessive-compulsive disorder, posttraumatic stress disorder, depersonalization disorder, and affective dysregulation and behavioral dyscontrol domains of borderline personality disorder. Less compelling evidence is present for use in behavioral and psychological symptoms of dementia and neuropsychiatric sequelae of traumatic brain injury. No evidence supports use in autism spectrum disorder or acute unipolar depression.

CONCLUSIONS

LAM is an important addition to the psychopharmacological armamentarium. Level of evidence supporting the use of LAM in off-label indications is highly variable, and hence, sound clinical judgment is necessary for its proper use and placement in real-life psychiatric practice and psychopharmacotherapy algorithms.

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.

Epidemiology of hallucinogen use in the U.S. results from the National epidemiologic survey on alcohol and related conditions III

BACKGROUND

Population-based data regarding the epidemiology of hallucinogen use and co-occurring psychiatric disorders is largely absent from the literature. We aim to present findings on the prevalence, sociodemographic correlates, psychiatric comorbidity, treatment utilization, social support and associated disability of hallucinogen use using nationally representative data.

METHOD

We analyzed data from the National Epidemiologic Study on Alcohol and Related Conditions-III (2011-2012, N = 36,309). We conducted multivariate logistic regression analyses in unadjusted and adjusted models in order to explore the odds of psychiatric disorders and associated disability among hallucinogen users.

RESULTS

Prevalence of twelve-month and lifetime hallucinogen use was 0.62% and 9.32%, respectively. Hallucinogen use was found to be significantly associated with mood disorders, anxiety disorders, eating disorders, personality disorders and substance use disorders. Following adjustment, significant associations were retained with several substance use disorders (adjusted odds ratio (AOR) for heroin use disorder = 4.89 (95% CI, 1.90-12.58), personality disorders (AOR = 2.10 (95% CI, 1.81-2.44)), Post-Traumatic Stress Disorder (AOR = 1.86, 95% CI 1.00-3.45) and past suicide attempts (AOR = 1.49, 95% CI 1.21-1.85).

CONCLUSIONS

Lifetime hallucinogen use in the US is prevalent and highly comorbid with other substance use and psychiatric disorders. Hallucinogen Use Disorder is relatively uncommon, with a low risk of development following exposure to hallucinogens. There are significant associations between hallucinogen use and substance use disorders, personality disorders, PTSD and past suicide attempts. The evolving therapeutic utility of this class of substances requires further assessment of short- and long-term risks of use, before large scale clinical application is pursued.

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.

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

Hallucinogen-persisting perception disorder (HPPD) is a syndrome characterized by prolonged or reoccurring perceptual symptoms, reminiscent of acute hallucinogen effects. HPPD was associated with a broader range of LSD (lysergic acid diethylamide)-like substances, cannabis, methylenedioxymethamphetamine (MDMA), psilocybin, mescaline, and psychostimulants. The recent emergence of novel psychoactive substances (NPS) posed a critical concern regarding the new onset of psychiatric symptoms/syndromes, including cases of HPPD. Symptomatology mainly comprises visual disorders (i.e., geometric pseudo-hallucinations, haloes, flashes of colors/lights, motion-perception deficits, afterimages, micropsia, more acute awareness of floaters, etc.), even though depressive symptoms and thought disorders may be comorbidly present. Although HPPD was first described in 1954, it was just established as a fully syndrome in 2000, with the revised fourth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). HPPD neural substrates, risk factors, and aetiopathogenesys still largely remain unknown and under investigation, and many questions about its pharmacological targets remain unanswered too. A critical mini review on psychopathological bases, etiological hypothesis, and psychopharmacological approaches toward HPPD, including the association with some novel substances, are provided here, by means of a literature search on PubMed/Medline, Google Scholar, and Scopus databases without time restrictions, by using a specific set of keywords. Pharmacological and clinical issues are considered, and practical psychopharmacological recommendations and clinical guidelines are suggested.

Hallucinogen Persisting Perception Disorder and Risk of Suicide

A 30-year-old male patient developed a hallucinogen persisting perception disorder (HPPD) after smoking cannabis laced with phencyclidine (PCP) or lysergic acid diethylamide (LSD) 10 years prior to hospital admission. Clinically, he reported seeing vivid, saturated colors and caricature-like objects. The patient described perceiving objects or people in motion as moving faster than normal. He reported living in a dream-like state and feeling numb and detached from other people and his surroundings. Upon pharmacotherapy initiation, facility transfer, and subsequent discharge from an acute psychiatry unit, he ultimately committed suicide. Although hallucinogen abuse is common in the United States, this case suggests that HPPD maybe significantly underdiagnosed and undertreated. In some cases, this oversight may perpetuate years of unnecessary patient suffering and can ultimately lead to severe depression and suicide.

Psychedelics

Psychedelics (serotonergic hallucinogens) are powerful psychoactive substances that alter perception and mood and affect numerous cognitive processes. They are generally considered physiologically safe and do not lead to dependence or addiction. Their origin predates written history, and they were employed by early cultures in many sociocultural and ritual contexts. After the virtually contemporaneous discovery of (5R,8R)-(+)-lysergic acid-N,N-diethylamide (LSD)-25 and the identification of serotonin in the brain, early research focused intensively on the possibility that LSD and other psychedelics had a serotonergic basis for their action. Today there is a consensus that psychedelics are agonists or partial agonists at brain serotonin 5-hydroxytryptamine 2A receptors, with particular importance on those expressed on apical dendrites of neocortical pyramidal cells in layer V. Several useful rodent models have been developed over the years to help unravel the neurochemical correlates of serotonin 5-hydroxytryptamine 2A receptor activation in the brain, and a variety of imaging techniques have been employed to identify key brain areas that are directly affected by psychedelics. Recent and exciting developments in the field have occurred in clinical research, where several double-blind placebo-controlled phase 2 studies of psilocybin-assisted psychotherapy in patients with cancer-related psychosocial distress have demonstrated unprecedented positive relief of anxiety and depression. Two small pilot studies of psilocybin-assisted psychotherapy also have shown positive benefit in treating both alcohol and nicotine addiction. Recently, blood oxygen level-dependent functional magnetic resonance imaging and magnetoencephalography have been employed for in vivo brain imaging in humans after administration of a psychedelic, and results indicate that intravenously administered psilocybin and LSD produce decreases in oscillatory power in areas of the brain's default mode network.

Exploring Hallucinogen Pharmacology and Psychedelic Medicine with Zebrafish Models

After decades of sociopolitical obstacles, the field of psychiatry is experiencing a revived interest in the use of hallucinogenic agents to treat brain disorders. Along with the use of ketamine for depression, recent pilot studies have highlighted the efficacy of classic serotonergic hallucinogens, such as lysergic acid diethylamide and psilocybin, in treating addiction, post-traumatic stress disorder, and anxiety. However, many basic pharmacological and toxicological questions remain unanswered with regard to these compounds. In this study, we discuss psychedelic medicine as well as the behavioral and toxicological effects of hallucinogenic drugs in zebrafish. We emphasize this aquatic organism as a model ideally suited to assess both the potential toxic and therapeutic effects of major known classes of hallucinogenic compounds. In addition, novel drugs with hallucinogenic properties can be efficiently screened using zebrafish models. Well-designed preclinical studies utilizing zebrafish can contribute to the reemerging treatment paradigm of psychedelic medicine, leading to new avenues of clinical exploration for psychiatric disorders.

Ophthalmological assessment of cannabis-induced persisting perception disorder: is there a direct retinal effect?

PURPOSE

Cannabis is a psychotomimetic agent that induces impairment of sensory perception. We present detailed clinical and electrophysiological data of patients with hallucinogen persisting perception disorder (HPPD) after marijuana consumption.

METHODS

A HPPD patient and four heavy cannabis smokers with no visual disturbances (controls) underwent complete ophthalmological examination including psychophysical tests (visual acuity, color vision, visual field, and dark adaptation) and detailed electrophysiological examinations, including extended Ganzfeld ERG, multifocal ERG, and electrooculography (EOG). Furthermore, electrically evoked phosphene thresholds (EPTs) were measured to further evaluate retinal function.

RESULTS

Ophthalmological and most electrophysiological examinations were within normal limits for the HPPD patient and for all control subjects. Interestingly, EOG results of the HPPD patient showed a slightly reduced fast oscillation ratio, diminished standing potentials of the slow oscillations, and a light peak within normal range resulting in higher Arden ratios. The EPTs of the patient were reduced, in particular for pulses with long durations (50 ms) causing visual sensations even at lowest possible currents of the neurostimulator. The control subjects did not reveal such alterations.

CONCLUSIONS

Our findings suggest a direct effect of cannabinoids on the retina and retinal pigment epithelium function, which may be involved in disturbances of the visual function experienced after drug consumption. The observations presented here may contribute to the elucidation of the detailed mechanism. Furthermore, EOG and EPT measurements may be useful tools to demonstrate long-term retinal alterations in cannabis-induced HPPD in patients.

Neurologic complications of illicit drug abuse

PURPOSE OF REVIEW

This review familiarizes clinicians with the symptoms of overdose and withdrawal, as well as neurologic complications, associated with particular illicit drugs.

RECENT FINDINGS

Recent arrivals on the recreational drug scene include synthetic cathinone analogs, synthetic cannabinoid agonists, and a variety of novel hallucinogens.

SUMMARY

Clinicians need to be aware of neurologic disorders associated with particular illicit drugs and should consider drug abuse in any patient with unexplained symptoms and signs.In addition to tobacco and alcohol, a large number of substances, legal and illegal, are used recreationally. Broad categories include opioids, psychostimulants, marijuana and related agents, sedatives, hallucinogens, inhalants, phencyclidine and related agents, and anticholinergics. Each type of agent has its own characteristic symptoms of overdose and withdrawal, and many agents are associated with trauma, infection, seizures, stroke, cognitive impairment, and teratogenicity. Some drugs have unique neurologic complications not encountered with other agents. A history of recreational drug use should be sought in any neurologic patient regardless of age or socioeconomic status.