Metabolism of lysergic acid diethylamide (LSD): an update

Lysergic acid diethylamide (LSD) is the most potent hallucinogen known and its pharmacological effect results from stimulation of central serotonin receptors (5-HT₂). Since LSD is seen as physiologically safe compound with low toxicity, its use in therapeutics has been renewed during the last few years. This review aims to discuss LSD metabolism, by presenting all metabolites as well as clinical and toxicological relevance. LSD is rapidly and extensively metabolized into inactive metabolites; whose detection window is higher than parent compound. The metabolite 2-oxo-3-hydroxy LSD is the major human metabolite, which detection and quantification is important for clinical and forensic toxicology. Indeed, information about LSD pharmacokinetics in humans is limited and for this reason, more research studies are needed.

DARK Classics in Chemical Neuroscience: Atropine, Scopolamine, and Other Anticholinergic Deliriant Hallucinogens

Anticholinergic drugs based on tropane alkaloids, including atropine, scopolamine, and hyoscyamine, have been used for various medicinal and toxic purposes for millennia. These drugs are competitive antagonists of acetylcholine muscarinic (M-) receptors that potently modulate the central nervous system (CNS). Currently used clinically to treat vomiting, nausea, and bradycardia, as well as alongside other anesthetics to avoid vagal inhibition, these drugs also evoke potent psychotropic effects, including characteristic delirium-like states with hallucinations, altered mood, and cognitive deficits. Given the growing clinical importance of anti-M deliriant hallucinogens, here we discuss their use and abuse, clinical importance, and the growing value in preclinical (experimental) animal models relevant to modeling CNS functions and dysfunctions.

Ayahuasca: Psychological and Physiologic Effects, Pharmacology and Potential Uses in Addiction and Mental Illness

Background:

Ayahuasca, a traditional Amazonian decoction with psychoactive properties, is made from bark of the Banisteriopsis caapi vine (containing beta-carboline alkaloids) and leaves of the Psychotria viridis bush (supplying the hallucinogen N,N-dimethyltryptamine, DMT). Originally used by indigenous shamans for the purposes of spirit communi-cation, magical experiences, healing, and religious rituals across several South American countries, ayahuasca has been in-corporated into folk medicine and spiritual healing, and several Brazilian churches use it routinely to foster a spiritual experi-ence. More recently, it is being used in Europe and North America, not only for religious or healing reasons, but also for rec-reation.

Objective:

To review ayahuasca’s behavioral effects, possible adverse effects, proposed mechanisms of action and potential clinical uses in mental illness.

Method:

We searched Medline, in English, using the terms ayahuasca, dimethyltryptamine, Banisteriopsis caapi, and Psy-chotria viridis and reviewed the relevant publications.

Results:

The following aspects of ayahuasca are summarized: Political and legal factors; acute and chronic psychological ef-fects; electrophysiological studies and imaging; physiological effects; safety and adverse effects; pharmacology; potential psychiatric uses.

Conclusion:

Many years of shamanic wisdom have indicated potential therapeutic uses for ayahuasca, and several present day studies suggest that it may be useful for treating various psychiatric disorders and addictions. The side effect profile ap-pears to be relatively mild, but more detailed studies need to be done. Several prominent researchers believe that government regulations with regard to ayahuasca should be relaxed so that it could be provided more readily to recognized, credible re-searchers to conduct comprehensive clinical trials.

Prevalence of reagent test-kit use and perceptions of purity among ecstasy users in an electronic dance music scene in New York City

INTRODUCTION AND AIMS

Ecstasy users in the electronic dance music scene are at high risk for using ecstasy adulterated with new psychoactive substances and/or methamphetamine. We examined self-reported testing of ecstasy among users in this scene.

DESIGN AND METHODS

We surveyed individuals (aged 18-40 years) entering electronic dance music parties in New York City in 2017. Past-year ecstasy users (n = 351) were asked if they had tested their ecstasy in the past year. We estimated prevalence and correlates of having tested one's ecstasy.

RESULTS

23.1% reported having tested their ecstasy in the past year. Those with some college (adjusted prevalence ratio [aPR] = 0.49, P = 0.014) or a college degree (aPR = 0.41, P = 0.025) were less likely to test their ecstasy than those with a high school diploma or less. Using ecstasy pills (aPR = 1.89, P = 0.036) or crystals (aPR = 1.90, P = 0.006) ≥3 times in the past year was associated with increased likelihood of testing one's ecstasy, and purchasing from an unknown or untrustworthy dealer was associated with decreased likelihood (aPR = 0.63, P = 0.034) of testing one's ecstasy. Half (51.1%) of ecstasy users reported finding out or suspecting their ecstasy had contained a drug other than MDMA. Of these, 49.2% reported finding out their ecstasy contained methamphetamine or speed/amphetamine. Most ecstasy users reported that they would be less likely to use again upon learning their ecstasy contained 'bath salts' (54.8%) or methamphetamine (54.3%).

DISCUSSION AND CONCLUSIONS

Drug testing appears to help ecstasy users detect adulterants and results can help inform harm reduction efforts. Less frequent users in particular may require education about adulteration and drug-testing.

Designer drugs – still a threat?

INTRODUCTION

In Poland, an increasing number of psychoactive substances are becoming prohibited by law as psychotropic or narcotic substances, or as new psychoactive substances (NPSs). Owing to the enormous technological possibilities offered by today’s science, synthesis of new derivatives of prohibited compounds is no longer a problem. The moment a dangerous substance is outlawed, new designer drugs (in Poland known as ‘dopalacze’) appear on the market.

STATE OF KNOWLEDGE

An amendment to the Act on Counteracting Drug Addiction issued in July 2018 made it possible for the NPS to be considered drugs by law. Synthetic cannabinoids and cathinone derivatives make up the majority of NPSs identified by the authorities in Poland. Synthetic cannabinoids which can, unlike cannabinoid receptor agonists of plant origin, cause death by somatic toxicity, are particularly dangerous. The ability to quickly recognize poisoning with synthetic opioids is crucial, since an antidote reversing the depressive effect of opioids on the respiratory center can be administered.

SUMMARY

This work collects the most important and up-to-date information on designer drugs, based on reports and articles published between 2015 and 2019. The covered aspects include: the current definition of designer drugs in relation to the Polish law, their exact division due to the clinical effects they cause and the description of the threats they pose. Emphasis was given to the current situation of the designer drug market in Poland.

The moderating effect of psychedelics on the prospective relationship between prescription opioid use and suicide risk among marginalized women

BACKGROUND/AIMS

Given high rates of depression and suicide among marginalized women, and increasing calls to integrate trauma-informed biomedical and community-led structural interventions, this study longitudinally examines the potential moderating effect of psychedelic use on the relationship between other illicit drug use and suicide risk.

METHODS

Data (2010-2017) were drawn from a community-based, prospective open cohort of marginalized women in Vancouver, Canada. Extended Cox regression analyses examined the moderating effect of psychedelic use on the association between other illicit drug use and incidence of suicidal ideation or attempt over follow-up.

RESULTS

Of 340 women without suicidal ideation or attempt at baseline, 16% ( n=53) reported a first suicidal episode during follow-up, with an incidence density of 4.63 per 100 person-years (95% confidence interval 3.53-6.07). In unadjusted analysis, psychedelic use moderated the relationship between prescription opioid use and suicide risk: among women who did not use psychedelics, prescription opioid use increased the hazard of suicide (hazard ratio 2.91; 95% confidence interval 1.40-6.03) whereas prescription opioid use was not associated with increased suicidal ideation or attempt among those who used psychedelics (hazard ratio 0.69; 95% confidence interval 0.27-1.73) (interaction term p-value: 0.016). The moderating effect of psychedelics remained significant when adjusted for confounders (interaction term p-value: 0.036).

CONCLUSIONS

Psychedelic use had a protective moderating effect on the relationship between prescription opioid use and suicide risk. In the context of a severe public health crisis around prescription opioids and lack of addiction services tailored to marginalized women, this study supports calls for innovative, evidence-based and trauma-informed interventions, including further research on the potential benefits of psychedelics.

Psychedelics and Personality

In the past decade, an increasing number of clinical trials are reporting evidence that psychedelics or serotonergic hallucinogens (such as lysergic acid diethylamide, psilocybin, and ayahuasca/dimethyltryptamine) could be effective in the treatment of mood, anxiety, and substance use disorders. The mechanisms responsible for these effects are not fully understood but seem to involve changes in bran dynamics in areas rich in serotonergic 5-HT_2A receptors and in personality. In the present text, we present a brief and critical overview of the current research in this field, pointing out both promises and limitations of these studies.

The DARK Side of Total Synthesis: Strategies and Tactics in Psychoactive Drug Production

Humankind has used and abused psychoactive drugs for millennia. Formally, a psychoactive drug is any agent that alters cognition and mood. The term "psychotropic drug" is neutral and describes the entire class of substrates, licit and illicit, of interest to governmental drug policy. While these drugs are prescribed for issues ranging from pain management to anxiety, they are also used recreationally. In fact, the current opioid epidemic is the deadliest drug crisis in American history. While the topic is highly politicized with racial, gender, and socioeconomic elements, there is no denying the toll drug mis- and overuse is taking on this country. Overdose, fueled by opioids, is the leading cause of death for Americans under 50 years of age, killing ca. 64,000 people in 2016. From a chemistry standpoint, the question is in what ways, if any, did organic chemists contribute to this problem? In this targeted review, we provide brief historical accounts of the main classes of psychoactive drugs and discuss several foundational total syntheses that ultimately provide the groundwork for producing these molecules in academic, industrial, and clandestine settings.

The re-emergence of hallucinogenic research

Due to the intractability, at times, in the treatment of PTSD, clinicians and researchers continue to explore different options for treatment. This article discusses the renewed interest in hallucinogens for such treatment.

Psychedelics as anti-inflammatory agents

Serotonin (5-hydroxytryptamine, 5-HT)_2A receptor agonists have recently emerged as promising new treatment options for a variety of disorders. The recent success of these agonists, also known as psychedelics, like psilocybin for the treatment of anxiety, depression, obsessive-compulsive disorder (OCD), and addiction, has ushered in a renaissance in the way these compounds are perceived in the medical community and populace at large. One emerging therapeutic area that holds significant promise is their use as anti-inflammatory agents. Activation of 5-HT_2A receptors produces potent anti-inflammatory effects in animal models of human inflammatory disorders at sub-behavioural levels. This review discusses the role of the 5-HT_2A receptor in the inflammatory response, as well as highlight studies using the 5-HT_2A agonist (R)-2,5-dimethoxy-4-iodoamphetamine [(R)-DOI] to treat inflammation in cellular and animal models. It also examines potential mechanisms by which 5-HT_2A agonists produce their therapeutic effects. Overall, psychedelics regulate inflammatory pathways via novel mechanisms, and may represent a new and exciting treatment strategy for several inflammatory disorders.

Current perspectives on psychedelic therapy: use of serotonergic hallucinogens in clinical interventions

Humans have used serotonergic hallucinogens (i.e. psychedelics) for spiritual, ceremonial, and recreational purposes for thousands of years, but their administration as part of a structured therapeutic intervention is still a relatively novel practice within Western medical and psychological frameworks. In the mid-20^th century, considerable advances were made in developing therapeutic approaches integrating administration of low (psycholytic) and high (psychedelic) doses of serotonergic hallucinogens for treatment of a variety of conditions, often incorporating psychoanalytic concepts prevalent at that time. This work contributed seminal insights regarding how these substances may be employed with efficacy and safety in targeted therapeutic interventions, including the importance of optimizing set (frame of mind) and setting (therapeutic environment). More recently, clinical and pharmacological research has revisited the effects and therapeutic potential of psychedelics utilizing a variety of approaches. The current article provides an overview of past and present models of psychedelic therapy, and discusses important considerations for future interventions incorporating the use of psychedelics in research and clinical practice.

The future of the international drug control system and national drug prohibitions

A major impediment to any nation abandoning the policy of drug prohibition has been the fact that international drug treaties to which the majority of United Nations (UN) member states are signatory prohibit the non-medical use of amphetamines, cannabis, cocaine and heroin. The future of these treaties is now uncertain because of decisions by Uruguay, eight US states and Canada to legalize cannabis use. This paper: (1) provides a brief account of the international drug control treaties; (2) outlines the major criticisms of the treaties; (3) analyses critically proposals for treaty reform; and (4) provides a personal view on policies that nation states could adopt to minimize the harms from the use of cannabis, party drugs and hallucinogens, opioids, stimulants and new psychoactive substances. It is argued that: a major risk of cannabis legalization in the United States is promotion of heavy use and increased harm by a weakly regulated industry; some cautious national experiments with the regulation of party drugs and hallucinogens would be informative; a strong case remains for prohibiting the nonmedical use of opioids while mitigating the adverse effects that this policy has on opioid-dependent people; stimulant legalization will probably increase problem use but prohibition is difficult to enforce, highlighting the urgency of finding better ways to reduce demand for these drugs and respond to problem users; and that it is unclear what the best approach is to reducing possible harms that may arise from the use of new psychoactive substances.

Ibogaine Acute Administration in Rats Promotes Wakefulness, Long-Lasting REM Sleep Suppression, and a Distinctive Motor Profile

Ibogaine is a potent psychedelic alkaloid that has been the focus of intense research because of its intriguing anti-addictive properties. According to anecdotic reports, ibogaine has been originally classified as an oneirogenic psychedelic; i.e., induces a dream-like cognitive activity while awake. However, the effects of ibogaine administration on wakefulness (W) and sleep have not been thoroughly assessed. The main aim of our study was to characterize the acute effects of ibogaine administration on W and sleep. For this purpose, polysomnographic recordings on chronically prepared rats were performed in the light phase during 6 h. Animals were treated with ibogaine (20 and 40 mg/kg) or vehicle, immediately before the beginning of the recordings. Furthermore, in order to evaluate associated motor behaviors during the W period, a different group of animals was tested for 2 h after ibogaine treatment on an open field with video-tracking software. Compared to control, animals treated with ibogaine showed an increase in time spent in W. This effect was accompanied by a decrease in slow wave sleep (SWS) and rapid-eye movements (REM) sleep time. REM sleep latency was significantly increased in animals treated with the higher ibogaine dose. While the effects on W and SWS were observed during the first 2 h of recordings, the decrement in REM sleep time was observed throughout the recording time. Accordingly, ibogaine treatment with the lower dose promoted an increase on locomotion, while tremor and flat body posture were observed only with the higher dose in a time-dependent manner. In contrast, head shake response, a behavior which has been associated in rats with the 5HT_2A receptor activation by hallucinogens, was not modified. We conclude that ibogaine promotes a waking state that is accompanied by a robust and long-lasting REM sleep suppression. In addition, it produces a dose-dependent unusual motor profile along with other serotonin-related behaviors. Since ibogaine is metabolized to produce noribogaine, further experiments are needed to elucidate if the metabolite and/or the parent drug produced these effects.

Epidemiology and Effects of Substance Use in Pregnancy

Substance use during pregnancy has important implications for health care providers and policymakers and can negatively affect a woman's health and the health of her children. Understanding trends, patterns of use, and outcomes are critical to developing prevention campaigns, building awareness, and providing effective care. This review critically examines the current literature on substance use in pregnancy and during the postpartum period in terms of epidemiology, risk factors, and implications. The risk factors for substance use in pregnancy, the challenges associated with reporting these cases, and the adverse effects of common substances on maternal and fetal health are discussed.

Screening and Management of Substance Use in Pregnancy: A Review

Substance use during pregnancy has important implications for health care providers, policy makers, and can negatively impact a woman's health and the health of her children. Understanding trends, patterns of use and outcomes are critical to prevention campaigns, building awareness, and providing effective care. This review will discuss the current therapeutic approaches and recommendations for screening and patient management for substance use in pregnancy and during the postpartum period, and it is geared towards any care providers who care for patients or those who may care for patients who may be at risk for substance use during pregnancy.

Role of the 5-HT2A Receptor in Self- and Other-Initiated Social Interaction in Lysergic Acid Diethylamide-Induced States: A Pharmacological fMRI Study

Distortions of self-experience are critical symptoms of psychiatric disorders and have detrimental effects on social interactions. In light of the immense need for improved and targeted interventions for social impairments, it is important to better understand the neurochemical substrates of social interaction abilities. We therefore investigated the pharmacological and neural correlates of self- and other-initiated social interaction. In a double-blind, randomized, counterbalanced, crossover study 24 healthy human participants (18 males and 6 females) received either (1) placebo + placebo, (2) placebo + lysergic acid diethylamide (LSD; 100 μg, p.o.), or (3) ketanserin (40 mg, p.o.) + LSD (100 μg, p.o.) on three different occasions. Participants took part in an interactive task using eye-tracking and functional magnetic resonance imaging completing trials of self- and other-initiated joint and non-joint attention. Results demonstrate first, that LSD reduced activity in brain areas important for self-processing, but also social cognition; second, that change in brain activity was linked to subjective experience; and third, that LSD decreased the efficiency of establishing joint attention. Furthermore, LSD-induced effects were blocked by the serotonin 2A receptor (5-HT_2AR) antagonist ketanserin, indicating that effects of LSD are attributable to 5-HT_2AR stimulation. The current results demonstrate that activity in areas of the "social brain" can be modulated via the 5-HT_2AR thereby pointing toward this system as a potential target for the treatment of social impairments associated with psychiatric disorders.SIGNIFICANCE STATEMENT Distortions of self-representation and, potentially related to this, dysfunctional social cognition are central hallmarks of various psychiatric disorders and critically impact disease development, progression, treatment, as well as real-world functioning. However, these deficits are insufficiently targeted by current treatment approaches. The administration of lysergic acid diethylamide (LSD) in combination with functional magnetic resonance imaging and real-time eye-tracking offers the unique opportunity to study alterations in self-experience, their relation to social cognition, and the underlying neuropharmacology. Results demonstrate that LSD alters self-experience as well as basic social cognition processing in areas of the "social brain". Furthermore, these alterations are attributable to 5-HT_2A receptor stimulation, thereby pinpointing toward this receptor system in the development of pharmacotherapies for sociocognitive deficits in psychiatric disorders.

The Meaning-Enhancing Properties of Psychedelics and Their Mediator Role in Psychedelic Therapy, Spirituality, and Creativity

Past research has demonstrated to the ability of psychedelics to enhance suggestibility, and pointed to their ability to amplify perception of meaning. This paper examines the existing evidence for the meaning-enhancing properties of psychedelics, and argues that the tendency of these agents to enhance the perception of significance offers valuable clues to explaining their reported ability to stimulate a variety of therapeutic processes, enhance creativity, and instigate mystical-type experiences. Building upon previous research, which suggested the potential role of psychedelic meaning-enhancement in enhancing placebo response, the paper explores the mechanisms by which the meaning-amplifying properties of psychedelics might also play a role in enhancing creativity, as well as in effecting mystical-type experiences. The wider social and public-health implications of this hypothesis are discussed, and suggestions are made as to the various ways in which scientific understanding of the meaning-enhancing properties of psychedelics might be advanced and utilized.

Neuroendocrine Associations Underlying the Persistent Therapeutic Effects of Classic Serotonergic Psychedelics

Recent reports on the effects of psychedelic-assisted therapies for mood disorders and addiction, as well as the effects of psychedelics in the treatment of cluster headache, have demonstrated promising therapeutic results. In addition, the beneficial effects appear to persist well after limited exposure to the drugs, making them particularly appealing as treatments for chronic neuropsychiatric and headache disorders. Understanding the basis of the long-lasting effects, however, will be critical for the continued use and development of this drug class. Several mechanisms, including biological and psychological ones, have been suggested to explain the long-lasting effects of psychedelics. Actions on the neuroendocrine system are some such mechanisms that warrant further investigation in the study of persisting psychedelic effects. In this report, we review certain structural and functional neuroendocrinological pathologies associated with neuropsychiatric disorders and cluster headache. We then review the effects that psychedelic drugs have on those systems and provide preliminary support for potential long-term effects. The circadian biology of cluster headache is of particular relevance in this area. We also discuss methodologic considerations for future investigations of neuroendocrine system involvement in the therapeutic benefits of psychedelic drugs.

The Psychedelic Debriefing in Alcohol Dependence Treatment: Illustrating Key Change Phenomena through Qualitative Content Analysis of Clinical Sessions

Research on the clinical applications of psychedelic-assisted psychotherapy has demonstrated promising early results for treatment of alcohol dependence. Detailed description of the content and methods of psychedelic-assisted psychotherapy, as it is conducted in clinical settings, is scarce.

Methods: An open-label pilot (proof-of-concept) study of psilocybin-assisted treatment of alcohol dependence (NCT01534494) was conducted to generate data for a phase 2 RCT (NCT02061293) of a similar treatment in a larger population. The present paper presents a qualitative content analysis of the 17 debriefing sessions conducted in the pilot study, which occurred the day after corresponding psilocybin medication sessions.

Results: Participants articulated a series of key phenomena related to change in drinking outcomes and acute subjective effects of psilocybin.

Discussion: The data illuminate change processes in patients' own words during clinical sessions, shedding light on potential therapeutic mechanisms of change and how participants express effects of psilocybin. This study is unique in analyzing actual clinical sessions, as opposed to interviews of patients conducted separately from treatment.

The Experience Elicited by Hallucinogens Presents the Highest Similarity to Dreaming within a Large Database of Psychoactive Substance Reports

Ever since the modern rediscovery of psychedelic substances by Western society, several authors have independently proposed that their effects bear a high resemblance to the dreams and dreamlike experiences occurring naturally during the sleep-wake cycle. Recent studies in humans have provided neurophysiological evidence supporting this hypothesis. However, a rigorous comparative analysis of the phenomenology (“what it feels like” to experience these states) is currently lacking. We investigated the semantic similarity between a large number of subjective reports of psychoactive substances and reports of high/low lucidity dreams, and found that the highest-ranking substance in terms of the similarity to high lucidity dreams was the serotonergic psychedelic lysergic acid diethylamide (LSD), whereas the highest-ranking in terms of the similarity to dreams of low lucidity were plants of the Datura genus, rich in deliriant tropane alkaloids. Conversely, sedatives, stimulants, antipsychotics, and antidepressants comprised most of the lowest-ranking substances. An analysis of the most frequent words in the subjective reports of dreams and hallucinogens revealed that terms associated with perception (“see,” “visual,” “face,” “reality,” “color”), emotion (“fear”), setting (“outside,” “inside,” “street,” “front,” “behind”) and relatives (“mom,” “dad,” “brother,” “parent,” “family”) were the most prevalent across both experiences. In summary, we applied novel quantitative analyses to a large volume of empirical data to confirm the hypothesis that, among all psychoactive substances, hallucinogen drugs elicit experiences with the highest semantic similarity to those of dreams. Our results and the associated methodological developments open the way to study the comparative phenomenology of different altered states of consciousness and its relationship with non-invasive measurements of brain physiology.

Psychedelic Fauna for Psychonaut Hunters: A Mini-Review

Currently different classes of psychoactive substances are easily available for abuse, including several hundred novel psychoactive substances (NPS). Some of these drugs occur naturally in plants and animals or are chemically modified from plant or animal compounds and have been abused by humans over millennia. Recently, the occurrence of a new "drug culture" (e.g., psychonauts) who consume a great variety of NPS with hallucinogenic/psychedelic properties, facilitated the development of a new "psychedelic trend" toward the consumption of substances contained in some species of animals ("psychedelic fauna"). The present review aims at providing an overview of the most commonly abused "psychedelic animals," by combining a dual search strategy coming from online psychonauts' experiences and English literature searches on the PubMed/Medline Google Scholar databases. A multilingual qualitative assessment on a range of websites and online resources was performed in order to identify a list of animals who possess some psychoactive properties and could be abused by humans for recreational purposes. Several species are implicated (i.e., ants, amphibians, fish). Routes of administration depend on the animal, substance included, metabolism, toxicity and individual, social and cultural variability. Online purchase and access are easy through tourism-related search strategies ("frog trip," "help of charmer snake," "religious trip").

When good times go bad: managing 'legal high' complications in the emergency department

Patients can use numerous drugs that exist outside of existing regulatory statutes in order to get "legal highs." Legal psychoactive substances represent a challenge to the emergency medicine physician due to the sheer number of available agents, their multiple toxidromes and presentations, their escaping traditional methods of analysis, and the reluctance of patients to divulge their use of these agents. This paper endeavors to cover a wide variety of "legal highs," or uncontrolled psychoactive substances that may have abuse potential and may result in serious toxicity. These agents include not only some novel psychoactive substances aka "designer drugs," but also a wide variety of over-the-counter medications, herbal supplements, and even a household culinary spice. The care of patients in the emergency department who have used "legal high" substances is challenging. Patients may misunderstand the substance they have been exposed to, there are rarely any readily available laboratory confirmatory tests for these substances, and the exact substances being abused may change on a near-daily basis. This review will attempt to group legal agents into expected toxidromes and discuss associated common clinical manifestations and management. A focus on aggressive symptom-based supportive care as well as management of end-organ dysfunction is the mainstay of treatment for these patients in the emergency department.

Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations

OBJECTIVE

It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system.

METHOD

100 μg LSD was administrated orally to 20 healthy participants prior to fMRI assessment. Whole brain thalamic functional connectivity was measured using ROI-to-ROI and ROI-to-voxel approaches. Correlation analyses were used to explore relationships between thalamic connectivity to regions involved in auditory and visual hallucinations and subjective ratings on auditory and visual drug effects.

RESULTS

LSD caused significant alterations in all dimensions of the 5D-ASC scale and significantly increased thalamic functional connectivity to various cortical regions. Furthermore, LSD-induced functional connectivity measures between the thalamus and the right fusiform gyrus and insula correlated significantly with subjective auditory and visual drug effects.

CONCLUSION

Hallucinogenic drug effects might be provoked by facilitations of cortical excitability via thalamocortical interactions. Our findings have implications for the understanding of the mechanism of action of hallucinogenic drugs and provide further insight into the role of the 5-HT_2A -receptor in altered states of consciousness.