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.

Loss of Consciousness and Visual Hallucinations Related to 5-MeO-DALT Intake, a Case Report Confirmed by Toxicological Analyses

5-MeO-DALT or 5-methoxy-N,N-diallyltryptamine is a derivative of tryptamines, consumed for its hallucinogenic and entheogenic effects. We report the case of a 46-year-old-man, presenting with a brief loss of consciousness and visual hallucinations, after the consumption of three 5-MeO-DALT tablets bought online. Liquid chromatography coupled to tandem mass spectrometry method (LC-MS/MS) was performed, and 5-Meo-DALT was quantified in both the tablets (32,5 mg per tablet, 11% of purity) and the patient's plasma (7 ng/ml - 8 hours between the consumption and the blood sample). 5-MeO-DALT poisonings are rarely described. Given the broad availability of these products, it is important that emergency department physicians and clinical toxicologists do not overlook the possibility of the ingestion of recreational tryptamines, especially since they are not detected by most routine toxicological screening.

The role of restraint in fatal excited delirium: a research synthesis and pooled analysis

The purpose of the present study was to perform a comprehensive scientific literature review and pooled data risk factor analysis of excited delirium syndrome (ExDS) and agitated delirium (AgDS). All cases of ExDS or AgDS described individually in the literature published before April 23, 2020 were used to create a database of cases, including demographics, use of force, drug intoxication, mental illness, and survival outcome. Odds ratios were used to quantify the association between death and diagnosis (ExDS vs. AgDS) across the covariates. There were 61 articles describing 168 cases of ExDS or AgDS, of which 104 (62%) were fatal. ExDS was diagnosed in 120 (71%) cases, and AgDS in 48 (29%). Fatalities were more likely to be diagnosed as ExDS (OR: 9.9, p < 0.0001). Aggressive restraint (i.e. manhandling, handcuffs, and hobble ties) was more common in ExDS (ORs: 4.7, 14, 29.2, respectively, p < 0.0001) and fatal cases (ORs: 7.4, 10.7, 50, respectively, p < 0.0001). Sedation was more common in AgDS and survived cases (OR:11, 25, respectively, p < 0.0001). The results of the study indicate that a diagnosis of ExDS is far more likely to be associated with both aggressive restraint and death, in comparison with AgDS. There is no evidence to support ExDS as a cause of death in the absence of restraint. These findings are at odds with previously published theories indicating that ExDS-related death is due to an occult pathophysiologic process. When death has occurred in an aggressively restrained individual who fits the profile of either ExDS or AgDS, restraint-related asphyxia must be considered a likely cause of the death.

UHPLC-MS/MS method for simultaneously detecting 16 tryptamines and their metabolites in human hair and applications to real forensics cases

Tryptamines are hallucinogenic substances many of which have appeared recently as novel psychoactive substances (NPS). Herein, we describe the establishment of a rapid UHPLC-MS/MS quantitative method for the targeted screening of 16 tryptamines of abuse in hair. Twenty milligram pieces of hair were pulverized below 4 °C in 0.5 mL of deionized water containing 0.1% formic acid and an internal standard (2 ng/mL psilocin-d₁₀ and psilocybin-d₄). After subsequent centrifugation, 5 μL of the supernatant was injected into a LC-MS/MS system fitted with a Waters Acquity UPLC HSS T₃ column (100 mm × 2.1 mm, 1.8 μm). The column was gradient eluted at 0.3 mL/min with mobile phases composed of 20 mmol/L ammonium acetate, 5% acetonitrile, and 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Limits of detection ranged between 0.1 and 20 pg/mg, with limits of quantitation ranging from 3 to 50 pg/mg. The calibration curves for all analytes were linear (r > 0.992). Accuracies varied between 91% and 114%, with intraday precision RSDs < 14% and interday precision RSDs of between 1.3% and 14%. The recoveries of all tryptamines were in the 85-115% range, with the matrix effect ranging from 95% to 112%. The validated method was successfully used to analyse 191 hair samples from suspected tryptamine users, 77 of which were 5-MeO-DiPT-positive, while the 16 tryptamines and their metabolites were not detected in the remaining 114 hair samples. 5-MeO-DiPT and its 5-MeO-NiPT, 5-OH-DiPT, and 4-OH-DiPT metabolites were concurrently detected in 34 hair samples. 5-MeO-DiPT, as the parent drug, was the parent substance found in the hair samples.

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 (GABA_A) or GABA_B 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-HT_2A) 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.

New psychoactive substances: a review and updates

New psychoactive substances (NPS) are a heterogeneous group of substances. They are associated with a number of health and social harms on an individual and societal level. NPS toxicity and dependence syndromes are recognised in primary care, emergency departments, psychiatric inpatient and community care settings. One pragmatic classification system is to divide NPS into one of four groups: synthetic stimulants, synthetic cannabinoids, synthetic hallucinogens and synthetic depressants (which include synthetic opioids and benzodiazepines). We review these four classes of NPS, including their chemical structures, mechanism of action, modes of use, intended intoxicant effects, and their associated physical and mental health harms. The current challenges faced by laboratory testing for NPS are also explored, in the context of the diverse range of NPS currently available, rate of production and emergence of new substances, the different formulations, and methods of acquisition and distribution.

Multi-drug cocktails: Impurities in commonly used illicit drugs seized by police in Queensland, Australia

BACKGROUND

Impurities in commonly used illicit drugs raise concerns for unwitting consumers when pharmacologically active adulterants, especially new psychoactive substances (NPS), are used. This study examines impurities detected in illicit drugs seized in one Australian jurisdiction.

METHODS

Queensland Health Forensic and Scientific Services provided analytical data. Data described the chemical composition of 9346 samples of 11 illicit drugs seized by police during 2015-2016. Impurities present in primary drugs were summarized and tabulated. A systematic search for published evidence reporting similar analyses was conducted.

RESULTS

Methamphetamine was the primary drug in 6608 samples, followed by MDMA (1232 samples) and cocaine (516 samples). Purity of primary drugs ranged from ∼30% for cocaine, 2-CB and GHB to >90% for THC, methamphetamine, heroin and MDMA. Methamphetamine and MDMA contained the largest variety of impurities: 22 and 18 variants, respectively. Drug adulteration patterns were broadly similar to those found elsewhere, including NPS, but in some primary drugs impurities were found which had not been reported elsewhere. Psychostimulants were adulterated with each other. Levamisole was a common impurity in cocaine. Psychedelics were adulterated with methamphetamine and NPS. Opioids were quite pure, but some samples contained methamphetamine and synthetic opioids.

CONCLUSIONS

Impurities detected were mostly pharmacologically active adulterants probably added to enhance desired effects or for active bulking. Given the designer nature of these drug cocktails, the effects of the adulterated drugs on users from possible complex multi-drug interactions is unpredictable. Awareness-raising among users, research into complex multi-drug effects and ongoing monitoring is required.

Investigating the ability of the microbial model Cunninghamella elegans for the metabolism of synthetic tryptamines

Tryptamines can occur naturally in plants, mushrooms, microbes, and amphibians. Synthetic tryptamines are sold as new psychoactive substances (NPS) because of their hallucinogenic effects. When it comes to NPS, metabolism studies are of crucial importance, due to the lack of pharmacological and toxicological data. Different approaches can be taken to study in vitro and in vivo metabolism of xenobiotica. The zygomycete fungus Cunninghamella elegans (C. elegans) can be used as a microbial model for the study of drug metabolism. The current study investigated the biotransformation of four naturally occurring and synthetic tryptamines [N,N-Dimethyltryptamine (DMT), 4-hydroxy-N-methyl-N-ethyltryptamine (4-HO-MET), N,N-di allyl-5-methoxy tryptamine (5-MeO-DALT) and 5-methoxy-N-methyl-N-isoporpoyltryptamine (5-MeO-MiPT)] in C. elegans after incubation for 72 hours. Metabolites were identified using liquid chromatography-high resolution-tandem mass spectrometry (LC-HR-MS/MS) with a quadrupole time-of-flight (QqTOF) instrument. Results were compared to already published data on these substances. C. elegans was capable of producing all major biotransformation steps: hydroxylation, N-oxide formation, carboxylation, deamination, and demethylation. On average 63% of phase I metabolites found in the literature could also be detected in C. elegans. Additionally, metabolites specific for C. elegans were identified. Therefore, C. elegans is a suitable complementary model to other in vitro or in vivo methods to study the metabolism of naturally occurring or synthetic tryptamines.

Trends in DMT and other tryptamine use among young adults in the United States

BACKGROUND AND OBJECTIVES

The popularity of tryptamines such as N,N-dimethyltryptamine (DMT) appears to be increasing in the United States (US), but epidemiologic literature on prevalence of use is scant. This paper aims to determine trends in prevalence and correlates of past-year tryptamine use among a nationally representative sample of young adults in the US.

METHODS

Participants in the National Survey on Drug Use and Health survey were queried about past-year use of tryptamines-specifically DMT, α-methyltryptamine (AMT), and 5-MeO-DIPT ("Foxy"). Data were examined from young adults (ages 18-25), years 2007-2014 (N = 144,787). Linear trends in prevalence of past-year tryptamine use were examined in the full sample and stratified by specific demographic and drug use characteristics.

RESULTS

Tryptamine use is rare, but increased from .2% in 2007/08 to .7% in 2013/14, a 273% relative increase (p < .001). While prevalence increased among all demographic groups, prevalence was substantially higher among individuals who use other drugs. In particular, between 2007/08 and 2013/14, prevalence of tryptamine use increased among past-year ecstasy users (from 2.1% to 10.0%) and LSD users (from 7.0% to 15.5%) (ps < .01). Prevalence of tryptamine use tended to be higher among lifetime and past-year users of psychedelic drugs compared to users of non-psychedelic drugs.

CONCLUSION

While tryptamine use is not prevalent in the general young adult population, prevalence is increasing. Users of various other drugs-particularly drugs with psychedelic effects-report higher prevalence of tryptamine use.

SCIENTIFIC SIGNIFICANCE

Users of other drugs can be targeted when disseminating information about tryptamines to ensure user safety. (Am J Addict 2018;27:578-585).

Excited Delirium: A Systematic Review

OBJECTIVE

We aimed to clarify the definition, epidemiology, and pathophysiology of excited delirium syndrome (ExDS) and to summarize evidence-based treatment recommendations.

METHODS

We conducted a systematic literature search of MEDLINE, Ovid, Web of Knowledge, and Cochrane Library for articles published to March 18, 2017. We also searched the gray literature (Google Scholar) and official police or medical expert reports to complete specific epidemiologic data. Search results and full-text articles were independently assessed by two investigators and agreements between reviewers assessed with K statistics. We classified articles by study type, setting, and evidence level.

RESULTS

After reviewing the title and abstract of 3,604 references, we fully reviewed 284 potentially relevant references, from which 66 were selected for final review. Six contributed to the definition of ExDS, 24 to its epidemiology, 38 to its pathophysiology, and 27 to its management. The incidence of ExDS varies widely with medical or medicolegal context. Mortality is estimated to be as much as 8.3% to 16.5%. Patients are predominantly male. Male sex, young age, African-American race, and being overweight are independent risk factors. Pathophysiology hypotheses mostly implicate dopaminergic pathways. Most cases occur with psychostimulant use or among psychiatric patients or both. Proposed treatments are symptomatic, often with rapid sedation with benzodiazepines or antipsychotic agents. Ketamine is suggested as an alternative.

CONCLUSION

The overall quality of studies was poor. A universally recognized definition is lacking, remaining mostly syndromic and based on clinical subjective criteria. High mortality rate may be due to definition inconsistency and reporting bias. Our results suggest that ExDS is a real clinical entity that still kills people and that has probably specific mechanisms and risk factors. No comparative study has been performed to conclude whether one treatment approach is preferable to another in the case of ExDS.

Locomotor and discriminative stimulus effects of four novel hallucinogens in rodents

There has been increasing use of novel synthetic hallucinogenic compounds, 2-(4-bromo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine hydrochloride (25B-NBOMe), 2-(4-chloro-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine hydrochloride (25C-NBOMe), 2-(4-iodo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine hydrochloride (25I-NBOMe), and N,N-diallyl-5-methoxy tryptamine (5-MeO-DALT), which have been associated with severe toxicities. These four compounds were tested for discriminative stimulus effects similar to a prototypical hallucinogen (-)-2,5-dimethoxy-4-methylamphetamine (DOM) and the entactogen (±)-3,4-methylenedioxymethamphetamine (MDMA). Locomotor activity in mice was tested to obtain dose range and time-course information. 25B-NBOMe, 25C-NBOMe, and 25I-NBOMe decreased locomotor activity. 5-MeO-DALT dose dependently increased locomotor activity, with a peak at 10 mg/kg. A higher dose (25 mg/kg) suppressed activity. 25B-NBOMe fully substituted (≥80%) in both DOM-trained and MDMA-trained rats at 0.5 mg/kg. However, higher doses produced much lower levels of drug-appropriate responding in both DOM-trained and MDMA-trained rats. 25C-NBOMe fully substituted in DOM-trained rats, but produced only 67% drug-appropriate responding in MDMA-trained rats at doses that suppressed responding. 25I-NBOMe produced 74-78% drug-appropriate responding in DOM-trained and MDMA-trained rats at doses that suppressed responding. 5-MeO-DALT fully substituted for DOM, but produced few or no MDMA-like effects. All of the compounds, except 25I-NBOMe, fully substituted for DOM, whereas only 25B-NBOMe fully substituted for MDMA. However, the failure of 25I-NBOMe to fully substitute for either MDMA or DOM was more likely because of its substantial rate-depressant effects than weak discriminative stimulus effects. All of the compounds are likely to attract recreational users for their hallucinogenic properties, but probably of much less interest as substitutes for MDMA. Although no acute adverse effects were observed at the doses tested, the substantial toxicities reported in humans, coupled with the high likelihood for illicit use, suggests that these compounds have the same potential for abuse as other, currently scheduled compounds.

The Novel Psychoactive Substances in the UK Project: empirical and conceptual review work to produce research recommendations

Background

Although illegal drug use has largely been declining in the UK over the past decade, this period has witnessed the emergence of a range of novel psychoactive substances (NPS) (‘legal highs’). These are new, mostly synthetic, substances that mimic the effects of existing drugs). Despite there being many causes for concern in relation to NPS, there has been little prior study of the burden associated with their use in public health terms. Clarity is lacking on research priorities in this rapidly developing literature.

Objectives

To inform the development of public health intervention research on NPS by reviewing existing data on their use, associated problems and potential responses to such problems.

Design

A scoping review and narrative synthesis of selected bodies of evidence was undertaken to summarise and evaluate what is known about NPS use and the related harms of, and responses to, such use. Relevant literature was identified from electronic databases (covering January 2006 to June 2016 inclusive), Google (Google Inc., Mountain View, CA, USA), relevant websites and online drug forums and by contacting experts. Articles were included if they were primary studies, secondary studies involving the analysis and interpretation of primary research or discussion papers. A conceptual framework postulating an evidence-informed public health approach to NPS use in the UK was developed through a pragmatic literature review, the iterative development of concepts and finalisation in light of the results from the empirical review work. The process also involved feedback from various stakeholders. Research recommendations were developed from both strands of work.

Results

A total of 995 articles were included in the scoping review, the majority of which related to individual-level health-related adverse effects attributable to NPS use. The prevalence of lifetime NPS use varied widely between (e.g. with higher prevalence in young males) and within population subgroups. The most commonly reported adverse effects were psychiatric/other neurological, cardiovascular, renal and gastrointestinal manifestations, and there is limited evidence available on responses. In these and other respects, available evidence is at an early stage of development. Initial evidence challenges the view that NPS should be treated differently from other illicit drugs. The conceptual framework indicated that much of the evidence that would be useful to inform public health responses does not yet exist. We propose a systems-based prevention approach that develops existing responses, is multilevel and life course informed in character, and emphasises commonalities between NPS and other legal and illegal drug use. We make 20 recommendations for research, including nine key recommendations.

Limitations

Scoping reviews do not interrogate evidence in depth, and the disjunction between the scoping review and the conceptual framework findings is worthy of careful attention.

Conclusions

Key research recommendations build on those that have previously been made and offer more evidence-based justification and detail, as previous recommendations have not yet been acted on. The case for decision-making on commissioning new research based on these recommendations is both strong and urgent.

Future work

The validity of recommendations generated through this project could be enhanced via further work with research commissioners, policy-makers, researchers and the public.

Study registration

The systematic review element of this study is registered as PROSPERO CRD42016026415.

Funding

The National Institute for Health Research Public Health Research programme.

Metabolism of the tryptamine-derived new psychoactive substances 5-MeO-2-Me-DALT, 5-MeO-2-Me-ALCHT, and 5-MeO-2-Me-DIPT and their detectability in urine studied by GC-MS, LC-MSn , and LC-HR-MS/MS

Many N,N-dialkylated tryptamines show psychoactive properties and were encountered as new psychoactive substances. The aims of the presented work were to study the phase I and II metabolism and the detectability in standard urine screening approaches (SUSA) of 5-methoxy-2-methyl-N,N-diallyltryptamine (5-MeO-2-Me-DALT), 5-methoxy-2-methyl-N-allyl-N-cyclohexyltryptamine (5-MeO-2-Me-ALCHT), and 5-methoxy-2-methyl-N,N-diisopropyltryptamine (5-MeO-2-Me-DIPT) using gas chromatography-mass spectrometry (GC-MS), liquid chromatography coupled with multistage accurate mass spectrometry (LC-MSⁿ ), and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS). For metabolism studies, urine was collected over a 24 h period after administration of the compounds to male Wistar rats at 20 mg/kg body weight (BW). Phase I and II metabolites were identified after urine precipitation with acetonitrile by LC-HR-MS/MS. 5-MeO-2-Me-DALT (24 phase I and 12 phase II metabolites), 5-MeO-2-Me-ALCHT (24 phase I and 14 phase II metabolites), and 5-MeO-2-Me-DIPT (20 phase I and 11 phase II metabolites) were mainly metabolized by O-demethylation, hydroxylation, N-dealkylation, and combinations of them as well as by glucuronidation and sulfation of phase I metabolites. Incubations with mixtures of pooled human liver microsomes and cytosols (pHLM and pHLC) confirmed that the main metabolic reactions in humans and rats might be identical. Furthermore, initial CYP activity screenings revealed that CYP1A2, CYP2C19, CYP2D6, and CYP3A4 were involved in hydroxylation, CYP2C19 and CYP2D6 in O-demethylation, and CYP2C19, CYP2D6, and CYP3A4 in N-dealkylation. For SUSAs, GC-MS, LC-MSⁿ , and LC-HR-MS/MS were applied to rat urine samples after 1 or 0.1 mg/kg BW doses, respectively. In contrast to the GC-MS SUSA, both LC-MS SUSAs were able to detect an intake of 5-MeO-2-Me-ALCHT and 5-MeO-2-Me-DIPT via their metabolites following 1 mg/kg BW administrations and 5-MeO-2-Me-DALT following 0.1 mg/kg BW dosage. Copyright © 2017 John Wiley & Sons, Ltd.

Analytical characterization of N,N-diallyltryptamine (DALT) and 16 ring-substituted derivatives

Many N,N-dialkylated tryptamines show psychoactive properties in humans and the number of derivatives involved in multidisciplinary areas of research has grown over the last few decades. Whereas some derivatives form the basis of a range of medicinal products, others are predominantly encountered as recreational drugs, and in some cases, the areas of therapeutic and recreational use can overlap. In recent years, 5-methoxy-N,N-diallyltryptamine (5-MeO-DALT) has appeared as a new psychoactive substance (NPS) and 'research chemical' whereas 4-acetoxy-DALT and the ring-unsubstituted DALT have only been detected very recently. Strategies pursued in the authors' laboratories included the preparation and biological evaluation of previously unreported N,N-diallyltryptamines (DALTs). This report describes the analytical characterization of 17 DALTs. Fifteen DALTs were prepared by a microwave-accelerated Speeter and Anthony procedure following established procedures developed previously in the authors' laboratories. In addition to DALT, the substances included in this study were 2-phenyl-, 4-acetoxy-, 4-hydroxy-, 4,5-ethylenedioxy-, 5-methyl-, 5-methoxy-, 5-methoxy-2-methyl-, 5-ethoxy-, 5-fluoro-, 5-fluoro-2-methyl-, 5-chloro-, 5-bromo-, 5,6-methylenedioxy-, 6-fluoro-, 7-methyl, and 7-ethyl-DALT, respectively. The DALTs were characterized by nuclear magnetic resonance spectroscopy (NMR), gas chromatography (GC) quadrupole and ion trap (EI/CI) mass spectrometry (MS), low and high mass accuracy MS/MS, photodiode array detection, and GC solid-state infrared analysis, respectively. A comprehensive collection of spectral data was obtained that are provided to research communities who face the challenge of encountering newly emerging substances where analytical data are not available. These data are also relevant to researchers who might wish to explore the clinical and non-clinical uses of these substances. Copyright © 2016 John Wiley & Sons, Ltd.

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.

Receptor binding profiles and quantitative structure-affinity relationships of some 5-substituted-N,N-diallyltryptamines

N,N-Diallyltryptamine (DALT) and 5-methoxy-N,N-diallyltryptamine (5-MeO-DALT) are two tryptamines synthesized and tested by Alexander Shulgin. In self-experiments, 5-MeO-DALT was reported to be psychoactive in the 12-20mg range, while the unsubstituted compound DALT had few discernible effects in the 42-80 mg range. Recently, 5-MeO-DALT has been used in nonmedical settings for its psychoactive effects, but these effects have been poorly characterized and little is known of its pharmacological properties. We extended the work of Shulgin by synthesizing additional 5-substituted-DALTs. We then compared them to DALT and 5-MeO-DALT for their binding affinities at 45 cloned receptors and transporter proteins. Based on in vitro binding affinity, we identified 27 potential receptor targets for the 5-substituted-DALT compounds. Five of the DALT compounds had affinity in the 10-80 nM range for serotonin 5-HT1A and 5-HT2B receptors, while the affinity of DALT itself at 5-HT1A receptors was slightly lower at 100 nM. Among the 5-HT2 subtypes, the weakest affinity was at 5-HT2A receptors, spanning 250-730 nM. Five of the DALT compounds had affinity in the 50-400 nM range for serotonin 5-HT1D, 5-HT6, and 5-HT7 receptors; again, it was the unsubstituted DALT that had the weakest affinity at all three subtypes. The test drugs had even weaker affinity for 5-HT1B, 5-HT1E, and 5-HT5A subtypes and little or no affinity for the 5-HT3 subtype. These compounds also had generally nanomolar affinities for adrenergic α2A, α2B, and α2C receptors, sigma receptors σ1 and σ2, histamine H1 receptors, and norepinephrine and serotonin uptake transporters. They also bound to other targets in the nanomolar-to-low micromolar range. Based on these binding results, it is likely that multiple serotonin receptors, as well as several nonserotonergic sites are important for the psychoactive effects of DALT drugs. To learn whether any quantitative structure-affinity relationships existed, we evaluated correlations among physicochemical properties of the congeneric 5-substituted-DALT compounds. The descriptors included electronic (σp), hydrophobic (π), and steric (CMR) parameters. The binding affinity at 5-HT1A, 5-HT1D, 5-HT7, and κ opioid receptors was positively correlated with the steric volume parameter CMR. At α2A, α2B, and α2C receptors, and at the histamine H1 receptor, binding affinity was correlated with the Hammett substituent parameter σp; higher affinity was associated with larger σp values. At the σ2 receptor, higher affinity was correlated with increasing π. These correlations should aid in the development of more potent and selective drugs within this family of compounds.

Legal highs: staying on top of the flood of novel psychoactive substances

There has been growing clinical, public, and media awareness and concern about the availability and potential harmfulness of so-called 'legal highs', which are more appropriately called new or novel psychoactive substances (NPS). A cat-and-mouse process has emerged wherein unknown chemists and laboratories are producing new, and as yet nonproscribed, compounds for human consumption; and as soon as they are banned, which they inevitably are, slightly modified analogues are produced to circumvent new laws. This rapidly changing environment, 81 new substances were identified in 2013 alone, has led to confusion for clinicians, psychopharmacologists, and the public at large. Our difficulties in keeping up with the process has had a two-fold negative effect: the danger of ignoring what is confusing; and the problem that some of the newer synthesized compounds appear ever more potent. This review aims to circumscribe a quick moving and growing field, and to categorize NPS into five major groups based upon their 'parent' compounds: stimulants similar to cocaine, amphetamines and ecstasy; cannabinoids; benzodiazepine based drugs; dissociatives similar to ketamine and phencyclidine (PCP); and those modelled after classic hallucinogens such as LSD and psilocybin. Pharmacodynamic actions, subjective and physical effects, harmfulness, risk of dependency and, where appropriate, putative clinical potentials are described for each class. Clinicians might encounter NPS in various ways: anecdotal reportage; acute intoxication; as part of a substance misuse profile; and as a precipitant or perpetuating factor for longer-term physical and psychological ill health. Current data are overall limited, and much of our knowledge and treatment strategies are based upon those of the 'parent' compound. There is a critical need for more research in this field, and for professionals to make themselves more aware of this growing issue and how it might affect those we see clinically and try to help: a brave new world of so-called 'psychonauts' consuming NPS will also need informed 'psychotherapeutonauts'. The paper should serve as a primer for clinicians and interested readers, as well as provide a framework into which to place the new substances that will inevitably be synthesized in the future.

Recreational use, analysis and toxicity of tryptamines

The definition New psychoactive substances (NPS) refers to emerging drugs whose chemical structures are similar to other psychoactive compounds but not identical, representing a "legal" alternative to internationally controlled drugs. There are many categories of NPS, such as synthetic cannabinoids, synthetic cathinones, phenylethylamines, piperazines, ketamine derivatives and tryptamines. Tryptamines are naturally occurring compounds, which can derive from the amino acid tryptophan by several biosynthetic pathways: their structure is a combination of a benzene ring and a pyrrole ring, with the addition of a 2-carbon side chain. Tryptamines include serotonin and melatonin as well as other compounds known for their hallucinogenic properties, such as psilocybin in 'Magic mushrooms' and dimethyltryptamine (DMT) in Ayahuasca brews.

AIM

To review the scientific literature regarding tryptamines and their derivatives, providing a summary of all the available information about the structure of these compounds, their effects in relationship with the routes of administration, their pharmacology and toxicity, including articles reporting cases of death related to intake of these substances.

METHODS

A comprehensive review of the published scientific literature was performed, using also non peer-reviewed information sources, such as books, government publications and drug user web fora.

CONCLUSIONS

Information from Internet and from published scientific literature, organized in the way we proposed in this review, provides an effective tool for specialists facing the emerging NPS threat to public health and public security, including the personnel working in Emergency Department.

Emerging drugs in Europe

PURPOSE OF REVIEW

New psychoactive substances refer to emerging substances that have appeared on the market and are not under international control. NPS have been categorized in different main groups (e.g. synthetic cannabinoids, synthetic cathinones, phenethylamines, piperazines, ketamine and phencyclidine-type substances, tryptamines). This article reviews the recent literature regarding emerging trends of NPS in Europe.

RECENT FINDINGS

According to the last report of the European Union Early warning system (EWS), 73 NPS were officially identified for the first time. The more frequent NPS self-reported or detected are synthetic cannabinoids and cathinones. A combination of different NPS and also mixed with other drugs, mainly cannabis and ecstasy, is usual among experienced drug users. Acute NPS toxicity includes significant psychoactive and sympathomimetic effects.

SUMMARY

This article summarizes new European epidemiological and clinical data published between January and December 2013 on NPS. In the last few years, there has been a rapid increase in the number of NPS launched on the European drugs market. The presence of some of these new substances has been detected through surveys/questionnaires, studies in drug samples and biological fluids, and case reports and NPS-induced fatalities.