Exploring protective associations between the use of classic psychedelics and cocaine use disorder: a population-based survey study

Psilocybin reduces heroin seeking behavior and modulates inflammatory gene expression in the nucleus accumbens and prefrontal cortex of male rats

Preclinical and human studies indicate psilocybin may reduce perseverant maladaptive behaviors, including nicotine and alcohol seeking. Such studies in the opioid field are lacking, though opioids are involved in more >50% of overdose deaths. Psilocybin is an agonist at the serotonin 2A receptor (5-HT2AR), a well-documented target for modulation of drug seeking, and evidence suggests 5-HT2AR agonists may dampen motivation for opioids. We sought to investigate the therapeutic efficacy of psilocybin in mediating cessation of opioid use and maintenance of long-lasting abstinence from opioid seeking behavior in a rat model of heroin self-administration (SA). Psilocybin or 5-HT2AR antagonists ketanserin and volinanserin were administered systemically to rats prior to SA of 0.075 mg/kg/infusion of heroin, or relapse following forced abstinence. Psilocybin did not alter heroin taking, but a single exposure to 3.0 mg/kg psilocybin 4-24 hours prior to a relapse test blunted cue-induced heroin seeking. Conversely, 5-HT2AR antagonists exacerbated heroin relapse. To begin to elucidate mechanisms of psilocybin, drug-naïve rats received psilocybin and/or ketanserin, and tissue was collected from the prefrontal cortex (PFC), a region critical for drug seeking and responsive to psilocybin, 24 hours later for RNA-sequencing. 3.0 mg/kg psilocybin regulated ~2-fold more genes in the PFC than 1.0 mg/kg, including genes involved in the cytoskeleton and cytokine signaling. Ketanserin blocked >90% of psilocybin-regulated genes, including the IL-17a cytokine receptor, Il17ra. Psychedelic compounds have reported anti-inflammatory properties, and therefore we performed a gene expression array to measure chemokine/cytokine molecules in the PFC of animals that displayed psilocybin-mediated inhibition of heroin seeking. Psilocybin regulated 4 genes, including Il17a, and a subset of genes correlated with relapse behavior. Selective inhibition of PFC IL-17a was sufficient to reduce heroin relapse. We conclude that psilocybin reduces heroin relapse and highlight IL-17a signaling as a potential downstream pathway of psilocybin that also reduces heroin seeking.

Factors associated with the use of psychedelics, ketamine and MDMA among sexual and gender minority youths in Canada: a machine learning analysis

BACKGROUND

Substance use is increasing among sexual and gender minority youth (SGMY). This increase may be due to changes in social norms and socialisation, or due to SGMY exploring the potential therapeutic value of drugs such as psychedelics. We identified predictors of psychedelics, MDMA and ketamine use.

METHODS

Data were obtained from 1414 SGMY participants who completed the ongoing longitudinal 2SLGBTQ+ Tobacco Project in Canada between November 2020 to January 2021. We examined the association between 80 potential features (including sociodemographic factors, mental health-related factors and substance use-related factors) with the use of psychedelics, MDMA and ketamine in the past year. Random forest classifier was used to identify the predictors most associated with reported use of these drugs.

RESULTS

18.1% of participants have used psychedelics in the past year; 21.9% used at least one of the three drugs. Cannabis and cocaine use were the predictors most strongly associated with any of these drugs, while cannabis, but not cocaine use, was the one most associated with psychedelic use. Other mental health and 2SLGBTQ+ stigma-related factors were also associated with the use of these drugs.

CONCLUSION

The use of psychedelics, MDMA and ketamine among 2SLGBTQ+ individuals appeared to be largely driven by those who used them together with other drugs. Depression scores also appeared in the top 10 factors associated with these illicit drugs, suggesting that there were individuals who may benefit from the potential therapeutic value of these drugs. These characteristics should be further investigated in future studies.

μ-opioid receptor agonists and psychedelics: pharmacological opportunities and challenges

Opioid misuse and opioid-involved overdose deaths are a massive public health problem involving the intertwined misuse of prescription opioids for pain management with the emergence of extremely potent fentanyl derivatives, sold as standalone products or adulterants in counterfeit prescription opioids or heroin. The incidence of repeated opioid overdose events indicates a problematic use pattern consistent with the development of the medical condition of opioid use disorder (OUD). Prescription and illicit opioids reduce pain perception by activating µ-opioid receptors (MOR) localized to the central nervous system (CNS). Dysregulation of meso-corticolimbic circuitry that subserves reward and adaptive behaviors is fundamentally involved in the progressive behavioral changes that promote and are consequent to OUD. Although opioid-induced analgesia and the rewarding effects of abused opioids are primarily mediated through MOR activation, serotonin (5-HT) is an important contributor to the pharmacology of opioid abused drugs (including heroin and prescription opioids) and OUD. There is a recent resurgence of interest into psychedelic compounds that act primarily through the 5-HT2A receptor (5-HT 2A R) as a new frontier in combatting such diseases (e.g., depression, anxiety, and substance use disorders). Emerging data suggest that the MOR and 5-HT2AR crosstalk at the cellular level and within key nodes of OUD circuitry, highlighting a major opportunity for novel pharmacological intervention for OUD. There is an important gap in the preclinical profiling of psychedelic 5-HT2AR agonists in OUD models. Further, as these molecules carry risks, additional analyses of the profiles of non-hallucinogenic 5-HT2AR agonists and/or 5-HT2AR positive allosteric modulators may provide a new pathway for 5-HT2AR therapeutics. In this review, we discuss the opportunities and challenges associated with utilizing 5-HT2AR agonists as therapeutics for OUD.

Race and ethnicity moderate the associations between lifetime psilocybin use and crime arrests

Introduction

Psilocybin use has been linked to lowered odds of crime-related outcomes across a host of observational studies. No studies have investigated how these associations may differ among those of different races and ethnicities.

Methods

Using a nationally-representative sample of 734,061 adults from the National Survey on Drug Use and Health (2002-2020), we investigated whether race and ethnicity moderate the associations between lifetime psilocybin use and four measures of crime arrests (property crime, assault, serious violence, and miscellaneous crimes).

Results

First, we replicated prior findings and demonstrated that psilocybin confers lowered odds of crime arrests for all four outcomes in question. Second, we demonstrated that race and ethnicity moderate the associations between lifetime psilocybin use and crime arrests for three of our four outcomes. Third, we examined the associations between psilocybin and crime arrests across different races and ethnicities (White, Black, Indigenous, Asian, Multiracial, and Hispanic participants). Psilocybin conferred lowered odds of at least one crime arrest outcome for all racial and ethnic groups except for Black and Hispanic participants.

Discussion

Future investigations should take an intersectional approach to studying the interrelationship of sociodemographic factors, psychedelic use, and crime, examine the structural factors (i.e., systemic racism) that may underlie these results, and investigate whether psychedelics can alleviate mental health disorders that contribute to cycles of recriminalization for communities of color.

Psychedelic therapy in the treatment of addiction: the past, present and future

Psychedelic therapy has witnessed a resurgence in interest in the last decade from the scientific and medical communities with evidence now building for its safety and efficacy in treating a range of psychiatric disorders including addiction. In this review we will chart the research investigating the role of these interventions in individuals with addiction beginning with an overview of the current socioeconomic impact of addiction, treatment options, and outcomes. We will start by examining historical studies from the first psychedelic research era of the mid-late 1900s, followed by an overview of the available real-world evidence gathered from naturalistic, observational, and survey-based studies. We will then cover modern-day clinical trials of psychedelic therapies in addiction from first-in-human to phase II clinical trials. Finally, we will provide an overview of the different translational human neuropsychopharmacology techniques, including functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), that can be applied to foster a mechanistic understanding of therapeutic mechanisms. A more granular understanding of the treatment effects of psychedelics will facilitate the optimisation of the psychedelic therapy drug development landscape, and ultimately improve patient outcomes.

Ketamine and serotonergic psychedelics: An update on the mechanisms and biosignatures underlying rapid-acting antidepressant treatment

The discovery of ketamine as a rapid-acting antidepressant spurred significant research to understand its underlying mechanisms of action and to identify other novel compounds that may act similarly. Serotonergic psychedelics (SPs) have shown initial promise in treating depression, though the challenge of conducting randomized controlled trials with SPs and the necessity of long-term clinical observation are important limitations. This review summarizes the similarities and differences between the psychoactive effects associated with both ketamine and SPs and the mechanisms of action of these compounds, with a focus on the monoaminergic, glutamatergic, gamma-aminobutyric acid (GABA)-ergic, opioid, and inflammatory systems. Both molecular and neuroimaging aspects are considered. While their main mechanisms of action differ-SPs increase serotonergic signaling while ketamine is a glutamatergic modulator-evidence suggests that the downstream mechanisms of action of both ketamine and SPs include mechanistic target of rapamycin complex 1 (mTORC1) signaling and downstream GABAA receptor activity. The similarities in downstream mechanisms may explain why ketamine, and potentially SPs, exert rapid-acting antidepressant effects. However, research on SPs is still in its infancy compared to the ongoing research that has been conducted with ketamine. For both therapeutics, issues with regulation and proper controls should be addressed before more widespread implementation. This article is part of the Special Issue on "Ketamine and its Metabolites".

Examining associations between MDMA/ecstasy and classic psychedelic use and impairments in social functioning in a U.S. adult sample

Impairment in social functioning is a common source of morbidity across many mental health disorders, yet there is a dearth of effective and easily implemented interventions to support social functioning. MDMA/ecstasy and classic psychedelics (psilocybin, LSD, peyote, mescaline) represent two potential treatments for impairments in social functioning, as evidence suggests these compounds may be supportive for alleviating social difficulties. Using a nationally representative sample of U.S. adults from the National Survey on Drug Use and Health (2015-2019) (N = 214,505), we used survey-weighted multivariable ordinal and logistic regression to examine the associations between lifetime use of the aforementioned compounds and impairments in social functioning in the past year. Lifetime MDMA/ecstasy use was associated with lowered odds of three of our four social impairment outcomes: difficulty dealing with strangers (aOR 0.92), difficulty participating in social activities (aOR 0.90), and being prevented from participating in social activities (aOR 0.84). Lifetime mescaline use was also associated with lowered odds of difficulty dealing with strangers (aOR 0.85). All other substances either shared no relationship with impairments in social functioning or conferred increased odds of our outcomes. Future experimental studies can assess whether these relationships are causal.

Associations between MDMA/ecstasy, classic psychedelics, and suicidal thoughts and behaviors in a sample of U.S. adolescents

Suicide is one of the leading causes of death amongst adolescents and decades of research have failed to curb suicide rates within this population. There is thus a need to better understand factors that correlate with adolescent suicidal thoughts and behaviors (STBs). MDMA/ecstasy and classic psychedelics represent two areas for exploration, as use of these substances has been associated with both increased and lowered odds of STBs. Thus, the goal of this study was to test the associations between MDMA/ecstasy and classic psychedelics (psilocybin, peyote, mescaline, LSD) and STBs in a nationally representative sample of U.S. adolescents. We tested these associations in a sample of adolescents aged 12-17 years old from the National Survey on Drug Use and Health (2004-2019) (N = 262,617) using survey-weighted multivariable logistic regression models. Lifetime psilocybin use was associated with lowered odds of lifetime suicidal thinking, planning, and attempts (aOR range 0.77-0.85). Conversely, LSD was associated with increased odds of these same outcomes (aOR range 1.20-1.35). MDMA/ecstasy, peyote, and mescaline did not share associations with STBs. Our study demonstrates that individual classic psychedelics share varying relationships to STBs among adolescents. Future cross-sectional and longitudinal studies are needed to further elucidate the link between classic psychedelic use and STBs in youth.

Race and ethnicity moderate the associations between lifetime psychedelic use (MDMA and psilocybin) and psychological distress and suicidality

Psychedelic compounds have been linked to salutary mental health outcomes in both naturalistic and clinical settings; however, current research on psychedelics suffers from a lack of inclusion and focus on racial and ethnic minorities. Thus, the goal of our study was to assess whether race and ethnicity moderate the associations that naturalistic lifetime MDMA (3,4-Methylenedioxymethamphetamine) use and psilocybin use share with past month psychological distress and past year suicidality (ideation and planning). Using data from the National Survey on Drug Use and Health (NSDUH) (2008-2019) (N = 484,732), we conducted survey-weighted multivariable logistic regression to conduct interaction tests and to assess the associations that MDMA use and psilocybin use share with the aforementioned outcomes for each racial and ethnic group. Race and ethnicity significantly moderated the associations between MDMA and psilocybin use and psychological distress and suicidality. For White participants, MDMA and psilocybin use conferred lowered odds of all distress and suicidality outcomes. For racial and ethnic minority participants, the associations between psychedelic use and suicidality were far fewer. These findings invite further research into the impact of race, ethnicity, and other identity factors (e.g., socioeconomic status, sexual/gender minority status) on the effects of psychedelic substances.

Deepening our understanding of psychedelics by expanding psychedelic data collection in the United States National Survey on Drug Use and Health

Amid a reappraisal of the medicinal and societal worth of psychedelics in many countries, regulatory and financial barriers to conducting clinical research with these compounds appear to be receding. Still, there remains a strong need for a clearer understanding of naturalistic psychedelic use and its associated epidemiology, since this type of psychedelic use, which is growing in many places, will almost certainly always exceed clinical use. Furthermore, psychedelics behave differently depending on the settings in which they are used, meaning many research findings on their effects may significantly differ depending on the contexts in which they are observed. Therefore, improving the collection of data on real-world psychedelic use should be of higher priority for the public health community. Expanding data collection on psychedelic use in the United States National Survey on Drug Use and Health, an already vital tool for researchers examining naturalistic psychedelic use, could address this important public health need, helping ensure the general public, the scientific community, and regulators have access to high-quality information as peoples across the world reevaluate what psychedelics' place in medicine and society should be.

Associations between classic psychedelics and nicotine dependence in a nationally representative sample

Tobacco use is the single largest cause of preventable death worldwide, but none of the established treatments aimed at smoking cessation work for a majority of smokers. As such, there is an urgent need for interventions capable of reliably treating nicotine addiction. The use of classic psychedelics has been associated with lower odds of many forms of substance dependence. Here we tested whether lifetime use of classic psychedelics (tryptamine, lysergamide, and phenethylamine) is associated with lower odds of current nicotine dependence. We tested these associations in a sample of 214,505 adult participants in the National Survey on Drug Use and Health (2015–2019) using multivariable logistic regression models. Lifetime psilocybin use was associated with reduced odds of odds of current nicotine dependence (aOR 0.87–0.93). Lifetime use of peyote and mescaline also conferred reduced odds of multiple subdomains of a main nicotine dependence measure (Nicotine Dependence Syndrome Scale [NDSS]) (aOR 0.79–0.91). Conversely, lifetime use of LSD was associated with increased odds of nicotine dependence (aOR 1.17–1.24). Psilocybin, mescaline, and peyote use are associated with lowered odds of nicotine dependence. Experimental studies are needed to establish whether these associations are causal. These results make the case for further research into the efficacy of both tryptamine and phenethylamine psychedelics in promoting smoking cessation.

Associations between classic psychedelics and opioid use disorder in a nationally-representative U.S. adult sample

Opioid use disorder (OUD) is a major source of morbidity and mortality in the U.S. and there is a pressing need to identify additional treatments for the disorder. Classic psychedelics (psilocybin, peyote, mescaline, LSD) have been linked to the alleviation of various substance use disorders and may hold promise as potential treatments for OUD. The aim of this study was to assess whether the aforementioned classic psychedelic substances conferred lowered odds of OUD. Furthermore, this study aimed to replicate and extend findings from Pisano et al. (2017) who found classic psychedelic use to be linked to lowered odds of OUD in a nationally representative sample. We used recent data from the National Survey on Drug Use and Health (2015–2019) (N = 214,505) and multivariable logistic regression to test whether lifetime use (yes/no) of classic psychedelics was associated with lowered odds of OUD. Lifetime psilocybin use was associated with lowered odds of OUD (aOR: 0.70; 95% CI [0.60, 0.83]). No other substances, including other classic psychedelics, were associated with lowered odds of OUD. Additionally, sensitivity analyses revealed psilocybin use to be associated with lowered odds of seven of the 11 DSM-IV criteria for OUD (aOR range: 0.66–0.83). Future clinical trials and longitudinal studies are needed to determine whether these associations are causal.