In vitro and in vivo metabolism of psilocybin's active metabolite psilocin.

In vivo, psilocybin is rapidly dephosphorylated to psilocin which induces psychedelic effects by interacting with the 5-HT2A receptor. Psilocin primarily undergoes glucuronidation or conversion to 4-hydroxyindole-3-acetic acid (4-HIAA). Herein, we investigated psilocybin's metabolic pathways in vitro and in vivo, conducting a thorough analysis of the enzymes involved. Metabolism studies were performed using human liver microsomes (HLM), cytochrome P450 (CYP) enzymes, monoamine oxidase (MAO), and UDP-glucuronosyltransferase (UGT). In vivo, metabolism was examined using male C57BL/6J mice and human plasma samples. Approximately 29% of psilocin was metabolized by HLM, while recombinant CYP2D6 and CYP3A4 enzymes metabolized nearly 100% and 40% of psilocin, respectively. Notably, 4-HIAA and 4-hydroxytryptophol (4-HTP) were detected with HLM but not with recombinant CYPs. MAO-A transformed psilocin into minimal amounts of 4-HIAA and 4-HTP. 4-HTP was only present in vitro. Neither 4-HIAA nor 4-HTP showed relevant interactions at assessed 5-HT receptors. In contrast to in vivo data, UGT1A10 did not extensively metabolize psilocin in vitro. Furthermore, two putative metabolites were observed. N-methyl-4-hydroxytryptamine (norpsilocin) was identified in vitro (CYP2D6) and in mice, while an oxidized metabolite was detected in vitro (CYP2D6) and in humans. However, the CYP2D6 genotype did not influence psilocin plasma concentrations in the investigated study population. In conclusion, MAO-A, CYP2D6, and CYP3A4 are involved in psilocin's metabolism. The discovery of putative norpsilocin in mice and oxidized psilocin in humans further unravels psilocin's metabolism. Despite limitations in replicating phase II metabolism in vitro, these findings hold significance for studying drug-drug interactions and advancing research on psilocybin as a therapeutic agent.

Derivatization-free determination of chiral plasma pharmacokinetics of MDMA and its enantiomers.

3,4-Methylenedioxymethamphetamine (MDMA) is an entactogen with therapeutic potential. The two enantiomers of MDMA differ regarding their pharmacokinetics and pharmacodynamics but the chiral pharmacology of MDMA needs further study in clinical trials. Here, an achiral and an enantioselective high performance liquid chromatography-tandem mass spectrometry method for the quantification of MDMA and its psychoactive phase I metabolite 3,4-methylenedioxyamphetamine (MDA) in human plasma were developed and validated. The analytes were detected by positive electrospray ionization followed by multiple reaction monitoring. The calibration range was 0.5-500 ng/mL for the achiral analysis of both analytes, 0.5-1,000 ng/mL for chiral MDMA analysis, and 1-1,000 ng/mL for chiral MDA analysis. Accuracy, precision, selectivity, and sensitivity of both bioanalytical methods were in accordance with regulatory guidelines. Furthermore, accuracy and precision of the enantioselective method were maintained when racemic calibrations were used to measure quality control samples containing only one of the enantiomers. Likewise, enantiomeric calibrations could be used to reliably quantify enantiomers in racemic samples. The achiral and enantioselective methods were employed to assess pharmacokinetic parameters in clinical study participants treated with racemic MDMA or one of its enantiomers. The pharmacokinetic parameters assessed with both bioanalytical methods were comparable. In conclusion, the enantioselective method is useful for the simultaneous quantification of both enantiomers in subjects treated with racemic MDMA. However, as MDMA and MDA do not undergo chiral inversion, enantioselective separation is not necessary in subjects treated with only one of the enantiomers.

Development and validation of an LC-MS/MS method for quantifying diamorphine and its major metabolites 6-monoacetylmorphine, morphine, morphine-3-glucuronide, and morphine-6-glucuronide in human plasma.

Diamorphine, commonly known as heroin, is a semi-synthetic opioid analgesic. In the context of heroin-assisted treatment for opioid-dependent patients, diamorphine is mostly administered intravenously. However, recent attention has shifted towards intranasal administration as a better-tolerated alternative to the intravenous route. Here, we developed and validated a rapid bioanalytical method for the simultaneous quantification of diamorphine and its major metabolites 6-monoacetylmorphine, morphine, morphine-3-glucuronide, and morphine-6-glucuronide in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A straightforward protein precipitation extraction step was used for sample preparation. Chromatographic analyte separation was achieved using a Kinetex EVO C18 analytical column and a mobile phase gradient comprising an aqueous solution of ammonium hydrogen carbonate and methanol supplied with formic acid. Employing positive electrospray ionization and scheduled multiple reaction monitoring, we established a quantification range of 1-1,000 ng/mL for all analytes. Our validation results demonstrate a mean intra-assay accuracy of 91-106% and an intra-assay precision (CV) between 2 and 9% for all analytes and over three validation runs. The method exhibits a high extraction recovery (> 87%) and a negligible matrix effect (99-125%). Furthermore, no interferences with endogenous plasma compounds were detected. Lastly, we applied the method to assess the plasma concentrations of an opioid-dependent patient after the intranasal administration of diamorphine in a clinical study. In summary, we have successfully developed a rapid, highly reliable, and straightforward bioanalytical method for quantifying diamorphine and its metabolites in low amounts of clinical plasma samples.

Psychopathological characteristics in patients with arginine vasopressin deficiency (central diabetes insipidus) and primary polydipsia compared to healthy controls.

OBJECTIVE: Distinguishing arginine vasopressin deficiency (AVP-D; central diabetes insipidus) from primary polydipsia (PP), commonly referred to as psychogenic polydipsia, is challenging. Psychopathologic findings, commonly used for PP diagnosis in clinical practice, are rarely evaluated in AVP-D patients, and no comparative data between the two conditions currently exist. DESIGN: Data from two studies involving 82 participants [39 AVP-D, 28 PP, and 15 healthy controls (HC)]. METHODS: Psychological evaluations were conducted using standardized questionnaires measuring anxiety [State-Trait Anxiety Inventory (STAI)], alexithymia [Toronto Alexithymia Scale (TAS-20)], depressive symptoms (Beck's Depression Inventory-II (BDI-II), and overall mental health [Short Form-36 Health Survey (SF-36)]. Higher STAI, TAS-20, and BDI-II scores suggest elevated anxiety, alexithymia, and depression, while higher SF-36 scores signify better overall mental health. RESULTS: Compared to HC, patients with AVP-D and PP showed higher levels of anxiety (HC 28 points [24-31] vs AVP-D 36 points [31-45]; vs PP 38 points [33-46], P < .01), alexithymia (HC 30 points [29-37] vs AVP-D 43 points [35-54]; vs PP 46 points [37-55], P < .01), and depression (HC 1 point [0-2] vs AVP-D 7 points [4-14]; vs PP 7 points [3-13], P < .01). Levels of anxiety, alexithymia, and depression showed no difference between both patient groups (P = .58, P = .90, P = .50, respectively). Compared to HC, patients with AVP-D and PP reported similarly reduced self-reported overall mental health scores (HC 84 [68-88] vs AVP-D 60 [52-80], P = .05; vs PP 60 [47-74], P < .01). CONCLUSION: This study reveals heightened anxiety, alexithymia, depression, and diminished overall mental health in patients with AVP-D and PP. The results emphasize the need for careful interpretation of psychopathological characteristics to differentiate between AVP-D and PP.

Serotonergic Psychedelics: A Comparative Review of Efficacy, Safety, Pharmacokinetics, and Binding Profile.

Psychedelic compounds, including psilocybin, LSD (lysergic acid diethylamide), DMT (N,N -dimethyltryptamine), and 5-MeO-DMT (5-methoxy-N,N-dimethyltryptamine), all of which are serotonin 2A receptor agonists, are being investigated as potential treatments. This review aims to summarize the current clinical research on these 4 compounds and mescaline to guide future research. Their mechanism(s) of action, pharmacokinetics, pharmacodynamics, efficacy, and safety were reviewed. While evidence for therapeutic indications, with the exception of psilocybin for depression, is still relatively scarce, we noted no differences in psychedelic effects beyond effect duration. Therefore, it remains unclear whether different receptor profiles contribute to the therapeutic potential of these compounds. More research is needed to differentiate these compounds in order to inform which compounds might be best for different therapeutic uses.

The novel non-hallucinogenic compound DM506 (3-methyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole) induces sedative- and anxiolytic-like activity in mice by a mechanism involving 5-HT2A receptor activation.

The anxiolytic and sedative-like effects of 3-methyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole (DM506), a non-hallucinogenic compound derived from ibogamine, were studied in mice. The behavioral effects were examined using Elevated O-maze and novelty suppressed feeding (NSFT) tests, open field test, and loss of righting reflex (LORR) test. The results showed that 15 mg/kg DM506 induced acute and long-lasting anxiolytic-like activity in naive and stressed/anxious mice, respectively. Repeated administration of 5 mg/kg DM506 did not cause cumulative anxiolytic activity or any side effects. Higher doses of DM506 (40 mg/kg) induced sedative-like activity, which was inhibited by a selective 5-HT2A receptor antagonist, volinanserin. Electroencephalography results showed that 15 mg/kg DM506 fumarate increased the transition from a highly alert state (fast γ wavelength) to a more synchronized deep-sleeping activity (δ wavelength), which is reflected in the sedative/anxiolytic activity in mice but without the head-twitch response observed in hallucinogens. The functional, radioligand binding, and molecular docking results showed that DM506 binds to the agonist sites of human 5-HT2A (Ki = 24 nM) and 5-HT2B (Ki = 16 nM) receptors and activates them with a potency (EC50) of 9 nM and 3 nM, respectively. DM506 was relatively less potent and behaved as a partial agonist (efficacy <80%) for both receptor subtypes compared to the full agonist DOI (2,5-dimethoxy-4-iodoamphetamine). Our study showed for the first time that the non-hallucinogenic compound DM506 induces anxiolytic- and sedative-like activities in naïve and stressed/anxious mice in a dose-, time-, and volinanserin-sensitive manner, likely through mechanisms involving 5-HT2A receptor activation.

Pharmacokinetics, pharmacodynamics and urinary recovery of oral lysergic acid diethylamide administration in healthy participants.

AIMS: Lysergic acid diethylamide (LSD) is currently investigated for several neurological and psychiatric illnesses. Various studies have investigated the pharmacokinetics and the pharmacokinetic-pharmacodynamic relationship of LSD in healthy participants, but data on urinary recovery and confirmatory studies are missing. METHODS: The present study characterized the pharmacokinetics, pharmacokinetic-pharmacodynamic relationship and urinary recovery of LSD at doses of 85 and 170 µg administered orally in 28 healthy participants. The plasma concentrations and subjective effects of LSD were continuously evaluated over a period of 24 h. Urine was collected during 3 time intervals (0-8, 8-16 and 16-24 h after LSD administration). Pharmacokinetic parameters were determined using compartmental modelling. Concentration-subjective effect relationships were described using pharmacokinetic-pharmacodynamic modelling. RESULTS: Mean (95% confidence interval) maximal LSD concentrations were 1.8 ng/mL (1.6-2.0) and 3.4 ng/mL (3.0-3.8) after the administration of 85 and 170 µg LSD, respectively. Maximal concentrations were achieved on average after 1.7 h. Elimination half-lives were 3.7 h (3.4-4.1) and 4.0 h (3.6-4.4), for 85 and 170 µg LSD, respectively. Only 1% of the administered dose was recovered from urine unchanged within the first 24 h, 16% was eliminated as 2-oxo-3-hydroxy-LSD. Urinary recovery was dose proportional. Mean (±standard deviation) durations of subjective effects were 9.3 ± 3.2 and 11 ± 3.7 h, and maximal effects (any drug effects) were 77 ± 18% and 87 ± 13% after 85 and 170 µg of LSD, respectively. CONCLUSION: The present novel study validates previous findings. LSD exhibited dose-proportional pharmacokinetics and first-order elimination kinetics and dose-dependent duration and intensity of subjective effects. LSD is extensively metabolized and shows dose-proportional urinary recovery.

The revival of the psychedelic experience scale: Revealing its extended-mystical, visual, and distressing experiential spectrum with LSD and psilocybin studies.

BACKGROUND: Research with the Psychedelic Experience Questionnaire/Scale (PES) focuses on questions relating to mystical experience (Mystical Experience Questionnaire (MEQ)). The psychometric potential of the non-MEQ items of the PES remains largely unexplored. AIMS: We investigated whether the PES also yields subscales besides the MEQ30 subscales. METHODS: Data from 239 PES measurements (140 healthy participants) from six studies with moderate to high doses of lysergic acid diethylamide and/or psilocybin were included. New subscales (with items other than MEQ30) were created and validated as follows: (1) theoretical derivation of candidate items; (2) removal of items with rare experiences; (3) exploratory factor analysis; and (4) confirmatory factor analysis. Correlations of subscales within the PES and between the PES and the 5-Dimensional Altered States of Consciousness Scale (5D-ASC) were performed. In addition, a cluster analysis using all items (except rare experiences) was performed. RESULTS: The reliability of the four original factors of the MEQ30 was confirmed and four additional factors for the non-MEQ items were revealed: paradoxicality, connectedness, visual experience, and distressing experience. The first two additional factors were strongly correlated with the MEQ30 mystical subscale. Adding the new subscales to the MEQ30 subscales increased the explained variance with the 5D-ASC. The cluster analysis confirmed our main results and provided additional insights for future psychedelic psychometrics. CONCLUSION: The study yields a new validated 6-factor structure for extended mystical experience (MEQ40: MEQ30 + Paradoxicality + Connectedness) and covers psychedelic experience as a whole more comprehensively than has hitherto been possible within a single questionnaire (PES48). The entire PES (PES100) can also be used for further future psychedelic-psychometric research.

Acute psychotropic, autonomic, and endocrine effects of 5,6-methylenedioxy-2-aminoindane (MDAI) compared with 3,4-methylenedioxymethamphetamine (MDMA) in human volunteers: A self-administration study.

The acute psychoactive, autonomic, and endocrine effects of the new psychoactive substance (NPS) 5,6-methylenedioxy-2-aminoindane (MDAI; 3.0 mg/kg, range 180-228 mg) were investigated in six healthy volunteers (four males, two females) in a non-blinded fashion without placebo. Subjective, cardiovascular, and endocrine responses were compared with two different doses of 3,4-methylenedioxymethamphetamine (MDMA) (75 mg and 125 mg) described in previously published placebo-controlled studies, which used identical outcome measures including Visual Analogue Scales (VAS), the Adjective Mood Rating Scale (AMRS), and the 5 Dimensions of Altered States of Consciousness (5D-ASC) scale. MDAI was well tolerated and produced subjective effects comparable with those of 125 mg MDMA. MDAI increased blood pressure similar to 125 mg MDMA but did not increase heart rate or body temperature. MDAI increased cortisol and prolactin levels and could be detected in serum about 20 min post ingestion and remained detectable at least for 4 days. In urine, MDAI was detectable over a period of at least 6 days. Further clinical investigations are warranted to assess whether MDAI could serve as drug with medicinal properties.

Self-discharge during treatment for acute recreational drug toxicity: an observational study from emergency departments in seven European countries.

BACKGROUND: Self-discharge is a risk factor for readmission and excess mortality. We assess the rate of self-discharge from the emergency department (ED) among presentations for acute recreational drug toxicity and identify factors associated with self-discharge. METHODS: From the Euro-DEN Plus database of presentations to the ED with acute recreational drug toxicity, we extracted data from 11 centres in seven European countries from 2014 to 2017. Self-discharge was defined as taking one's own discharge or escaping from the ED before being medically cleared. We used multiple logistic regression analyses to look for factors associated with self-discharge. RESULTS: Among 15,135 included presentations, 1807 (11.9%) self-discharged. Self-discharge rates varied from 1.7 to 17.1% between centres. Synthetic cannabinoids were associated with self-discharge, adjusted odds ratio 1.44 (95% confidence interval 1.10-1.89), as were heroin, 1.44 (1.26-1.64), agitation, 1.27 (1.10-1.46), and naloxone treatment, 1.27 (1.07-1.51), while sedation protected from self-discharge, 0.38 (0.30-0.48). CONCLUSION: One in eight presentations self-discharged. There was a large variation in self-discharge rates across the participating centres, possibly partly reflecting different discharge procedures and practices. Measures to improve the management of agitation and cautious administration of naloxone to avoid opioid withdrawal symptoms may be approaches worth exploring to reduce self-discharge.

Case report: Maintaining altered states of consciousness over repeated ketamine infusions may be key to facilitate long-lasting antidepressant effects: some initial lessons from a personalized-dosing single-case study.

Background: The interest in psychoactive agents for treating mental disorders has gathered a growing body of scientific interest. However, research on the relationship between altered states of consciousness (ASCs) and ketamine's antidepressant properties is still limited. Likewise, approaches to sustain early treatment success for the long-term are needed. Taking both aspects into account, the question arises whether the persistence of recurrent ASCs during the subsequent infusion sessions is crucial for the preservation of antidepressant effects during prolonged continued ketamine therapy. Aim: In this case study we explored whether recurrent ASC experiences across a large number of infusions are associated with improved antidepressant effects in a single case study. Methods: A 62-year-old patient with treatment-resistant depression, who has been suffering from depressive episodes for over 20 years, was observed for 12 consecutive infusions across 16 weeks. ASCs during ketamine sessions were measured with the 5D-ASC, and pre/post-infusion depression scores with the BDI-II questionnaire. To emphasize psychoactive experiences a personalized antidepressant dose regimen was used. Results: We found a strong correlation between the experienced ASCs during ketamine infusions and the antidepressant effect: the stronger the ASCs overall, the stronger the resulting antidepressant effect. This correlation was consistently observed throughout the infusion series, independent of the number of ketamine sessions completed before. However, despite a personalized dose regimen, neither peri-infusion ASCs nor antidepressant effects could be established on a regular basis, leading overall to no improvement in treatment outcome. Conclusion: Maintaining psychoactive effects over repeated ketamine infusions may be key to facilitate long-lasting antidepressant effects. However, for some depressed individuals maintenance of antidepressant effects and/or peri-infusion ASCs might not be achieved, even when personalized dosing is used.

Determinants of Admission to Critical Care Following Acute Recreational Drug Toxicity: A Euro-DEN Plus Study.

This study aimed to characterize patients admitted to critical care following Emergency Department (ED) presentation with acute recreational drug toxicity and to identify determinants of admission to critical care. A retrospective multicenter matched case-control study was conducted by the European Drug Emergency Network Plus (Euro-DEN Plus) over the period 2014-2021. The cases were ED presentations with acute recreational drug toxicity admitted to critical care, the controls consisted of ED presentations with acute recreational drug toxicity medically discharged directly from the ED. The potential determinants of admission to critical care were assessed through multivariable conditional stepwise logistic regression analysis and multiple imputation was used to account for the missing data. From 2014 to 2021, 3448 Euro-DEN Plus presentations involved patients admitted to critical care (76.9% males; mean age 33.2 years; SD 10.9 years). Patient age ≥35 years (as compared to ≤18 years) was a determinant of admission to critical care following acute recreational drug toxicity (adjusted odds ratio, aOR, 1.51, 95% confidence interval, CI, 1.15-1.99), along with polydrug use (aOR 1.39, 95% CI 1.22-1.59), ethanol co-ingestion (aOR 1.44, 95% CI 1.26-1.64), and the use of gamma-hydroxybutyrate/gamma-butyrolactone (GHB/GBL, aOR 3.08, 95% CI 2.66-3.57). Conversely, lower odds of admission to critical care were associated with the use of cocaine (aOR 0.85, 95% CI 0.74-0.99), cannabis (aOR 0.44, 95% CI 0.37-0.52), heroin (aOR 0.80, 95% CI 0.69-0.93), and amphetamine (aOR 0.65, 95% CI 0.54-0.78), as was the arrival to the ED during the night (8 p.m.-8 a.m., aOR 0.88, 95% CI 0.79-0.98). These findings, which deserve confirmation and further investigation, could contribute to a more complete understanding of the decision-making process underlying the admission to critical care of patients with acute recreational drug toxicity.

Effective Connectivity of Thalamocortical Interactions Following d-Amphetamine, LSD, and MDMA Administration.

BACKGROUND: While the exploration of serotonergic psychedelics as psychiatric medicines deepens, so does the pressure to better understand how these compounds act on the brain. METHODS: We used a double-blind, placebo-controlled, crossover design and administered lysergic acid diethylamide (LSD), 3,4-methylenedioxymethamphetamine (MDMA), and d-amphetamine in 25 healthy participants. By using spectral dynamic causal modeling, we mapped substance-induced changes in effective connectivity between the thalamus and different cortex types (unimodal vs. transmodal) derived from a previous study with resting-state functional magnetic resonance imaging data. Due to the distinct pharmacological modes of action of the 3 substances, we were able to investigate specific effects mainly driven by different neurotransmitter systems on thalamocortical and corticothalamic interactions. RESULTS: Compared with placebo, all 3 substances increased the effective connectivity from the thalamus to specific unimodal cortices, whereas the influence of these cortices on the thalamus was reduced. These results indicate increased bottom-up and decreased top-down information flow between the thalamus and some unimodal cortices. However, for the amphetamines, we found the opposite effects when examining the effective connectivity with transmodal cortices, including parts of the salience network. Intriguingly, LSD increased the effective connectivity from the thalamus to both unimodal and transmodal cortices, indicating a breach in the hierarchical organization of ongoing brain activity. CONCLUSIONS: The results advance our knowledge about the action of psychedelics on the brain and refine current models aiming to explain the underlying neurobiological processes.

Pharmacokinetics of ivermectin metabolites and their activity against Anopheles stephensi mosquitoes.

BACKGROUND: Ivermectin (22,23-dihydroavermectin B1a: H2B1a) is an endectocide used to treat worm infections and ectoparasites including lice and scabies mites. Furthermore, survival of malaria transmitting Anopheles mosquitoes is strongly decreased after feeding on humans recently treated with ivermectin. Currently, mass drug administration of ivermectin is under investigation as a potential novel malaria vector control tool to reduce Plasmodium transmission by mosquitoes. A "post-ivermectin effect" has also been reported, in which the survival of mosquitoes remains reduced even after ivermectin is no longer detectable in blood meals. In the present study, existing material from human clinical trials was analysed to understand the pharmacokinetics of ivermectin metabolites and feeding experiments were performed in Anopheles stephensi mosquitoes to assess whether ivermectin metabolites contribute to the mosquitocidal action of ivermectin and whether they may be responsible for the post-ivermectin effect. METHODS: Ivermectin was incubated in the presence of recombinant human cytochrome P450 3A4/5 (CYP 3A4/5) to produce ivermectin metabolites. In total, nine metabolites were purified by semi-preparative high-pressure liquid chromatography. The pharmacokinetics of the metabolites were assessed over three days in twelve healthy volunteers who received a single oral dose of 12 mg ivermectin. Blank whole blood was spiked with the isolated metabolites at levels matching the maximal blood concentration (Cmax) observed in pharmacokinetics study samples. These samples were fed to An. stephensi mosquitoes, and their survival and vitality was recorded daily over 3 days. RESULTS: Human CYP3A4 metabolised ivermectin more rapidly than CYP3A5. Ivermectin metabolites M1-M8 were predominantly formed by CYP3A4, whereas metabolite M9 (hydroxy-H2B1a) was mainly produced by CYP3A5. Both desmethyl-H2B1a (M1) and hydroxy-H2B1a (M2) killed all mosquitoes within three days post-feeding, while administration of desmethyl, hydroxy-H2B1a (M4) reduced survival to 35% over an observation period of 3 days. Ivermectin metabolites that underwent deglycosylation or hydroxylation at spiroketal moiety were not active against An. stephensi at Cmax levels. Interestingly, half-lives of M1 (54.2 ± 4.7 h) and M4 (57.5 ± 13.2 h) were considerably longer than that of the parent compound ivermectin (38.9 ± 20.8 h). CONCLUSION: In conclusion, the ivermectin metabolites M1 and M2 contribute to the activity of ivermectin against An. stephensi mosquitoes and could be responsible for the "post-ivermectin effect".

Oxytocin in response to MDMA provocation test in patients with arginine vasopressin deficiency (central diabetes insipidus): a single-centre, case-control study with nested, randomised, double-blind, placebo-controlled crossover trial.

BACKGROUND: Disruptions of the hypothalamic-pituitary axis can cause an arginine vasopressin deficiency, also known as central diabetes insipidus. Patients with this condition are at high risk of additional oxytocin deficiency owing to the close anatomical proximity of oxytocin-producing neurons; however, no conclusive evidence for such a deficiency has been reported. We aimed to use 3,4-methylenedioxymethamphetamine (MDMA, also known as ecstasy), a strong activator of the central oxytocinergic system, as a biochemical and psychoactive provocation test to investigate oxytocin deficiency in patients with arginine vasopressin deficiency (central diabetes insipidus). METHODS: This single-centre, case-control study with nested, randomised, double-blind, placebo-controlled crossover trial included patients with arginine vasopressin deficiency (central diabetes insipidus) and healthy controls (matched 1:1 by age, sex, and BMI) and was conducted at the University Hospital Basel, Basel, Switzerland. We used block randomisation to assign participants to receive either a single oral dose of MDMA (100 mg) or placebo in the first experimental session; patients received the opposite treatment at the next session, with a wash-out period of at least 2 weeks between the two sessions. Participants and investigators assessing the outcomes were masked to assignment. Oxytocin concentrations were measured at 0, 90, 120, 150, 180, and 300 min after MDMA or placebo. The primary outcome was the area under the plasma oxytocin concentration curve (AUC) after drug intake. The AUC was compared between groups and conditions using a linear mixed-effects model. Subjective drug effects were assessed throughout the study using ten-point visual analogue scales. Acute adverse effects were assessed before and 360 min after drug intake using a 66-item list of complaints. This trial is registered with ClinicalTrials.gov, NCT04648137. FINDINGS: Between Feb 1, 2021, and May 1, 2022, we recruited 15 patients with arginine vasopressin deficiency (central diabetes insipidus) and 15 healthy controls. All participants completed the study and were included in the analyses. In healthy controls, median plasma oxytocin concentration was 77 pg/mL (IQR 59-94) at baseline and increased by 659 pg/mL (355-914) in response to MDMA, resulting in an AUC of 102 095 pg/mL (41 782-129 565); in patients, baseline oxytocin concentration was 60 pg/mL (51-74) and only slightly increased by 66 pg/mL (16-94) in response to MDMA, resulting in an AUC of 6446 pg/mL (1291-11 577). The effect of MDMA on oxytocin was significantly different between groups: the AUC for oxytocin was 82% (95% CI 70-186) higher in healthy controls than in patients (difference 85 678 pg/mL [95% CI 63 356-108 000], p<0·0001). The increase in oxytocin in healthy controls was associated with typical strong subjective prosocial, empathic, and anxiolytic effects, whereas only minimal subjective effects were observed in patients, in agreement with the lack of increase in oxytocin concentrations. The most frequently reported adverse effects were fatigue (eight [53%] healthy controls and eight [53%] patients), lack of appetite (ten [67%] healthy controls and eight [53%] patients), lack of concentration (eight [53%] healthy controls and seven [47%] patients), and dry mouth (eight [53%] healthy controls and eight [53%] patients). In addition, two (13%) healthy controls and four (27%) patients developed transient mild hypokalaemia. INTERPRETATION: These findings are highly suggestive of clinically meaningful oxytocin deficiency in patients with arginine vasopressin deficiency (central diabetes insipidus), laying the groundwork for a new hypothalamic-pituitary disease entity. FUNDING: Swiss National Science Foundation, Swiss Academy of Medical Sciences, and the G&J Bangerter-Rhyner Foundation.

Acute effects of MDMA and LSD co-administration in a double-blind placebo-controlled study in healthy participants.

There is renewed interest in the use of lysergic acid diethylamide (LSD) in psychiatric research and practice. Although acute subjective effects of LSD are mostly positive, negative subjective effects, including anxiety, may occur. The induction of overall positive acute subjective effects is desired in psychedelic-assisted therapy because positive acute experiences are associated with greater therapeutic long-term benefits. 3,4-Methylenedioxymethamphetamine (MDMA) produces marked positive subjective effects and is used recreationally with LSD, known as "candyflipping." The present study investigated whether the co-administration of MDMA can be used to augment acute subjective effects of LSD. We used a double-blind, randomized, placebo-controlled, crossover design with 24 healthy subjects (12 women, 12 men) to compare the co-administration of MDMA (100 mg) and LSD (100 µg) with MDMA and LSD administration alone and placebo. Outcome measures included subjective, autonomic, and endocrine effects and pharmacokinetics. MDMA co-administration with LSD did not change the quality of acute subjective effects compared with LSD alone. However, acute subjective effects lasted longer after LSD + MDMA co-administration compared with LSD and MDMA alone, consistent with higher plasma concentrations of LSD (Cmax and area under the curve) and a longer plasma elimination half-life of LSD when MDMA was co-administered. The LSD + MDMA combination increased blood pressure, heart rate, and pupil size more than LSD alone. Both MDMA alone and the LSD + MDMA combination increased oxytocin levels more than LSD alone. Overall, the co-administration of MDMA (100 mg) did not improve acute effects or the safety profile of LSD (100 µg). The combined use of MDMA and LSD is unlikely to provide relevant benefits over LSD alone in psychedelic-assisted therapy. Trial registration: ClinicalTrials.gov identifier: NCT04516902.

Comparative acute effects of mescaline, lysergic acid diethylamide, and psilocybin in a randomized, double-blind, placebo-controlled cross-over study in healthy participants.

Mescaline, lysergic acid diethylamide (LSD), and psilocybin are classic serotonergic psychedelics. A valid, direct comparison of the effects of these substances is lacking. The main goal of the present study was to investigate potential pharmacological, physiological and phenomenological differences at psychoactive-equivalent doses of mescaline, LSD, and psilocybin. The present study used a randomized, double-blind, placebo-controlled, cross-over design to compare the acute subjective effects, autonomic effects, and pharmacokinetics of typically used, moderate to high doses of mescaline (300 and 500 mg), LSD (100 µg), and psilocybin (20 mg) in 32 healthy participants. A mescaline dose of 300 mg was used in the first 16 participants and 500 mg was used in the subsequent 16 participants. Acute subjective effects of 500 mg mescaline, LSD, and psilocybin were comparable across various psychometric scales. Autonomic effects of 500 mg mescaline, LSD, and psilocybin were moderate, with psilocybin causing a higher increase in diastolic blood pressure compared with LSD, and LSD showing a trend toward an increase in heart rate compared with psilocybin. The tolerability of mescaline, LSD, and psilocybin was comparable, with mescaline at both doses inducing slightly more subacute adverse effects (12-24 h) than LSD and psilocybin. Clear distinctions were seen in the duration of action between the three substances. Mescaline had the longest effect duration (mean: 11.1 h), followed by LSD (mean: 8.2 h), and psilocybin (mean: 4.9 h). Plasma elimination half-lives of mescaline and LSD were similar (approximately 3.5 h). The longer effect duration of mescaline compared with LSD was due to the longer time to reach maximal plasma concentrations and related peak effects. Mescaline and LSD, but not psilocybin, enhanced circulating oxytocin. None of the substances altered plasma brain-derived neurotrophic factor concentrations. In conclusion, the present study found no evidence of qualitative differences in altered states of consciousness that were induced by equally strong doses of mescaline, LSD, and psilocybin. The results indicate that any differences in the pharmacological profiles of mescaline, LSD, and psilocybin do not translate into relevant differences in the subjective experience. ClinicalTrials.gov identifier: NCT04227756.

The effect of lysergic acid diethylamide (LSD) on whole-brain functional and effective connectivity.

Psychedelics have emerged as promising candidate treatments for various psychiatric conditions, and given their clinical potential, there is a need to identify biomarkers that underlie their effects. Here, we investigate the neural mechanisms of lysergic acid diethylamide (LSD) using regression dynamic causal modelling (rDCM), a novel technique that assesses whole-brain effective connectivity (EC) during resting-state functional magnetic resonance imaging (fMRI). We modelled data from two randomised, placebo-controlled, double-blind, cross-over trials, in which 45 participants were administered 100 µg LSD and placebo in two resting-state fMRI sessions. We compared EC against whole-brain functional connectivity (FC) using classical statistics and machine learning methods. Multivariate analyses of EC parameters revealed predominantly stronger interregional connectivity and reduced self-inhibition under LSD compared to placebo, with the notable exception of weakened interregional connectivity and increased self-inhibition in occipital brain regions as well as subcortical regions. Together, these findings suggests that LSD perturbs the Excitation/Inhibition balance of the brain. Notably, whole-brain EC did not only provide additional mechanistic insight into the effects of LSD on the Excitation/Inhibition balance of the brain, but EC also correlated with global subjective effects of LSD and discriminated experimental conditions in a machine learning-based analysis with high accuracy (91.11%), highlighting the potential of using whole-brain EC to decode or predict subjective effects of LSD in the future.

Acute effects of intravenous DMT in a randomized placebo-controlled study in healthy participants.

N,N-dimethyltryptamine (DMT) is distinct among classic serotonergic psychedelics because of its short-lasting effects when administered intravenously. Despite growing interest in the experimental and therapeutic use of intravenous DMT, data are lacking on its clinical pharmacology. We conducted a double-blind, randomized, placebo-controlled crossover trial in 27 healthy participants to test different intravenous DMT administration regimens: placebo, low infusion (0.6 mg/min), high infusion (1 mg/min), low bolus + low infusion (15 mg + 0.6 mg/min), and high bolus + high infusion (25 mg + 1 mg/min). Study sessions lasted for 5 h and were separated by at least 1 week. Participant's lifetime use of psychedelics was ≤20 times. Outcome measures included subjective, autonomic, and adverse effects, pharmacokinetics of DMT, and plasma levels of brain-derived neurotropic factor (BDNF) and oxytocin. Low (15 mg) and high (25 mg) DMT bolus doses rapidly induced very intense psychedelic effects that peaked within 2 min. DMT infusions (0.6 or 1 mg/min) without a bolus induced slowly increasing and dose-dependent psychedelic effects that reached plateaus after 30 min. Both bolus doses produced more negative subjective effects and anxiety than infusions. After stopping the infusion, all drug effects rapidly decreased and completely subsided within 15 min, consistent with a short early plasma elimination half-life (t1/2α) of 5.0-5.8 min, followed by longer late elimination (t1/2ß = 14-16 min) after 15-20 min. Subjective effects of DMT were stable from 30 to 90 min, despite further increasing plasma concentrations, thus indicating acute tolerance to continuous DMT administration. Intravenous DMT, particularly when administered as an infusion, is a promising tool for the controlled induction of a psychedelic state that can be tailored to the specific needs of patients and therapeutic sessions.Trial registration: ClinicalTrials.gov identifier: NCT04353024.