OPEN Foundation

New substances

Beyond ecstasy: Alternative entactogens to 3,4-methylenedioxymethamphetamine with potential applications in psychotherapy


The last two decades have seen a revival of interest in the entactogen 3,4-methylenedioxy-N-methylamphetamine (MDMA) as an adjunct to psychotherapy, particularly for the treatment of post-traumatic stress disorder. While clinical results are highly promising, and MDMA is expected to be approved as a treatment in the near future, it is currently the only compound in its class of action that is being actively investigated as a medicine. This lack of alternatives to MDMA may prove detrimental to patients who do not respond well to the particular mechanism of action of MDMA or whose treatment calls for a modification of MDMA’s effects. For instance, patients with existing cardiovascular conditions or with a prolonged history of stimulant drug use may not fit into the current model of MDMA-assisted psychotherapy, and could benefit from alternative drugs. This review examines the existing literature on a host of entactogenic drugs, which may prove to be useful alternatives in the future, paying particularly close attention to any neurotoxic risks, neuropharmacological mechanism of action and entactogenic commonalities with MDMA. The substances examined derive from the 1,3-benzodioxole, cathinone, benzofuran, aminoindane, indole and amphetamine classes. Several compounds from these classes are identified as potential alternatives to MDMA.

Oeri H. E. (2021). Beyond ecstasy: Alternative entactogens to 3,4-methylenedioxymethamphetamine with potential applications in psychotherapy. Journal of psychopharmacology (Oxford, England), 35(5), 512–536.

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In vitro structure-activity relationship determination of 30 psychedelic new psychoactive substances by means of β-arrestin 2 recruitment to the serotonin 2A receptor


Serotonergic psychedelics, substances exerting their effects primarily through the serotonin 2A receptor (5-HT2AR), continue to comprise a substantial portion of reported new psychoactive substances (NPS). The exact mechanisms of action of psychedelics still remain to be elucidated further, and certain pathways remain largely unexplored on a molecular level for this group of compounds. A systematic comparison of substances belonging to different subclasses, monitoring the receptor-proximal β-arrestin 2 recruitment, is lacking. Based on a previously reported in vitro bioassay employing functional complementation of a split nanoluciferase to monitor β-arrestin 2 recruitment to the 5-HT2AR, we here report on the setup of a stable HEK 293 T cell-based bioassay. Following verification of the performance of this new stable cell system as compared to a system based on transient transfection, the stable expression system was deemed suitable for the pharmacological characterization of psychedelic NPS. Subsequently, it was applied for the in vitro assessment of the structure-activity relationship of a set of 30 substances, representing different subclasses of phenylalkylamine psychedelics, among which 12 phenethylamine derivatives (2C-X), 7 phenylisopropylamines (DOx) and 11 N-benzylderivatives (25X-NB). The resulting potency and efficacy values provide insights into the structure-activity relationship of the tested compounds, overall confirm findings observed with other reported in vitro assays, and even show a significant correlation with estimated common doses. This approach, in which a large series of psychedelic NPS belonging to different subclasses is comparatively tested, using a same assay setup, monitoring a receptor-proximal event, not only gives pharmacological insights, but may also allow prioritization of legal actions related to the most potent -and potentially dangerous- compounds.

Pottie, E., Cannaert, A., & Stove, C. P. (2020). In vitro structure–activity relationship determination of 30 psychedelic new psychoactive substances by means of β-arrestin 2 recruitment to the serotonin 2A receptor. Archives of Toxicology94(10), 3449-3460; 10.1007/s00204-020-02836-w
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In vivo effects of 3,4-methylenedioxymethamphetamine (MDMA) and its deuterated form in rodents: Drug discrimination and thermoregulation.



Recent clinical studies support the use of 3,4-methylenedioxymethamphetamine (MDMA) as an adjunct treatment for posttraumatic stress disorder (PTSD). Despite these promising findings, MDMA administration in controlled settings can increase blood pressure, heart rate, and body temperature. Previous studies indicate thatO-demethylated metabolites of MDMA contribute to its adverse effects. As such, limiting the conversion of MDMA to reactive metabolites may mitigate some of its adverse effects and potentially improve its safety profile for therapeutic use.


We compared the interoceptive and hyperthermic effects of a deuterium-substituted form of MDMA (d2-MDMA) to MDMA using rodent drug discrimination and biotelemetry procedures, respectively.


Compared to MDMA, d2-MDMA produced full substitution for a 1.5 mg/kg MDMA training stimulus with equal potency and effectiveness in the drug discrimination experiment. In addition, d2-MDMA produced increases in body temperature that were shorter-lasting and of lower magnitude compared to equivalent doses of MDMA. Last, d2-MDMA and MDMA were equally effective in reversing the hypothermic effects of the selective 5-HT2A/2C antagonist ketanserin.


These findings indicate that deuterium substitution of hydrogen at the methylenedioxy ring moiety does not impact MDMA’s interoceptive effects, and compared to MDMA, d2-MDMA has less potential for producing hyperthermic effects and likely has similar pharmacodynamic properties. Given that d2-MDMA produces less adverse effects than MDMA, but retains similar desirable effects that are thought to relate to the effective treatment of PTSD, additional investigations into its effects on cardiovascular functioning and pharmacokinetic properties are warranted.

Berquist, M. D., Leth-Petersen, S., Kristensen, J. L., & Fantegrossi, W. E. (2020). In vivo effects of 3, 4-methylenedioxymethamphetamine (MDMA) and its deuterated form in rodents: drug discrimination and thermoregulation. Drug and Alcohol Dependence, 107850., 10.1016/j.drugalcdep.2020.107850
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From Egoism to Ecoism: Psychedelics Increase Nature Relatedness in a State-Mediated and Context-Dependent Manner.


(1) Background: There appears to be a growing disconnection between humans and their natural environments which has been linked to poor mental health and ecological destruction. Previous research suggests that individual levels of nature relatedness can be increased through the use of classical psychedelic compounds, although a causal link between psychedelic use and nature relatedness has not yet been established. (2) Methods: Using correlations and generalized linear mixed regression modelling, we investigated the association between psychedelic use and nature relatedness in a prospective online study. Individuals planning to use a psychedelic received questionnaires 1 week before (N = 654), plus one day, 2 weeks, 4 weeks, and 2 years after a psychedelic experience. (3) Results: The frequency of lifetime psychedelic use was positively correlated with nature relatedness at baseline. Nature relatedness was significantly increased 2 weeks, 4 weeks and 2 years after the psychedelic experience. This increase was positively correlated with concomitant increases in psychological well-being and was dependent on the extent of ego-dissolution and the perceived influence of natural surroundings during the acute psychedelic state. (4) Conclusions: The here presented evidence for a context- and state-dependent causal effect of psychedelic use on nature relatedness bears relevance for psychedelic treatment models in mental health and, in the face of the current ecological crisis, planetary health.
Kettner, H., Gandy, S., Haijen, E. C., & Carhart-Harris, R. L. (2019). From Egoism to Ecoism: Psychedelics Increase Nature Relatedness in a State-Mediated and Context-Dependent Manner. International Journal of Environmental Research and Public Health16(24), 5147.,
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Locomotor effects of 3,4-methylenedioxymethamphetamine (MDMA) and its deuterated form in mice: psychostimulant effects, stereotypy, and sensitization



There is a renewed interest in the use of 3,4-methylenedioxymethamphetamine (MDMA) for treating psychiatric conditions. Although MDMA has entered phase II clinical trials and shows promise as an adjunct treatment, there is an extensive literature detailing the potential neurotoxicity and adverse neurobehavioral effects associated with MDMA use. Previous research indicates that the adverse effects of MDMA may be due to its metabolism into reactive catechols that can enter the brain and serve directly as neurotoxicants. One approach to mitigate MDMA’s potential for adverse effects is to reduce O-demethylation by deuterating the methylenedioxy ring of MDMA. There are no studies that have evaluated the effects of deuterating MDMA on behavioral outcomes.


The purpose of the present study was to assess the motor-stimulant effects of deuterated MDMA (d2-MDMA) and compare them to MDMA in male mice.


Two experiments were performed to quantify mouse locomotor activity and to vary the drug administration regimen (single bolus administration or cumulative administration).


The results of Experiments 1 and 2 indicate that d2-MDMA is less effective at eliciting horizontal locomotion than MDMA; however, the differences between the compounds diminish as the number of cumulative administrations increase. Both d2-MDMA and MDMA can elicit sensitized responses, and these effects cross-sensitize to the prototypical drug of abuse methamphetamine. Thus, d2-MDMA functions as a locomotor stimulant similar to MDMA, but, depending on the dosing regimen, may be less susceptible to inducing sensitization to stereotyped movements.


These findings indicate that d2-MDMA is behaviorally active and produces locomotor effects that are similar to MDMA, which warrant additional assessments of d2-MDMA’s behavioral and physiological effects to determine the conditions under which this compound may serve as a relatively safer alternative to MDMA for clinical use.
Berquist, M. D., Leth-Petersen, S., Kristensen, J. L., & Fantegrossi, W. E. (2020). Locomotor effects of 3, 4-methylenedioxymethamphetamine (MDMA) and its deuterated form in mice: psychostimulant effects, stereotypy, and sensitization. Psychopharmacology237(2), 431-442;

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Effects of the synthetic psychedelic 2,5-dimethoxy-4-iodoamphetamine (DOI) on ethanol consumption and place conditioning in male mice.


Approximately 20 million adults in the USA have an alcohol use disorder (AUD). There are clinical and preclinical data suggesting that psychedelics may have benefits for AUD.
To investigate the effects of the synthetic psychedelic 2,5-dimethoxy-4-iodoamphetamine (DOI) on the behavioral effects of ethanol.
The effects of DOI were examined using ethanol-induced place conditioning (1.8 g/kg ethanol) and 2-bottle choice ethanol drinking (20% v/v), using a dose of DOI (3 mg/kg) that produced the maximal response in the serotonin 2A (5-HT2A) receptor-dependent head-twitch assay. Interactions between DOI and ethanol (3 g/kg) were examined using the ethanol-induced loss of righting reflex procedure and blood-ethanol analysis. To examine additional mechanisms by which psychedelics may interact with ethanol, we determined whether DOI reverses ethanol-induced nitric oxide release in macrophages, a marker of inflammation.
DOI significantly attenuated ethanol-induced place conditioning and ethanol drinking. DOI-induced suppression of alcohol drinking depended upon 5-HT2A receptors, was selective for alcohol over water, and was selective for high alcohol-preferring subjects. DOI had no apparent pharmacokinetic interactions with ethanol, and DOI reduced ethanol-induced nitric oxide release.
Our findings demonstrate that DOI blocks ethanol place conditioning and selectively reduces voluntary ethanol consumption. This may be related to modulation of the effects of ethanol in the reward circuitry of the brain, ethanol-induced neuroinflammation, or a combination of both. Additional studies to elucidate the mechanisms through which psychedelics attenuate the effects of ethanol would inform the pathophysiology of AUD and potentially provide new treatment options.
Oppong-Damoah, A., Curry, K. E., Blough, B. E., Rice, K. C., & Murnane, K. S. (2019). Effects of the synthetic psychedelic 2, 5-dimethoxy-4-iodoamphetamine (DOI) on ethanol consumption and place conditioning in male mice. Psychopharmacology, 1-12.,
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Return of the lysergamides. Part V: Analytical and behavioural characterization of 1-butanoyl-d-lysergic acid diethylamide (1B-LSD).


The psychedelic properties of lysergic acid diethylamide (LSD) have captured the imagination of researchers for many years and its rediscovery as an important research tool is evidenced by its clinical use within neuroscientific and therapeutic settings. At the same time, a number of novel LSD analogs have recently emerged as recreational drugs, which makes it necessary to study their analytical and pharmacological properties. One recent addition to this series of LSD analogs is 1-butanoyl-LSD (1B-LSD), a constitutional isomer of 1-propanoyl-6-ethyl-6-nor-lysergic acid diethylamide (1P-ETH-LAD), another LSD analog that was described previously. This study presents a comprehensive analytical characterization of 1B-LSD employing nuclear magnetic resonance spectroscopy (NMR), low- and high-resolution mass spectrometry platforms, gas- and liquid chromatography (GC and LC), and GC-condensed phase and attenuated total reflection infrared spectroscopy analyses. Analytical differentiation of 1B-LSD from 1P-ETH-LAD was straightforward. LSD and other serotonergic hallucinogens induce the head-twitch response (HTR) in rats and mice, which is believed to be mediated largely by 5-HT2A receptor activation. HTR studies were conducted in C57BL/6J mice to assess whether 1B-LSD has LSD-like behavioral effects. 1B-LSD produced a dose-dependent increase in HTR counts, acting with ~14% (ED50  = 976.7 nmol/kg) of the potency of LSD (ED50  = 132.8 nmol/kg). This finding suggests that the behavioral effects of 1B-LSD are reminiscent of LSD and other serotonergic hallucinogens. The possibility exists that 1B-LSD serves as a pro-drug for LSD. Further investigations are warranted to confirm whether 1B-LSD produces LSD-like psychoactive effects in humans.

Brandt, S. D., Kavanagh, P. V., Westphal, F., Stratford, A., Elliott, S. P., Dowling, G., … & Halberstadt, A. L. (2019). Return of the lysergamides. Part V: Analytical and behavioural characterization of 1‐butanoyl‐d‐lysergic acid diethylamide (1B‐LSD). Drug testing and analysis.,
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Self-Experiments with Psychoactive Substances: A Historical Perspective


The purpose of this chapter is to highlight the rich tradition of self-experiments (SEs) with psychoactive substances carried out by scientists and therapists for more than a century. Scientifically inspired controlled SEs dominated until the end of the twentieth century, when ethical requirements minimized controlled SEs and “wild” SEs expanded particularly with the emergence of new psychoactive substances. The review focuses on laughing gas (nitrous oxide), cannabis, cocaine, hallucinogens, entactogens, and dissociative hallucinogens. This is due to the fact that substances that induce “complex” effects such as alteration of space/time experience, ego dissolution, and increased feelings and insights (e.g., hallucinogens, entactogens) represent by far the majority of SEs, whereas SEs with substances inducing “simple” effects such as euphoria, anxiolysis, dissociation, or emotional blunting (e.g., cocaine, opioids) are much rarer or even absent (e.g., benzodiazepines). Complex drug effects are much harder to describe, thus allowing SEs to fulfill a more important function.

SEs with psychoactive drugs appeared to emerge in the mid-eighteenth century, which triggered a long-standing tradition throughout the nineteenth and early twentieth century. SEs have been de facto performed for a variety of reasons, ranging from establishing scientific knowledge and gaining philosophical insights to compensating for personal deficits. Self-experimenters can be divided into two general types. Besides their scientific intentions, “exploratory” self-experimenters intend to expand awareness and insight, whereas “compensatory” self-experimenters might aim for coping with psychiatric symptoms or personality deficits. Scientific limitations of SEs are obvious when compared to double-blind, randomized, placebo-controlled trials. Whereas the former might lead to more “realistic” detailed description of subjective effects, the latter lead to more solid results in respect to objectively measurable “average” effects. Possible adverse effects of SEs were identified that resulted in loss of scientific objectivity and decreased control over substance use and addiction, development of isolation, problematic group dynamics, and “social autism.”

Passie, T., & Brandt, S. D. (2018). Self-Experiments with Psychoactive Substances: A Historical Perspective., 10.1007/164_2018_177
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Kappa Opioid Receptor Agonist Mesyl Sal B Attenuates Behavioral Sensitization to Cocaine with Fewer Aversive Side-Effects than Salvinorin A in Rodents.


The acute activation of kappa opioid receptors (KOPr) produces antinociceptive and anti-cocaine effects, however, their side-effects have limited further clinical development. Mesyl Sal B is a potent and selective KOPr analogue of Salvinorin A (Sal A), a psychoactive natural product isolated from the plant Salvia divinorum. We assessed the antinociceptive, anti-cocaine, and side-effects of Mesyl Sal B. The anti-cocaine effects are evaluated in cocaine-induced hyperactivity and behavioral sensitization to cocaine in male Sprague Dawley rats. Mesyl Sal B was assessed for anhedonia (conditioned taste aversion), aversion (conditioned place aversion), pro-depressive effects (forced swim test), anxiety (elevated plus maze) and learning and memory deficits (novel object recognition). In male B6.SJL mice, the antinociceptive effects were evaluated in warm-water (50 °C) tail withdrawal and intraplantar formaldehyde (2%) assays and the sedative effects measured with the rotarod performance task. Mesyl Sal B (0.3 mg/kg) attenuated cocaine-induced hyperactivity and behavioral sensitization to cocaine without modulating sucrose self-administration and without producing aversion, sedation, anxiety, or learning and memory impairment in rats. However, increased immobility was observed in the forced swim test indicating pro-depressive effects. Mesyl Sal B was not as potent as Sal A at reducing pain in the antinociceptive assays. In conclusion, Mesyl Sal B possesses anti-cocaine effects, is longer acting in vivo and has fewer side-effects when compared to Sal A, however, the antinociceptive effects are limited.
Kivell, B., Paton, K., Kumar, N., Morani, A., Culverhouse, A., Shepherd, A., … & Prisinzano, T. (2018). Kappa Opioid Receptor Agonist Mesyl Sal B Attenuates Behavioral Sensitization to Cocaine with Fewer Aversive Side-Effects than Salvinorin A in Rodents. Molecules23(10), 2602., 10.3390/molecules23102602
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30 April - Q&A with Rick Strassman