Psychedelic and entactogenic drugs in the treatment of depression

Symptom specificity of ayahuasca's effect on depressive symptoms

Background

Ayahuasca's effects on symptoms of depression have generated considerable optimism. Clients frequently report more concern about some symptoms than others, and available treatments alter symptoms differentially. Few studies address the symptom specificity of this psychoactive brew.

Aims

We examined self-reported effects of ayahuasca on the individual symptoms of depression assessed by the 10-item short-form of Center for Epidemiological Studies of Depression (CESD-10).

Methods

We asked over 120 participants to complete a retrospective assessment of CESD-10 symptoms one month before and one month after using ayahuasca.

Results

Participants indicated that ayahuasca had a larger influence on affective symptoms like hope, depressed mood, and happiness, than cognitive, interpersonal, and somatic symptoms like restless sleep, loneliness, and difficulty focusing.

Conclusions

Potential clients might appreciate identifying if different treatments provide more relief for some depressive symptoms than others. We examined retrospective reports of ayahuasca's potential for differential impact. Those eager to alter hope, happiness, and other affective symptoms will likely find ayahuasca more helpful than those who want an intervention for restless sleep, loneliness, or trouble focusing. This symptom specificity parallels the effects of serotonergic antidepressant medications, suggesting that psychedelic-assisted psychotherapy using ayahuasca might have considerable appeal for those who seek comparable relief but would rather not use prescription serotonergic medications. Jumpstarting psychotherapy with the rapid onset of ayahuasca-induced relief also appears to have potential.

Novel Phenethylamines and Their Potential Interactions With Prescription Drugs: A Systematic Critical Review

BACKGROUND

The novel phenethylamines 4-fluoroamphetamine (4-FA) and 2,5-dimethoxy-4-bromophenethylamine (2C-B) fall in the top 10 most used new psychoactive substances (NPSs) among high-risk substance users. Various phenethylamines and NPS are also highly used in populations with mental disorders, depression, or attention deficit hyperactivity disorder (ADHD). Moreover, NPS use is highly prevalent among men and women with risky sexual behavior. Considering these specific populations and their frequent concurrent use of drugs, such as antidepressants, ADHD medication, and antiretrovirals, reports on potential interactions between these drugs, and phenethylamines 4-FA and 2C-B, were reviewed.

METHODS

The authors performed a systematic literature review on 4-FA and 2C-B interactions with antidepressants (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, duloxetine, bupropion, venlafaxine, phenelzine, moclobemide, and tranylcypromine), ADHD medications (atomoxetine, dexamphetamine, methylphenidate, and modafinil), and antiretrovirals.

RESULTS

Limited literature exists on the pharmacokinetics and drug-drug interactions of 2C-B and 4-FA. Only one case report indicated a possible interaction between 4-FA and ADHD medication. Although pharmacokinetic interactions between 4-FA and prescription drugs remain speculative, their pharmacodynamic points toward interactions between 4-FA and ADHD medication and antidepressants. The pharmacokinetic and pharmacodynamic profile of 2C-B also points toward such interactions, between 2C-B and prescription drugs such as antidepressants and ADHD medication.

CONCLUSIONS

A drug-drug (phenethylamine-prescription drug) interaction potential is anticipated, mainly involving monoamine oxidases for 2C-B and 4-FA, with monoamine transporters being more specific to 4-FA.

Hallucinogenic/psychedelic 5HT2A receptor agonists as rapid antidepressant therapeutics: Evidence and mechanisms of action

Major depressive disorder (MDD) is among the most prevalent mental health disorders worldwide, and it is associated with a reduced quality of life and enormous costs to health care systems. Available drug treatments show low-to-moderate response in most patients, with almost a third of patients being non-responders (treatment-resistant). Furthermore, most currently available medications need several weeks to achieve therapeutic effects, and the long-term use of these drugs is often associated with significant unwanted side effects and resultant reductions in treatment compliance. Therefore, more effective, safer, and faster-acting antidepressants with enduring effects are needed. Together with ketamine, psychedelics (or classic or serotoninergic hallucinogens) such as lysergic acid diethylamide (LSD), psilocybin, and ayahuasca are among the few compounds with recent human evidence of fast-acting antidepressant effects. Several studies in the 1950s to 1970s reported antidepressive and anxiolytic effects of these drugs, which are being confirmed by modern trials (LSD, one trial; psilocybin, five trials; ayahuasca, two trials). The effects of these drugs appear to be produced primarily by their agonism at serotonin (5-hydroxytryptamine, 5-HT) receptors, especially the 5-HT_2A receptor. Considering the overall burden of MDD and the necessity of new therapeutic options, the promising (but currently limited) evidence of safety and efficacy of psychedelics has encouraged the scientific community to explore more fully their beneficial effects in MDD.

Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms

Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT_2A and 5-HT_1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.

Combining Cognitive-Behavioral Conjoint Therapy for PTSD with 3,4-Methylenedioxymethamphetamine (MDMA): A Case Example

Treatments for posttraumatic stress disorder (PTSD) have evolved significantly in the past 35 years. From what was historically viewed as a pervasive, intractable condition have emerged multiple evidence-based intervention options. These treatments, predominantly cognitive behavioral in orientation, provide significant symptom improvement in 50-60% of recipients. The treatment of PTSD with MDMA-assisted psychotherapy using a supportive, non-directive approach has yielded promising results. It is unknown, however, how different therapeutic modalities could impact or improve outcomes. Therefore, to capitalize on the strengths of both approaches, Cognitive Behavioral Conjoint Therapy for PTSD (CBCT) was combined with MDMA in a small pilot trial. The current article provides a case study of one couple involved in the trial, chosen to provide a demographically representative example of the study participants and a case with a severe trauma history, to offer a detailed account of the methodology and choices made to integrate CBCT and MDMA, as well as an account of their experience through the treatment and their treatment gains. This article offers a description of the combination of CBCT for PTSD and MDMA, and demonstrates that it can produce reductions in PTSD symptoms and improvements in relationship satisfaction.

Aromatic Bromination Abolishes the Psychomotor Features and Pro-social Responses of MDMA ("Ecstasy") in Rats and Preserves Affinity for the Serotonin Transporter (SERT)

The entactogen MDMA (3,4-methylenedioxy-methamphetamine, “Ecstasy”) exerts its psychotropic effects acting primarily as a substrate of the serotonin transporter (SERT) to induce a non-exocytotic release of serotonin. Nevertheless, the roles of specific positions of the aromatic ring of MDMA associated with the modulation of typical entactogenic effects, using analogs derived from the MDMA template, are still not fully understood. Among many possibilities, aromatic halogenation of the phenylalkylamine moiety may favor distribution to the brain due to increased lipophilicity, and sometimes renders psychotropic substances of high affinity for their molecular targets and high potency in humans. In the present work, a new MDMA analog brominated at C(2) of the aromatic ring (2-Br-4,5-MDMA) has been synthesized and pharmacologically characterized in vitro and in vivo. First, binding competition experiments against the SERT-blocker citalopram were carried out in human platelets and compared with MDMA. Besides, its effects on platelet aggregation were performed in platelet enriched human plasma using collagen as aggregation inductor. Second, as platelets are considered an appropriate peripheral model for estimating central serotonin availability, the functional effects of 2-Br-4,5-MDMA and MDMA on ATP release during human platelet aggregation were evaluated. The results obtained showed that 2-Br-4,5-MDMA exhibits higher affinity for SERT than MDMA and fully abolishes both platelet aggregation and ATP release, resembling the pharmacological profile of citalopram. Subsequent in vivo evaluation in rats at three dose levels showed that 2-Br-4,5-MDMA lacks all key MDMA-like behavioral responses in rats, including hyperlocomotion, enhanced active avoidance conditioning responses and increased social interaction. Taken together, the results obtained are consistent with the notion that 2-Br-4,5-MDMA should not be expected to be an MDMA-like substrate of SERT, indicating that aromatic bromination at C(2) modulates the pharmacodynamic properties of the substrate MDMA, yielding a citalopram-like compound.

Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine

Better known as "ecstasy", 3,4-methylenedioxymethamphetamine (MDMA) is a small molecule that has played a prominent role in defining the ethos of today's teenagers and young adults, much like lysergic acid diethylamide (LSD) did in the 1960s. Though MDMA possesses structural similarities to compounds like amphetamine and mescaline, it produces subjective effects that are unlike any of the classical psychostimulants or hallucinogens and is one of the few compounds capable of reliably producing prosocial behavioral states. As a result, MDMA has captured the attention of recreational users, the media, artists, psychiatrists, and neuropharmacologists alike. Here, we detail the synthesis of MDMA as well as its pharmacology, metabolism, adverse effects, and potential use in medicine. Finally, we discuss its history and why it is perhaps the most important compound for the future of psychedelic science-having the potential to either facilitate new psychedelic research initiatives, or to usher in a second Dark Age for the field.

(±)-MDMA and its enantiomers: potential therapeutic advantages of R(-)-MDMA

The use of (±)-3,4-methylenedioxymethamphetamine ((±)-MDMA) as an adjunct to psychotherapy in the treatment of psychiatric and behavioral disorders dates back over 50 years. Only in recent years have controlled and peer-reviewed preclinical and clinical studies lent support to (±)-MDMA's hypothesized clinical utility. However, the clinical utility of (±)-MDMA is potentially mitigated by a range of demonstrated adverse effects. One potential solution could lie in the individual S(+) and R(-) enantiomers that comprise (±)-MDMA. Individual enantiomers of racemic compounds have been employed in psychiatry to improve a drug's therapeutic index. Although no research has explored the individual effects of either S(+)-MDMA or R(-)-MDMA in humans in a controlled manner, preclinical research has examined similarities and differences between the two molecules and the racemic compound. This review addresses information related to the pharmacodynamics, neurotoxicity, physiological effects, and behavioral effects of S(+)-MDMA and R(-)-MDMA that might guide preclinical and clinical research. The current preclinical evidence suggests that R(-)-MDMA may provide an improved therapeutic index, maintaining the therapeutic effects of (±)-MDMA with a reduced side effect profile, and that future investigations should investigate the therapeutic potential of R(-)-MDMA.

Developing Guidelines and Competencies for the Training of Psychedelic Therapists

Research since the 1950s has shown that psychedelic-assisted psychotherapy has had significant positive effects in reductions of specific clinical symptoms and increases in quality of life as measured on a variety of indices. The intensity of focus on evidence-based outcomes, however, has resulted in a paucity of active discussions and research on the core competencies of the therapists themselves. The context of the history of psychedelic research reveals how this neglect of therapist variables occurred. With current discussions of Phase 3 and expanded access research programs for psilocybin-assisted and MDMA-assisted psychotherapies, there will be a great need for competent therapists trained in this clinical specialty. This is particularly the case if less restricted, legal medical use is approved within the next 6 to 10 years. This article is the first review and compilation of psychedelic therapist competencies derived from the psychedelic literature. These six therapist competencies are empathetic abiding presence; trust enhancement; spiritual intelligence; knowledge of the physical and psychological effects of psychedelics; therapist self-awareness and ethical integrity; and proficiency in complementary techniques. A further contribution of this review is a delineation of the 12 fundamental curricular domains of study for the training and development of these therapist competencies. As current legal restrictions evolve, aspects of these training guidelines will develop accordingly.

On the Science of Consciousness: Epistemological Reflections and Clinical Implications

Consciousness has been one of the most important and tantalizing issues ever since the origin of philosophy and medicine. The concept of consciousness and the so-called "hard problem" (i.e., the mind-brain relationship) are highly complex topics that have yet to be elucidated, involving the realms of both science and philosophy with profound epistemological implications. In the lively debate on the foundations of the science of consciousness there are several potential biases of an essentially philosophical nature, such as those related to the paradigm and axioms adopted, and the ostensible logical contradiction between monism and dualism. Their origin dates back largely to Descartes' thinking and the birth of the new sciences as a compromise with the Inquisition, but they have been handed down through the Enlightenment and Positivism. A proper investigation of consciousness and the world of subjectivity demands a careful reflection on the paradigm of scientific medicine to identify possible flaws and overcome the limits of the mechanistic-reductionist approach.

Antidepressive and anxiolytic effects of ayahuasca: a systematic literature review of animal and human studies

OBJECTIVE

To conduct a systematic literature review of animal and human studies reporting anxiolytic or antidepressive effects of ayahuasca or some of its isolated alkaloids (dimethyltryptamine, harmine, tetrahydroharmine, and harmaline).

METHODS

Papers published until 3 April 2015 were retrieved from the PubMed, LILACS and SciELO databases following a comprehensive search strategy and using a predetermined set of criteria for article selection.

RESULTS

Five hundred and fourteen studies were identified, of which 21 met the established criteria. Studies in animals have shown anxiolytic and antidepressive effects of ayahuasca, harmine, and harmaline, and experimental studies in humans and mental health assessments of experienced ayahuasca consumers also suggest that ayahuasca is associated with reductions in anxiety and depressive symptoms. A pilot study reported rapid antidepressive effects of a single ayahuasca dose in six patients with recurrent depression.

CONCLUSION

Considering the need for new drugs that produce fewer adverse effects and are more effective in reducing anxiety and depression symptomatology, the described effects of ayahuasca and its alkaloids should be further investigated.

The serotonin 5-HT2C receptor and the non-addictive nature of classic hallucinogens

Classic hallucinogens share pharmacology as serotonin 5-HT_2A, 5-HT_2B, and 5-HT_2C receptor agonists. Unique among most other Schedule 1 drugs, they are generally non-addictive and can be effective tools in the treatment of addiction. Mechanisms underlying these attributes are largely unknown. However, many preclinical studies show that 5-HT_2C agonists counteract the addictive effects of drugs from several classes, suggesting this pharmacological property of classic hallucinogens may be significant. Drawing from a comprehensive analysis of preclinical behavior, neuroanatomy, and neurochemistry studies, this review builds rationale for this hypothesis, and also proposes a testable, neurobiological framework. 5-HT_2C agonists work, in part, by modulating dopamine neuron activity in the ventral tegmental area-nucleus accumbens (NAc) reward pathway. We argue that activation of 5-HT_2C receptors on NAc shell, GABAergic, medium spiny neurons inhibits potassium Kv1.x channels, thereby enhancing inhibitory activity via intrinsic mechanisms. Together with experiments that show that addictive drugs, such as cocaine, potentiate Kv1.x channels, thereby suppressing NAc shell GABAergic activity, this hypothesis provides a mechanism by which classic hallucinogen-mediated stimulation of 5-HT_2C receptors could thwart addiction. It also provides a potential reason for the non-addictive nature of classic hallucinogens.

Psychointegrators: Multidisciplinary Perspectives on the Therapeutic Effects of Hallucinogens

Vision-inducing plants ("hallucinogens") are important in many societies, evoking powerful emotional, psychological, cognitive, religious, spiritual, therapeutic and political reactions. These substances' psychophysiological properties shape cross- cultural similarities in patterns of use and experiences, while political factors shape their cultural desirability. Neurological studies illustrate that common effects are based in intervention in serotonergic neurotransmission. Effects upon neural, sensory, emotional, and cognitive processes stimulate integrative information processing, justifying a new term-"psychointegrators." Psychointegrators disin hibit sensory and emotional processes. They stimulate systemic integration of brain information-processing functions, enhancing integration of limbic system self and emotional dynamics with neocortical processes. Their therapeutic applications are reviewed from perspectives of cross-cultural and clinical studies.

Antidepressive, anxiolytic, and antiaddictive effects of ayahuasca, psilocybin and lysergic acid diethylamide (LSD): a systematic review of clinical trials published in the last 25 years

To date, pharmacological treatments for mood and anxiety disorders and for drug dependence show limited efficacy, leaving a large number of patients suffering severe and persistent symptoms. Preliminary studies in animals and humans suggest that ayahuasca, psilocybin and lysergic acid diethylamide (LSD) may have antidepressive, anxiolytic, and antiaddictive properties. Thus, we conducted a systematic review of clinical trials published from 1990 until 2015, assessing these therapeutic properties. Electronic searches were performed using the PubMed, LILACS, and SciELO databases. Only clinical trials published in peer-reviewed journals were included. Of these, 151 studies were identified, of which six met the established criteria. Reviewed studies suggest beneficial effects for treatment-resistant depression, anxiety and depression associated with life-threatening diseases, and tobacco and alcohol dependence. All drugs were well tolerated. In conclusion, ayahuasca, psilocybin and LSD may be useful pharmacological tools for the treatment of drug dependence, and anxiety and mood disorders, especially in treatment-resistant patients. These drugs may also be useful pharmacological tools to understand psychiatric disorders and to develop new therapeutic agents. However, all studies reviewed had small sample sizes, and half of them were open-label, proof-of-concept studies. Randomized, double-blind, placebo-controlled studies with more patients are needed to replicate these preliminary findings.

MDMA-assisted therapy: A new treatment model for social anxiety in autistic adults

The first study of 3,4-methylenedioxymethamphetamine (MDMA)-assisted therapy for the treatment of social anxiety in autistic adults commenced in the spring of 2014. The search for psychotherapeutic options for autistic individuals is imperative considering the lack of effective conventional treatments for mental health diagnoses that are common in this population. Serious Adverse Events (SAEs) involving the administration of MDMA in clinical trials have been rare and non-life threatening. To date, MDMA has been administered to over 1133 individuals for research purposes without the occurrence of unexpected drug-related SAEs that require expedited reporting per FDA regulations. Now that safety parameters for limited use of MDMA in clinical settings have been established, a case can be made to further develop MDMA-assisted therapeutic interventions that could support autistic adults in increasing social adaptability among the typically developing population. As in the case with classic hallucinogens and other psychedelic drugs, MDMA catalyzes shifts toward openness and introspection that do not require ongoing administration to achieve lasting benefits. This infrequent dosing mitigates adverse event frequency and improves the risk/benefit ratio of MDMA, which may provide a significant advantage over medications that require daily dosing. Consequently, clinicians could employ new treatment models for social anxiety or similar types of distress administering MDMA on one to several occasions within the context of a supportive and integrative psychotherapy protocol.

Psilocybin-Induced Decrease in Amygdala Reactivity Correlates with Enhanced Positive Mood in Healthy Volunteers

BACKGROUND

The amygdala is a key structure in serotonergic emotion-processing circuits. In healthy volunteers, acute administration of the serotonin 1A/2A/2C receptor agonist psilocybin reduces neural responses to negative stimuli and induces mood changes toward positive states. However, it is little-known whether psilocybin reduces amygdala reactivity to negative stimuli and whether any change in amygdala reactivity is related to mood change.

METHODS

This study assessed the effects of acute administration of the hallucinogen psilocybin (.16 mg/kg) versus placebo on amygdala reactivity to negative stimuli in 25 healthy volunteers using blood oxygen level-dependent functional magnetic resonance imaging. Mood changes were assessed using the Positive and Negative Affect Schedule and the state portion of the State-Trait Anxiety Inventory. A double-blind, randomized, cross-over design was used with volunteers counterbalanced to receive psilocybin and placebo in two separate sessions at least 14 days apart.

RESULTS

Amygdala reactivity to negative and neutral stimuli was lower after psilocybin administration than after placebo administration. The psilocybin-induced attenuation of right amygdala reactivity in response to negative stimuli was related to the psilocybin-induced increase in positive mood state.

CONCLUSIONS

These results demonstrate that acute treatment with psilocybin decreased amygdala reactivity during emotion processing and that this was associated with an increase of positive mood in healthy volunteers. These findings may be relevant to the normalization of amygdala hyperactivity and negative mood states in patients with major depression.

3,4-methylenedioxymethamphetamine (MDMA): current perspectives

Ecstasy is a widely used recreational drug that usually consists primarily of 3,4-methylenedioxymethamphetamine (MDMA). Most ecstasy users consume other substances as well, which complicates the interpretation of research in this field. The positively rated effects of MDMA consumption include euphoria, arousal, enhanced mood, increased sociability, and heightened perceptions; some common adverse reactions are nausea, headache, tachycardia, bruxism, and trismus. Lowering of mood is an aftereffect that is sometimes reported from 2 to 5 days after a session of ecstasy use. The acute effects of MDMA in ecstasy users have been attributed primarily to increased release and inhibited reuptake of serotonin (5-HT) and norepinephrine, along with possible release of the neuropeptide oxytocin. Repeated or high-dose MDMA/ecstasy use has been associated with tolerance, depressive symptomatology, and persisting cognitive deficits, particularly in memory tests. Animal studies have demonstrated that high doses of MDMA can lead to long-term decreases in forebrain 5-HT concentrations, tryptophan hydroxylase activity, serotonin transporter (SERT) expression, and visualization of axons immunoreactive for 5-HT or SERT. These neurotoxic effects may reflect either a drug-induced degeneration of serotonergic fibers or a long-lasting downregulation in 5-HT and SERT biosynthesis. Possible neurotoxicity in heavy ecstasy users has been revealed by neuroimaging studies showing reduced SERT binding and increased 5-HT_2A receptor binding in several cortical and/or subcortical areas. MDMA overdose or use with certain other drugs can also cause severe morbidity and even death. Repeated use of MDMA may lead to dose escalation and the development of dependence, although such dependence is usually not as profound as is seen with many other drugs of abuse. MDMA/ecstasy-dependent patients are treated with standard addiction programs, since there are no specific programs for this substance and no proven medications. Finally, even though MDMA is listed as a Schedule I compound by the Drug Enforcement Agency, MDMA-assisted psychotherapy for patients with chronic, treatment-resistant posttraumatic stress disorder is currently under investigation. Initial results show efficacy for this treatment approach, although considerably more research must be performed to confirm such efficacy and to ensure that the benefits of MDMA-assisted therapy outweigh the risks to the patients.

MDMA-assisted psychotherapy using low doses in a small sample of women with chronic posttraumatic stress disorder

The purpose of this study was to investigate the safety of different doses of MDMA-assisted psychotherapy administered in a psychotherapeutic setting to women with chronic PTSD secondary to a sexual assault, and also to obtain preliminary data regarding efficacy. Although this study was originally planned to include 29 subjects, political pressures led to the closing of the study before it could be finished, at which time only six subjects had been treated. Preliminary results from those six subjects are presented here. We found that low doses of MDMA (between 50 and 75 mg) were both psychologically and physiologically safe for all the subjects. Future studies in larger samples and using larger doses are needed in order to further clarify the safety and efficacy of MDMA in the clinical setting in subjects with PTSD.

Lack of persistent effects of ketamine in rodent models of depression

RATIONALE

We investigated the immediate and enduring effects of ketamine in behavioral and neurochemical assays predictive of antidepressant activity.

MATERIALS AND METHODS

One week after a single administration of ketamine (50-160 mg/kg), otherwise experimentally naive rats and mice were tested either in the forced swim test (FST) or the tail suspension test (TST). Other mice were also tested twice in the FST: immediately and 2 weeks after a single dose (1.25-50 mg/kg) of ketamine. In the next series of experiments, rats treated for 2 weeks twice daily with ketamine (50 or 160 mg/kg) or desipramine (10 mg/kg) were challenged with apomorphine and scored for locomotor activity and assayed for the density of cortical beta-adrenoceptors. The latter test was also carried out in rats that had received a single dose of ketamine (50 mg/kg) 1 week before the assay. The antidepressant-like (FST) and locomotor effects of ketamine (50 mg/kg) and desipramine (10 mg/kg) were assessed after their chronic (2 weeks, twice daily) administration as well.

RESULTS

We report the lack of enduring antidepressant-like effect of ketamine in both rats and mice. A 2-week treatment with ketamine neither changed apomorphine-evoked locomotor hyperactivity nor did it decrease the density of cortical beta-adrenoceptors. However, some tolerance to the antidepressant-like effect of ketamine was noted in the FST, but it was accompanied by sensitization to its locomotor stimulatory effects.

CONCLUSIONS

These data indicate that ketamine neither produces enduring antidepressant-like effects in rodents nor does it display antidepressant-like behavioral or neurochemical effects after chronic treatment.

The psychotherapeutic potential of MDMA (3,4-methylenedioxymethamphetamine): an evidence-based review

AIMS AND RATIONALE: The purpose of this study was to review whether methylenedioxymethamphetamine (MDMA) has the appropriate pharmacodynamic profile to be a therapeutic agent.

MATERIALS AND METHODS

Empirical descriptions of MDMA's subjective effects in humans will be reviewed to evaluate the proposal that MDMA has psychotherapeutic properties. The focus will be published evidence on its functional effects in therapeutic, medical, and other situations.

RESULTS

MDMA is a powerful central nervous system (CNS) stimulant which affects several neurotransmitter systems and intensifies a range of psychobiological functions. Its acute mood effects can be very positive and life enhancing, and the affirmative cognitions engendered during MDMA therapy may well endure afterwards. However, MDMA also has a number of potential anti-therapeutic characteristics. Acutely, it can also intensify negative cognitions, and these may similarly endure over time. Psychotherapists have found that setting, intention, and expectancy are crucial for a positive outcome, but these factors cannot be guaranteed. Post-MDMA, there is a period of neurotransmitter recovery when low moods predominate, and these may exacerbate psychiatric distress. The explanations proposed for MDMA-assisted therapy are all psychodynamic, and a neurochemical model needs to be outlined. It has been suggested that enduring therapeutic gains can follow a single session, but again, this lacks a clear psychopharmacological rationale. Finally, diathesis-stress models suggest that psychiatric individuals are more prone to acute and chronic abreactions to CNS stimulants such as MDMA.

CONCLUSIONS

There are a number of issues which need to be addressed before it can be argued that MDMA might be clinically useful for psychotherapy.

An extended nondrug MDMA-like experience evoked through posthypnotic suggestion

This research explored whether hypnotic suggestion could produce a subjective mindbody condition similar to that produced by the psychoactive drug methylenedioxy methamphetamine (MDMA, Ecstasy). Twelve participants received posthypnotic instructions to re-experience an MDMA-like state posthypnotically, similar to one in their prior experience, for one hour. Three separate self report measures and qualitative self reports showed that the posthypnotic condition effectively mimicked an MDMA-like experience, lasting an hour at a stable level. Participant ratings in real time and in retrospect ranged from 36% to 100% similarity to a drug-induced experience. The qualitative reports and rating scales enabled a phenomenological description of the subjective experience. Scores on the Tellegen Absorption Scale correlated significantly with the strength of the posthypnotic condition (Spearman rho .87, p = .0003). The participants successfully carried out various intentional activities during this time (e.g., self reflection, talking with partners about relationships, artwork, walking in nature). Applications for this technique as an adjunct to therapy and health treatments are discussed.

An exploration of the history and controversies surrounding MDMA and MDA

In existence for nearly a century, 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") have gained quite a reputation. Perceived by some as dangerous neurotoxins, and by others as potential psychotherapeutics, these compounds have become a center of controversy among academics and law enforcement officials, and in the process have gained extensive media exposure. The classification of these drugs as illicit, controlled substances in the United States has not prevented their use, and MDMA, or Ecstasy, is currently one of the most popular substances used recreationally in North America. The scheduling of MDMA and MDA has, however, led to the distribution of contaminated, or falsely represented, Ecstasy tablets, and prevented responsible research into the detrimental and therapeutic effects of these drugs. A look at the history of these compounds suggests that they have the potential to be used safely as psychotherapeutic tools, and that the legal status of MDMA and MDA may be worth reconsidering.

Hallucinogens, serotonin and obsessive-compulsive disorder

The serotonin (5-HT) neurotransmitter system has been implicated in the pathophysiology of several neuropsychiatric disorders, especially obsessive-compulsive disorder (OCD). Blockade of 5-HT reuptake appears to be an important initial neurobiological event in the therapeutic mechanism of action of antiobsessional drugs. However, for reasons that continue to be poorly understood, clinical improvement following initiation of treatment with 5-HT reuptake inhibitors can take up to eight to 12 weeks, and most patients do not fully improve. Recent data suggest that activation of 5-HT2A and/or 5-HT2C receptors may be important for the improvement of OCD symptoms. Most psychedelic drugs are potent agonists at 5-HT2A and 5-HT2C receptors and their binding potency to these receptors is strongly correlated with their human potency as hallucinogens. This article will briefly review the relevant clinical and preclinical studies relating to the effects of hallucinogens on OCD. These data suggest that activation of 5-HT2 receptors by hallucinogens may lead to acute reduction of, as well as possible longer-lasting beneficial effects on, the symptoms of OCD. Evidence for and against involvement of 5-HT2A and/or 5-HT2C receptors in the therapeutic effects of drug therapies for OCD are reviewed. Issues related to the pharmacological properties and safety of psychedelic drugs, when considered as potential treatments for patients with OCD, are summarized. The authors suggest that controlled trials of potent 5-HT2 agonists in people suffering from OCD are warranted.