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Ketamine as the prototype glutamatergic antidepressant: pharmacodynamic actions, and a systematic review and meta-analysis of efficacy

October 22, 2013 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , ,

Abstract

The burden of depressive disorders and the frequent inadequacy of their current pharmacological treatments are well established. The anaesthetic and hallucinogenic drug ketamine has provoked much interest over the past decade or so as an extremely rapidly acting antidepressant that does not modify ‘classical’ monoaminergic receptors. Current evidence has shown several ways through which it might exert therapeutic antidepressant actions: blockade of glutamatergic NMDA receptors and relative upregulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) subtypes may alter cortical connectivity patterns; through intracellular changes in protein expression, including the proteins mammalian target of rapamycin (mTOR) and brain-derived neurotrophic factor (BDNF); and alteration of intracellular signalling cascades. The clinical evidence demonstrates rapid improvements in mood and suicidal thinking in most participants, although study numbers have generally been small and many trials are unblinded and methodologically weak. There is a small body of work to suggest ketamine might also augment electroconvulsive therapy and potentially have a role as a surgical anaesthetic in depressed patients. A major problem is that the effects of ketamine appear temporary, disappearing after days to weeks (although longer benefits have been sustained in some), and attempts to circumvent this through pharmacological augmentation have been disappointing thus far. These exciting data are providing new insights into neurobiological models of depression, and potentially opening up a new class of antidepressants, but there are significant practical and ethical issues about any future mainstream clinical role it might have.

Caddy, C., Giaroli, G., White, T. P., Sukhwinder, S. S. & Tracy, D. K. (2014). Ketamine as the prototype glutamatergic antidepressant: pharmacodynamic actions, and a systematic review and meta-analysis of efficacy. Therapeutic Advances in Psychopharmacology, 4(2), 75-79. http://dx.doi.org/10.1177/2045125313507739
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Serotonergic hyperactivity as a potential factor in developmental, acquired and drug-induced synesthesia

October 21, 2013 / LSD, Mescaline / Cacti, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / By /

Abstract

Though synesthesia research has seen a huge growth in recent decades, and tremendous progress has been made in terms of understanding the mechanism and cause of synesthesia, we are still left mostly in the dark when it comes to the mechanistic commonalities (if any) among developmental, acquired and drug-induced synesthesia. We know that many forms of synesthesia involve aberrant structural or functional brain connectivity. Proposed mechanisms include direct projection and disinhibited feedback mechanisms, in which information from two otherwise structurally or functionally separate brain regions mix. We also know that synesthesia sometimes runs in families. However, it is unclear what causes its onset. Studies of psychedelic drugs, such as psilocybin, LSD and mescaline, reveal that exposure to these drugs can induce synesthesia. One neurotransmitter suspected to be central to the perceptual changes is serotonin. Excessive serotonin in the brain may cause many of the characteristics of psychedelic intoxication. Excessive serotonin levels may also play a role in synesthesia acquired after brain injury. In brain injury sudden cell death floods local brain regions with serotonin and glutamate. This neurotransmitter flooding could perhaps result in unusual feature binding. Finally, developmental synesthesia that occurs in individuals with autism may be a result of alterations in the serotonergic system, leading to a blockage of regular gating mechanisms. I conclude on these grounds that one commonality among at least some cases of acquired, developmental and drug-induced synesthesia may be the presence of excessive levels of serotonin, which increases the excitability and connectedness of sensory brain regions.

Brogaard, B. (2013). Serotonergic hyperactivity as a potential factor in developmental, acquired and drug-induced synesthesia. Frontiers in Human Neuroscience, 7, 1-13. http://dx.doi.org/10.3389/fnhum.2013.00657
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Ayahuasca and cancer treatment

October 21, 2013 / Anthropology & Sociology, Ayahuasca, Biology & Ethnobotany, Papers, Psychiatry & Medicine, Publications / By /

Abstract

Objectives
Comprehensively review the evidence regarding the use of ayahuasca, an Amerindian medicine traditionally used to treat many different illnesses and diseases, to treat some types of cancer.

Methods
An in-depth review of the literature was conducted using PubMed, books, institutional magazines, conferences and online texts in nonprofessional sources regarding the biomedical knowledge about ayahuasca in general with a specific focus in its possible relations to the treatment of cancer.

Results
At least nine case reports regarding the use of ayahuasca in the treatment of prostate, brain, ovarian, uterine, stomach, breast, and colon cancers were found. Several of these were considered improvements, one case was considered worse, and one case was rated as difficult to evaluate. A theoretical model is presented which explains these effects at the cellular, molecular, and psychosocial levels. Particular attention is given to ayahuasca’s pharmacological effects through the activity of N,N-dimethyltryptamine at intracellular sigma-1 receptors. The effects of other components of ayahuasca, such as harmine, tetrahydroharmine, and harmaline, are also considered.

Conclusion
The proposed model, based on the molecular and cellular biology of ayahuasca’s known active components and the available clinical reports, suggests that these accounts may have consistent biological underpinnings. Further study of ayahuasca’s possible antitumor effects is important because cancer patients continue to seek out this traditional medicine. Consequently, based on the social and anthropological observations of the use of this brew, suggestions are provided for further research into the safety and efficacy of ayahuasca as a possible medicinal aid in the treatment of cancer.

Schenberg, E. E. (2013). Ayahuasca and cancer treatment. SAGE Open Medicine, 1, 1-12. http://dx.doi.org/10.1177/2050312113508389
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The induction of synaesthesia with chemical agents: a systematic review

October 17, 2013 / Ayahuasca, DMT, Iboga / Ibogaine, Ketamine, LSD, MDMA, Mescaline / Cacti, Mushrooms / Psilocybin, Papers, Psychology, Publications, Salvia / Salvinorin A / By / ,

Abstract

Despite the general consensus that synaesthesia emerges at an early developmental stage and is only rarely acquired during adulthood, the transient induction of synaesthesia with chemical agents has been frequently reported in research on different psychoactive substances. Nevertheless, these effects remain poorly understood and have not been systematically incorporated. Here we review the known published studies in which chemical agents were observed to elicit synaesthesia. Across studies there is consistent evidence that serotonin agonists elicit transient experiences of synaesthesia. Despite convergent results across studies, studies investigating the induction of synaesthesia with chemical agents have numerous methodological limitations and little experimental research has been conducted. Cumulatively, these studies implicate the serotonergic system in synaesthesia and have implications for the neurochemical mechanisms underlying this phenomenon but methodological limitations in this research area preclude making firm conclusions regarding whether chemical agents can induce genuine synaesthesia.

Luke, D. P., & Terhune, D. B. (2013). The induction of synaesthesia with chemical agents: a systematic review. Frontiers in Psychology, 4, 1-11. http://dx.doi.org/10.3389/fpsyg.2013.00753
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Pharmacological enhancement of exposure-based treatment in PTSD: a qualitative review

October 17, 2013 / Anxiety Disorders / PTSD, MDMA, Papers, Psychology, Publications / By / , ,

Abstract

There is a good amount of evidence that exposure therapy is an effective treatment for posttraumatic stress disorder (PTSD). Notwithstanding its efficacy, there is room for improvement, since a large proportion of patients does not benefit from treatment. Recently, an interesting new direction in the improvement of exposure therapy efficacy for PTSD emerged. Basic research found evidence of the pharmacological enhancement of the underlying learning and memory processes of exposure therapy. The current review aims to give an overview of clinical studies on pharmacological enhancement of exposure-based treatment for PTSD. The working mechanisms, efficacy studies in PTSD patients, and clinical utility of four different pharmacological enhancers will be discussed: d-cycloserine, MDMA, hydrocortisone, and propranolol.

de Kleine, R. A., Rothbaum, B. O., & van Minnen, A. (2013). Pharmacological enhancement of exposure-based treatment in PTSD: a qualitative review. European Journal of Psychotraumatoly, 17(4), 1-15. http://dx.doi.org/10.3402/ejpt.v4i0.21626
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Effect of Iboga Alkaloids on µ-Opioid Receptor-Coupled G Protein Activation

October 16, 2013 / Iboga / Ibogaine, Papers, Publications / By / , , , , , ,

Abstract

Objective

The iboga alkaloids are a class of small molecules defined structurally on the basis of a common ibogamine skeleton, some of which modify opioid withdrawal and drug self-administration in humans and preclinical models. These compounds may represent an innovative approach to neurobiological investigation and development of addiction pharmacotherapy. In particular, the use of the prototypic iboga alkaloid ibogaine for opioid detoxification in humans raises the question of whether its effect is mediated by an opioid agonist action, or if it represents alternative and possibly novel mechanism of action. The aim of this study was to independently replicate and extend evidence regarding the activation of μ-opioid receptor (MOR)-related G proteins by iboga alkaloids.

Methods

Ibogaine, its major metabolite noribogaine, and 18-methoxycoronaridine (18-MC), a synthetic congener, were evaluated by agonist-stimulated guanosine-5´-O-(γ-thio)-triphosphate ([fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][35S]GTPγS) binding in cells overexpressing the recombinant MOR, in rat thalamic membranes, and autoradiography in rat brain slices.

Results And Significance

In rat thalamic membranes ibogaine, noribogaine and 18-MC were MOR antagonists with functional Ke values ranging from 3 uM (ibogaine) to 13 uM (noribogaine and 18MC). Noribogaine and 18-MC did not stimulate [35S]GTPγS binding in Chinese hamster ovary cells expressing human or rat MORs, and had only limited partial agonist effects in human embryonic kidney cells expressing mouse MORs. Ibogaine did not did not stimulate [35S]GTPγS binding in any MOR expressing cells. Noribogaine did not stimulate [35S]GTPγS binding in brain slices using autoradiography. An MOR agonist action does not appear to account for the effect of these iboga alkaloids on opioid withdrawal. Taken together with existing evidence that their mechanism of action also differs from that of other non-opioids with clinical effects on opioid tolerance and withdrawal, these findings suggest a novel mechanism of action, and further justify the search for alternative targets of iboga alkaloids.

Antonio, T., Childers, S. R., Rothman, R. B., Dersch, C. M., King, C., Kuehne, M., … & Alper, K. (2013). Effect of Iboga Alkaloids on µ-Opioid Receptor-Coupled G Protein Activation. PloS one, 8(10), https://dx.doi.org/10.1371/journal.pone.0077262
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Survey: New Drugs for Mental Health

December 6, 2021 / Publications / By

After the recent published study on psychedelic substances and mental health, researchers are looking to explore this relation more deeply. The main aim of the survey is to gain novel insight towards un-noted benefits (and harms) of recreationally used drugs on mental health.

This survey was created by Imperial college, Prof D. Nutt, Dr R. Carhart-Harris and their team. According to the researchers, little is yet known about the effects on mental health of people who experiment with psychedelic substances. They are asking questions to gather information about potential usefulness for mental health of these new drugs and also to discover whether they have any unrecognised negative effects. Please click this link to participate in this recently launched online survey regarding psychoactive drugs and mental health.

Participants can fill in a different survey for each drug they want to say something about. Please only complete a survey if you have personal experience with a particular drug.

Responses will be treated as clinical information and are protected by medical confidentiality law. Your personal details will not be requested or stored.

MDMA enhances emotional empathy and prosocial behavior

October 4, 2013 / Anxiety Disorders / PTSD, MDMA, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

3,4-Methylenedioxymethamphetamine (MDMA, ‘ecstasy’) releases serotonin and norepinephrine. MDMA is reported to produce empathogenic and prosocial feelings. It is unknown whether MDMA in fact alters empathic concern and prosocial behavior. We investigated the acute effects of MDMA using the Multifaceted Empathy Test (MET), dynamic Face Emotion Recognition Task (FERT) and Social Value Orientation (SVO) test. We also assessed effects of MDMA on plasma levels of hormones involved in social behavior using a placebo-controlled, double-blind, random-order, cross-over design in 32 healthy volunteers (16 women). MDMA enhanced explicit and implicit emotional empathy in the MET and increased prosocial behavior in the SVO test in men. MDMA did not alter cognitive empathy in the MET but impaired the identification of negative emotions, including fearful, angry and sad faces, in the FERT, particularly in women. MDMA increased plasma levels of cortisol and prolactin, which are markers of serotonergic and noradrenergic activity, and of oxytocin, which has been associated with prosocial behavior. In summary, MDMA sex-specifically altered the recognition of emotions, emotional empathy and prosociality. These effects likely enhance sociability when MDMA is used recreationally and may be useful when MDMA is administered in conjunction with psychotherapy in patients with social dysfunction or post-traumatic stress disorder.

Hysek, C. M., Schmid, Y., Simmler, L. D., Domes, G., Heinrichs, M., Eisenegger, C., … Liechti, M. E. (2013). MDMA enhances emotional empathy and prosocial behavior. Social Cognitive & Affective Neuroscience, 9(11), 1645-1652. http://dx.doi.org/10.1093/scan/nst161
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Effective interventions in the problematic use of alcohol and other drugs

October 1, 2013 / LSD, Papers, Psychology, Publications, Substance Use Disorder / By / , , , ,

Abstract

OBJECTIVE:
Synthesize and assess the available scientific evidence from the period 2008-2012 on interventions of demonstrated efficacy in the treatment and rehabilitation of adolescents and adults engaged in the problematic use of alcohol and other substances.

METHODS:
A systematic review was undertaken with search and analysis of national and international literature on the subject in Spanish and English in the main international databases: PubMed/MEDLINE, LILACS, Embase, PsycINFO, SciELO, the databases of the York University Centre for Reviews and Dissemination (DARE, ETS Database), the Cochrane Library, and other sources of gray literature. The search criteria included randomized clinical trials and systematic reviews but excluded observational studies, qualitative studies, and articles of poor methodological quality.

RESULTS:
The final sample consisted of 69 studies. The psychosocial interventions shown to be effective were cognitive behavioral therapy, family interventions, self-help interventions using the Internet, couples behavioral therapy, community strengthening and family training, telephone monitoring and support, and integrated therapy for substance abuse disorder with anxiety and depression comorbidity. Pharmacological interventions of demonstrated effectiveness were acamprosate, lysergic acid diethylamide (LSD), and benzodiazepines in problematic alcohol use, as well as maintenance therapy with high-dose opioids.

CONCLUSIONS:
The demonstrated effectiveness of psychosocial and pharmacological interventions is slight but significant. However, strongly multidisciplinary interventions that use a cognitive behavioral approach and the involvement of people close to the consumer, as well as some of the specific pharmacological interventions, have been shown to yield the best results in terms of indicators of abstinence and prevention of relapses.

Lefio L. Á., Villarroel S.R., Rebolledo C., Zamorano P., & Rivas K. (2013). Effective interventions in the problematic use of alcohol and other drugs. Revista Panamericana de Salud Pública, 34(4), 257-266.
Link to full text (only available in Spanish)

Antidepressant efficacy of ketamine in treatment-resistant major depression: a two-site randomized controlled trial

October 1, 2013 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , , , ,

Abstract

OBJECTIVE:
Synthesize and assess the available scientific evidence from the period 2008-2012 on interventions of demonstrated efficacy in the treatment and rehabilitation of adolescents and adults engaged in the problematic use of alcohol and other substances.

METHODS:
A systematic review was undertaken with search and analysis of national and international literature on the subject in Spanish and English in the main international databases: PubMed/MEDLINE, LILACS, Embase, PsycINFO, SciELO, the databases of the York University Centre for Reviews and Dissemination (DARE, ETS Database), the Cochrane Library, and other sources of gray literature. The search criteria included randomized clinical trials and systematic reviews but excluded observational studies, qualitative studies, and articles of poor methodological quality.

RESULTS:
The final sample consisted of 69 studies. The psychosocial interventions shown to be effective were cognitive behavioral therapy, family interventions, self-help interventions using the Internet, couples behavioral therapy, community strengthening and family training, telephone monitoring and support, and integrated therapy for substance abuse disorder with anxiety and depression comorbidity. Pharmacological interventions of demonstrated effectiveness were acamprosate, lysergic acid diethylamide (LSD), and benzodiazepines in problematic alcohol use, as well as maintenance therapy with high-dose opioids.

CONCLUSIONS:
The demonstrated effectiveness of psychosocial and pharmacological interventions is slight but significant. However, strongly multidisciplinary interventions that use a cognitive behavioral approach and the involvement of people close to the consumer, as well as some of the specific pharmacological interventions, have been shown to yield the best results in terms of indicators of abstinence and prevention of relapses.

Murrough, J. W., Iosifescu, D. V., Chang, L. C., Al Jurdi, R. K., Green, C. E., Perez, A. M., … Mathew, S. J. (2013). Antidepressant efficacy of ketamine in treatment-resistant major depression: a two-site randomized controlled trial. American Journal of Psychiatry, 170(10), 1134-1142. http://dx.doi.org/10.1176/appi.ajp.2013.13030392
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