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Psychology

The Therapeutic Potential of Ayahuasca

December 1, 2016 / Anxiety Disorders / PTSD, Ayahuasca, Biology & Ethnobotany, Depressive Disorders, Papers, Psychology, Publications / By / ,

Abstract

Ayahuasca is a plant-based psychoactive decoction traditionally utilized by cultural groups throughout parts of Brazil, Peru, Colombia, Bolivia, Venezuela, and Ecuador during rites of passage, divination, warfare, magico-religious practices, and for healing in ethnomedical contexts. Over the last 150 years, ayahuasca has entered the global sphere and become a focus of scientific inquiry due to its reported use as an effective medicine to diagnose and treat illness. As a result, the use of ayahuasca within a healing context has become widespread and prompted researchers to investigate its putative therapeutic potential. In this chapter, the authors discuss current therapeutic applications of ayahuasca to treat addiction, depression, and anxiety. In this context, we highlight several studies to help facilitate a greater understanding of the therapeutic potential of ayahuasca.

Coe, M. A., & McKenna, D. J. (2017). The Therapeutic Potential of Ayahuasca. In Evidence-Based Herbal and Nutritional Treatments for Anxiety in Psychiatric Disorders (pp. 123-137). Springer International Publishing. 10.1007/978-3-319-42307-4_7

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Serotonergic Hallucinogen-Induced Visual Perceptual Alterations

November 30, 2016 / DMT, LSD, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / By / ,

Abstract

Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD), psilocybin, and N,N-dimethyltryptamine (DMT), are famous for their capacity to temporally and profoundly alter an individual’s visual experiences. These visual alterations show consistent attributes despite large inter- and intra-individual variances. Many reports document a common perception of colors as more saturated, with increased brightness and contrast in the environment (“Visual Intensifications”). Environmental objects might be altered in size (“Visual illusions”) or take on a modified and special meaning for the subject (“Altered self-reference”). Subjects may perceive light flashes or geometrical figures containing recurrent patterns (“Elementary imagery and hallucinations”) influenced by auditory stimuli (“Audiovisual synesthesia”), or they may envision images of people, animals, or landscapes (“Complex imagery and hallucinations”) without any physical stimuli supporting their percepts. This wide assortment of visual phenomena suggests that one single neuropsychopharmacological mechanism is unlikely to explain such vast phenomenological diversity. Starting with mechanisms that act at the cellular level, the key role of 5-HT2A receptor activation and the subsequent increased cortical excitation will be considered. Next, it will be shown that area specific anatomical and dynamical features link increased excitation to the specific visual contents of hallucinations. The decrease of alpha oscillations by hallucinogens will then be introduced as a systemic mechanism for amplifying internal-driven excitation that overwhelms stimulus-induced excitations. Finally, the hallucinogen-induced parallel decrease of the N170 visual evoked potential and increased medial P1 potential will be discussed as key mechanisms for inducing a dysbalance between global integration and early visual gain that may explain several hallucinogen-induced visual experiences, including visual hallucinations, illusions, and intensifications.

Kometer, M., & Vollenweider, F. X. (2016). Serotonergic Hallucinogen-Induced Visual Perceptual Alterations. 10.1007/7854_2016_461
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Ketamine’s Mechanisms of Rapid Antidepressant Activity: Evidence from Preclinical Studies

November 30, 2016 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / ,

Abstract

Enthusiasm over the growing series of reports describing ketamine’s rapid onset of robust antidepressant activity in clinical trials has ignited a large number of back-translational efforts attempting to employ rodent models to better characterize the antidepressant properties of the drug and to improve our understanding of its underlying mechanisms of antidepressant action. On balance, these preclinical studies have yielded fairly consistent findings demonstrating that ketamine has a broad range of behavioral effects consistent with antidepressant activity in a variety of rodent models. Many of these studies further suggest that ketamine’s effects are unique from other classic antidepressant drugs in producing more durable effects in some models and more rapidly reversing the behavioral effects of chronic stressor exposure in other models. The preclinical studies are also beginning to elucidate the drug’s mechanisms of antidepressant activity, with the majority of recent studies suggesting that increased levels of regional alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA) receptor activation and brain-derived neurotrophic factor (BDNF) expression, as well as enhanced synaptic plasticity, are critical components of the response. However, there remain several points of disagreement and inconsistency in the preclinical literature that require additional investigation, including the effectiveness of other NMDA receptor-targeting drugs and the specific targets of ketamine’s proximal effects. This chapter provides an overview and critical review of this preclinical literature. It is anticipated that a more complete understanding of ketamine’s mechanisms of antidepressant action will allow for a safer and more efficient use of ketamine in the clinical setting and afford us new opportunities for novel drug development.

Hermes, G., & Sanacora, G. (2016). Ketamine’s Mechanisms of Rapid Antidepressant Activity: Evidence from Preclinical Studies. In Ketamine for Treatment-Resistant Depression (pp. 73-98). Springer International Publishing. 10.1007/978-3-319-42925-0_6

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Ayahuasca Exposure: Descriptive Analysis of Calls to US Poison Control Centers from 2005 to 2015

November 28, 2016 / Ayahuasca, Papers, Psychology, Publications / By / ,

Abstract

Background: Ayahuasca is a hallucinogenic plant preparation which usually contains the vine Banisteriopsis caapi and the shrub Psychotria viridis. This tea originates from the Amazon Basin where it is used in religious ceremonies. Because interest in these religious groups spreading as well as awareness of use of ayahuasca for therapeutic and recreational purposes, its use is increasing. Banisteriopsis caapi is rich in β-carbolines, especially harmine, tetrahydroharmine and harmaline, which have monoamine oxidase inhibiting (MAOI) activity. Psychotria viridis contains the 5HT2A/2C/1A receptor agonist hallucinogen N,N-dimethyltryptamine (DMT). Usual desired effects include hallucination, dissociation, mood alteration and perception change. Undesired findings previously reported are nausea, vomiting, hypertension, and tachycardia.

Methods: All human exposure calls reported to the American Association of Poison Controls Centers’ (AAPCC) National Poison Data System (NPDS) between September 1, 2005 and September 1, 2015 were reviewed. Cases were filtered for specific plant derived ayahuasca-related product codes. Abstracted data included the following: case age and gender, exposure reason, exposure route, clinical manifestations, treatments given, medical outcomes and fatality.

Results: Five hundred and thirty-eight exposures to ayahuasca botanical products were reported. The majority of the calls to poison control centers came from healthcare facilities (83%). The most common route of exposure was ingestion. Most cases were men (437, 81%, 95% CI 77.7% – 84.3%). The median age was 21 (IQR 18-29). Most exposures were acute. Three hundred thirty-seven (63%) were reported to have a major or moderate clinical effect. The most common clinical manifestations reported were hallucinations (35%), tachycardia (34%), agitation (34%), hypertension (16%), mydriasis (13%) and vomiting (6%). Benzodiazepines were commonly given (30%). There were 28 cases in the series who required endotracheal intubation (5%). Four cases were reported to have had a cardiac arrest and 7 a respiratory arrest. Twelve cases had a seizure. Reports of exposures called to poison centers appeared to increase during this period based on annual estimates. Three fatalities were reported.

Conclusions: Ayahuasca use appears to be rising in the United States based on calls to poison control centers. While most use is reported to be safe and well tolerated, with possible beneficial effects, serious and life threatening adverse manifestations are possible. Most of the exposures reported to poison control centers were young people, more likely to be men and already in a healthcare facility. Further research, which includes comprehensive drug testing, will be needed to better identify the risks and effects of ayahuasca use.

Heise, C. W., & Brooks, D. E. (2016). Ayahuasca exposure: descriptive analysis of calls to US poison control centers from 2005 to 2015. Journal of medical toxicology, 1-4. 10.1007/s13181-016-0593-1

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Integrative analysis of sex differences in the rapid antidepressant effects of ketamine in preclinical models for individualized clinical outcomes

November 26, 2016 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , ,

Abstract

In major depressive disorder, women exhibit higher lifetime prevalence and different antidepressant response rates than men, which illustrates the importance of examining individual differences in the pathophysiology of depression and therapeutic response. In recent years, the consideration of sex in related preclinical research has thus gained interest — particularly in light of novel evidence for rapid-acting antidepressants. Notably, the literature recently revealed a higher sensitivity of females to the antidepressant effects of the N-methyl-d-aspartate receptor antagonist ketamine, in both baseline and preclinical conditions. Combined with its fast-acting and relatively sustained properties, this evidence highlights ketamine as a particularly interesting therapeutic alternative for this sensitive population, and supports the value in considering sex as a critical factor for improved individualized therapeutic strategies.

Saland, S. K., Duclot, F., & Kabbaj, M. (2017). Integrative analysis of sex differences in the rapid antidepressant effects of ketamine in preclinical models for individualized clinical outcomes. Current Opinion in Behavioral Sciences, 14, 19-26. 10.1016/j.cobeha.2016.11.002
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d-Lysergic Acid Diethylamide (LSD) as a Model of Psychosis: Mechanism of Action and Pharmacology

November 23, 2016 / LSD, Neuroscience, Papers, Psychology, Psychotic Disorders, Publications / By / , , ,

Abstract

d-Lysergic Acid Diethylamide (LSD) is known for its hallucinogenic properties and psychotic-like symptoms, especially at high doses. It is indeed used as a pharmacological model of psychosis in preclinical research. The goal of this review was to understand the mechanism of action of psychotic-like effects of LSD. We searched Pubmed, Web of Science, Scopus, Google Scholar and articles’ reference lists for preclinical studies regarding the mechanism of action involved in the psychotic-like effects induced by LSD. LSD’s mechanism of action is pleiotropic, primarily mediated by the serotonergic system in the Dorsal Raphe, binding the 5-HT2Areceptor as a partial agonist and 5-HT1A as an agonist. LSD also modulates the Ventral Tegmental Area, at higher doses, by stimulating dopamine D2, Trace Amine Associate receptor 1 (TAAR1) and 5-HT2A. More studies clarifying the mechanism of action of the psychotic-like symptoms or psychosis induced by LSD in humans are needed. LSD’s effects are mediated by a pleiotropic mechanism involving serotonergic, dopaminergic, and glutamatergic neurotransmission. Thus, the LSD-induced psychosis is a useful model to test the therapeutic efficacy of potential novel antipsychotic drugs, particularly drugs with dual serotonergic and dopaminergic (DA) mechanism or acting on TAAR1 receptors.

De Gregorio, D., Comai, S., Posa, L., & Gobbi, G. (2016). d-Lysergic Acid Diethylamide (LSD) as a Model of Psychosis: Mechanism of Action and Pharmacology. International Journal of Molecular Sciences, 17(11), 1953. 10.3390/ijms17111953
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Risks Associated with Misuse of Ketamine as a Rapid-Acting Antidepressant

November 22, 2016 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , , , , ,

Abstract

Major depression is a serious psychiatric disorder and remains a leading cause of disability worldwide. Conventional antidepressants take at least several weeks to achieve a therapeutic response and this lag period has hindered their ability to attain beneficial effects in depressed individuals at high risk of suicide. The non-competitive N-methyl-D-aspartate glutamate receptor antagonist ketamine has been shown to have rapid antidepressant effects in both rodents and humans. The emergence of ketamine as a fast-acting antidepressant provides promising new insights into the development of a rapid treatment response in patients with clinical depression. However, its safety and toxicity remain a concern. In this review, we focus on the limitations of ketamine, including neurotoxicity, cognitive dysfunction, adverse events associated with mental status, psychotomimetic effects, cardiovascular events, and uropathic effects. Studies have shown that its safety and tolerability profiles are generally good at low doses and with short-term treatment in depressed patients. The adverse events associated with ketamine usually occur with very high doses that are administered for prolonged periods of time and can be relieved by cessation. The antidepressant actions of its two enantiomers, S-ketamine (esketamine) and R-ketamine, are also discussed. R-ketamine has greater antidepressant actions than S-ketamine, without ketamine-related side-effects. Future treatment strategies should consider using R-ketamine for the treatment of depressed patients to decrease the risk of adverse events associated with long-term ketamine use.

Zhu, W., Ding, Z., Zhang, Y., Shi, J., Hashimoto, K., & Lu, L. (2016). Risks associated with misuse of ketamine as a rapid-acting antidepressant. Neuroscience Bulletin, 32(6), 557-564. 10.1007/s12264-016-0081-2

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