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Psychopharmacological Agents and Suicide Risk Reduction: Ketamine and Other Approaches

/ Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / / , ,

Abstract

Suicide is a major global public health problem and the leading cause of injury mortality in the USA. Suicide is a complex phenomenon involving several systems and neurobiological pathways, with interacting genetic and environmental mechanisms. The literature on the neurobiology and pharmacotherapy of suicide has been limited. To date, no medications have proven efficacious for treating acute suicidal crises. There is an emerging literature supporting a rapid anti-suicidal effect of ketamine, a non-competitive N-methyl-d-aspartate (NMDA) glutamate receptor antagonist, among depressed patients with suicidal ideation. Potential ketamine’s anti-suicidal effect mechanisms are linked to interruption of the kynurenine pathway and modulating pro-inflammatory cytokines exacerbation. However, available data are not sufficient for its routine integration in clinical practice, and larger and replicated randomized control studies are needed.

Al Jurdi, R. K., Swann, A., & Mathew, S. J. (2015). Psychopharmacological Agents and Suicide Risk Reduction: Ketamine and Other Approaches. Current psychiatry reports, 17(10), 1-10. https://dx.doi.org/10.1007/s11920-015-0614-9

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5-HTTLPR Genotype Moderates the Effects of Past Ecstasy Use on Verbal Memory Performance in Adolescent and Emerging Adults: A Pilot Study

/ MDMA, Neuroscience, Papers, Publications / / , , , ,

Abstract

OBJECTIVE: Ecstasy use is associated with memory deficits. Serotonin transporter gene (5-HTTLPR) polymorphisms have been linked with memory function in healthy samples. The present pilot study investigated the influence of 5-HTTLPR polymorphisms on memory performance in ecstasy users, marijuana-using controls, and non-drug-using controls, after a minimum of 7 days of abstinence.

METHOD: Data were collected from 116 young adults (18-25 years-old), including 45 controls, 42 marijuana users, and 29 ecstasy users, and were balanced for 5-HTTLPR genotype. Participants were abstinent seven days prior to completing memory testing. Three MANCOVAs and one ANCOVA were run to examine whether drug group, 5-HTTLPR genotype, and their interactions predicted verbal and visual memory after controlling for gender, past year alcohol use, other drug use, and nicotine cotinine levels.

RESULTS: MANCOVA and ANCOVA analysis revealed a significant interaction between drug group and genotype (p = .03) such that ecstasy users with the L/L genotype performed significantly worse on CVLT-2 total recall (p = .05), short (p = .008) and long delay free recall (p = .01), and recognition (p = .006), with the reverse pattern found in controls. Ecstasy did not significantly predict visual memory. 5-HTTLPR genotype significantly predicted memory for faces (p = .02); short allele carriers performed better than those with L/L genotype.

CONCLUSIONS: 5-HTTLPR genotype moderated the effects of ecstasy on verbal memory, with L/L carriers performing worse compared to controls. Future research should continue to examine individual differences in ecstasy’s impact on neurocognitive performance as well as relationships with neuronal structure. Additional screening and prevention efforts focused on adolescents and emerging adults are necessary to prevent ecstasy consumption.

Wright, N. E., Strong, J. A., Gilbart, E. R., Shollenbarger, S. G., & Lisdahl, K. M. (2015). 5-HTTLPR Genotype Moderates the Effects of Past Ecstasy Use on Verbal Memory Performance in Adolescent and Emerging Adults: A Pilot Study. PloS one, 10(7), e0134708. http://dx.doi.org/10.1371/journal.pone.0134708

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Greater sexual risk-taking in female and male recreational MDMA/ecstasy users compared with alcohol drinkers: a questionnaire study

/ MDMA, Papers, Publications / / ,

Abstract

AIMS: Previous studies have shown increased sexual risk-taking in experienced MDMA/ecstasy users. The main objectives of this study were to compare levels of sexual risk-taking between a young student sample of predominantly heterosexual MDMA users and alcohol-drinker controls and investigate potential gender differences.

METHODS: Recreational drug use and sexual risk questionnaires were completed by 20 MDMA users (10 females, 10 males) and 20 non-user controls (10 females, 10 males). They were predominantly university students, aged between 20-22 years, mainly heterosexual (n = 37), with three bisexual participants.

RESULTS: MDMA users displayed significantly greater levels of sexual risk-taking than the alcohol-drinker controls. It involved significantly higher rates of casual sex, non-condom use during sex, and penetrative sexual risks. This increase in sexual riskiness occurred to a similar extent in males and females.

CONCLUSIONS: These findings indicate that both female and male ecstasy/MDMA users reported more risky sexual behaviours, than the non-user controls. Further research into the sexual behaviour and sexual risk-taking of heterosexual MDMA users should be conducted because much of the past literature has focused on homosexual participants.

May, A. L., & Parrott, A. C. (2015). Greater sexual risk‐taking in female and male recreational MDMA/ecstasy users compared with alcohol drinkers: a questionnaire study. Human Psychopharmacology: Clinical and Experimental, 30(4), 272-275. http://dx.doi.org/10.1002/hup.2432

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The potential utility of some legal highs in CNS disorders

/ Anxiety Disorders / PTSD, Depressive Disorders, Ketamine, LSD, MDMA, Mushrooms / Psilocybin, Papers, Psychiatry & Medicine, Psychology, Publications, Substance Use Disorder / / ,

Abstract

Over the last decade there has been an explosion of new drugs of abuse, so called legal highs or novel psychoactive substances (NPS). Many of these abused drugs have unknown pharmacology, but their biological effects can be anticipated from their molecular structure and possibly also from online user reports. When considered with the findings that some prescription medications are increasingly abused and that some abused drugs have been tested clinically one could argue that there has been a blurring of the line between drugs of abuse and clinically used drugs. In this review we examine these legal highs/NPS and consider whether, based on their known or predicted pharmacology, some might have the potential to be clinically useful in CNS disorders.

Davidson, C., & Schifano, F. (2015). The potential utility of some legal highs in CNS disorders. Progress in Neuro-Psychopharmacology and Biological Psychiatry. https://dx.doi.org/10.1016/j.pnpbp.2015.07.010
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Developmental outcomes of 3,4-methylenedioxymethamphetamine (ecstasy)-exposed infants in the UK

/ MDMA, Neuroscience, Papers, Publications / / , , , , , ,

Abstract

OBJECTIVE: This paper aims to review findings from a longitudinal study of prenatal methylenedioxymethamphetamine (MDMA, “ecstasy”) on infant development.

METHODS: In a prospective, longitudinal cohort design, we followed 28 MDMA-exposed and 68 non-MDMA-exposed infants from birth to 2 years of age. Women recruited voluntarily into a study of recreational drug use during pregnancy were interviewed to obtain type, frequency, and amount of recreational drug use. Their children were followed for a 2-year period after birth. A large number of drug and environmental covariates were controlled. Infants were seen at 1, 4, 12, 18, and 24 months using standardized normative tests of mental and motor development.

RESULTS: There were no differences between MDMA-exposed and non-MDMA-exposed infants at birth except that MDMA-exposed infants were more likely to be male. Motor delays were evident in MDMA infants at each age and amount of MDMA exposure predicted motor deficits at 12 months in a dose-dependent fashion.

CONCLUSIONS: Prenatal MDMA exposure is related to fine and gross motor delays in the first 2 years of life. Follow-up studies are needed to determine long-term effects.

Singer, L. T., Moore, D. G., Min, M. O., Goodwin, J., Turner, J. J., Fulton, S., & Parrott, A. C. (2015). Developmental outcomes of 3, 4‐methylenedioxymethamphetamine (ecstasy)‐exposed infants in the UK. Human Psychopharmacology: Clinical and Experimental, 30(4), 290-294. http://dx.doi.org/0.1002/hup.2459

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Antidepressant mechanism of ketamine: perspective from preclinical studies

/ Depressive Disorders, Ketamine, Neuroscience, Papers, Psychiatry & Medicine, Psychology, Publications / / , , ,

Abstract

A debilitating mental disorder, major depressive disorder is a leading cause of global disease burden. Existing antidepressant drugs are not adequate for the majority of depressed patients, and large clinical studies have demonstrated their limited efficacy and slow response onset. Growing evidence of low-dose ketamine’s rapid and potent antidepressant effects offers strong potential for future antidepressant agents. However, ketamine has considerable drawbacks such as its abuse potential, psychomimetic effects, and increased oxidative stress in the brain, thus limiting its widespread clinical use. To develop superior antidepressant drugs, it is crucial to better understand ketamine’s antidepressant mechanism of action. Recent preclinical studies indicate that ketamine’s antidepressant mechanism involves mammalian target of rapamycin pathway activation and subsequent synaptogenesis in the prefrontal cortex, as well as glycogen synthase kinase-3 beta (GSK-3β) inactivation. Adjunct GSK-3β inhibitors, such as lithium, can enhance ketamine’s efficacy by augmenting and prolonging its antidepressant effects. Given the potential for depressive relapses, lithium in addition to ketamine is a promising solution for this clinical issue.

Scheuing, L., Chiu, C. T., Liao, H. M., & Chuang, D. M. (2015). Antidepressant mechanism of ketamine: perspective from preclinical studies. Frontiers in Neuroscience, 9. http://dx.doi.org/10.3389/fnins.2015.00249
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Acute ketamine challenge increases resting state prefrontal-hippocampal connectivity in both humans and rats.

/ Ketamine, Neuroscience, Papers, Psychology, Psychotic Disorders, Publications / / , , , , , ,

Abstract

RATIONALE:

Aberrant prefrontal-hippocampal (PFC-HC) connectivity is disrupted in several psychiatric and at-risk conditions. Advances in rodent functional imaging have opened the possibility that this phenotype could serve as a translational imaging marker for psychiatric research. Recent evidence from functional magnetic resonance imaging (fMRI) studies has indicated an increase in PFC-HC coupling during working-memory tasks in both schizophrenic patients and at-risk populations, in contrast to a decrease in resting-state PFC-HC connectivity. Acute ketamine challenge is widely used in both humans and rats as a pharmacological model to study the mechanisms of N-methyl-D-aspartate (NMDA) receptor hypofunction in the context of psychiatric disorders.

OBJECTIVES:

We aimed to establish whether acute ketamine challenge has consistent effects in rats and humans by investigating resting-state fMRI PFC-HC connectivity and thus to corroborate its potential utility as a translational probe.

METHODS:

Twenty-four healthy human subjects (12 females, mean age 25 years) received intravenous doses of either saline (placebo) or ketamine (0.5 mg/kg body weight). Eighteen Sprague-Dawley male rats received either saline or ketamine (25 mg/kg). Resting-state fMRI measurements took place after injections, and the data were analyzed for PFC-HC functional connectivity.

RESULTS:

In both species, ketamine induced a robust increase in PFC-HC coupling, in contrast to findings in chronic schizophrenia.

CONCLUSIONS:

This translational comparison demonstrates a cross-species consistency in pharmacological effect and elucidates ketamine-induced alterations in PFC-HC coupling, a phenotype often disrupted in pathological conditions, which may give clue to understanding of psychiatric disorders and their onset, and help in the development of new treatments.

Grimm, O., Gass, N., Weber-Fahr, W., Sartorius, A., Schenker, E., Spedding, M., … & Meyer-Lindenberg, A. (2015). Acute ketamine challenge increases resting state prefrontal-hippocampal connectivity in both humans and rats. Psychopharmacology, 1-11.
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Neurovascular and neuroimaging effects of the hallucinogenic serotonin receptor agonist psilocin in the rat brain.

/ Mushrooms / Psilocybin, Neuroscience, Papers, Publications / / , , , , ,

Abstract

The development of pharmacological magnetic resonance imaging (phMRI) has presented the opportunity for investigation of the neurophysiological effects of drugs in vivo. Psilocin, a hallucinogen metabolised from psilocybin, was recently reported to evoke brain region-specific, phMRI signal changes in humans. The present study investigated the effects of psilocin in a rat model using phMRI and then probed the relationship between neuronal and haemodynamic responses using a multimodal measurement preparation. Psilocin (2 mg/kg or 0.03 mg/kg i.v.) or vehicle was administered to rats (N = 6/group) during either phMRI scanning or concurrent imaging of cortical blood flow and recording of local field potentials. Compared to vehicle controls psilocin (2 mg/kg) evoked phMRI signal increases in a number of regions including olfactory and limbic areas and elements of the visual system. PhMRI signal decreases were seen in other regions including somatosensory and motor cortices. Investigation of neurovascular coupling revealed that whilst neuronal responses (local field potentials) to sensory stimuli were decreased in amplitude by psilocin administration, concurrently measured haemodynamic responses (cerebral blood flow) were enhanced. The present findings show that psilocin evoked region-specific changes in phMRI signals in the rat, confirming recent human data. However, the results also suggest that the haemodynamic signal changes underlying phMRI responses reflect changes in both neuronal activity and neurovascular coupling. This highlights the importance of understanding the neurovascular effects of pharmacological manipulations for interpreting haemodynamic neuroimaging data.

Spain, A., Howarth, C., Khrapitchev, A., Sharp, T., Sibson, N. R., & Martin, C. (2015). Neurovascular and neuroimaging effects of the hallucinogenic serotonin receptor agonist psilocin in the rat brain. Neuropharmacology. https://dx.doi.org/10.1016/j.neuropharm.2015.07.018
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Ketamine induces anxiolytic effects in adult zebrafish: A multivariate statistics approach.

/ Anxiety Disorders / PTSD, Ketamine, Neuroscience, Papers, Psychology, Publications / / , ,

Abstract

Ketamine inappropriate use has been associated with serious consequences for human health. Anesthetic properties of ketamine are well-known but its side effects are poorly described, including the effects on anxiety. In this context, animal models are a safe way to conduct this neurobehavioral research and zebrafish (Danio rerio) is an interesting model which has several advantages. The validation and interpretation of results of behavioral assays requires a suitable statistical approach and the use of multivariate statistical methods has been little explored, especially in zebrafish behavioral models. Here, we investigated the anxiolytic-induced effects of ketamine in adult zebrafish, using Light-Dark Test and Multivariate Statistics methods (PCA, HCA and SIMCA). In addition, we compared the processing of data to the one carried out by analysis of variance (ANOVA) Ketamine produced significant concentration of exposure-dependent anxiolytic effects, increasing time in white area and number of crossings and decreasing latency to first access to white area. Average entry duration behavior resulted in a slight decrease from control to treatment groups, with an observed concentration-dependent increase among the exposed groups. PCA results indicated that two principal components represent 88.74% of all the system information. HCA and PCA results showed a higher similarity among control and treatment groups exposed to lower concentrations of ketamine and among treatment groups exposed to concentrations of 40 and 60 mg.L-1. In SIMCA results, interclasses distances were concentration of exposure-dependent increased and misclassifications and interclasses residues results also support these findings. These findings confirm the anxiolytic potential of ketamine and zebrafish sensibility to this drug. In summary, our study confirms that zebrafish and multivariate statistics data validation is an appropriate and viable behavioral model for the study of psychoactive substances, providing a detailed and reliable analysis.

De Campos, E. G., Bruni, A. T., & De Martinis, B. S. (2015). Ketamine induces anxiolytic effects in adult zebrafish: A multivariate statistics approach. Behavioural Brain Research.  https://dx.doi.org/10.1016/j.bbr.2015.07.017
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‘Whatever you want to believe’ kaleidoscopic individualism and ayahuasca healing in Australia

/ Anthropology & Sociology, Ayahuasca, Biology & Ethnobotany, Papers, Psychology, Publications / /

Abstract

Over the last fifteen years the use of the indigenous Amazonian psychoactive beverage ayahuasca has been reimagined in alternative healing circles of Western countries. This paper explores the practice of ayahuasca neoshamanism in Australia and examines ways in which acts of vomiting and ecstatic trance-visions involve heightened affective states and moral projects of healing. Aspects of everyday life are purged, rearticulated, and reconstituted in rituals where codes of conduct and discursive exchange encourage practices of personal evaluation and reflexivity that appear to index ideologies of individualism. Through exploring social and discursive prohibitions and forms of sensory organisation, the practice of drinking ayahuasca in Australia is shown to be constituted by ritual conventions that define the individual as autonomous and responsible in relation to ecstatic trance and articulations of wellbeing.

Gearin, A. K. (2015). ‘Whatever you want to believe’kaleidoscopic individualism and ayahuasca healing in Australia. The Australian Journal of Anthropology. https://dx.doi.org/10.1111/taja.12143
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