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Depressive Disorders

(R,S)-Ketamine metabolites (R,S)-norketamine and (2S,6S)-hydroxynorketamine increase the mammalian target of rapamycin function

July 1, 2014 / Depressive Disorders, Ketamine, Neuroscience, Papers, Publications / By / , , , , , ,

Abstract

BACKGROUND: Subanesthetic doses of (R,S)-ketamine are used in the treatment of neuropathic pain and depression. In the rat, the antidepressant effects of (R,S)-ketamine are associated with increased activity and function of mammalian target of rapamycin (mTOR); however, (R,S)-ketamine is extensively metabolized and the contribution of its metabolites to increased mTOR signaling is unknown.

METHODS: Rats (n = 3 per time point) were given (R,S)-ketamine, (R,S)-norketamine, and (2S,6S)-hydroxynorketamine and their effect on the mTOR pathway determined after 20, 30, and 60 min. PC-12 pheochromocytoma cells (n = 3 per experiment) were treated with escalating concentrations of each compound and the impact on the mTOR pathway was determined.

RESULTS: The phosphorylation of mTOR and its downstream targets was significantly increased in rat prefrontal cortex tissue by more than ~2.5-, ~25-, and ~2-fold, respectively, in response to a 60-min postadministration of (R,S)-ketamine, (R,S)-norketamine, and (2S,6S)-hydroxynorketamine (P < 0.05, ANOVA analysis). In PC-12 pheochromocytoma cells, the test compounds activated the mTOR pathway in a concentration-dependent manner, which resulted in a significantly higher expression of serine racemase with ~2-fold increases at 0.05 nM (2S,6S)-hydroxynorketamine, 10 nM (R,S)-norketamine, and 1,000 nM (R,S)-ketamine. The potency of the effect reflected antagonistic activity of the test compounds at the α7-nicotinic acetylcholine receptor.

CONCLUSIONS: The data demonstrate that (R,S)-norketamine and (2S,6S)-hydroxynorketamine have potent pharmacological activity both in vitro and in vivo and contribute to the molecular effects produced by subanesthetic doses of (R,S)-ketamine. The results suggest that the determination of the mechanisms underlying the antidepressant and analgesic effects of (R,S)-ketamine requires a full study of the parent compound and its metabolites.

Paul, R. K., Singh, N. S., Khadeer, M., Moaddel, R., Sanghvi, M., Green, C. E., … & Wainer, I. W. (2014). (R, S)-Ketamine metabolites (R, S)-norketamine and (2S, 6S)-hydroxynorketamine increase the mammalian target of rapamycin function. The Journal of the American Society of Anesthesiologists, 121(1), 149-159. http://dx.doi.org/10.1097/ALN.0000000000000285
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Harmine for catatonic schizophrenia. A forgotten experiment

June 30, 2014 / Depressive Disorders, Humanities & Art, Papers, Psychiatry & Medicine, Psychology, Publications / By / , ,

Abstract

The purpose of this letter is to present a lesser-known experiment suggesting a positive response of catatonic schizophrenia to Harmine, a monoamine oxidase A inhibitor(MAO-A), a study conducted by Petre Tomescu, in the late 1920’s.

 

Hostiuc, S., Buda, O., & Ion, D. A. (2014). Harmine for catatonic schizophrenia. A forgotten experiment. Schizophrenia research, 1(159), 249-250. http://dx.doi.org/10.1016/j.schres.2014.08.006

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Repeated lysergic acid diethylamide in an animal model of depression: Normalisation of learning behaviour and hippocampal serotonin 5-HT2 signalling

April 30, 2014 / Depressive Disorders, LSD, Neuroscience, Papers, Psychology, Publications / By / , , ,

Abstract

A re-balance of postsynaptic serotonin (5-HT) receptor signalling, with an increase in 5-HT1A and a decrease in 5-HT2A signalling, is a final common pathway multiple antidepressants share. Given that the 5-HT1A/2A agonist lysergic acid diethylamide (LSD), when repeatedly applied, selectively downregulates 5-HT2A, but not 5-HT1A receptors, one might expect LSD to similarly re-balance the postsynaptic 5-HT signalling. Challenging this idea, we use an animal model of depression specifically responding to repeated antidepressant treatment (olfactory bulbectomy), and test the antidepressant-like properties of repeated LSD treatment (0.13 mg/kg/d, 11 d). In line with former findings, we observe that bulbectomised rats show marked deficits in active avoidance learning. These deficits, similarly as we earlier noted with imipramine, are largely reversed by repeated LSD administration. Additionally, bulbectomised rats exhibit distinct anomalies of monoamine receptor signalling in hippocampus and/or frontal cortex; from these, only the hippocampal decrease in 5-HT2 related [35S]-GTP-gamma-S binding is normalised by LSD. Importantly, the sham-operated rats do not profit from LSD, and exhibit reduced hippocampal 5-HT2 signalling. As behavioural deficits after bulbectomy respond to agents classified as antidepressants only, we conclude that the effect of LSD in this model can be considered antidepressant-like, and discuss it in terms of a re-balance of hippocampal 5-HT2/5-HT1A signalling.

Buchborn, T., Schröder, H., Höllt, V., & Grecksch, G. (2014). Repeated lysergic acid diethylamide in an animal model of depression: Normalisation of learning behaviour and hippocampal serotonin 5-HT2 signalling. Journal of Psychopharmacology, 28(6), 545-552. https://dx.doi.org/10.1177/0269881114531666
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Psilocybin-Induced Decrease in Amygdala Reactivity Correlates with Enhanced Positive Mood in Healthy Volunteers

April 26, 2014 / Depressive Disorders, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

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.

Kraehenmann, R., Preller, K. H., Scheidegger, M., Pokorny, T., Bosch, O. G., Seifritz, E., & Vollenwieder, F. X. (2014). Psilocybin-Induced Decrease in Amygdala Reactivity Correlates with Enhanced Positive Mood in Healthy Volunteers. Biological Psychiatry. http://dx.doi.org/10.1016/j.biopsych.2014.04.010
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Classical hallucinogens as antidepressants? A review of pharmacodynamics and putative clinical roles

March 17, 2014 / Anxiety Disorders / PTSD, Depressive Disorders, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications / By / , , ,

Abstract

Hallucinogens have been part of spiritual practice for millennia, but controversy surrounding their mind-manifesting effects led to their proscription by the mid-20th century, largely without evidence of harm or toxicity and despite nascent data suggesting therapeutic utility in treating depressive illnesses. This review explores their pharmacodynamic actions and the current limited data on their clinic effectiveness. These drugs appear to exert their psychedelic effects through their agonist or partial agonist activity at the serotonergic 5-HT2A receptor, though they also have affinity for other metabotropic serotonin receptors. Hallucinogen binding affects a wide range of intracellular signalling pathways, the precise nature of which remains incompletely understood. They alter the serotonergic tone of brainstem raphe nuclei that project through the brain; they interact with receptors in the prefrontal cortex altering connectivity patterns and intracellular functioning; and they disrupt inhibitory control of sensory input via the thalamus to the cortex. The serotonergic system has long been implicated in anxiety and depressive disorders, and is a major target of most existing antidepressants. Classical hallucinogens alter the functioning of this system, but not in the same way current medications do: whilst there are identified receptors and neurotransmitter pathways through which hallucinogens could therein produce therapeutic effects, the neurobiology of this remains speculative at this time. There is currently an extremely limited but growing literature on hallucinogen safety and clinical application. The drugs appear well tolerated by healthy controls and clinical populations, and the rapid tolerance to repeated administration might reduce the possibility of dependency. Clinical trials reported over the past decade have generally shown positive therapeutic potential, but they are notably few in number. Legislative policy has had a freezing effect on evaluation of these compounds, a better understanding of which might improve our knowledge of the processes involved in consciousness, the neuropathology of depression, and potentially open up new pharmacological therapies.

Baumeister, D., Barnes, G., Giaroli, G., & Tracy, D. (2014). Classical hallucinogens as antidepressants? A review of pharmacodynamics and putative clinical roles. Therapeutic Advances in Psychopharmacology, 4(4), 156-159. http://dx.doi.org/10.1177/2045125314527985
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Why Psychiatry Needs Psychedelics and Psychedelics Need Psychiatry

March 11, 2014 / Anxiety Disorders / PTSD, Depressive Disorders, LSD, MDMA, Mushrooms / Psilocybin, Papers, Psychology, Publications, Substance Use Disorder / By /

Abstract

Without researching psychedelic drugs for medical therapy, psychiatry is turning its back on a group of compounds that could have great potential. Without the validation of the medical profession, the psychedelic drugs, and those who take them off-license, remain archaic sentiments of the past, with the users maligned as recreational drug abusers and subject to continued negative opinion. These two disparate groups—psychiatrists and recreational psychedelic drug users—are united by their shared recognition of the healing potential of these compounds. A resolution of this conflict is essential for the future of psychiatric medicine and psychedelic culture alike. Progression will come from professionals working in the field adapting to fit a conservative paradigm. In this way, they can provide the public with important treatments and also raise the profile of expanded consciousness in mainstream society.

Sessa, B. (2014). Why Psychiatry Needs Psychedelics and Psychedelics Need Psychiatry. Journal of Psychoactive Drugs, 46(1), 57–62. http://dx.doi.org/10.1080/02791072.2014.877322
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Do the dissociative side effects of ketamine mediate its antidepressant effects?

February 18, 2014 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychiatry & Medicine, Psychology, Publications / By / , , , , , , ,

Abstract

Background

The N-methyl-d-aspartate receptor antagonist ketamine has rapid antidepressant effects in major depression. Psychotomimetic symptoms, dissociation and hemodynamic changes are known side effects of ketamine, but it is unclear if these side effects relate to its antidepressant efficacy.

Methods

Data from 108 treatment-resistant inpatients meeting criteria for major depressive disorder and bipolar disorder who received a single subanesthetic ketamine infusion were analyzed. Pearson correlations were performed to examine potential associations between rapid changes in dissociation and psychotomimesis with the Clinician-Administered Dissociative States Scale (CADSS) and Brief Psychiatric Rating Scale (BPRS), respectively, manic symptoms with Young Mania Rating Scale (YMRS), and vital sign changes, with percent change in the 17-item Hamilton Depression Rating scale (HDRS) at 40 and 230 min and Days 1 and 7.

Results

Pearson correlations showed significant association between increased CADSS score at 40 min and percent improvement with ketamine in HDRS at 230 min (r=−0.35, p=0.007) and Day 7 (r=−0.41, p=0.01). Changes in YMRS or BPRS Positive Symptom score at 40 min were not significantly correlated with percent HDRS improvement at any time point with ketamine. Changes in systolic blood pressure, diastolic blood pressure, and pulse were also not significantly related to HDRS change.

Limitations

Secondary data analysis, combined diagnostic groups, potential unblinding.

Conclusions

Among the examined mediators of ketamine׳s antidepressant response, only dissociative side effects predicted a more robust and sustained antidepressant. Prospective, mechanistic investigations are critically needed to understand why intra-infusion dissociation correlates with a more robust antidepressant efficacy of ketamine.

Luckenbaugh, D. A., Niciu, M. J., Ionescu, D. F., Nolan, N. M., Richards, E. M., Brutsche, N. E., … & Zarate, C. A. (2014). Do the dissociative side effects of ketamine mediate its antidepressant effects?. Journal of affective disorders, 159, 56-61. http://dx.doi.org/10.1016/j.jad.2014.02.017

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IJTS Special Topic Section: Ketamine ● Making Ketamine Work in the Long Run

January 1, 2014 / Depressive Disorders, Humanities & Art, Ketamine, Papers, Psychiatry & Medicine, Psychology, Publications / By /

Abstract

Treatments such as ketamine psychotherapy face substantial financial and regulatory obstacles to dissemination into widespread use. Newly patented medications are able to generate enough capital to pay for studies required for FDA approval, personnel to apply for coverage on insurance plans, and marketing to establish a successful launch. Ketamine is an older drug with considerable evidence of efficacy for treatment resistant depression, and almost 50 years of data concerning safety as an anesthetic agent. However, it can no longer be patented, so there is no incentive for pharmaceutical companies to help get it into widespread use. In this paper we discuss some of the complex issues surrounding use of ketamine in the outpatient setting and share information and practice pearls that have been gathered through communication with other practitioners and through direct experience with over 1000 treatments involving 120 patients in the last eight years. The safety and appropriateness of intramuscular ketamine treatment in the outpatient psychiatric office is discussed. We hope to help proponents of effective mental health interventions navigate the actual and potential challenges involved in safe application of this treatment option outside of hospital-based programs.

Early, T. S. (2014). Making Ketamine Work in the Long Run. International Journal of Transpersonal Studies, 33(2).
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IJTS Special Topic Section: Ketamine ● Ketamine for Depression: A Mixed-Methods Study

January 1, 2014 / Depressive Disorders, Ketamine, Papers, Psychiatry & Medicine, Psychology, Publications / By /

Abstract

Prior studies have reported variously on the presence or absence of dissociative effects at subanesthtetic doses of ketamine administered for treatment-resistant depression. This mixedmethods study emulated the protocol used for the studies in question, with IV administration of 0.5mg/kg over 40 minutes with eight experienced ketamine users. Quantitative measures were generally insignificant since this was not a population reporting depression; blood pressure increased as expected by 20-30mm systolic and 6-20mm diastolic, falling rapidly by 20 minutes after completion of the infusion. Individual qualitative reports reports of relaxation, pleasant sensation, decreased cognitive function, and some disabling of ordinary capacities. As experienced users, subjects commented freely on what was characterized as the triviality of the experience, and typically expressed skepticism that ketamine could have antidepressant properties when administered at this dose or in this manner, as well as disbelief that it could be beneficial except perhaps as a period of relaxation, or as a partial break from ordinary states of mind in naïve subjects. Group discussion produced a consensus recommendation in favor of threshold- and higher-dosage transformative work beginning with a 40-50mg IM bolus, potentially in a series of sessions with higher dosages if indicated, with the number of sessions to be determined by clinical practice; such work should occur in a closely monitored psychotherapeutic setting.

Wolfson, P. E. (2014). Ketamine for Depression: A Mixed-Methods Study. International Journal of Transpersonal Studies, 33(2).
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IJTS Special Topic Section: Ketamine ● Ketamine and Depression: A Review

January 1, 2014 / Depressive Disorders, Ketamine, Papers, Psychiatry & Medicine, Psychology, Publications / By / , ,

Abstract

Ketamine, via intravenous infusions, has emerged as a novel therapy for treatment-resistant depression, given rapid onset and demonstrable efficacy in both unipolar and bipolar depression. Duration of benefit, on the order of days, varies between these subtypes, but appears longer in unipolar depression. A unique property is reduction in suicidality although data are more limited. Strategies to extend duration, via multiple doses, maintenance treatment, or subsequent augmenting medications have yielded mixed results. There is a relative paucity of data regarding alternate methods of administration such as intramuscular, intranasal, and oral routes, though preliminary results are promising. Adverse effects most reliably include dissociative and sympathomimetic effects, both transient and mild, and suggest good tolerability. Ketamine’s unique effects may represent an opportunity for a paradigm shift in the pharmacologic treatment of depression.

Ryan, W. C., Marta, C. J., & Koek, R. J. (2014). Ketamine and depression: A review. International Journal of Transpersonal Studies, 33(2), 40-74.
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