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Ketamine

Reviewing the Potential of Psychedelics for the Treatment of PTSD.

Abstract

There are few medications with demonstrated efficacy for the treatment of posttraumatic stress disorder (PTSD). Treatment guidelines have unequivocally designated psychotherapy as a first line treatment for PTSD. Yet, even after psychotherapy, PTSD often remains a chronic illness, with high rates of psychiatric and medical comorbidity. Meanwhile, the search and development of drugs with new mechanisms of action has stalled. Therefore, there is an urgent need to explore not just novel compounds, but novel approaches for the treatment of PTSD. A promising new approach involves the use of psychedelic drugs. Within the past few years, two psychedelics have received breakthrough designations for psychiatric indications from the US Food and Drug Administration, and several psychedelics are currently being investigated for the treatment of PTSD. This review discusses four types of compounds: 3,4-methylenedioxymethamphetamine (MDMA), ketamine, classical psychedelics (e.g. psilocybin and LSD) and cannabinoids. We describe the therapeutic rationale, the setting in which they are being administered, and their current state of evidence in the treatment of PTSD. Each compound provides unique qualities for the treatment of PTSD, from their use to rapidly target symptoms, to their use as adjuncts to facilitate psychotherapeutic treatments. Several questions are formulated that outline an agenda for future research.
Krediet, E., Bostoen, T., Breeksema, J., van Schagen, A., Passie, T., & Vermetten, E. (2020). Reviewing the Potential of Psychedelics for the Treatment of PTSD. International Journal of Neuropsychopharmacology., https://doi.org/10.1093/ijnp/pyaa018
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Benefit-Risk Assessment of Esketamine Nasal Spray vs. Placebo in Treatment-Resistant Depression

Abstract

This post hoc analysis assessed the benefit-risk profile of esketamine nasal spray + oral antidepressant (AD) induction and maintenance treatment in patients with treatment-resistant depression (TRD). The Benefit-Risk Action Team framework was utilized to assess the benefit-risk profile using data from three induction studies and one maintenance study. Benefits were proportion of remitters or responders in induction studies and proportion of stable remitters or stable responders who remained relapse-free in the maintenance study. Risks were death, suicidal ideation, most common adverse events (AEs), and potential long-term risks. Per 100 patients on esketamine + AD vs. AD + placebo in induction therapy, 5-21 additional patients would remit and 14-17 additional patients would respond. In maintenance therapy, 19-32 fewer relapses would occur with esketamine. In both cases, there was little difference in serious or severe common AEs (primarily dissociation, vertigo, and dizziness). These findings support a positive benefit-risk balance for esketamine + AD as induction and maintenance treatment in patients with TRD.
McIntyre, R. S., Rosenblat, J. D., Nemeroff, C. B., Sanacora, G., Murrough, J. W., Berk, M., … & Stahl, S. (2021). Synthesizing the Evidence for Ketamine and Esketamine in Treatment-Resistant Depression: An International Expert Opinion on the Available Evidence and Implementation. American Journal of Psychiatry, appi-ajp., https://doi.org/10.1002/cpt.2024
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Antidepressant and neurocognitive effects of serial ketamine administration versus ECT in depressed patients

Abstract

BACKGROUND:

While electroconvulsive therapy (ECT) is considered the gold standard for acute treatment of patients with otherwise treatment-resistant depression, ketamine has recently emerged as a fast-acting treatment alternative for these patients. Efficacy and onset of action are currently among the main factors that influence clinical decision making, however, the effect of these treatments on cognitive functions should also be a crucial point, given that cognitive impairment in depression is strongly related to disease burden and functional recovery. ECT is known to induce transient cognitive impairment, while little is known about ketamine’s impact on cognition. This study therefore aims to compare ECT and serial ketamine administration not only with regard to their antidepressant efficacy but also to acute neurocognitive effects.

METHODS:

Fifty patients suffering from depression were treated with either serial ketamine infusions or ECT. Depression severity and cognitive functions were assessed before, during, and after treatment.

RESULTS:

ECT and ketamine administration were equally effective, however, the antidepressant effects of ketamine occurred faster. Ketamine improved neurocognitive functioning, especially attention and executive functions, whereas ECT was related to a small overall decrease in cognitive performance.

CONCLUSIONS:

Due to its pro-cognitive effects and faster antidepressant effect, serial ketamine administration might be a more favorable short-term treatment option than ECT.

LIMITATIONS:

As this research employed a naturalistic study design, patients were not systematically randomized, there was no control group and patients received concurrent and partially changing medications during treatment.

CLINICAL TRIALS REGISTRATION:

Functional and Metabolic Changes in the Course of Antidepressive Treatment, https://clinicaltrials.gov/ct2/show/NCT02099630NCT02099630.

Basso, L., Bönke, L., Aust, S., Gärtner, M., Heuser-Collier, I., Otte, C., … & Grimm, S. (2020). Antidepressant and neurocognitive effects of serial ketamine administration versus ECT in depressed patients. Journal of Psychiatric Research.,  10.1016/j.jpsychires.2020.01.002

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Decreased directed functional connectivity in the psychedelic state.

Abstract

Neuroimaging studies of the psychedelic state offer a unique window onto the neural basis of conscious perception and selfhood. Despite well understood pharmacological mechanisms of action, the large-scale changes in neural dynamics induced by psychedelic compounds remain poorly understood. Using source-localised, steady-state MEG recordings, we describe changes in functional connectivity following the controlled administration of LSD, psilocybin and low-dose ketamine, as well as, for comparison, the (non-psychedelic) anticonvulsant drug tiagabine. We compare both undirected and directed measures of functional connectivity between placebo and drug conditions. We observe a general decrease in directed functional connectivity for all three psychedelics, as measured by Granger causality, throughout the brain. These data support the view that the psychedelic state involves a breakdown in patterns of functional organisation or information flow in the brain. In the case of LSD, the decrease in directed functional connectivity is coupled with an increase in undirected functional connectivity, which we measure using correlation and coherence. This surprising opposite movement of directed and undirected measures is of more general interest for functional connectivity analyses, which we interpret using analytical modelling. Overall, our results uncover the neural dynamics of information flow in the psychedelic state, and highlight the importance of comparing multiple measures of functional connectivity when analysing time-resolved neuroimaging data.

Barnett, L., Muthukumaraswamy, S. D., Carhart-Harris, R. L., & Seth, A. K. (2019). Decreased directed functional connectivity in the psychedelic state. NeuroImage, 116462., https://doi.org/10.1016/j.neuroimage.2019.116462
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The relationship between subjective effects induced by a single dose of ketamine and treatment response in patients with major depressive disorder: A systematic review.

Abstract

OBJECTIVE:
The relationship between ketamine’s hallucinogenic- and dissociative-type effects and antidepressant mechanism of action is poorly understood. This paper reviewed the correlation between subjective effects defined by various psychometric scales and observed clinical outcomes in the treatment of patients with Major Depressive Disorder (MDD).
METHODS:
Based on PRISMA guidelines, we reviewed the dissociative and psychotomimetic mental state induced with ketamine during MDD treatment. Our selected studies correlated depression rating with validated scales collected at regular intervals throughout the study period such as the Clinician-Administered Dissociative States Scale (CADSS), Brief Psychiatric Rating Scale (BPRS), and the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC). We excluded studies with bipolar depression or with repeated dosing and no single-dose phase. We included 8 of 556 screened reports.
RESULTS:
Two of five CADSS studies found significant negative correlations between increases in CADSS scores and depression scores. One of six BPRS studies demonstrated correlations between BPRS scores and depression scores. The 5D-ASC’s one study found no correlation with the MADRS.
CONCLUSIONS:
Ketamine’s dissociative and psychotomimetic effects were correlated with depression changes in 37.5% of studies, but most studies did not examine this relationship and future studies should consider this association since it appears important for MDMA and psilocybin therapies.
Mathai, D. S., Meyer, M. J., Storch, E. A., & Kosten, T. R. (2020). The relationship between subjective effects induced by a single dose of ketamine and treatment response in patients with major depressive disorder: A systematic review. Journal of Affective Disorders264, 123-129., https://doi.org/10.1016/j.jad.2019.12.023
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Neurotrophic mechanisms of psychedelic therapy

Abstract

Psychedelic drugs, often referred to as hallucinogens, are quite distinct from other classes of psychotropic drugs. Although the subjective and behavioral effects they induce are quite dramatic, they possess little addictive potential when compared to nicotine, alcohol or opiates. Since the discovery of ketamine antidepressant effects, there has been growing interest for these molecules. Serotonergic psychedelics such as psilocybin and lysergic acid diethylamide (LSD) are gaining attention as potential treatments for depression and addiction, similarly to 3,4-methylenedioxymethamphetamine (MDMA) for post-traumatic stress disorder (PTSD), and ibogaine for addiction. Although they possess distinct pharmacological profiles, their kinetics of action are quite similar: the therapeutic effects are felt within the hours following administration, and last well beyond drug elimination by the organism. This strongly suggests the induction of neurogenic and plastic mechanisms, including the involvement of trophic factors. This review will explore the literature dealing with the effects of psychedelics on neurotrophins, as well as the plastic adaptations that they induce, in an attempt to understand their surprising therapeutic potential. We will show that although ketamine and serotonergic psychedelics have affinity for very different receptors (NMDA, 5-HT2A), they ultimately initiate similar plastic adaptations in the prefrontal cortex through the involvement of the brain-derived neurotrophic factor (BDNF). We will see that although MDMA uses the same receptors as serotonergic psychedelics to alleviate PTSD symptoms, its effect on BDNF levels seem paradoxical and quite different. Finally, we show how ibogaine could exert its anti-addictive properties through a completely different neurotrophic factor than other psychedelic drugs, the glial cell line-derived neurotrophic factor (GDNF). While the current literature concerning the psychiatric applications of psychedelic therapy is encouraging, it remains to be determined whether their benefits could be obtained without their psychotomimetic effects, or concerns over potential toxicity.
Corne, R., & Mongeau, R. (2019). Neurotrophic mechanisms of psychedelic therapy. Biologie aujourd’hui213(3-4), 121., https://doi.org/10.1051/jbio/2019015
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High-dose ketamine infusion for the treatment of posttraumatic stress disorder in combat veterans.

Abstract

INTRODUCTION:
Combat veterans are at high risk for the development of posttraumatic stress disorder (PTSD) and substance use disorders. Ketamine has been shown to be an effective treatment for numerous mental health disorders, although research on its efficacy in combat-related PTSD in veterans is very limited.
METHODS:
The study population consisted of 30 US military veterans with combat-related PTSD. Participants underwent a standard induction series of six 1-hour ketamine infusions with the goal of obtaining a transpersonal dissociative experience. Participants were given a series of self-report questionnaires to assess for changes in symptoms of depression, PTSD, and substance use prior to the first and sixth infusions.
RESULTS:
Symptoms of depression as measured by change in score on the Patient Health Questionnaire decreased significantly from an average of 18.9 to 9.5 (P < .001). Similarly, symptoms of PTSD as measured by change in score on the PSTD Checklist for DSM-5 dropped significantly from an average of 56.2 to 31.3 (P < .001). Self-reported levels of substance use did not significantly decrease during the study period, although the level of use trended down.
CONCLUSIONS:
This observational study suggests that high-dose ketamine infusion therapy, which induced a transpersonal dissociative experience, could be a valuable tool in the treatment of combat-related PTSD. Further study is needed to better elucidate ketamine’s mechanism of action with regards to the treatment of PTSD.
Ross, C., Jain, R., Bonnett, C. J., & Wolfson, P. (2019). High-dose ketamine infusion for the treatment of posttraumatic stress disorder in combat veterans. Annals of clinical psychiatry: official journal of the American Academy of Clinical Psychiatrists31(4), 271-279., https://www.ncbi.nlm.nih.gov/pubmed/31675388
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Online Event - Psychedelic Care in Recreational Settings - 3 October 2024

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