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Depressive Disorders

Repeated intranasal ketamine for treatment-resistant depression – the way to go? Results from a pilot randomised controlled trial

March 15, 2018 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , , , ,

Abstract

BACKGROUND:
Ketamine research in depression has mostly used intravenous, weight-based approaches, which are difficult to translate clinically. Intranasal (IN) ketamine is a promising alternative but no controlled data has been published on the feasibility, safety and potential efficacy of repeated IN ketamine treatments.
METHODS:
This randomised, double-blind, placebo-controlled pilot study compared a 4-week course of eight treatments of 100 mg ketamine or 4.5 mg midazolam. Each treatment was given as 10 separate IN sprays, self-administered 5 min apart. The study was stopped early due to poor tolerability after five treatment-resistant depressed participants were included. Feasibility, safety (acute and cumulative), cognitive and efficacy outcomes were assessed. Plasma ketamine and norketamine concentrations were assayed after the first treatment.
RESULTS:
Significant acute cardiovascular, psychotomimetic and neurological side effects occurred at doses < 100 mg ketamine. No participants were able to self-administer all 10 ketamine sprays due to incoordination; treatment time occasionally had to be extended (>45 min) due to acute side effects. No hepatic, cognitive or urinary changes were observed after the treatment course in either group. There was an approximately two-fold variation in ketamine and norketamine plasma concentrations between ketamine participants. At course end, one participant had remitted in each of the ketamine and midazolam groups.
CONCLUSIONS:
IN ketamine, with the drug formulation and delivery device used, was not a useful treatment approach in this study. Absorption was variable between individuals and acute tolerability was poor, requiring prolonged treatment administration time in some individuals. The drug formulation, the delivery device, the insufflation technique and individual patient factors play an important role in tolerability and efficacy when using IN ketamine for TRD.
Gálvez, V., Li, A., Huggins, C., Glue, P., Martin, D., Somogyi, A. A., … & Loo, C. K. (2018). Repeated intranasal ketamine for treatment-resistant depression–the way to go? Results from a pilot randomised controlled trial. Journal of Psychopharmacology, 32(4), 397-407. 10.1177/0269881118760660
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Serotonergic Psychedelics: Experimental Approaches for Assessing Mechanisms of Action

March 13, 2018 / Depressive Disorders, LSD, Mushrooms / Psilocybin, Papers, Psychology, Publications / By /

Abstract

Recent, well-controlled – albeit small-scale – clinical trials show that serotonergic psychedelics, including psilocybin and lysergic acid diethylamide, possess great promise for treating psychiatric disorders, including treatment-resistant depression. Additionally, fresh results from a deluge of clinical neuroimaging studies are unveiling the dynamic effects of serotonergic psychedelics on functional activity within, and connectivity across, discrete neural systems. These observations have led to testable hypotheses regarding neural processing mechanisms that contribute to psychedelic effects and therapeutic benefits. Despite these advances and a plethora of preclinical and clinical observations supporting a central role for brain serotonin 5-HT2A receptors in producing serotonergic psychedelic effects, lingering and new questions about mechanisms abound. These chiefly pertain to molecular neuropharmacology. This chapter is devoted to illuminating and discussing such questions in the context of preclinical experimental approaches for studying mechanisms of action of serotonergic psychedelics, classic and new.

Canal, C. E. (2018). Serotonergic Psychedelics: Experimental Approaches for Assessing Mechanisms of Action. 10.1007/164_2018_107
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Sex differences in sub-anesthetic ketamine’s antidepressant effects and abuse liability.

March 2, 2018 / Depressive Disorders, Ketamine, Papers, Psychology, Publications, Substance Use Disorder / By / ,

Abstract

Sub-anesthetic ketamine produces rapid antidepressant effects in patients with bipolar and unipolar major depression where conventional monoaminergic-based antidepressant drugs have been ineffective or ridden with side effects. A single ketamine infusion can produce antidepressant effects lasting up to two weeks, and multiple ketamine infusions prolong this effect. Pre-clinical studies are underway to uncover ketamine’s mechanisms of action, but there are still many questions unanswered regarding the safety of its long-term use. Abuse liability is one area of concern, as recreational ketamine use is an ongoing issue in many parts of the world. Another understudied area is sex differences in responsivity to ketamine. Women are twice as likely as men to be diagnosed with depression, and they progress through stages of drug addiction more rapidly than their male counterparts. Despite this, preclinical studies in ketamine’s antidepressant and addictive-like behaviors in females are limited. These intersecting factors in recent clinical and pre-clinical studies are reviewed to characterize ketamine’s therapeutic potential, its limitations, and its potential mechanisms of action.
Wright, K. N., & Kabbaj, M. (2018). Sex differences in sub-anesthetic ketamine’s antidepressant effects and abuse liability. Current opinion in behavioral sciences, 23, 36-41., 10.1016/j.cobeha.2018.02.001
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Sex differences in sub-anesthetic ketamine's antidepressant effects and abuse liability.

March 2, 2018 / Depressive Disorders, Ketamine, Papers, Psychology, Publications, Substance Use Disorder / By / ,

Abstract

Sub-anesthetic ketamine produces rapid antidepressant effects in patients with bipolar and unipolar major depression where conventional monoaminergic-based antidepressant drugs have been ineffective or ridden with side effects. A single ketamine infusion can produce antidepressant effects lasting up to two weeks, and multiple ketamine infusions prolong this effect. Pre-clinical studies are underway to uncover ketamine’s mechanisms of action, but there are still many questions unanswered regarding the safety of its long-term use. Abuse liability is one area of concern, as recreational ketamine use is an ongoing issue in many parts of the world. Another understudied area is sex differences in responsivity to ketamine. Women are twice as likely as men to be diagnosed with depression, and they progress through stages of drug addiction more rapidly than their male counterparts. Despite this, preclinical studies in ketamine’s antidepressant and addictive-like behaviors in females are limited. These intersecting factors in recent clinical and pre-clinical studies are reviewed to characterize ketamine’s therapeutic potential, its limitations, and its potential mechanisms of action.
Wright, K. N., & Kabbaj, M. (2018). Sex differences in sub-anesthetic ketamine’s antidepressant effects and abuse liability. Current opinion in behavioral sciences, 23, 36-41., 10.1016/j.cobeha.2018.02.001
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Convergent Mechanisms Underlying Rapid Antidepressant Action

March 1, 2018 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , , , ,

Abstract

Traditional pharmacological treatments for depression have a delayed therapeutic onset, ranging from several weeks to months, and there is a high percentage of individuals who never respond to treatment. In contrast, ketamine produces rapid-onset antidepressant, anti-suicidal, and anti-anhedonic actions following a single administration to patients with depression. Proposed mechanisms of the antidepressant action of ketamine include N-methyl-D-aspartate receptor (NMDAR) modulation, gamma aminobutyric acid (GABA)-ergic interneuron disinhibition, and direct actions of its hydroxynorketamine (HNK) metabolites. Downstream actions include activation of the mechanistic target of rapamycin (mTOR), deactivation of glycogen synthase kinase-3 and eukaryotic elongation factor 2 (eEF2), enhanced brain-derived neurotrophic factor (BDNF) signaling, and activation of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptors (AMPARs). These putative mechanisms of ketamine action are not mutually exclusive and may complement each other to induce potentiation of excitatory synapses in affective-regulating brain circuits, which results in amelioration of depression symptoms. We review these proposed mechanisms of ketamine action in the context of how such mechanisms are informing the development of novel putative rapid-acting antidepressant drugs. Such drugs that have undergone pre-clinical, and in some cases clinical, testing include the muscarinic acetylcholine receptor antagonist scopolamine, GluN2B-NMDAR antagonists (i.e., CP-101,606, MK-0657), (2R,6R)-HNK, NMDAR glycine site modulators (i.e., 4-chlorokynurenine, pro-drug of the glycineB NMDAR antagonist 7-chlorokynurenic acid), NMDAR agonists [i.e., GLYX-13 (rapastinel)], metabotropic glutamate receptor 2/3 (mGluR2/3) antagonists, GABAA receptor modulators, and drugs acting on various serotonin receptor subtypes. These ongoing studies suggest that the future acute treatment of depression will typically occur within hours, rather than months, of treatment initiation.
Zanos, P., Thompson, S. M., Duman, R. S., Zarate, C. A., & Gould, T. D. (2018). Convergent mechanisms underlying rapid antidepressant action. CNS drugs, 1-31. 10.1007/s40263-018-0492-x
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Neuroendocrine Associations Underlying the Persistent Therapeutic Effects of Classic Serotonergic Psychedelics

March 1, 2018 / Depressive Disorders, Mushrooms / Psilocybin, Papers, Psychology, Publications / By / , , ,

Abstract

Recent reports on the effects of psychedelic-assisted therapies for mood disorders and addiction, as well as the effects of psychedelics in the treatment of cluster headache, have demonstrated promising therapeutic results. In addition, the beneficial effects appear to persist well after limited exposure to the drugs, making them particularly appealing as treatments for chronic neuropsychiatric and headache disorders. Understanding the basis of the long-lasting effects, however, will be critical for the continued use and development of this drug class. Several mechanisms, including biological and psychological ones, have been suggested to explain the long-lasting effects of psychedelics. Actions on the neuroendocrine system are some such mechanisms that warrant further investigation in the study of persisting psychedelic effects. In this report, we review certain structural and functional neuroendocrinological pathologies associated with neuropsychiatric disorders and cluster headache. We then review the effects that psychedelic drugs have on those systems and provide preliminary support for potential long-term effects. The circadian biology of cluster headache is of particular relevance in this area. We also discuss methodologic considerations for future investigations of neuroendocrine system involvement in the therapeutic benefits of psychedelic drugs.
Schindler, E. A. D., Wallace, R. M., Sloshower, J. A., & D’Souza, D. C. (2018). Neuroendocrine associations underlying the persistent therapeutic effects of classic serotonergic psychedelics. Frontiers in pharmacology, 9, 177. 10.3389/fphar.2018.00177
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Ketamine-Associated Brain Changes: A Review of the Neuroimaging Literature

February 20, 2018 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

Major depressive disorder (MDD) is one of the most prevalent conditions in psychiatry. Patients who do not respond to traditional monoaminergic antidepressant treatments have an especially difficult-to-treat type of MDD termed treatment-resistant depression. Subanesthetic doses of ketamine-a glutamatergic modulator-have shown great promise for rapidly treating patients with the most severe forms of depression. As such, ketamine represents a promising probe for understanding the pathophysiology of depression and treatment response. Through neuroimaging, ketamine’s mechanism may be elucidated in humans. Here, we review 47 articles of ketamine’s effects as revealed by neuroimaging studies. Some important brain areas emerge, especially the subgenual anterior cingulate cortex. Furthermore, ketamine may decrease the ability to self-monitor, may increase emotional blunting, and may increase activity in reward processing. Further studies are needed, however, to elucidate ketamine’s mechanism of antidepressant action.
Ionescu, D. F., Felicione, J. M., Gosai, A., Cusin, C., Shin, P., Shapero, B. G., & Deckersbach, T. (2018). Ketamine-Associated Brain Changes: A Review of the Neuroimaging Literature. Harvard review of psychiatry. 10.1097/HRP.0000000000000179
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Features of dissociation differentially predict antidepressant response to ketamine in treatment-resistant depression

February 17, 2018 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , , , ,

Abstract

BACKGROUND:
Ketamine induces rapid and robust antidepressant effects, and many patients also describe dissociation, which is associated with antidepressant response. This follow-up study investigated whether antidepressant efficacy is uniquely related to dissociative symptom clusters.
METHODS:
Treatment-resistant patients with major depressive disorder (MDD) or bipolar disorder (BD) (n = 126) drawn from three studies received a single subanesthetic (0.5 mg/kg) ketamine infusion. Dissociative effects were measured using the Clinician-Administered Dissociative States Scale (CADSS). Antidepressant response was measured using the 17-item Hamilton Depression Rating Scale (HAM-D). A confirmatory factor analysis established the validity of CADSS subscales (derealization, depersonalization, amnesia), and a general linear model with repeated measures was fitted to test whether subscale scores were associated with antidepressant response.
RESULTS:
Factor validity was supported, with a root mean square error of approximation of .06, a comparative fit index of .97, and a Tucker-Lewis index of .96. Across all studies and timepoints, the depersonalization subscale was positively related to HAM-D percent change. A significant effect of derealization on HAM-D percent change was observed at one timepoint (Day 7) in one study. The amnesia subscale was unrelated to HAM-D percent change.
LIMITATIONS:
Possible inadequate blinding; combined MDD/BD datasets might have underrepresented ketamine’s antidepressant efficacy; the possibility of Type I errors in secondary analyses.
CONCLUSIONS:
From a psychometric perspective, researchers may elect to administer only the CADSS depersonalization subscale, given that it was most closely related to antidepressant response. From a neurobiological perspective, mechanistic similarities may exist between ketamine-induced depersonalization and antidepressant response, although off-target effects cannot be excluded.
Niciu, M. J., Shovestul, B. J., Jaso, B. A., Farmer, C., Luckenbaugh, D. A., Brutsche, N. E., … & Zarate, C. A. (2018). Features of dissociation differentially predict antidepressant response to ketamine in treatment-resistant depression. Journal of affective disorders, 232, 310-315. 10.1016/j.jad.2018.02.049
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Ketamine blocks bursting in the lateral habenula to rapidly relieve depression

February 14, 2018 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

The N-methyl-d-aspartate receptor (NMDAR) antagonist ketamine has attracted enormous interest in mental health research owing to its rapid antidepressant actions, but its mechanism of action has remained elusive. Here we show that blockade of NMDAR-dependent bursting activity in the ‘anti-reward center’, the lateral habenula (LHb), mediates the rapid antidepressant actions of ketamine in rat and mouse models of depression. LHb neurons show a significant increase in burst activity and theta-band synchronization in depressive-like animals, which is reversed by ketamine. Burst-evoking photostimulation of LHb drives behavioural despair and anhedonia. Pharmacology and modelling experiments reveal that LHb bursting requires both NMDARs and low-voltage-sensitive T-type calcium channels (T-VSCCs). Furthermore, local blockade of NMDAR or T-VSCCs in the LHb is sufficient to induce rapid antidepressant effects. Our results suggest a simple model whereby ketamine quickly elevates mood by blocking NMDAR-dependent bursting activity of LHb neurons to disinhibit downstream monoaminergic reward centres, and provide a framework for developing new rapid-acting antidepressants.
Yang, Y., Cui, Y., Sang, K., Dong, Y., Ni, Z., Ma, S., & Hu, H. (2018). Ketamine blocks bursting in the lateral habenula to rapidly relieve depression. Nature, 554(7692), 317. 10.1038/nature25509
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Psychedelics and related drugs: therapeutic possibilities, mechanisms and regulation

February 14, 2018 / Anxiety Disorders / PTSD, Depressive Disorders, Ketamine, LSD, MDMA, Mushrooms / Psilocybin, Papers, Psychology, Publications, Substance Use Disorder / By / , ,

Abstract

The word “psychedelic” derives from the Greek terms for mind—psyche—and “delos” which means “clear, manifest,” so in essence, psychedelic drugs can be seen as the prototype “window on the mind” concept. The term was originally coined in the 1950s to describe lysergic acid diethylamide (LSD), mescaline, and other hallucinogens, drugs that profoundly alter human experience. These have subsequently been shown to act primarily as agonists at the 5-HT2Areceptor in the brain. Research into the therapeutic potential and mechanisms of action of psychedelic and related drugs peaked in the late 1960s but then stagnated for 50 years after the 1971 UN Psychotropics Convention made psychedelic research with humans almost impossible to carry out (Kyzar et al. 2017).

Recently, however, this area is experiencing a renaissance as drugs often associated with recreational use—such as LSD, ketamine, and cannabis/cannabinoids—have been shown to have therapeutic potential in a range of disorders such as treatment-resistant depression, suicidal ideation, and some pediatric epilepsies. Further, recent pilot studies suggest that MDMA as well as the classic psychedelics, LSD, and psilocybin may contribute to the pharmacopeia for post-traumatic stress disorder (PTSD) and other difficult-to-treat psychiatric disorders. Research has also been stimulated by functional neuroimaging studies of single doses of psychedelics showing that they produce widespread changes in brain connectivity as well as profound alterations to perception and cognition. At the same time, as one would expect from a relatively fledgling area, many questions remain about mechanisms of action, safety, and efficacy. These include what type of psychological therapies best combine with which type of psychedelic drug, whether some types of drug have benefits even without psychological treatment, what the optimal doses are, from single dose through to intermittent or repeated dosing. The current renaissance in empirical psychedelic research stimulated this Special Issue of Psychopharmacology. The articles are grouped into three sections: Clinical efficacy and clinical issues; Effects and Mechanisms of action; Regulation and history.

Curran, H. V., Nutt, D., & de Wit, H. (2018). Psychedelics and related drugs: therapeutic possibilities, mechanisms and regulation. 10.1007/s00213-017-4822-3
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