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Novel pharmacological targets in drug development for the treatment of anxiety and anxiety-related disorders

August 27, 2019 / Anxiety Disorders / PTSD, Ketamine, MDMA, Papers, Psychiatry & Medicine, Publications / By / ,

Abstract

Current medication for anxiety disorders is suboptimal in terms of efficiency and tolerability, highlighting the need for improved drug treatments. In this review an overview of drugs being studied in different phases of clinical trials for their potential in the treatment of fear-, anxiety- and trauma-related disorders is presented. One strategy followed in drug development is refining and improving compounds interacting with existing anxiolytic drug targets, such as serotonergic and prototypical GABAergic benzodiazepines. A more innovative approach involves the search for compounds with novel mechanisms of anxiolytic action using the growing knowledge base concerning the relevant neurocircuitries and neurobiological mechanisms underlying pathological fear and anxiety. The target systems evaluated in clinical trials include glutamate, endocannabinoid and neuropeptide systems, as well as ion channels and targets derived from phytochemicals. Examples of promising novel candidates currently in clinical development for generalised anxiety disorder, social anxiety disorder, panic disorder, obsessive compulsive disorder or post-traumatic stress disorder include ketamine, riluzole, xenon with one common pharmacological action of modulation of glutamatergic neurotransmission, as well as the neurosteroid aloradine. Finally, compounds such as D-cycloserine, MDMA, L-DOPA and cannabinoids have shown efficacy in enhancing fear-extinction learning in humans. They are thus investigated in clinical trials as an augmentative strategy for speeding up and enhancing the long-term effectiveness of exposure-based psychotherapy, which could render chronic anxiolytic drug treatment dispensable for many patients. These efforts are indicative of a rekindled interest and renewed optimism in the anxiety drug discovery field, after decades of relative stagnation.

Sartori, S. B., & Singewald, N. (2019). Novel pharmacological targets in drug development for the treatment of anxiety and anxiety-related disorders. Pharmacology & therapeutics, 107402., 10.1016/j.pharmthera.2019.107402
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Ketamine and depression: a narrative review.

August 27, 2019 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / ,

Abstract

Depression is the third leading cause of disability in the world. Depressive symptoms may be reduced within several weeks after the start of conventional antidepressants, but treatment resistance concerns one-third of patients who fail to achieve recovery. Over the last 20 years, ketamine, an antagonist of the N-methyl-D-aspartate receptor, has been described to have antidepressant properties. A literature review was conducted through an exhaustive electronic search. It was restricted to Cochrane reviews, meta-analyses, and randomized controlled trials (RCTs) of ketamine for major depressive disorder and/or bipolar disorder. This review included two Cochrane reviews, 14 meta-analyses and 15 trials. Ketamine was studied versus placebo, versus other comparators and as an anesthetic adjuvant before electroconvulsive therapy. In 14 publications, ketamine provided a rapid antidepressant effect with a maximum efficacy reached at 24 hrs. Its effect lasted for 1-2 weeks after infusion, but a longer-term effect is little reported. Ketamine does not seem to improve depressive symptoms at the end of electroconvulsive sessions. Safety and tolerability profiles with ketamine at low single dose are generally good in depressed patients. However, there is a lack of data concerning ketamine with repeated administration at higher doses. The clinical use of ketamine is increasing. Intranasal (S)-ketamine has recently been approved for depression by the Food and Drug Administration. It could be a promising treatment in depressed patients with suicidal ideation. Collectively, the level of proof of efficacy remains low and more RCTs are needed to explore efficacy and safety issues of ketamine in depression.
Corriger, A., & Pickering, G. (2019). Ketamine and depression: a narrative review. Drug design, development and therapy, 13, 3051., https://doi.org/10.2147/DDDT.S221437
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Efficacy of 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for posttraumatic stress disorder: A systematic review and meta-analysis.

August 19, 2019 / Anxiety Disorders / PTSD, MDMA, Papers, Psychology, Publications / By / , , ,

Abstract

BACKGROUND:
Posttraumatic stress disorder (PTSD) is a common psychiatric condition that can develop following a traumatic experience. PTSD is associated with significant disability, a large economic burden, and despite the range of therapies to treat PTSD, response to antidepressants is limited. A growing body of clinical research suggests the efficacy of 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy in individuals with treatment-refractory PTSD.
AIM:
To assess the effectiveness and safety of MDMA-assisted psychotherapy for reducing symptoms of PTSD, a systematic review and meta-analysis was undertaken.
METHODS:
Six online databases were searched from inception to December 2018. Reference lists of relevant articles were manually searched as well as electronic sources of ongoing trials and conference proceedings. Researchers active in the subject were also contacted. Eligible studies included randomized and quasi-randomized clinical trials using MDMA-assisted psychotherapy for PTSD in comparison with other medications, placebo or no medication (supportive care). We used standard methodological procedures expected by the Cochrane Collaboration. Two authors assessed studies for inclusion and extracted data. Using random-effects meta-analysis with Cochrane’s Review Manager 5.3, we obtained standardized mean differences [SMD] and rate ratios [RR] for reduction in PTSD symptomatology.
RESULTS:
A total of 5 trials met inclusion criteria, totaling 106 participants (average age: 35-40 years, 70% female). Studies were rated as moderate in quality. MDMA-assisted psychotherapy demonstrated a high rate of clinical response (RR = 3.47, 95% CI: 1.70, 7.06), remission (RR = 2.63, 95% CI: 1.37, 5.02), with a large effect size at reducing the symptoms of PTSD (SMD = 1.30, 95% CI: 0.66, 1.94). Available evidence indicates that MDMA was well-tolerated, with few serious adverse events reported across studies.
CONCLUSIONS:
MDMA-assisted psychotherapy appears to be a potentially safe, effective, and durable treatment for individuals with chronic, treatment-refractory PTSD. However, future studies involving larger samples and longer durations of treatment and follow-up are warranted-and underway.
Bahji, A., Forsyth, A., Groll, D., & Hawken, E. R. (2019). Efficacy of 3, 4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for posttraumatic stress disorder: A systematic review and meta-analysis. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 109735., https://doi.org/10.1016/j.pnpbp.2019.109735
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Psilocybin-assisted mindfulness training modulates self-consciousness and brain default mode network connectivity with lasting effects

August 1, 2019 / Mushrooms / Psilocybin, Papers, Psychology, Publications / By / , , ,

Abstract

Both psychedelics and meditation exert profound modulatory effects on consciousness, perception and cognition, but their combined, possibly synergistic effects on neurobiology are unknown. Accordingly, we conducted a randomized, double-blind, placebo-controlled study with 38 participants following a single administration of the psychedelic psilocybin (315 μg/kg p.o.) during a 5-day mindfulness retreat. Brain dynamics were quantified directly pre- and post-intervention by functional magnetic resonance imaging during the resting state and two meditation forms. The analysis of functional connectivity identified psilocybin-related and mental state–dependent alterations in self-referential processing regions of the default mode network (DMN). Notably, decoupling of medial prefrontal and posterior cingulate cortices, which is thought to mediate sense of self, was associated with the subjective ego dissolution effect during the psilocybin-assisted mindfulness session. The extent of ego dissolution and brain connectivity predicted positive changes in psycho-social functioning of participants 4 months later. Psilocybin, combined with meditation, facilitated neurodynamic modulations in self-referential networks, subserving the process of meditation by acting along the anterior–posterior DMN connection. The study highlights the link between altered self-experience and subsequent behavioral changes. Understanding how interventions facilitate transformative experiences may open novel therapeutic perspectives. Insights into the biology of discrete mental states foster our understanding of non-ordinary forms of human self-consciousness and their concomitant brain substrate.

Smigielski, L., Scheidegger, M., Kometer, M., & Vollenweider, F. X. (2019). Psilocybin-assisted mindfulness training modulates self-consciousness and brain default mode network connectivity with lasting effects. NeuroImage, 196, 207-215., https://doi.org/10.1016/j.neuroimage.2019.04.009
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Promises and concerns regarding the use of ketamine and esketamine in the treatment of depression.

August 1, 2019 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , ,

Pérez‐Esparza, R., Kobayashi‐Romero, L. F., García‐Mendoza, A. M., Lamas‐Aguilar, R. M., & Fonseca‐Perezamador, A. (2019). Promises and concerns regarding the use of ketamine and esketamine in the treatment of depression. Acta Psychiatrica Scandinavica, 140(2), 182-183., https://doi.org/10.1111/acps.13063
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Classical psychedelics for the treatment of depression and anxiety: A systematic review.

July 30, 2019 / Anxiety Disorders / PTSD, Ayahuasca, Depressive Disorders, LSD, Mushrooms / Psilocybin, Papers, Psychology, Publications / By / , ,

Abstract

BACKGROUND:
Depression and anxiety are prevalent psychiatric disorders that carry significant morbidity. Pharmacological and psychosocial interventions are used to manage these conditions, but their efficacy is limited. Recent interest into the use of psychedelic-assisted therapy using ayahuasca, psilocybin or lysergic acid diethylamide (LSD) may be a promising alternative for patients unresponsive to traditional treatments. This review aims to determine the efficacy and tolerability of psychedelics in the management of resistant depression.
METHODS:
Clinical trials investigating psychedelics in patients with depression and/or anxiety were searched via MEDLINE, EMBASE and PsychINFO. Efficacy was assessed by measuring symptom improvement from baseline, and tolerability was evaluated by noting the incidence and type of adverse effects reported. Risk of bias was assessed.
RESULTS:
Seven studies, with 130 patients, were analysed in this review. Three were conducted in patients with depression, two in patients with anxiety and two in patients with both. In a supportive setting, ayahuasca, psilocybin, and LSD consistently produced immediate and significant anti-depressant and anxiolytic effects that were endured for several months. Psychedelics were well-tolerated. The most common adverse effects were transient anxiety, short-lived headaches, nausea and mild increases in heart rate and blood pressure.
LIMITATIONS:
At present, the number of studies on this subject is very limited; and the number of participating patients within these is also limited as the treatment under investigations is a relatively novel concept.
CONCLUSIONS:
Though further evidence is required, psychedelics appear to be effective in significantly reducing symptoms of depression and anxiety and are well-tolerated.

Muttoni, S., Ardissino, M., & John, C. (2019). Classical psychedelics for the treatment of depression and anxiety: a systematic review. Journal of affective disorders., https://doi.org/10.1016/j.jad.2019.07.076
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Ketamine Enhances Visual Sensory Evoked Potential Long-term Potentiation in Patients With Major Depressive Disorder

January 27, 2022 / Depressive Disorders, Ketamine, Neuroscience, Papers / Leave a Comment / By / , , , , , , , , , , ,

Abstract

Background: The rapid-acting clinical effects of ketamine as a novel treatment for depression along with its complex pharmacology have made it a growing research area. One of the key mechanistic hypotheses for how ketamine works to alleviate depression is by enhancing long-term potentiation (LTP)-mediated neural plasticity.

Methods: The objective of this study was to investigate the plasticity hypothesis in 30 patients with depression noninvasively using visual LTP as an index of neural plasticity. In a double-blind, active placebo-controlled crossover trial, electroencephalography-based LTP was recorded approximately 3 to 4 hours following a single 0.44-mg/kg intravenous dose of ketamine or active placebo (1.7 ng/mL remifentanil) in 30 patients. Montgomery-Åsberg Depression Rating Scale scores were used to measure clinical symptoms. Visual LTP was measured as a change in the visually evoked potential following high-frequency visual stimulation. Dynamic causal modeling investigated the underlying neural architecture of visual LTP and the contribution of ketamine.

Results: Montgomery-Åsberg Depression Rating Scale scores revealed that 70% of participants experienced 50% or greater reduction in their depression symptoms within 1 day of receiving ketamine. LTP was demonstrated in the N1 (p = .00002) and P2 (p = 2.31 × 10-11) visually evoked components. Ketamine specifically enhanced P2 potentiation compared with placebo (p = .017). Dynamic causal modeling replicated the recruitment of forward and intrinsic connections for visual LTP and showed complementary effects of ketamine indicative of downstream and proplasticity modulation.

Conclusions: This study provides evidence that LTP-based neural plasticity increases within the time frame of the antidepressant effects of ketamine in humans and supports the hypothesis that changes to neural plasticity may be key to the antidepressant properties of ketamine.

Sumner, R. L., McMillan, R., Spriggs, M. J., Campbell, D., Malpas, G., Maxwell, E., Deng, C., Hay, J., Ponton, R., Kirk, I. J., Sundram, F., & Muthukumaraswamy, S. D. (2020). Ketamine Enhances Visual Sensory Evoked Potential Long-term Potentiation in Patients With Major Depressive Disorder. Biological psychiatry. Cognitive neuroscience and neuroimaging, 5(1), 45–55. https://doi.org/10.1016/j.bpsc.2019.07.002

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Metabolism of lysergic acid diethylamide (LSD): an update.

July 16, 2019 / LSD, Papers, Pharmacology & Chemistry, Psychology, Publications / By /

Abstract

Lysergic acid diethylamide (LSD) is the most potent hallucinogen known and its pharmacological effect results from stimulation of central serotonin receptors (5-HT2). Since LSD is seen as physiologically safe compound with low toxicity, its use in therapeutics has been renewed during the last few years. This review aims to discuss LSD metabolism, by presenting all metabolites as well as clinical and toxicological relevance. LSD is rapidly and extensively metabolized into inactive metabolites; whose detection window is higher than parent compound. The metabolite 2-oxo-3-hydroxy LSD is the major human metabolite, which detection and quantification is important for clinical and forensic toxicology. Indeed, information about LSD pharmacokinetics in humans is limited and for this reason, more research studies are needed.
Libânio Osório Marta, R. F. (2019). Metabolism of lysergic acid diethylamide (LSD): an update. Drug metabolism reviews, 51(3), 378-387. https://doi.org/10.1080/03602532.2019.1638931
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Esketamine for treatment resistant depression.

July 16, 2019 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , , , ,

Abstract

Introduction: Treatment Resistant Depression (TRD) is a common and burdensome condition with poor outcomes and few treatment options. Esketamine is the S-enantiomer of ketamine and has recently been FDA approved in the United States for treating depression that has failed to respond to trials of two or more antidepressants. Areas covered: This review will briefly discuss current treatment options for TRD, then review esketamine. Relevant literature was identified through online database searches, and clinical trial data were provided by Janssen Pharmaceuticals. Pharmacology, including kinetics and dynamics, is discussed, then clinical data regarding efficacy and safety for esketamine from Phase 2-3 trials are reviewed. Expert opinion: In the expert opinion, the authors discuss multiple factors including patient, physician, and social factors that will influence the use of esketamine. While the efficacy of esketamine compared to off-label use of racemic ketamine remains unclear, both esketamine’s approval for use in TRD and longer-term safety data may position it preferentially above racemic ketamine, although factors such as cost and monitoring requirements may limit its use. While questions remain regarding duration and frequency of treatment, as well as addictive potential, esketamine is a novel treatment option offering new hope for TRD.
Swainson, J., Thomas, R. K., Archer, S., Chrenek, C., MacKay, M. A., Baker, G., … & Demas, M. L. (2019). Esketamine for treatment resistant depression. Expert review of neurotherapeutics, 1-13., https://doi.org/10.1080/14737175.2019.1640604
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