Zuranolone - synthetic neurosteroid in treatment of mental disorders: narrative review

With each passing year, the number of people suffering from mental disorders grows at a disturbing speed. Neuroactive steroids are a new promising group of drugs with the potential for use in many diseases like postpartum depression, postnatal psychosis, major depression, insomnia, bipolar disorder, and Parkinson's tremor, due to their ability to modulate the activity of GABAA receptor. Neurosteroids are progesterone metabolites that are synthesized from cholesterol or steroid hormones in various brain regions. They regulate neuronal development, regeneration, and neurotransmission. They are implicated in mood disorders, anxiety disorders, schizophrenia, PTSD, and impulsive aggression. Neurosteroids have been studied for their potential to prevent or treat neurodegenerative diseases such as Alzheimer's disease and HIV-associated dementia. They can promote neurogenesis, neuronal survival, myelination, and memory function. They can also affect the growth and sensitivity of hormone-dependent brain tumors such as gliomas. Zuranolone, a newly registered neurosteroid drug has shown huge flexibility in both clinical and ambulatory treatment thanks to its pharmacokinetic traits, especially the possibility for oral administration, unlike its predecessor Brexanolone. Zuranolone is a synthetic positive allosteric modulator of the GABAA receptor that can be taken orally. The review aims to summarize the current knowledge on zuranolone as a novel neurosteroid drug for various mental disorders, especially for postpartum mental disorders for which this drug was meant originally. It covers studies indexed in the PubMed, Scopus, and Web of Science databases published since 2017. Keywords used in the search, as well as inclusion and exclusion criteria, are given in the aims and methodology section. The review explains the evidence for the role of neurosteroids, especially allopregnanolone, in the pathophysiology and treatment of postpartum depression. It discusses the mechanisms of neurosteroid action, the changes in neurosteroid levels during pregnancy and postpartum, and the clinical trials of brexanolone and zuranolone, two synthetic analogs of allopregnanolone, for postpartum depression. It provides an overview of the biosynthesis and metabolism of neurosteroids in the central and peripheral nervous system. Furthermore, it explains the different sources and pathways of neurosteroid production and the factors that influence their synthesis and regulation, such as stress, hormones, drugs, and genetic variations. The review also explores the potential relevance of neurosteroids for other psychiatric disorders, such as major depression, bipolar disorder, post-traumatic stress disorder (PTSD), schizophrenia, and premenstrual dysphoric disorder. Finally, it highlights the associations between neurosteroid levels and symptom severity and the effects of neurosteroid modulation on mood, cognition, and neuroplasticity.

Effects of estrogen and progesterone on neuroactive steroids and cytokines in patients with suicidality

BACKGROUND

In ovulating psychiatric patients experiencing suicidality, suicidal ideation (SI) often peaks perimenstrually. Our recent double-blind, placebo-controlled, crossover randomized clinical trial (RCT; NCT03720847) showed that perimenstrual administration of estradiol and progesterone (EP) can prevent this peak in SI and depressed mood. In this pre-registered follow-up analysis, we studied how the menstrual cycle and experimental manipulation affected two neurobiological systems associated with the menstrual cycle and suicide risk: GABAergic neuroactive steroids (NAS) and peripheral cytokines.

METHODS

In 26 psychiatric outpatients with natural menstrual cycles and past-month SI, we analyzed serum samples from three blood draws (midluteal, perimenstrual, midfollicular) per experimental condition (EP vs placebo) timed to a luteinizing hormone-surge ovulation test. Using gas chromatography/mass spectrometry (GC/MS), we measured the progesterone (P4)-derived pregnane NAS (3α,5α)- 3-hydroxypregnan20-one (3α,5α-THP), (3α,5β)- 3-hydroxypregnan-20-one (3α,5β-THP), (3α,5α)- 3,21-dihydroxypregnan-20-one (3α,5α-THDOC), (3α,5α)- 3-hydroxyandrostan-17-one (3α,5α-A), the androstane NAS (3α,5β)- 3-hydroxyandrostan-17-one (3α,5β-A), (3α,5α,17β)-androstane-3,17-diol (3α,5α-A-diol), (3α,5β,17β)-androstane-3,17-diol (3α,5β-A-diol), and their precursor pregnenolone. High sensitivity multiplex assay kits quantified peripheral cytokines IL-1β, IL-6, and TNF-α.

RESULTS

P4-derived NAS fluctuated in parallel with P4 and increased with exogenous perimenstrual administration of EP. Conversely, androstane NAS either did not fluctuate or fluctuated inversely from P4, and these NAS decreased with exogenous EP. Peripheral cytokines did not show cyclical patterns, but each significantly predicted SI, depressed mood, or anxiousness. Concomitant SSRI medication use predicted lower androstane NAS.

CONCLUSIONS

While preliminary and exploratory, our findings provide critical descriptive context for future studies. Further, our work presents menstrual cycle-related patterns for ten frequently-studied biomarkers, allowing for improved quality of comparisons involving naturally-cycling populations in research.

Prevention of suicide by clozapine in mental disorders: systematic review

BACKGROUND

Previous research has investigated the efficacy of clozapine in reducing suicidality in patients with schizophrenia and schizoaffective disorder. We aimed to systematically review published evidence, including studies concerning clozapine administration to treat: (a) refractory suicidality in other mental disorders, including bipolar disorder and borderline and other personality disorders; and (b) refractory cases of non-suicidal self-injury.

METHOD

We performed a PUBMED-search (last day: July 17, 2022) of English-language studies, combining the keywords "clozapine", "suicidality", and "suicide" with various psychopathological terms (e.g. "schizophrenia"). All duplications were eliminated.

RESULTS

Fifty-one studies were eligible for inclusion in the review. Most studies suggest a superior anti-suicide effect of clozapine in schizophrenia/schizoaffective disorder, compared to other antipsychotics, or no antipsychotic therapy, which is not due to the close monitoring of patients for blood dyscrasias. No consensus exists as to whether other antipsychotic drugs share this effect. Discontinuation of clozapine is associated with increases in suicidality. Reductions in refractory suicidality/NSSI are observed in clozapine-treated patients with bipolar disorder or borderline personality disorder, but the evidence is limited. Potential biological underpinnings of the anti-suicide effect of clozapine include its unique profile of modulation of brain neurotransmitters; its non-selectivity for neurotransmitter receptors; specific genetic and hormonal factors; effects on neuroinflammation; and ability to elicit epileptiform activity.

CONCLUSION

The superior anti-suicide effect of clozapine in schizophrenia/schizoaffective disorder patients is well established. It may have a role in severe and refractory cases of suicidality and non-suicidal self-injury in patients with bipolar disorder or borderline personality disorder, but the level and quality of supporting evidence is limited.

Non-pharmacological strategies for self-directed and interpersonal violence in people with severe mental illness: a rapid overview of systematic reviews

INTRODUCTION

Self-directed and interpersonal violence among people with severe mental illness has become a health priority. Though non-pharmacological interventions have been investigated, to our knowledge, no summary of all systematic reviews on this topic has been reported. We will conduct a rapid overview of reviews to synthesise evidence available by identifying systematic reviews on non-pharmacological interventions for self-directed or interpersonal violence in people with severe mental illness.

METHODS AND ANALYSIS

This is a protocol for a rapid overview of reviews. The overview will include any systematic reviews (with or without meta-analyses) of randomised controlled trials (RCTs) or cluster RCTs that examine the effect of non-pharmacological interventions on self-directed or interpersonal violence in people with severe mental illness. This protocol applies the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Protocols, the criteria for conducting overviews of reviews in the Cochrane Handbook of Systematic Reviews of Interventions and the criteria for the Cochrane Rapid Reviews. To identify studies, a search will be performed in the following databases: PubMed, EMBASE, PsycINFO, CINAHL, LILACS, SciELO, Web of Science, Scopus, ProQuest, the Cochrane Database of Systematic Reviews through the Cochrane Library and the Epistemonikos database of systematic reviews. The searches date from inception to September 2020. The study selection process will be described using a PRISMA flow diagram, we will assess the quality of evidence in systematic reviews included and the quality of the systematic reviews themselves and the main results will be summarised in categories to provide a map of the evidence available.

ETHICS AND DISSEMINATION

No patients or other participants will be involved in this study. The results will be presented at mental health conferences and for publication in a peer-reviewed journal.

REGISTRATION DETAILS

The protocol was registered on the Open Science Framework (https://osf.io/myzd9/).

Bipolar disorders

Bipolar disorders are a complex group of severe and chronic disorders that includes bipolar I disorder, defined by the presence of a syndromal, manic episode, and bipolar II disorder, defined by the presence of a syndromal, hypomanic episode and a major depressive episode. Bipolar disorders substantially reduce psychosocial functioning and are associated with a loss of approximately 10-20 potential years of life. The mortality gap between populations with bipolar disorders and the general population is principally a result of excess deaths from cardiovascular disease and suicide. Bipolar disorder has a high heritability (approximately 70%). Bipolar disorders share genetic risk alleles with other mental and medical disorders. Bipolar I has a closer genetic association with schizophrenia relative to bipolar II, which has a closer genetic association with major depressive disorder. Although the pathogenesis of bipolar disorders is unknown, implicated processes include disturbances in neuronal-glial plasticity, monoaminergic signalling, inflammatory homoeostasis, cellular metabolic pathways, and mitochondrial function. The high prevalence of childhood maltreatment in people with bipolar disorders and the association between childhood maltreatment and a more complex presentation of bipolar disorder (eg, one including suicidality) highlight the role of adverse environmental exposures on the presentation of bipolar disorders. Although mania defines bipolar I disorder, depressive episodes and symptoms dominate the longitudinal course of, and disproportionately account for morbidity and mortality in, bipolar disorders. Lithium is the gold standard mood-stabilising agent for the treatment of people with bipolar disorders, and has antimanic, antidepressant, and anti-suicide effects. Although antipsychotics are effective in treating mania, few antipsychotics have proven to be effective in bipolar depression. Divalproex and carbamazepine are effective in the treatment of acute mania and lamotrigine is effective at treating and preventing bipolar depression. Antidepressants are widely prescribed for bipolar disorders despite a paucity of compelling evidence for their short-term or long-term efficacy. Moreover, antidepressant prescription in bipolar disorder is associated, in many cases, with mood destabilisation, especially during maintenance treatment. Unfortunately, effective pharmacological treatments for bipolar disorders are not universally available, particularly in low-income and middle-income countries. Targeting medical and psychiatric comorbidity, integrating adjunctive psychosocial treatments, and involving caregivers have been shown to improve health outcomes for people with bipolar disorders. The aim of this Seminar, which is intended mainly for primary care physicians, is to provide an overview of diagnostic, pathogenetic, and treatment considerations in bipolar disorders. Towards the foregoing aim, we review and synthesise evidence on the epidemiology, mechanisms, screening, and treatment of bipolar disorders.

The neurobiology of suicide in psychosis: A systematic review

The lifetime risk of dying by suicide in schizophrenia and related psychoses has been estimated to be approximately between 5% and 7%, though some have estimated that the number is closer to 10%. The highest risk for suicide occurs within the first year after presentation, when patients have a 12 times greater risk of dying by suicide than the general population, or a 60% higher risk compared with patients in other phases of psychosis, although the risk continues for many years. Some 31% of all deaths in first and early episode samples are due to suicide. Studies in individuals at clinical high-risk for psychosis (CHR) or with attenuated positive symptoms also demonstrate that suicidality is common and problematic in these individuals. Therefore, suicide in psychosis is a particularly severe problem. In order to develop interventions aimed at reducing the risk of suicide in psychotic individuals, it will be critical to understand the neurobiology of suicide in psychosis. In this paper, I report on the results of a systematic review of the work done to date on the neurobiology of suicide in psychosis and on suicidality in the CHR period. I will also identify gaps in knowledge and discuss future strategies for studying the neurobiology of suicidality in psychosis that may help to disentangle the links between suicide and psychosis and, by doing so, allow us to gain a greater understanding of the relationship between suicide and psychosis, which is critical for developing interventions aimed at reducing the risk of suicide in psychotic individuals.

Can epigenetic biomarkers lead us to precision medicine in predicting treatment response and remission for patients being considered for ECT?

While electroconvulsive therapy (ECT) is the gold standard for the treatment of depression, there is currently a lack of clinically useful biomarkers predictive of treatment response. Epigenetics provides reasonable potential as a biomarker for treatment response for ECT, given that the study of epigenetics combines both the impact of biology and environment in the shaping of psychopathology. Initial limited studies are promising. Further studies to establish precision medicine in term of ECT treatment response using epigenetics predictors can provide great benefit to both patients and physicians in saving time, money, and frustration.

Widespread Cortical Thickness Is Associated With Neuroactive Steroid Levels

Background

Neuroactive steroids are endogenous molecules with regenerative and neuroprotective actions. Both cortical thickness and many neuroactive steroid levels decline with age and are decreased in several neuropsychiatric disorders. However, a systematic examination of the relationship between serum neuroactive steroid levels and in vivo measures of cortical thickness in humans is lacking.

Methods

Peripheral serum levels of seven neuroactive steroids were assayed in United States military veterans. All (n = 143) subsequently underwent high-resolution structural MRI, followed by parcellelation of the cortical surface into 148 anatomically defined regions. Regression modeling was applied to test the association between neuroactive steroid levels and hemispheric total gray matter volume as well as region-specific cortical thickness. False discovery rate (FDR) correction was used to control for Type 1 error from multiple testing.

Results

Neuroactive steroid levels of allopregnanolone and pregnenolone were positively correlated with gray matter thickness in multiple regions of cingulate, parietal, and occipital association cortices (r = 0.20–0.47; p < 0.05; FDR-corrected).

Conclusion

Positive associations between serum neuroactive steroid levels and gray matter cortical thickness are found in multiple brain regions. If these results are confirmed, neuroactive steroid levels and cortical thickness may help in monitoring the clinical response in future intervention studies of neuroregenerative therapies.

Clozapine in Treatment-Resistant Bipolar Disorder With Suicidality. Three Case Reports

Bipolar disorder is associated with a high risk of suicide attempts and suicide deaths. The suicide mortality of people with bipolar disorder is approximately 25 times higher than the general population. No approved pharmacological strategies for suicidal thoughts and attempts in bipolar disorder have been introduced so far, and lithium remains as the first-line treatment for suicidal subjects. Clozapine is also a potentially good candidate for this indication. This case series represents three treatment-resistant bipolar patients with severe suicidal ideation who responded to low-dose clozapine treatment.

The 5α-reductase inhibitor finasteride increases suicide-related aggressive behaviors and blocks clozapine-induced beneficial effects in an animal model of schizophrenia

Death by suicide is 5 times higher among schizophrenia patients than in the general population. There is now compelling evidence suggesting that the pathophysiology of suicide in schizophrenia does not involve central serotonergic neurotransmission disturbances, as has been shown in other contexts. We recently developed and characterized a murine Two-Hit Model of Suicide-related behavior in a schizophrenia-like context (THMS) (gestational inflammation with polyI:C at gestational day 12 followed by post-weaning social isolation). In this THMS model, we have recently shown that the atypical antipsychotic clozapine normalized the prepulse inhibition (PPI) deficits as well suicide-related, impulsive aggressive and anxiety-like behaviors. While the mechanisms underlying the suicide-reducing benefits of clozapine in schizophrenic patients are not well understood, previous works have revealed that clozapine alters brain levels of neurosteroids, such as allopregnanolone. In the present study, we thus investigated the role of endogenous neurosteroids in clozapine action by evaluating whether the 5α-reductase inhibitor finasteride could overturn the ability of clozapine to reduce suicide-related behaviors. We found that clozapine significantly improved the PPI deficits in THMS mice, which could not be reversed by finasteride treatment. However, finasteride counteracted the ability of clozapine to decrease the exploratory behaviors in the open-field test. In the resident-intruder test, THMS mice showed exacerbated aggressiveness and impulsivity following finasteride alone. In this resident-intruder paradigm, clozapine alone effectively blocked the finasteride-enhanced effects on aggression and impulsivity. Altogether, these findings support the existence of a complex interaction between clozapine and neurosteroids in THMS mice. Further investigations are now required to clarify the details of the molecular mechanisms involved.

Epidemiology, neurobiology and pharmacological interventions related to suicide deaths and suicide attempts in bipolar disorder: Part I of a report of the International Society for Bipolar Disorders Task Force on Suicide in Bipolar Disorder

OBJECTIVES

Bipolar disorder is associated with elevated risk of suicide attempts and deaths. Key aims of the International Society for Bipolar Disorders Task Force on Suicide included examining the extant literature on epidemiology, neurobiology and pharmacotherapy related to suicide attempts and deaths in bipolar disorder.

METHODS

Systematic review of studies from 1 January 1980 to 30 May 2014 examining suicide attempts or deaths in bipolar disorder, with a specific focus on the incidence and characterization of suicide attempts and deaths, genetic and non-genetic biological studies and pharmacotherapy studies specific to bipolar disorder. We conducted pooled, weighted analyses of suicide rates.

RESULTS

The pooled suicide rate in bipolar disorder is 164 per 100,000 person-years (95% confidence interval = [5, 324]). Sex-specific data on suicide rates identified a 1.7:1 ratio in men compared to women. People with bipolar disorder account for 3.4-14% of all suicide deaths, with self-poisoning and hanging being the most common methods. Epidemiological studies report that 23-26% of people with bipolar disorder attempt suicide, with higher rates in clinical samples. There are numerous genetic associations with suicide attempts and deaths in bipolar disorder, but few replication studies. Data on treatment with lithium or anticonvulsants are strongly suggestive for prevention of suicide attempts and deaths, but additional data are required before relative anti-suicide effects can be confirmed. There were limited data on potential anti-suicide effects of treatment with antipsychotics or antidepressants.

CONCLUSION

This analysis identified a lower estimated suicide rate in bipolar disorder than what was previously published. Understanding the overall risk of suicide deaths and attempts, and the most common methods, are important building blocks to greater awareness and improved interventions for suicide prevention in bipolar disorder. Replication of genetic findings and stronger prospective data on treatment options are required before more decisive conclusions can be made regarding the neurobiology and specific treatment of suicide risk in bipolar disorder.