Understanding the suicidal brain

Social and Biological Parameters Involved in Suicide Ideation During the COVID-19 Pandemic: A Narrative Review

Fear is an indispensable characteristic of any infectious disease, and the alarm will be further amplified when the infection spreads uncontrollable, unpredictable, and global. The novel corona virus (SARS CoV-2) lead Covid-19, has been declared as a global emergency by WHO as it has affected millions of people with a high mortality rate. The non-availability of medicine for Covid-19 and the various control measures such as social distancing, self-isolation, house quarantine, and the new normal implementation by different nations across the world to control the spread of Covid-19 made people vulnerable to fear and anxiety. As a result, considerable number of Covid-19-related suicidal deaths has been reported across the world during this pandemic. There have been several studies which describe the psychosocial aspects of suicidal ideation. However, the research on the biological aspects of suicidal ideation/suicidal risk factors that are related to pandemic are unreported. Hence this review article is intended to provide a comprehensive analysis of suicidal deaths during Covid-19 and also aimed to addresses the possible link between suicidal ideation and different factors, including psycho-social, behavioral, neurobiological factors (proximal, distal, and inflammatory) and immunity. The alterations in glutamatergic and GABAergic neurotransmitters had upregulated the GABARB3, GABARA4, GABARA3, GABARR1, GABARG2, and GAD2 gene expressions in suicidal victims. The changes in the Kynurenine (KYN) pathway, Hypothalamus-Pituitary-Adrenal axis (HPA axis) hyperactivation, and dysregulation of serotonin biosynthesis would significantly alter the brain chemistry in people with suicide ideation.

Psychiatric disorders and suicide risk among adults with disabilities: A nationwide retrospective cohort study

BACKGROUND

Adults with disabilities demonstrate a higher suicide risk than the general population; however, the association between mental illness and death by suicide among disabled adults remains relatively unknown. We aimed to explore the relationship between psychiatric disorders and suicide risk in adults with disabilities.

METHODS

We used nationally representative cohort data and included adults who registered as having a disability from 2004 to 2012, following up with them throughout 2013. We used the clinical diagnoses of all psychiatric disorders as an independent variable and death by suicide as a dependent variable to estimate the adjusted hazard ratio (AHR) of suicide risk using a Cox proportional hazards model.

RESULTS

Among adults with disabilities (n = 30,386), those who had any psychiatric disorder were at an increased risk of death by suicide compared to those without mental illness (AHR 1.42; 95% confidence interval [CI] 1.02-1.99). Adults with mild disabilities who had psychiatric or mood disorders were more likely to commit suicide than the comparison group (AHR 1.67, 3.00; 95% CI 1.13-2.46, 1.95-4.61, respectively).

LIMITATIONS

The actual time of disability onset could differ from the time of disability registration.

CONCLUSIONS

Adults with disabilities who have psychiatric disorders are at increased risk of suicide compared to those without mental illness. During rehabilitation treatment after disability diagnosis, mental health support should be provided to those who have psychiatric illnesses to potentially reduce the risk of death by suicide.

Coding and Non-Coding RNA Abnormalities in Bipolar Disorder

The molecular mechanisms underlying bipolar disorder (BPD) have remained largely unknown. Postmortem brain tissue studies comparing BPD patients with healthy controls have produced a heterogeneous array of potentially implicated protein-coding RNAs. We hypothesized that dysregulation of not only coding, but multiple classes of RNA (coding RNA, long non-coding (lnc) RNA, circular (circ) RNA, and/or alternative splicing) underlie the pathogenesis of BPD. Using non-polyadenylated libraries we performed RNA sequencing in postmortem human medial frontal gyrus tissue from BPD patients and healthy controls. Twenty genes, some of which not previously implicated in BPD, were differentially expressed (DE). PCR validation and replication confirmed the implication of these DE genes. Functional in silico analyses identified enrichment of angiogenesis, vascular system development and histone H3-K4 demethylation. In addition, ten lncRNA transcripts were differentially expressed. Furthermore, an overall increased number of alternative splicing events in BPD was detected, as well as an increase in the number of genes carrying alternative splicing events. Finally, a large reservoir of circRNAs populating brain tissue not affected by BPD is described, while in BPD altered levels of two circular transcripts, cNEBL and cEPHA3, are reported. cEPHA3, hitherto unlinked to BPD, is implicated in developmental processes in the central nervous system. Although we did not perform replication analyses of non-coding RNA findings, our findings hint that RNA dysregulation in BPD is not limited to coding regions, opening avenues for future pharmacological investigations and biomarker research.

Decision-making performance of depressed patients within 72 h following a suicide attempt

BACKGROUND

The significance of decision-making in suicidal behaviour is often highlighted; however, the performance of persons in suicide crisis is unknown. This study aimed to explore the comprehensive decision-making profile of depressed patients following a suicide attempt.

METHODS

Decision-making was measured by reward- ("ABCD") and punishment- ("EFGH") sensitive versions of the Iowa Gambling Task (IGT) in 59 medication-free depressed patients within 72 h after a suicide attempt and in 46 healthy control subjects. Severity of depressive symptoms was assessed in the patient group by the Hamilton Depression Rating Scale.

RESULTS

Performance of the two groups differed significantly on the IGT ABCD, while a trend towards significant differences was seen on the IGT EFGH. Severity of depressive symptoms did not affect the depressed participants' decision-making performance.

LIMITATIONS

Subjects were not matched for years of education. Administration of the IGT ABCD and IGT EFGH was not counterbalanced. Methods of suicide attempts and history of previous attempts were not collected.

CONCLUSIONS

Individuals with a recent suicide attempt showed decision-making dysfunction on both IGT versions. However, on the EFGH, the overall difference between groups was not significant, depressed participants' performance remained poor during all blocks. Their behaviour reflected a focus on best immediate possible outcomes, not regarding future adverse consequences. This could be a result of psychological and cognitive alterations which modulate suicidal behaviour independent from mood. Further longitudinal studies should verify this possibility. Investigation of state-dependent neuropsychological characteristics of suicidal behaviour might be essential for detecting acute suicidal crisis.

Psychiatric disorders biochemical pathways unraveled by human brain proteomics

Approximately 25 % of the world population is affected by a mental disorder at some point in their life. Yet, only in the mid-twentieth century a biological cause has been proposed for these diseases. Since then, several studies have been conducted toward a better comprehension of those disorders, and although a strong genetic influence was revealed, the role of these genes in disease mechanism is still unclear. This led most recent studies to focus on the molecular basis of mental disorders. One line of investigation that has risen in the post-genomic era is proteomics, due to its power of revealing proteins and biochemical pathways associated with biological systems. Therefore, this review compiled and analyzed data of differentially expressed proteins, which were found in postmortem brain studies of the three most prevalent psychiatric diseases: schizophrenia, bipolar disorder and major depressive disorders. Overviewing both the proteomic methods used in postmortem brain studies, the most consistent metabolic pathways found altered in these diseases. We have unraveled those disorders share about 21 % of proteins affected, and though most are related to energy metabolism pathways deregulation, the main differences found are 14-3-3-mediated signaling in schizophrenia, mitochondrial dysfunction in bipolar disorder and oxidative phosphorylation in depression.

Understanding epigenetic architecture of suicide neurobiology: A critical perspective

Current understanding of environmental cross-talk with genetic makeup is found to be mediated through an epigenetic interface which is associated with prominent reversible and heritable changes at gene expression level. Recent emergence of epigenetic modulation in shaping the genetic information has become a key regulatory factor in answering the underlying complexities associated with several mental disorders. A comprehensive understanding of the pertinent changes in the epigenetic makeup of suicide phenotype exhibits a characteristic signature with the possibility of using it as a biomarker to help predict the risk factors associated with suicide. Within the scope of this current review, the most sought after epigenetic changes of DNA methylation and histone modification are thoroughly scrutinized to understand their close functional association with the broad spectrum of suicide phenotype.

Genetic Vulnerability as a Distal Risk Factor for Suicidal Behaviour: Historical Perspective and Current Knowledge

INTRODUCTION

Suicide is a multidimensional problem. Observations of family history of suicide suggest the existence of a genetic vulnerability to suicidal behaviour.

AIM

Starting with a historical perspective, the article reviews current knowledge of a genetic vulnerability to suicidal behaviour, distinct from the genetic vulnerability to psychiatric disorders, focused on clinical and population-based studies, and findings from recent molecular genetics association studies.

METHOD

The review includes peer-reviewed research articles and review papers from the professional literature in English language, retrieved from PubMed/Medline and PsycINFO.

RESULTS

The research literature confirms a existence of a genetic vulnerability to suicidal behaviour. Even though the results of individual studies are difficult to compare, genetic influences could explain up to half of the variance of the occurrence of suicide.

CONCLUSION

Genetic vulnerability could be a distal risk factor for suicide, which helps us to understand the occurrence of suicide among vulnerable people. Ethical implications of such vulnerability are highlighted.

Personality factors underlying suicidal behavior among military youth

Background:

Suicidal behavior is one the most significant mental health problems in the military. Militaries are closed systems that operate in particular situations. Military service is associated with certain stressful conditions. On this basis, there is likely of trauma in the military environment. Measures of suicidal behavior are pathologically complex. A range of biological, psychological, social, and institutional factors are involved in the incidence and prevalence of these behaviors.

Objectives:

One of the underlying factors in suicidal behavior is individuals' personality.

Patients and Methods:

The study population comprised of the Iranian Armed Forces. To recruit the sample of the research, 1659 soldiers were selected by multistage sampling. Data were collected using the Beck Scale for Suicide Ideation (BSSI) and NEO-Five Factor Inventory.

Results:

There was a significant positive correlation (r = 0.323) between neuroticism and suicide ideation; however, significant negative correlations existed between three other personality traits --extraversion [r = -0.306], agreeableness [r = -0.227], and conscientiousness [r = -0.271] and suicidal ideation. Unlike neuroticism, extraversion and conscientiousness personality factors could reduce significantly (as much 14% as are predicted) levels of suicidal ideation.

Conclusions:

Based on these results, neuroticism might increase suicide, but extraversion and conscientiousness personality traits are associated with a reduced risk of suicide.

[Suicide in the elderly: age-related specificities?]

Suicide in the elderly raises the question of our relationship with aging and death. Suicide rate is relatively high in this group and is significantly related to depression widely under-diagnosed in the elderly. Suicidal behaviour in the elderly has clinical specificities including high intentionality and lethality, usually little personal history of suicidal behaviour and low levels of impulsivity-aggression. Suicidal vulnerability could rely on etiopathogenic mechanisms both common and different according to age; for example, a preponderance of early developmental factors and impulsivity-aggression in adolescents and young adults vs. pathological aging in older adults, but partly similar neurocognitive deficits leading individuals not to respond adequately to their environment (itself different with age). Direct comparisons between elderly and younger subjects would be required. The article concludes with a summary of the principles of recognition and management of suicide risk.

Campus suicide prevention: bridging paradigms and forging partnerships

Colleges and universities are increasingly recognizing the need to expand suicide-prevention efforts beyond the standard, clinical-intervention paradigm of suicide prevention, which relies on referral to, and treatment by, mental health services. These services frequently struggle, however, to provide effective, comprehensive care. After reviewing findings that support the need to adopt a broader, problem-focused paradigm, the article provides a framework for bridging this paradigm with the clinical-intervention approach and for conceptualizing a full continuum of preventive interventions. For each level of intervention (ranging from the individual to the ecological), we describe the goals and methods used, and provide examples to illustrate the role of psychiatrists and other campus mental health providers in the collaborative partnerships that must form to support a comprehensive, campus-wide suicide-prevention strategy.

Potential peripheral biological predictors of suicidal behavior in major depressive disorder

Previous studies have shown that dysfunctions in the serotonin system and hypothalamic-pituitary-adrenal axis (HPA) are associated strongly with suicidal behavior and suicide, especially among individuals with major depressive disorder. Suicidal behavior has been explained using both the stress-diathesis model and the state-trait interaction model. Specifically, diatheses, or trait-dependent risk factors, are associated with dysfunctions in the serotonin system; however, stress responses, or state-dependent factors, are associated with HPA hyperactivity. Decreases in cholesterol and brain-derived neurotrophic factor (BDNF) levels have been associated with impaired brain plasticity among individuals with suicidal behavior. Decreased serotonin functioning has been measured using cerebral spinal fluid (CSF) 5-HIAA, fenfluramine challenge studies, and platelet 5-HT2A receptors. HPA axis dysfunction has been evaluated with the dexamethasone suppression test. Cholesterol and BDNF levels have been measured in blood serum or plasma. Nevertheless, challenges to finding promising and accessible neurobiological predictors of suicide and suicidal behavior remain. As suicide behavior is a complex phenomenon, a combined or multidimensional approach, including each of the aforementioned methods, may be required to predict suicide risk among individuals with major depressive disorder.

Is impulsivity a link between childhood abuse and suicide?

Childhood abuse and neglect are known to affect psychological states through behavioral, emotional, and cognitive pathways. They increase the risk of having psychiatric diseases in adulthood and have been considered risk factors for suicidal behavior in all diagnostic categories. Early, prolonged, and severe trauma is also known to increase impulsivity, diminishing the capacity of the brain to inhibit negative actions and to control and modulate emotions. Many neurobiological studies hold that childhood maltreatment may lead to a persistent failure of the inhibitory processes ruled mainly by the frontal cortex over a fear-motivated hyperresponsive limbic system. Multiple neurotransmitters and hormones are involved in the stress response, but, to our knowledge, the two major biological consequences of the chronic exposure to trauma are the hypofunction of the serotonergic system and changes in the hypothalamic-pituitary-adrenal axis function. Some of these findings overlap with the neurobiological features of impulsivity and of suicidal behavior. Impulsivity has also been said to be both a consequence of trauma and a risk factor for the development of a pathological response to trauma. Thus, we suggest that impulsivity could be one of the links between childhood trauma and suicidal behavior. Prevention of childhood abuse could significantly reduce suicidal behavior in adolescents and adults, in part, through a decrease in the frequency of impulsive behaviors in the future.

Estrogen receptor gene 1 variants are not associated with suicidal behavior

Estrogen is thought to be involved in the pathophysiology of depression and suicidal behaviors. We studied gene variants of estrogen receptor alpha (rs827421, rs1913474, rs1801132, rs722207, rs974276 and rs910416) in 167 German suicide attempters (affective spectrum n=107, schizophrenia spectrum n=35, borderline personality disorder n=25), 92 German individuals who committed suicide and 312 German healthy subjects. Single markers and haplotype analysis in relation to suicidal behaviors (suicide attempters/completers) did not reveal any significant association. These were also not associated with related features, such as violence or impulsivity of suicide attempt, State-Trait Anger Expression Inventory (STAXI) and Questionnaire for Measuring Factors of Aggression (FAF) scores. In conclusion, our study does not support the hypothesis that estrogen receptor alpha gene variants are major contributors to suicide or to anger- or aggression-related behaviors.

Dopa decarboxylase and tyrosine hydroxylase gene variants in suicidal behavior

The dopaminergic system has been previously associated to behavioral facilitation and aggression, hence making the pathway a good candidate for suicidal behavior. We studied gene variants in the tyrosine hydroxylase (rs3842727, rs6356) and DOPA decarboxylase (rs1451371, rs1470750, rs998850) genes in a sample of 571 individuals consisting of 167 German suicide attempters (affective spectrum n = 107, schizophrenia spectrum n = 35, borderline personality disorder n = 25), 92 Caucasian individuals who committed suicide and 312 German control subjects. TH variants were not associated with suicide (uncorrected P = 0.023) and related traits. Some marginal associations could be observed for DDC with suicide, violence, anger, and aggression. In conclusion, our study does not support the involvement of TH gene variants as major contributors to suicide, whereas DDC variants could mediate some features related to suicide and be involved in violent suicidal behavior.

Neurobiology of suicidal behavior. An integration of biological and clinical findings

Suicide is among the top ten leading causes of death in individuals of all ages. An explanatory model for suicidal behavior that links clinical and psychological risk factors or endophenotypes, to the underlying neurobiological abnormalities associated with suicidal behavior may enhance prediction, help identify treatment options and have heuristic value. Our explanatory model proposes that developmental factors that are biological (genetics) and psychological or clinical (early childhood adversity) may have causal relevance to the disturbances found in subjects with suicidal behavior. In this way, our model integrates findings from several perspectives in suicidology and attempts to explain the relationship between various neurobiological, genetic, and clinical observations in suicide research, offering a comprehensive hypothesis to facilitate understanding of this complex outcome.

Tachykinin receptor 1 variants associated with aggression in suicidal behavior

Substance P is involved in the modulation of depression, anxiety, and suicidal-related behaviors. We studied gene variants of Tachykinin Receptor 1 (TACR1-rs3771810, rs3771825, rs726506, rs1477157) in 167 German suicide attempters (affective spectrum n = 107, schizophrenia spectrum n = 35, borderline personality disorder n = 25), 92 Caucasian individuals who committed suicide and 312 German healthy subjects. Single markers and haplotype analysis in relation to suicidal behaviors (suicide attempters/completers) did not reveal any significant association. The rarest rs3771825 T allele however showed a marginal association with higher Reactive Aggression scores on the Questionnaire for Measuring Factors of Aggression (FAF) (F = 9.86, df = 1; P = 0.0017). Haplotype analyses confirmed the finding. Violence or impulsivity of suicide attempt and State-Trait Anger Expression Inventory (STAXI) scores were not associated with gene variants. In conclusion, our study suggests that TACR1 gene variants have no major influence on suicidal behavior but may modulate aggression features.

Recent alcohol intake and suicidality — a neuropsychological perspective

BACKGROUND

Alcohol use disorders and suicidal behaviours are among the most prevalent and damaging of all psychiatric phenomena in Ireland and worldwide. Furthermore, alcohol use both chronic and acute has long been identified as a potent riskfactor for suicidal behaviour.

AIMS

In this paper, the authors review the observational and experimental evidence for the acute neuropsychological effects of alcohol intake on suicidal ideation and behaviour.

METHODS

A selective review of the literature was conducted, using the PubMed database. Search terms employed included 'alcohol', 'suicide', 'binge' and 'acute alcohol intake'.

RESULTS

Cognitive mechanisms implicated include alcohol-induced deficits in attention-allocation, prospective cognition, autobiographical memory and disinhibition. Emotional mechanisms include alcohol-induced dysphoria, depression and aggression.

CONCLUSIONS

This paper serves to highlight the importance of identifying and tackling acute alcohol intake and binge drinking as a risk factor for suicidal behaviour.

Self-harm

The term self-harm is commonly used to describe a wide range of behaviours and intentions including attempted hanging, impulsive self-poisoning, and superficial cutting in response to intolerable tension. As with suicide, rates of self-harm vary greatly between countries. 5-9% of adolescents in western countries report having self-harmed within the previous year. Risk factors include socioeconomic disadvantage, and psychiatric illness--particularly depression, substance abuse, and anxiety disorders. Cultural aspects of some societies may protect against suicide and self-harm and explain some of the international variation in rates of these events. Risk of repetition of self-harm and of later suicide is high. More than 5% of people who have been seen at a hospital after self-harm will have committed suicide within 9 years. Assessment after self-harm includes careful consideration of the patient's intent and beliefs about the lethality of the method used. Strong suicidal intent, high lethality, precautions against being discovered, and psychiatric illness are indicators of high suicide risk. Management after self-harm includes forming a trusting relationship with the patient, jointly identifying problems, ensuring support is available in a crisis, and treating psychiatric illness vigorously. Family and friends may also provide support. Large-scale studies of treatments for specific subgroups of people who self-harm might help to identify more effective treatments than are currently available. Although risk factors for self-harm are well established, aspects that protect people from engaging in self-harm need to be further explored.

A bitter pill. Overview of ecstasy (MDMA, MDA) related fatalities

RATIONALE

The issue of ecstasy-related fatalities has extensively attracted the attention of both the media and the general public, but less so of the scientific literature.

OBJECTIVES

The aim of the present review is to focus on the epidemiological, clinical and pharmacological issues related to ecstasy fatalities.

RESULTS

Possibly due to a number of different reasons, the rates of ecstasy-related deaths seem to have peaked in recent years. MDMA metabolism is regulated by the levels of CYP2D6 and COMT (both exhibit some genetic polymorphism), and range of activity of these enzymes may account for some inter-individual differences in terms of toxic responses to the drug. A small increase in MDMA dosage can lead to a significant rise in drug plasma concentration. Due to their tolerance to MDMA psychoactive effects, some individuals may binge with dosages that may be the cause of serious concern. In experienced users, a reverse tolerance phenomenon can also be observed. Together with ecstasy, most of the misusers take a number of different compounds and the possible rationale of this style of consumption is commented upon here. Frequently, the lethal complications observed after acute MDMA administration can be the consequence of the occurrence of a serotonin syndrome and/or of sympathomimetic overstimulation (both conditions are exacerbated by environmentally induced overheating).

CONCLUSIONS

A number of methodological problems can contribute to making difficult the interpretation of the role played by ecstasy in so-called ecstasy-related deaths, especially so if accurate information is not available.