Neuropathology of suicide: recent findings and future directions

Prenatal opioid exposure significantly impacts placental protein kinase C (PKC) and drug transporters, leading to drug resistance and neonatal opioid withdrawal syndrome

Background

Neonatal Opioid Withdrawal Syndrome (NOWS) is a consequence of in-utero exposure to prenatal maternal opioids, resulting in the manifestation of symptoms like irritability, feeding problems, tremors, and withdrawal signs. Opioid use disorder (OUD) during pregnancy can profoundly impact both mother and fetus, disrupting fetal brain neurotransmission and potentially leading to long-term neurological, behavioral, and vision issues, and increased infant mortality. Drug resistance complicates OUD and NOWS treatment, with protein kinase regulation of drug transporters not fully understood.

Methods

DNA methylation levels of ATP-binding cassette (ABC) and solute carrier (SLC) drug transporters, along with protein kinase C (PKC) genes, were assessed in 96 placental samples using the Illumina Infinium MethylationEPIC array (850K). Samples were collected from three distinct groups: 32 mothers with infants prenatally exposed to opioids who needed pharmacological intervention for NOWS, 32 mothers with prenatally opioid-exposed infants who did not necessitate NOWS treatment, and 32 mothers who were not exposed to opioids during pregnancy.

Results

We identified 69 significantly differentially methylated SLCs, with 24 hypermethylated and 34 hypomethylated, and 11 exhibiting both types of methylation changes including SLC13A3, SLC15A2, SLC16A11, SLC16A3, SLC19A2, and SLC26A1. We identified methylation changes in 11 ABC drug transporters (ABCA1, ABCA12, ABCA2, ABCB10, ABCB5, ABCC12, ABCC2, ABCC9, ABCE1, ABCC7, ABCB3): 3 showed hypermethylation, 3 hypomethylation, and 5 exhibited both. Additionally, 7 PKC family genes (PRKCQ, PRKAA1, PRKCA, PRKCB, PRKCH, PRKCI, and PRKCZ) showed methylation changes. These genes are associated with 13 pathways involved in NOWS, including ABC transporters, bile secretion, pancreatic secretion, insulin resistance, glutamatergic synapse, and gastric acid secretion.

Conclusion

We report epigenetic changes in PKC-related regulation of drug transporters, which could improve our understanding of clinical outcomes like drug resistance, pharmacokinetics, drug-drug interactions, and drug toxicity, leading to maternal relapse and severe NOWS. Novel drugs targeting PKC pathways and transporters may improve treatment outcomes for OUD in pregnancy and NOWS.

Dysregulated zinc homeostasis and microadenomas in the anterior pituitary: pathological insights into suicide risk

Background

Suicide is a significant public health problem influenced by various risk factors, including dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis. Zinc (Zn), essential for pituitary function in hormone synthesis and release, has been linked to suicide, with studies noting reduced serum levels and altered brain transport mechanisms. Despite Zn's crucial role in pituitary function and its involvement in suicidal behavior, information on pituitary Zn in suicide is scarce. Tumor cells modify Zn dynamics in tissues, and a previous report suggests microadenomas in the anterior pituitary as a risk factor for suicide.

Methods

Histopathological analysis with hematoxylin-eosin stain and histochemical techniques to assess Zn homeostasis were carried out on anterior pituitary postmortem samples from 14 suicide completers and 9 non-suicidal cases.

Results

Pituitary microadenomas were identified in 35% of suicide cases and none in the non-suicidal cases. Furthermore, compartmentalized Zn (detected via dithizone reactivity), but not free Zn levels (detected via zinquin reactivity), was lower in the suicide cases compared to the non-suicidal group.

Conclusion

This is the first report of a potential association between disrupted Zn homeostasis and microadenomas in the anterior pituitary as a feature in suicide and provides critical insights for future neuroendocrine Zn-related research.

Associations of altered leukocyte DDR1 promoter methylation and childhood trauma with bipolar disorder and suicidal behavior in euthymic patients

Altered DNA methylation (DNAm) patterns of discoidin domain receptor 1 (DDR1) have been found in the blood and brain of patients with schizophrenia (SCZ) and the brain of patients with bipolar disorder (BD). Childhood trauma (CT) is associated with changes in DNAm that in turn are related to suicidal behavior (SB) in patients with several psychiatric disorders. Here, using MassARRAY® technology, we studied 128 patients diagnosed with BD in remission and 141 healthy controls (HCs) to compare leukocyte DDR1 promoter DNAm patterns between patients and HCs and between patients with and without SB. Additionally, we investigated whether CT was associated with DDR1 DNAm and mediated SB. We found hypermethylation at DDR1 cg19215110 and cg23953820 sites and hypomethylation at cg14279856 and cg03270204 sites in patients with BD compared to HCs. Logistic regression models showed that hypermethylation of DDR1 cg23953820 but not cg19215110 and CT were risk factors for BD, while cg14279856 and cg03270204 hypomethylation were protective factors. In patients, CT was a risk factor for SB, but DDR1 DNAm, although associated with CT, did not mediate the association of CT with SB. This is the first study demonstrating altered leukocyte DDR1 promoter DNAm in euthymic patients with BD. We conclude that altered DDR1 DNAm may be related to immune and inflammatory mechanisms and could be a potential blood biomarker for the diagnosis and stratification of psychiatric patients.

Childhood sexual abuse and suicide attempts in patients with substance use disorders: The mediating role of emotion dysregulation

BACKGROUND

Suicide attempts (SA) are a public health concern because of increasing prevalence and clinical implications. Childhood trauma (CT) and emotion dysregulation (ED) have been proposed as predictors of SA, but few data are available in patients with Substance Use Disorder (SUD).

OBJECTIVE

Our study aims to investigate the association of sociodemographic/clinical variables, CT typologies, and ED features with SA in SUD patients.

PARTICIPANTS AND SETTING

Subjects with SUD were screened in an outpatient setting. The final sample consisted of 226 patients, subdivided according to the presence of lifetime SA (SUD, n = 163 vs. SUD-SA, n = 63).

METHODS

Participants were compared for sociodemographic and clinical information. CT and ED were assessed through the Childhood Trauma Questionnaire - Short Form (CTQ-SF) and the Difficulties in Emotion Regulation Scale (DERS), respectively. We performed a mediation analysis to test the effect of CT and ED on SA.

RESULTS

Patients with a history of SA (27.9 %) displayed more psychiatric comorbidities (p = 0.002) and hospitalizations (p < 0.001), higher scores at CTQ-SF sexual abuse (p < 0.001) and DERS 'impulse' (p = 0.002), 'goals', 'non-acceptance', 'strategies' (p < 0.001) subscales. The relationship between CTQ-SF sexual abuse and SA was significantly mediated by DERS 'strategies' (p = 0.04; bootstrapped 95 % LLCI-ULCI = 0.004-0.024).

CONCLUSIONS

CT and different dimensions of ED were associated with SA in SUD patients. In our sample, the effects of childhood sexual abuse on SA were mediated by limited access to emotion regulation strategies. SUD patients are burdened with higher all-cause mortality, and CT and lifetime SA can worsen clinical outcomes. Clarifying the reciprocal interactions of psychopathological dimensions may help deliver targeted interventions and reduce suicide risk in specific populations.

Ethological Problems with the Interpersonal Theory of Suicide

Joiner and colleagues' Interpersonal Theory of Suicide (IPTS), a prominent "desire-capability" model of suicide-based on the common-sense idea that people take their own lives because they want to, and can-is critiqued from a biological perspective. Tinbergen's ethological "four questions" guide the analysis: evolution, survival value, ontogeny, and proximate causation, each addressing a different aspect of biological understanding. Problems for IPTS emerge with all four. As a parsimonious solution, the desire-capability hypothesis is reconceived as an ultimate, instead of proximate, mode of explanation. By this light, desire and capability for suicide combined in our species' ancestral past, thus making suicide a recurrent survival threat, and driving the evolution of special-purpose defensive adaptations. This stance tallies with the pain-brain theory of the evolution of suicide, and with Joiner and colleagues' own investigation into organismic anti-suicide defenses, which appears to conflict conceptually with IPTS. These defenses' evolved algorithm may make suicide an intrinsically aleatory phenomenon, opaque to usefully accurate prediction. Positive implications for prevention and research are proposed.

Real-world evidence from a retrospective study on suicide during depression: clinical characteristics, treatment patterns and disease burden

BACKGROUND

Suicide stands as both a primary symptom and the direst outcome of major depressive disorder (MDD). The scarcity of effective treatment strategies makes managing MDD patients with suicide especially challenging. Hence, it is crucial to investigate disease characteristics and efficacious therapeutic strategies for these patients, drawing insights from disease databases and real-world data.

METHODS

In this retrospective study, MDD patients hospitalized between January 2013 and December 2020 were investigated using Electronic Health Records (EHR) data from Beijing Anding Hospital. The study enrolled 4138 MDD patients with suicidal ideation or behavior (MDS) and 3848 without (MDNS). Demographic data, clinical attributes, treatment approaches, disease burden, and re-hospitalization within one year of discharge were extracted and compared.

RESULTS

Patients in the MDS group were predominantly younger and female, exhibiting a higher prevalence of alcohol consumption, experiencing frequent life stress events, and having an earlier onset age. Re-hospitalizations within six months post-discharge in the MDS group were significantly higher than in the MDNS group (11.36% vs. 8.91%, p < 0.001). Moreover, a more considerable fraction of MDS patients underwent combined electroconvulsive therapy treatment (56.72% vs. 43.71%, p < 0.001). Approximately 38% of patients in both groups were prescribed two or more therapeutic regimes, and over 90% used antidepressants, either alone or combined. Selective serotonin reuptake inhibitors (SSRIs) were the predominant choice in both groups. Furthermore, antidepressants were often prescribed with antipsychotics or mood stabilizers. When medication alterations were necessary, the favoured options involved combination with antipsychotics or transitioning to alternative antidepressants. Yet, in the MDS group, following these initial modifications, the addition of mood stabilizers tended to be the more prioritized alternative.

CONCLUSIONS

MDD patients with suicidal ideation or behaviour displayed distinctive demographic and clinical features. They exhibited intricate treatment patterns, a pronounced burden of illness, and an increased likelihood of relapse.

Are big five personality traits associated to suicidal behaviour in adolescents? A systematic review and meta-analysis

BACKGROUND

Suicidal behaviour is one of the main causes of death worldwide, especially among teenagers, and its development is potentially associated with the development of personality. The aim of this systematic review and meta-analysis is to describe the association between the Big Five Personality Traits and suicidal behaviour in adolescents.

METHODS

Seven databases were systematically searched between June 2022 and July 2022 with no language or year restrictions. We searched for a combination of the following search items (suicid* OR suicidal behaviour OR suicidal ideation OR suicide attempts OR self injury OR self-destructive behaviour OR self-harm OR suicidal risk) AND (personality OR personality traits OR temperament OR neuroticism OR extraversion OR agreeableness OR openness to experience OR conscientiousness) AND (adolescents OR youth OR teenagers OR young adults). Meta-analysis procedures were performed using the R software. A random-effect-model was performed for the models through the incorporation of τ2, based on the DerSimonion Lard method.

RESULTS

Seven studies met all inclusion criteria and were included in this systematic review. Our meta-analysis showed that higher neuroticism are both associated and a risk factor for suicidal behaviour. Higher levels of openness to experience and agreeableness, and lower levels of extraversion and conscientiousness, were linked to suicidal behaviour, especially self-harm.

LIMITATIONS

Due to the heterogeneity of the studies, we were only able to perform meta-analysis regarding neuroticism.

CONCLUSION

The present study may help professionals to identify adolescents in higher risk for suicidal behaviour, enabling the development of early interventions to prevent suicidality in this population.

Psychiatric profiles in suicidal attempters: Relationships with suicide behaviour features

BACKGROUND

Suicide constitutes a major health concern worldwide, being a significant contributor of death, globally. The diagnosis of a mental disorder has been extensively linked to the varying forms of suicidal ideation and behaviour. The aim of our study was to identify the varying diagnostic profiles in a sample of suicide attempters.

METHODS

A sample of 683 adults (71.3% females, 40.10±15.74 years) admitted at a hospital emergency department due to a suicide attempt was recruited. Latent class analysis was used to identify diagnostic profiles and logistic regression to study the relationship between comorbidity profile membership and sociodemographic and clinical variables.

RESULTS

Two comorbidity profiles were identified (Class I: low comorbidity class, 71.3% of attempters; Class II: high comorbidity class, 28.7% of attempters). Class I members were featured by the diagnosis of depression and general anxiety disorder, and low comorbidity; by contrast, the high comorbidity profile was characterized by a higher probability of presenting two or more coexisting psychiatric disorders. Class II included more females, younger, with more depressive symptoms and with higher impulsivity levels. Moreover, Class II members showed more severe suicidal ideation, higher number of suicide behaviours and a greater number of previous suicide attempts (p<.01, for all the outcomes), compared to Class I members.

CONCLUSIONS

Psychiatric profiles may be considered for treatment provision and personalized psychiatric treatment in suicidal attempters as well as tackle suicide risk.

Whole-brain structural and functional neuroimaging of individuals who attempted suicide and people who did not: A systematic review and exploratory coordinate-based meta-analysis

Suicide is the cause of death of approximately 800,000 people a year. Despite the relevance of this behaviour, risk assessment tools rely on clinician experience and subjective ratings. Given that previous suicide attempts are the single strongest predictors of future attempts, we designed a systematic review and coordinate-based meta-analysis to demonstrate whether neuroimaging features can help distinguish individuals who attempted suicide from subjects who did not. Out of 5,659 publications from PubMed, Scopus, and Web of Science, we summarised 102 experiments and meta-analysed 23 of them. A cluster in the right superior temporal gyrus, a region implicated in emotional processing, might be functionally hyperactive in individuals who attempted suicide. No statistically significant differences in brain morphometry were evidenced. Furthermore, we used JuSpace to show that this cluster is enriched in 5-HT1A heteroreceptors in the general population. This exploratory meta-analysis provides a putative neural substrate linked to previous suicide attempts. Heterogeneity in the analytical techniques and weak or absent power analysis of the studies included in this review currently limit the applicability of the findings, the replication of which should be prioritised.

An in-depth analysis of the polyvagal theory in light of current findings in neuroscience and clinical research

The polyvagal theory has led to the understanding of the functions of the autonomic nervous system in biological development in humans, since the vagal system, a key structure within the polyvagal theory, plays a significant role in addressing challenges of the mother-child dyad. This article aims to summarize the neurobiological aspects of the polyvagal theory, highlighting some of its strengths and limitations through the lens of new evidence emerging in several research fields-including comparative anatomy, embryology, epigenetics, psychology, and neuroscience-in the 25 years since the theory's inception. Rereading and incorporating the polyvagal idea in light of modern scientific findings helps to interpret the role of the vagus nerve through the temporal dimension (beginning with intrauterine life) and spatial dimension (due to the numerous connections of the vagus with various structures and systems) in the achievement and maintenance of biopsychosocial well-being, from the uterus to adulthood.

Predicting suicidality in late-life depression by 3D convolutional neural network and cross-sample entropy analysis of resting-state fMRI

BACKGROUND

Predicting suicide is a pressing issue among older adults; however, predicting its risk is difficult. Capitalizing on the recent development of machine learning, considerable progress has been made in predicting complex behavior such as suicide. As depression remained the strongest risk for suicide, we aimed to apply deep learning algorithms to identify suicidality in a group with late-life depression (LLD).

METHODS

We enrolled 83 patients with LLD, 35 of which were non-suicidal and 48 were suicidal, including 26 with only suicidal ideation and 22 with past suicide attempts, for resting-state functional magnetic resonance imaging (MRI). Cross-sample entropy (CSE) analysis was conducted to examine the complexity of MRI signals among brain regions. Three-dimensional (3D) convolutional neural networks (CNNs) were used, and the classification accuracy in each brain region was averaged to predict suicidality after sixfold cross-validation.

RESULTS

We found brain regions with a mean accuracy above 75% to predict suicidality located mostly in default mode, fronto-parietal, and cingulo-opercular resting-state networks. The models with right amygdala and left caudate provided the most reliable accuracy in all cross-validation folds, indicating their neurobiological importance in late-life suicide.

CONCLUSION

Combining CSE analysis and the 3D CNN, several brain regions were found to be associated with suicidality.

Symptoms characteristics of personality disorders associated with suicidal ideation and behaviors in a clinical sample of adolescents with a depressive disorder

Introduction

Pathological personality traits have repeatedly been identified as important risk factors for suicidal ideation and behaviors. Moreover, impulsive-aggressive traits, have shown a consistent association with suicidal behaviors across the lifespan. Adolescence represents a critical period for the emergence of different personality traits, mood disorders, and suicidal behaviors, but the relationship between these variables remain poorly understood.

Methods

These variables were examined in a cross-sectional case-control design involving three groups: 30 adolescents with a depressive disorder and past suicide attempt (Mean Age = 16.2, Females = 26), 38 adolescents with a depressive disorder but without past suicide attempt (Mean age = 16.0, Females = 29), and 34 healthy adolescent controls (Mean age = 15.2, Females = 22). Suicidal ideations were indexed using Suicidal Behavior Questionnaire (SBQ-R), psychiatric disorder assessed using a semi-structured questionnaire (K-SADS-PL), depressive symptoms with the Beck Depressive Inventory (BDI), symptoms characteristics of personality disorders with the Scheduled Clinical Interview for the DSM-IV (SCID-II) screening questionnaire, and impulsivity with the Barratt Impulsivesness Scale (BIS).

Results

Findings showed that impulsivity (F = 11.0, p < 0.0001) and antisocial symptoms characteristics of personality disorders (p < 0.001, d = 0.70) displayed the most robust association with adolescent suicide attempts. Borderline symptoms characteristics of personality disorders did not discriminate attempters from non-attempters but presented high correlations with suicidal ideation and depression severity. In an item-wise analysis, suicide attempt status was uniquely correlated with symptoms characteristics of an antisocial personality disorder. Suicide attempt status also correlated with non-suicidal self-injury and a chronic feeling of emptiness.

Discussion

The caveats of this cross-sectional study include the stability of symptoms characteristics of personality disorders in adolescence and the limited sample size. In sum, suicidal behaviors were characteristically correlated with increased impulsivity and antisocial symptoms characteristics of personality disorders, but other symptoms characteristics of personality disorders were relevant to adolescent depression and suicidal ideation. Understanding the emergence of symptoms characteristics of personality disorders and suicidal behaviors in a developmental context can ultimately inform not only the neurobiological origin of suicidal behaviors, but also provide new avenues for early detection and intervention.

Positive personality traits moderate persistent high alcohol consumption, determined by polygenic risk in U.S. military veterans: results from a 10-year, population-based, observational cohort study

BACKGROUND

Understanding the interplay between psychosocial factors and polygenic risk scores (PRS) may help elucidate the biopsychosocial etiology of high alcohol consumption (HAC). This study examined the psychosocial moderators of HAC, determined by polygenic risk in a 10-year longitudinal study of US military veterans. We hypothesized that positive psychosocial traits (e.g. social support, personality traits, optimism, gratitude) may buffer risk of HAC in veterans with greater polygenic liability for alcohol consumption (AC).

METHODS

Data were analyzed from 1323 European-American US veterans who participated in the National Health and Resilience in Veterans Study, a 10-year, nationally representative longitudinal study of US military veterans. PRS reflecting genome-wide risk for AC (AUDIT-C) was derived from a Million Veteran Program genome-wide association study (N = 200 680).

RESULTS

Among the total sample, 328 (weighted 24.8%) had persistent HAC, 131 (weighted 9.9%) had new-onset HAC, 44 (weighted 3.3%) had remitted HAC, and 820 (weighted 62.0%) had no/low AC over the 10-year study period. AUDIT-C PRS was positively associated with persistent HAC relative to no/low AC [relative risk ratio (RRR) = 1.43, 95% confidence interval (CI) = 1.23-1.67] and remitted HAC (RRR = 1.63, 95% CI = 1.07-2.50). Among veterans with higher AUDIT-C PRS, greater baseline levels of agreeableness and greater dispositional gratitude were inversely associated with persistent HAC.

CONCLUSIONS

AUDIT-C PRS was prospectively associated with persistent HAC over a 10-year period, and agreeableness and dispositional gratitude moderated this association. Clinical interventions designed to target these modifiable psychological traits may help mitigate risk of persistent HAC in veterans with greater polygenic liability for persistent HAC.

Predicting treatment response in adolescents and young adults with major depressive episodes from fMRI using graph isomorphism network

BACKGROUND

Major depressive episode (MDE) is the main clinical feature of mood disorders (major depressive disorder and bipolar disorder) in adolescents and young adults and accounts for most of the disease course. However, 30%-40% of MDE patients not responding to clinical first-line interventions. It is crucial to predict treatment response in the early stages and identify biomarkers associated with treatment response. Graph Isomorphism Network (GIN), a deep learning method, is promising for predicting treatment response for individual MDE patients with more powerful representation ability to capture the features of brain functional connectivity.

METHODS

In this study, GIN was used to predict individual treatment response in 198 adolescents and young adults with MDE. The most discriminating regions were also identified for the treatment response prediction.

RESULTS

Using GIN approach, the baseline functional connectivity could predict 79.8% responders and 67.4% non-responders to treatment (accuracy 74.24%). Furthermore, the most discriminating brain regions were mainly involved in paralimbic and subcortical areas.

CONCLUSIONS

GIN has shown potential in predicting treatment response for individual patients, which may enable personalized treatment decisions. Furthermore, targeted interventions focused on modulating the activity and connectivity within paralimbic and subcortical regions could potentially improve treatment outcomes and enable personalized interventions for adolescents and young adults with MDE.

Functional genomic mechanisms of opioid action and opioid use disorder: a systematic review of animal models and human studies

In the past two decades, over-prescription of opioids for pain management has driven a steep increase in opioid use disorder (OUD) and death by overdose, exerting a dramatic toll on western countries. OUD is a chronic relapsing disease associated with a lifetime struggle to control drug consumption, suggesting that opioids trigger long-lasting brain adaptations, notably through functional genomic and epigenomic mechanisms. Current understanding of these processes, however, remain scarce, and have not been previously reviewed systematically. To do so, the goal of the present work was to synthesize current knowledge on genome-wide transcriptomic and epigenetic mechanisms of opioid action, in primate and rodent species. Using a prospectively registered methodology, comprehensive literature searches were completed in PubMed, Embase, and Web of Science. Of the 2709 articles identified, 73 met our inclusion criteria and were considered for qualitative analysis. Focusing on the 5 most studied nervous system structures (nucleus accumbens, frontal cortex, whole striatum, dorsal striatum, spinal cord; 44 articles), we also conducted a quantitative analysis of differentially expressed genes, in an effort to identify a putative core transcriptional signature of opioids. Only one gene, Cdkn1a, was consistently identified in eleven studies, and globally, our results unveil surprisingly low consistency across published work, even when considering most recent single-cell approaches. Analysis of sources of variability detected significant contributions from species, brain structure, duration of opioid exposure, strain, time-point of analysis, and batch effects, but not type of opioid. To go beyond those limitations, we leveraged threshold-free methods to illustrate how genome-wide comparisons may generate new findings and hypotheses. Finally, we discuss current methodological development in the field, and their implication for future research and, ultimately, better care.

Individual-level risk factors for suicide mortality in the general population: an umbrella review

BACKGROUND

Deaths by suicide remain a major public health challenge worldwide. Identifying and targeting risk factors for suicide mortality is a potential approach to prevention. We aimed to summarise current knowledge on the range and magnitude of individual-level risk factors for suicide mortality in the general population and evaluate the quality of the evidence.

METHODS

In this umbrella review, five bibliographic databases were systematically searched for articles published from database inception to Aug 31, 2022. We included meta-analyses of observational studies on individual-level risk factors for suicide mortality in the general population. Biological, genetic, perinatal, and ecological risk factors were beyond the scope of this study. Effect sizes were synthesised and compared across domains. To test robustness and consistency of the findings, evidence for small-study effects and excess significance bias (ie, the ratio between the overall meta-analysis effect size and that of its largest included study) was examined, and prediction intervals were calculated. Risk of bias was assessed by the Risk of Bias in Systematic Reviews instrument. The protocol was pre-registered with PROSPERO (CRD42021230119).

FINDINGS

We identified 33 meta-analyses on 38 risk factors for suicide mortality in the general population. 422 (93%) of the 454 primary studies included in the meta-analyses were from high-income countries. A previous suicide attempt and suicidal ideation emerged as strong risk factors (with effect sizes ranging from 6 to 16). Psychiatric disorders were associated with a greatly elevated risk of suicide mortality, with risk ratios in the range of 4-13. Suicide risk for physical illnesses (such as cancer and epilepsy) and sociodemographic factors (including unemployment and low education) were typically increased two-fold. Contact with the criminal justice system, state care in childhood, access to firearms, and parental death by suicide also increased the risk of suicide mortality. Among risk factors for which sex-stratified analyses were available, associations were generally similar for males and females. However, the quality of the evidence was limited by excess significance and high heterogeneity, and prediction intervals suggested poor replicability for almost two-thirds of identified risk factors.

INTERPRETATION

A wide range of risk factors were identified across various domains, which underscores suicide mortality as a multifactorial phenomenon. Prevention strategies that span individual and population approaches should account for the identified factors and their relative strengths. Despite the large number of risk factors investigated, few associations were supported by robust evidence. Evidence of causal inference will need to be tested in high-quality study designs.

FUNDING

Wellcome Trust.

Alterations of BDNF, mGluR5, Homer1a, p11 and excitatory/inhibitory balance in corticolimbic brain regions of suicide decedents

BACKGROUND

Developing biological based approaches for preventing suicide has become a priority. In recent years, there has been a surge in studies investigating the role of the glutamatergic system in suicide, although it remains unclear.

METHODS

We evaluated changes in the gene expression of the metabotropic glutamate receptor 5 (mGluR5) and its scaffolding proteins Homer1a and p11 in the dorsolateral prefrontal cortex (DLPFC), amygdala (AMY), and hippocampus (HIP) of 28 suicide decedents (S) (with no clinical psychiatric history or treatment with anxiolytics or antidepressants) and 26 controls (C) by real-time PCR (qPCR). Indeed, we measured BDNF gene expression and VGluT1 and VGAT immunoreactivities in the HIP by qPCR and immunohistochemistry, respectively. Cases and controls matched for age (C: 48.6 ± 11.6 years; S: 46.9 ± 14.5 years) and postmortem interval (PMI; C: 20.1 ± 13h; S: 16.9 ± 5h).

RESULTS

In DLPFC, S had lower p11 gene expression levels, but no differences were found in mGluR5 or Homer1a. In the AMY and HIP, mGluR5 and Homer1a were increased, p11 and BDNF were reduced. In the HIP, there were less VGAT-ir and more VGluT1-ir.

LIMITATIONS

Future studies are necessary to evaluate protein levels, and determine the cell types and potential compensatory mechanisms in a larger sample including S diagnosed with psychiatric disorders, females and different ethnicities.

CONCLUSIONS

This study identified significant alterations in mGluR5, Homer1a, p11, BDNF and excitatory/inhibitory balance in corticolimbic brain areas of S. These results further characterize the biological basis of suicide, contributing to the identification of potential biomarkers for suicide prevention.

Using electronic health record data to predict future self-harm or suicidal ideation in young people treated by child and youth mental health services

INTRODUCTION

Identifying young people who are at risk of self-harm or suicidal ideation (SHoSI) is a priority for mental health clinicians. We explore the utility of routinely collected data in developing a tool to aid early identification of those at risk.

METHOD

We used electronic health records of 4610 young people aged 5-19 years who were treated by Child and Youth Mental Health Services (CYMHS) in greater Brisbane, Australia. Two Lasso models were trained to predict the risk of future SHoSI in young people currently rated SHoSI; and those who were not.

RESULTS

For currently non-SHoSI children, an Area Under the Receiver Operating Characteristics (AUC) of 0.78 was achieved. Those with the highest risk were 4.97 (CI 4.35-5.66) times more likely to be categorized as SHoSI in the future. For current SHoSI children, the AUC was 0.62.

CONCLUSION

A prediction model with fair overall predictive power for currently non-SHoSI children was generated. Predicting persistence for SHoSI was more difficult. The electronic health records alone were not sufficient to discriminate at acceptable levels and may require adding unstructured data such as clinical notes. To optimally predict SHoSI models need to be tested and validated separately for those young people with varying degrees of risk.

Toward objective characterizations of suicide risk: A narrative review of laboratory-based cognitive and behavioral tasks

Although suicide is a leading cause of preventable death worldwide, current prevention efforts have failed to substantively mitigate suicide risk. Suicide research has traditionally relied on subjective reports that may not accurately differentiate those at high versus minimal risk. This narrative review supports the inclusion of objective task-based measures in suicide research to complement existing subjective batteries. The article: 1) outlines risk factors proposed by contemporary theories of suicide and highlights recent empirical findings supporting these theories; 2) discusses ongoing challenges associated with current risk assessment tools and their ability to accurately evaluate risk factors; and 3) analyzes objective laboratory measures that can be implemented alongside traditional measures to enhance the precision of risk assessment. To illustrate the potential of these methods to improve our understanding of suicide risk, the article reviews how acute stress responses in a laboratory setting can be modeled, given that stress is a major precipitant for suicidal behavior. More precise risk assessment strategies can emerge if objective measures are implemented in conjunction with traditional subjective measures.

A network approach to understand co-occurrence and relative importance of different reasons for suicide: a territory-wide study using 2002-2019 Hong Kong Coroner's Court reports

Background

Suicide is a complex and multifaceted issue, and suicidal behaviors are often driven by multiple, interacting factors. It has been challenging to identify reasons for suicide using existing scientific methodologies. This study aims to identify critical reasons for suicide and suicidal behaviors through the application of novel network science methods.

Methods

Based on cases investigated by the Hong Kong Coroner's Court from 2002 to 2019, we modelled identified reasons for 13,001 suicide cases as a co-occurrence network, and calculated each reason's eigencentrality to determine their respective relative importance. We then analyzed the temporal and demographic changes in the structure and eigencentrality of the network. We further conducted simulation studies based on the United Nations population projection to assess potential burden of different reasons for suicide on the population in the coming years.

Findings

School-related issues had the highest eigencentrality (eigencentrality = 0.49) for individuals younger than 20 years of age. Financial issues were crucial for adults aged 20-59 years, but their importance differed between males (eigencentrality = 0.51) and females (eigencentrality = 0.14). Physical illness (eigencentrality = 0.80) was the core concern for adults over 60 years. Across the Hong Kong population, the reasons for suicide appear to have shifted from financial issues in the early 2000s (eigencentrality = 0.46) to issues related to physical illnesses since 2011 (eigencentrality = 0.58). Simulation findings indicate that, by 2050, most suicides in Hong Kong will be due to physical illness-related issues (eigencentrality = 0.69) due to the rapidly aging population.

Interpretation

There have been important sex and age differences over time, in reasons for suicide. Given the projected increasing age of the Hong Kong population over the next decades, older adults with physical illnesses appear to be the highest contributors to suicide cases in the overall population. This novel network analysis approach provides important data-driven information upon which to base effective proactive public health suicide prevention strategies and interventions.

Funding

Hong Kong Jockey Club Charities Trust, Collaborative Research Fund (C7151-20G), and General Research Fund (17606521).

Event-related Oscillations to Emotional Faces are Related to a History of Internalizing Disorders

Event-related oscillations (EROs) may represent sensitive biomarkers or endophenotypes for disorders that underlie risk behaviors such as suicidal thoughts and actions. In this study, young adults of American Indian (AI) (n = 821) and Mexican American (MA) (n = 721) ancestry (age 18-30 yrs) were clinically assessed for internalizing and externalizing disorders, and an internalizing scale was generated by extracting core diagnostic items from 6 lifetime DSM5-compatible diagnoses (social phobia, panic disorder, agoraphobia, obsessive compulsive disorder, post-traumatic stress disorder, major depressive episode) and symptoms of suicidality. EROs were generated to sad, happy and neutral faces, and energy and phase locking of delta ERO oscillations were assessed in frontal areas. An increase in delta ERO energy was found in the frontal lead (FZ) following presentation of the sad facial expressions in those with a history of 10 or more internalizing symptoms compared to those with no symptoms. Increases in delta ERO energy in FZ were also associated with a diagnosis of major depressive disorder (MDD), but not with anxiety disorders or antisocial personality disorder/conduct disorders (ASP). Major depression was also associated with increases in cross-cortical phase-locking (FZ-PZ). A decrease in the percentage of correctly identified neutral faces also was seen among those with 10 or more internalizing symptoms compared to those without internalizing symptoms, and in those with anxiety disorders, but not in those with ASP or MDD as compared to their controls. These findings suggest ERO measures may represent important potential biomarkers of depressive disorders as well as risk indicators for suicidal behaviors.

A population-wide analysis of the familial risk of suicide in Utah, USA

BACKGROUND

The degree to which suicide risk aggregates in US families is unknown. The authors aimed to determine the familial risk of suicide in Utah, and tested whether familial risk varies based on the characteristics of the suicides and their relatives.

METHODS

A population-based sample of 12 160 suicides from 1904 to 2014 were identified from the Utah Population Database and matched 1:5 to controls based on sex and age using at-risk sampling. All first through third- and fifth-degree relatives of suicide probands and controls were identified (N = 13 480 122). The familial risk of suicide was estimated based on hazard ratios (HR) from an unsupervised Cox regression model in a unified framework. Moderation by sex of the proband or relative and age of the proband at time of suicide (<25 v. ⩾25 years) was examined.

RESULTS

Significantly elevated HRs were observed in first- (HR 3.45; 95% CI 3.12-3.82) through fifth-degree relatives (HR 1.07; 95% CI 1.02-1.12) of suicide probands. Among first-degree relatives of female suicide probands, the HR of suicide was 6.99 (95% CI 3.99-12.25) in mothers, 6.39 in sisters (95% CI 3.78-10.82), and 5.65 (95% CI 3.38-9.44) in daughters. The HR in first-degree relatives of suicide probands under 25 years at death was 4.29 (95% CI 3.49-5.26).

CONCLUSIONS

Elevated familial suicide risk in relatives of female and younger suicide probands suggests that there are unique risk groups to which prevention efforts should be directed - namely suicidal young adults and women with a strong family history of suicide.

The Suicide Prevention and Intervention Study (SURVIVE): Study protocol for a multisite cohort study with nested randomized-controlled trials

INTRODUCTION

Suicide is one of the leading causes of avoidable death. Gathering national data on suicidal behaviour incidence is crucial to develop evidence-based public policies. The study has two primary objectives: (1) to determine the incidence of suicide attempts in Spain and related risk factors, and (2) to analyze the efficacy of secondary prevention programmes to prevent suicide re-attempting in comparison to treatment as usual (TAU).

MATERIALS AND METHODS

Multisite, coordinated, cohort study with three nested randomized controlled trials. A cohort of 2000 individuals (age >=12) with suicidal behaviour will be recruited at ten sites distributed across Spain. Assessments will be conducted within 10 days of the suicide attempt (V0-baseline visit) and after 12 months (V4-last visit) and will include clinician reported and participant reported outcomes (PROs). Between V0 and V4, PROs will be collected remotely every three months (V1, V2 and V3). Optatively, cohort participants will participate in three nested randomized-controlled-trials (RCTs) evaluating different secondary prevention interventions: Participants aged 18 years and older will be randomly allocated to: Telephone-based Management+TAU vs. TAU or iFightDepression-Survive+TAU vs. TAU. Participants aged between 12 and 18 years will be allocated to a specific intervention for youths: Self Awareness of Mental Health+TAU vs. TAU.

RESULTS

This study will provide interesting data to estimate suicide attempt incidence in Spain. and will provide evidence on three.

CONCLUSIONS

Evidence on three potentially efficacious interventions for individuals at high risk of suicide will be obtained, and this could improve the treatment given to these individuals.

TRIAL REGISTRATION

NCT04343703.

The Role of Inflammation in the Pathophysiology of Depression and Suicidal Behavior: Implications for Treatment

Depression and suicidal behavior are 2 complex psychiatric conditions of significant public health concerns due to their debilitating nature. The need to enhance contemporary treatments and preventative approaches for these illnesses not only calls for distillation of current views on their pathogenesis but also provides an impetus for further elucidation of their novel etiological determinants. In this regard, inflammation has recently been recognized as a potentially important contributor to the development of depression and suicidal behavior. This review highlights key evidence that supports the presence of dysregulated neurometabolic and immunologic signaling and abnormal interaction with microbial species as putative etiological hallmarks of inflammation in depression as well as their contribution to the development of suicidal behavior. Furthermore, therapeutic insights addressing candidate mechanisms of pathological inflammation in these disorders are proposed.

ADRA2B and HTR1A: An Updated Study of the Biogenic Amine Receptors Reveals Novel Conserved Motifs Which Play Key Role in Mental Disorders

Mental disorders are strongly connected with several psychiatric conditions including depression, bipolar disorder, schizophrenia, eating disorder, and suicides. There are many biological conditions and pathways that define these complicated illnesses. For example, eating disorders are complex mental health conditions that require the intervention of geneticists, psychiatrists, and medical experts in order to alleviate their symptoms. A patient with suicidal ideation should first be identified and consequently monitored by a similar team of specialists. Both genetics and epigenetics can shed light on eating disorders and suicides as they are found in the main core of such investigations. In the present study, an analysis has been performed on two specific members of the GPCR family toward drawing conclusions regarding their functionality and implementation in mental disorders. Specifically, evolutionary and structural studies on the adrenoceptor alpha 2b (ADRA2B) and the 5-hydroxytryptamine receptor 1A (HTR1A) have been carried out. Both receptors are classified in the biogenic amine receptors sub-cluster of the GPCRs and have been connected in many studies with mental diseases and malnutrition conditions. The major goal of this study is the investigation of conserved motifs among biogenic amine receptors that play an important role in this family signaling pathway, through an updated evolutionary analysis and the correlation of this information with the structural features of the HTR1A and ADRA2B. Furthermore, the structural comparison of ADRA2B, HTR1A, and other members of GPCRs related to mental disorders is performed.

Homeorhesis: envisaging the logic of life trajectories in molecular research on trauma and its effects

What sets someone on a life trajectory? This question is at the heart of studies of 21st-century neurosciences that build on scientific models developed over the last 150 years that attempt to link psychopathology risk and human development. Historically, this research has documented persistent effects of singular, negative life experiences on people's subsequent development. More recently, studies have documented neuromolecular effects of early life adversity on life trajectories, resulting in models that frame lives as disproportionately affected by early negative experiences. This view is dominant, despite little evidence of the stability of the presumably early-developed molecular traits and their potential effects on phenotypes. We argue that in the context of gaps in knowledge and the need for scientists to reason across molecular and phenotypic scales, as well as time spans that can extend beyond an individual's life, specific interpretative frameworks shape the ways in which individual scientific findings are assessed. In the process, scientific reasoning oscillates between understandings of cellular homeostasis and organisms' homeorhesis, or life trajectory. Biologist and historian François Jacob described this framework as the "attitude" that researchers bring to bear on their "objects" of study. Through an analysis of, first, historical and contemporary scientific literature and then ethnographic research with neuroscientists, we consider how early life trauma came to be associated with specific psychological and neurobiological effects grounded in understandings of life trajectories. We conclude with a consideration of the conceptual, ontological, and ethical implications of interpreting life trajectories as the result of the persistence of long-embodied biological traits, persistent life environments, or both.

College students’ screening early warning factors in identification of suicide risk

This study aimed to explore the main influencing factors of suicide risk among Chinese students and establish an early warning model to provide interventions for high-risk students. We conducted surveys of students in their first and third years from a cohort study at Jining Medical College. Logistic regression models were used to screen the early warning factors, and four machine learning models were used to establish early warning models. There were 8 factors related to suicide risk that were eventually obtained through screening, including age, having a rough father, and CES-D, OHQ, ASLEC-4, BFI-Neuroticism, BFI-Openness, and MMC-AF-C scores. A random forest model with SMOTE was adopted, and it verified that these 8 early warning signs, for suicide risk can effectively predict suicide risk within 2 years with an AUC score of 0.947. Among the factors, we constructed a model that indicated that different personality traits affected suicide risk by different paths. Moreover, the factors obtained by screening can be used to identify college students in the same year with a high risk of suicide, with an AUC score that reached 0.953. Based on this study, we suggested some interventions to prevent students going high suicide risk.

Entangled: A mixed method analysis of nurses with mental health problems who die by suicide

Nurses die by suicide at a higher rate than the general population. Previous studies have observed mental health problems, including substance use, as a prominent antecedent before death. The purpose of this study was to explore the characteristics of nurses who died by suicide documented in the death investigation narratives from the National Violent Death Reporting System from 2003 to 2017 using thematic analysis and natural language processing. One thousand three hundred and fifty-eight subjects met these inclusion criteria. Narratives from 601 subjects were thematically analyzed and 2544 individual narratives were analyzed using natural language processing. The analyses revealed five themes: "mental health treatment," "poor general health and chronic pain," "substance use," "worsening mental health after bereavement," and "repeating a family member's suicide." Mental health/substance use, chronic illness, and chronic pain were seen to coexist in a complex, interdependent manner that appeared to be entangled in the nurses' narratives before death. These findings echo the need for reducing the stigmatization of mental health problems in nursing and removing barriers to help-seeking behaviors as early preventative interventions. Future research is needed to determine if a comprehensive healthcare integration approach to address these entangled problems would reduce suicide vulnerability in nurses and improve their quality of life.

C-Reactive Protein as a Potential Peripheral Biomarker for High-Lethality Suicide Attempts

The aim of the present study was to identify a cut-off of c-reactive protein (c-RP) potentially predictive of high-lethality suicide attempts (SA) in an inpatient psychiatric sample. After attempting suicide, subjects were admitted to the emergency ward of the IRCCS Ospedale Policlinico San Martino and later to the section of Psychiatry from 1 August 2013 to 31 July 2018. C-reactive protein was measured. The Area Under the Receiver Operating Characteristic (ROC_AUC) was used to assess the discriminative capacity of c-RP for high- vs. low-lethality SA, and a logistic regression was performed to detect the odds ratio, adjusted for age and sex. High-lethality suicide attempters were 133 (30.8%), while low-lethality suicide attempters were 299 (69.2%). The optimal cut-off threshold (and corresponding sensitivity and specificity values) for c-RP was 4.65 mg/L (68/71%). This cut-off corresponds to an AUC of 73.5%. An odds ratio of 4.70 was generated for current high-lethality SA after a logistic regression, adjusted for age and sex. Research on social and biological factors underlying the lethality of SA is crucial for a better understanding of this complex phenomenon. Identifying potential predictors of SA, especially those at high lethality, is essential to implement personalized preventive strategies.

Integrating biobehavioral information to predict mood disorder suicide risk

The will to live and the ability to maintain one's well-being are crucial for survival. Yet, almost a million people die by suicide globally each year (Aleman and Denys, 2014), making premature deaths due to suicide a significant public health problem (Saxena et al., 2013). The expression of suicidal behaviors is a complex phenotype with documented biological, psychological, clinical, and sociocultural risk factors (Turecki et al., 2019). From a brain disease perspective, suicide is associated with neuroanatomical, neurophysiological, and neurochemical dysregulations of brain networks involved in integrating and contextualizing cognitive and emotional regulatory behaviors. From a symptom perspective, diagnostic measures of dysregulated mood states like major depressive symptoms are associated with over sixty percent of suicide deaths worldwide (Saxena et al., 2013). This paper reviews the neurobiological and clinical phenotypic correlates for mood dysregulations and suicidal phenotypes. We further propose machine learning approaches to integrate neurobiological measures with dysregulated mood symptoms to elucidate the role of inflammatory processes as neurobiological risk factors for suicide.

Suicidal behavior-advances in clinical and neurobiological research and improvement of prevention strategies

Suicide is the 14^th leading cause of death worldwide. It is responsible for 1%-5% of all mortality. This article highlights the latest developments in universal, selective, and indicated prevention strategies. Concerning universal suicide prevention, current research has shown that strategies such as restricting access to lethal means (e.g., control of analgesics and hot-spots for suicide by jumping) and school-based awareness programs are most efficacious. Regarding selective prevention, substantial progress can be expected in psychological screening methods for suicidal behavior. The measurement of implicit cognition proved to be more valid in predicting future suicide attempts than classic clinical assessment. Latest developments are smartphone-based interventions and real-time monitoring of suicidal behavior. Great effort has been made to establish valid neurobiological screening methods (e.g., genetic and epigenetic risk factors for suicide, hypothalamic-pituitary-adrenal axis) without yielding a major bre-akthrough. Potentially, multiple biomarkers rather than a single one are necessary to identify individuals at risk. With regard to indicated prevention in form of psychopharmacological treatment, recent pharmacoepidemiological studies and meta-analyses have supported a protective role of antidepressants, lithium, and clozapine. However, the data concerning a specific anti-suicidal effect of these drugs are currently not consistent. Promising results exist for ketamine in reducing suicidal ideation, independently of its antidepressant effect. Concerning psychotherapy, recent findings suggest that psychotherapeutic interventions specifically designed to prevent suicide re-attempts are most efficacious. Specifically, cognitive behavioral therapy and psychodynamic therapy approaches proved to decrease the number of suicide re-attempts significantly.

Childhood Trauma and Suicide: The Mediating Effect of Stress and Sleep

This study aimed to investigate the relationship between suicide risk, perceived stress, and sleep quality through a structural equation modeling approach. This study used convenience sampling to survey 780 undergraduate and graduate students aged 18–30 years. Students were invited to participate in the online questionnaires, which included the Beck Scale for Suicide Ideation, the Suicidal Behaviors Questionnaire-Revised, the Perceived Stress Scale, the Childhood Trauma Questionnaire-Short Form, and the Pittsburgh Sleep Quality Index. The results showed that suicide ideation and suicidal behavior were positively correlated with childhood trauma, stress, and sleep. A well-fitted structural equation model (χ2 = 1.52, df = 1, χ2/df = 1.52, RMSEA = 0.03, CFI = 1.00, NFI = 1.00) was constructed in this study. The hierarchical regression test showed significance in all the path coefficients of the model. The total effect of emotional abuse on suicide behaviors was 49.5%. The mediating effects accounted for 73.7% of the total effects of emotional abuse on suicidal behaviors. The results demonstrate efforts targeting stress and poor sleep might mitigate the risk of suicidal behaviors among individuals with early emotional abuse experiences.

Blood hormones and suicidal behaviour: A systematic review and meta-analysis

This study was to evaluate the relationship between blood hormone levels and suicidal behaviour. We reviewed Web of Science, PubMed and Embase for literature published up to 10 April 2022. Studies were restricted to English-language articles. Studies measuring blood hormone levels in suicidal and non-suicidal subjects were eligible. Standardized mean differences (SMDs) were applied to evaluate group differences. Overall, 57 studies were eligible, of which 51 evaluated suicide attempts, and 9 assessed suicidal ideation. Random-effects meta-analysis indicated that levels of thyrotropin stimulating hormone (TSH) (SMD = 0.50; 95% CI, 0.27-0.72), leptin (SMD = -1.16; 95% CI, -1.94 to -0.38) and dehydroepiandrosterone sulfate (DHEAS) (SMD = -0.67; 95% CI, -1.13 to -0.21) were related to suicide attempts, whereas progesterone levels (SMD = 0.22; 95% CI, 0.03-0.41) were related to suicidal ideation. This analysis offers evidence linking abnormalities of blood hormones with suicidal behaviour, which may be essential for identifying individuals with suicide attempts and suicidal ideation. Large prospective studies are needed for further clarification of roles of hormones in suicidal behaviour.

Exploring the role of serum lipid profile and neutrophil-to-lymphocyte ratio in violent suicide attempters: a cross sectional study

BACKGROUND

Suicidality is one of the most common complications of mental disorders, so that the identification of potential biomarkers may be relevant in clinical practice. To date, the role of serum lipids and neutrophil/lymphocyte ratio (NLR) has been explored albeit with conflicting results. To the best of our knowledge, no study has explored lipid levels concomitantly with NLR in relation to violent suicide attempts. Therefore, we aimed to investigate whether serum lipid levels and NLR might be associated with the violent method of suicide attempts.

METHODS

The study group consisted of 163 inpatients who attempted suicide. Blood samples were collected at the beginning of hospitalization to measure total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein, very-low-density lipoprotein (VLDL), triglycerides, and NLR. Descriptive analyses of the total sample were performed. The included patients were divided into two groups according to violent/nonviolent method. Groups were compared in terms of lipid (MANCOVAs).

RESULTS

Plasma levels of total cholesterol (F = 5.66; P = .02), LDL (F = 4.94; P = .03), VLDL (F = 5.66; P = .02), and NLR (F = 8.17; P < .01) resulted to be significantly lower in patients that used a violent method compared to patients who attempted suicide with a nonviolent method.

CONCLUSIONS

Low cholesterol, LDL, and VLDL levels as well as low NLR value were associated with a violent method of suicide attempt in patients with mental disorders. Further studies are needed to confirm these results.

Microglia as a Hub for Suicide Neuropathology: Future Investigation and Prevention Targets

Suicide is a complex public health challenge associated worldwide with one death every 40 s. Research advances in the neuropathology of suicidal behaviors (SB) have defined discrete brain changes which may hold the key to suicide prevention. Physiological differences in microglia, the resident immune cells of the brain, are present in post-mortem tissue samples of individuals who died by suicide. Furthermore, microglia are mechanistically implicated in the outcomes of important risk factors for SB, including early-life adversity, stressful life events, and psychiatric disorders. SB risk factors result in inflammatory and oxidative stress activities which could converge to microglial synaptic remodeling affecting susceptibility or resistance to SB. To push further this perspective, in this Review we summarize current areas of opportunity that could untangle the functional participation of microglia in the context of suicide. Our discussion centers around microglial state diversity in respect to morphology, gene and protein expression, as well as function, depending on various factors, namely brain region, age, and sex.

Dynamic connectivity alterations in anterior cingulate cortex associated with suicide attempts in bipolar disorders with a current major depressive episode

OBJECTIVE

Considering that the physiological mechanism of the anterior cingulate cortex (ACC) in suicide brain remains elusive for bipolar disorder (BD) patients. The study aims to investigate the intrinsic relevance between ACC and suicide attempts (SA) through transient functional connectivity (FC).

METHODS

We enrolled 50 un-medicated BD patients with at least one SA, 67 none-suicide attempt patients (NSA) and 75 healthy controls (HCs). The sliding window approach was utilized to study the dynamic FC of ACC via resting-state functional MRI data. Subsequently, we probed into the temporal properties of dynamic FC and then estimated the relationship between dynamic characteristics and clinical variables using the Pearson correlation.

RESULTS

We found six distinct FC states in all populations, with one of them being more associated with SA. Compared with NSA and HCs, the suicide-related functional state showed significantly reduced dwell time in SA patients, accompanied by a significantly increased FC strength between the right ACC and the regions within the subcortical (SubC) network. In addition, the number of transitions was significantly increased in SA patients relative to other groups. All these altered indicators were significantly correlated with the suicide risk.

CONCLUSIONS

The results suggested that the dysfunction of ACC was relevant to SA from a dynamic FC perspective in BD patients. It highlights the temporal properties in dynamic FC of ACC that could be used as a putative target of suicide risk assessment for BD patients.

Association study of Catechol-O-Methyltransferase (COMT) rs4680 Val158Met gene polymorphism and suicide attempt in Mexican adolescents with major depressive disorder

AIM

We analyzed the association between SLC6A4, DRD2, COMT and MAOA genes and suicide attempt (SA) in Mexican adolescent patients with major depressive disorder (MDD).

METHODS

The sample included 197 adolescents (127 females and 70 males) with principal diagnosis of MDD. Among them, 63 patients had SA at least once and 134 had not SA. The mean age of patients with and without SA was 15 ± 1.4 and 14 ± 1.5 years, respectively. We analyzed the genotype and allele distribution between patients with and without SA of SLC6A4 (5HTTLPR/rs25531), DRD2 (rs6275), COMT (rs4680), and MAOA (uVNTR).

RESULTS

We did not find genotype or allele association between SA and SLC6A4 (χ²=0.67, p = 0.71; χ²=0.07, p = 0.77, respectively), DRD2 (χ²=0.05, p = 0.97; χ²=0.003, p = 0.95), and MAOA (females: χ²=0.86, p = 0.64; χ²=0, p = 1/males: χ²=0.008, p = 0.92) genes. However, there were differences in genotype frequencies of COMT/rs4680 between patients with SA and without SA (χ²=11.17, p = 0.003). Also, we observed a high frequency of Met158 allele showing an increased risk of having presented at least one SA (χ²=10.6, p = 0.001; OR = 1.43; 95% CI, 1.17-1.74).

CONCLUSIONS

Our findings showed an association between low activity genotype and allele of Val158Met polymorphism of COMT gene and SA in Mexican adolescents with MDD.

Oral ketamine reduces the experience of stress in people with chronic suicidality

BACKGROUND

Stress is prevalent in people experiencing suicidality and is a major contributor to the development of mental disorders. Evidence suggests ketamine shows capacity to reverse stress-induced brain changes. Though stress and ketamine have been explored individually for suicidality, this study is the first to examine ketamine treatment for self-reported stress in adults with chronic suicidality, building on pre-clinical evidence of ketamine's capacity to normalize stress-induced responses and contributing to our understanding of oral ketamine in clinical populations.

METHODS

Thirty two adult participants (22-72 years; 17 female) with chronic suicidality completed 6 weeks of active treatment, receiving low (0.5 mg/kg - 3.0 mg/kg) doses of oral ketamine once per week, with a 4-week follow-up phase, to assess the effect of ketamine on their perceived stress. Stress was measured via self-report utilizing the Depression Anxiety Stress Scale-21(DASS-21), and analysed at pre-treatment (week 0), post-treatment (week 6) and at follow-up (week 10).

RESULTS

Repeated measures ANOVA showed a significant reduction in stress (p<.001) post-treatment and Reliable Change Index calculations confirmed this to be clinically significant. Furthermore, those classified as 'prolonged responders' demonstrated a sustained reduction in stress at follow-up (i.e. after 4 weeks of nil ketamine).

LIMITATIONS

Small sample size, open label design, expectancy, secondary analysis CONCLUSIONS: Ketamine showed the capacity to produce a robust and sustained improvement in stress symptoms, in people with chronic suicidality. Future larger, controlled studies examining treatment suitability in a range of stress related disorders are warranted.

Insomnia symptoms are associated with impaired resilience in bipolar disorder: Potential links with early life stressors may affect mood features and suicidal risk

AIM

The study aimed to investigate resilience and its association with early exposure to stressful events on the clinical manifestations of bipolar disorders (BDs), such as severity of mood symptoms, suicidal ideation and behaviors focusing on the possible role of insomnia symptoms.

METHOD

A sample of 188 adult participants with BD of type I or II were assessed during depressed phase using the Structural Clinical Interview for DSM-5 (SCID-5), the Beck Depression Inventory-II (BDI-II), the Young Mania Rating Scale (YMRS), the Early Trauma Inventory Self Report-Short Form (ETISR-SF), Resilience Scale for Adults (RSA), the Insomnia Severity Index (ISI) and the Scale for Suicide Ideation (SSI). Participants with or without clinically significant insomnia were compared and we carried out correlations, regression and mediation analyses.

RESULTS

Participants with insomnia showed a greater severity of depressive symptoms as well as of suicidal risk, early life stressors and lower level of resilience. Insomnia symptoms mediated the association between early life stress and low resilience, between low resilience in planning future and depressive symptoms (Z = 2.17, p = 0.029) and low resilience and suicidal risk (Z = 3.05, p = 0.0002) CONCLUSION: Insomnia may be related to the severity of BDs, to higher early life stressors and lower level of resilience. Assessing and targeting insomnia symptoms may potentially promote resilience in BDs in response to early life stressful events. These results should be interpreted in light of several limitations including the cross-sectional design affecting causal interpretations.

Proteins associated with future suicide attempts in bipolar disorder: A large-scale biomarker discovery study

Suicide is a major cause of death worldwide. Several biological systems have been implicated in suicidal behavior but studies of candidate biomarkers have failed to produce clinically relevant biomarkers for suicide prediction. The objective of the present study was to identify novel candidate biomarkers for suicidal behavior. We used a nested case-control study design where a large cohort of patients with bipolar disorder (N = 5 110) were followed up to 8 years after blood sampling. We included patients that attempted suicide during follow-up (N = 348) and matched bipolar disorder patients from the same cohort who did not attempt suicide during the study period (N = 348) and analyzed a total of 92 proteins with a neuro exploratory multiplex panel. Using a multivariate classification algorithm devised to minimize bias in variable selection, we identified a parsimonious set of proteins that best discriminated bipolar disorder patients with and without prospective suicide attempts. The algorithm selected 16 proteins for the minimal-optimal classification model, which outperformed 500 models with permuted outcome (p = 0.0004) but had low sensitivity (53%) and specificity (64%). The candidate proteins were then entered in separate logistic regression models to calculate protein-specific associations with prospective suicide attempts. In individual analyses, three of these proteins were significantly associated with prospective suicide attempt (SCGB1A1, ANXA10, and CETN2). Most of the candidate proteins are novel to suicide research.

Large-Scale Transcriptomics Studies Provide Insight Into Sex Differences in Depression

Major depressive disorder (MDD) is a leading cause of disability, affecting more than 300 million people worldwide. We first review the well-known sex difference in incidence of MDD, with women being twice as likely to be diagnosed as men, and briefly summarize how the impact of MDD varies between men and women, with sex differences in symptoms, severity, and antidepressant drug response. We then attempt to deconstruct the biological bases for MDD and discuss implications for sex differences research. Next, we review findings from human postmortem studies, both from selected candidate gene studies and from well-powered, unbiased transcriptomics studies, which suggest distinct, and possibly opposite, molecular changes in the brains of depressed men and women. We then discuss inherent challenges of research on the human postmortem brain and suggest paths forward that rely on thoughtful cohort design. Although studies indicate that circulating gonadal hormones might underlie the observed sex differences in MDD, we discuss how additional sex-specific factors, such as genetic sex and developmental exposure to gonadal hormones, may also contribute to altered vulnerability, and we highlight various nuances that we believe should be considered when determining mechanisms underlying observed sex differences. Altogether, this review highlights not only how various sex-specific factors might influence susceptibility or resilience to depression, but also how those sex-specific factors might result in divergent pathology in men and women.

Association Between Serum Uric Acid Levels and Suicide Attempts in Adolescents and Young Adults with Major Depressive Disorder: A Retrospective Study

PURPOSE

Uric acid (UA) is thought to exert neuroprotective roles. The purpose of this study was to examine the association of serum UA with suicide attempts (SA) in adolescents and young adults with major depressive disorder (MDD).

PATIENTS AND METHODS

We retrospectively recruited 533 participants with MDD aged 13 to 25 years, of which 168 had a history of SA in the past three months and 365 did not have a history of SA. Serum UA levels were measured using the uricase-peroxidase coupling method. In addition to overall serum UA level comparison in MDD individuals with and without SA, a stratified analysis by biological sex was carried out.

RESULTS

Compared to MDD individuals without a history of SA, serum UA levels were significantly lower in MDD individuals with SA (P < 0.001). Female MDD, but not male MDD individuals, with SA exhibited lower levels of UA than those without SA (P < 0.01). Importantly, serum UA remained significantly associated with SA in MDD individuals (OR = 0.996, 95% CI: 0.993~0.999, P < 0.01) when controlling for possible confounding variables.

CONCLUSION

This research identifies a relationship between serum UA levels and SA in adolescents and young adults with MDD. UA may represent a biological risk marker for SA, in particular for female MDD individuals.

Psychobiological risk factors for suicidal thoughts and behaviors in adolescence: a consideration of the role of puberty

Suicide is the second leading cause of death among adolescents. While clinicians and researchers have begun to recognize the importance of considering multidimensional factors in understanding risk for suicidal thoughts and behaviors (STBs) during this developmental period, the role of puberty has been largely ignored. In this review, we contend that the hormonal events that occur during puberty have significant effects on the organization and development of brain systems implicated in the regulation of social stressors, including amygdala, hippocampus, striatum, medial prefrontal cortex, orbitofrontal cortex, and anterior cingulate cortex. Guided by previous experimental work in adults, we also propose that the influence of pubertal hormones and social stressors on neural systems related to risk for STBs is especially critical to consider in adolescents with a neurobiological sensitivity to hormonal changes. Furthermore, facets of the pubertal transition, such as pubertal timing, warrant deeper investigation and may help us gain a more comprehensive understanding of sex differences in the neurobiological and psychosocial mechanisms underlying adolescent STBs. Ultimately, advancing our understanding of the pubertal processes that contribute to suicide risk will improve early detection and facilitate the development of more effective, sex-specific, psychiatric interventions for adolescents.

BDNF methylation and mRNA expression in brain and blood of completed suicides in Slovenia

BACKGROUND

Suicide is a major public health problem. Worldwide, around 800000 people die by suicide every year. Suicide is a multifactorial disorder, with numerous environmental and genetic risk factors involved. Among the candidate genes, changes in the BDNF locus at the gene, epigenetic, mRNA, and protein expression levels have been implicated in psychiatric disorders, including suicidal behavior and completed suicides.

AIM

To investigate changes in BDNF methylation and expression of four alternative BDNF transcripts for association with completed suicide.

METHODS

This case-control study included 42 unrelated male Caucasian subjects, where 20 were control subjects who died following acute cardiac arrest, and 22 were suicide victims who died by hanging. DNA and RNA were extracted from brain tissue (Brodmann area 9 and hippocampus) and from blood. DNA methylation and mRNA expression levels were determined by targeted bisulfite next-generation sequencing and reverse-transcription quantitative PCR. Statistical analysis was done by use of two-tailed Student’s t tests for two independent samples, and the Benjamini-Hochberg procedure was implemented for correction for multiple comparisons.

RESULTS

In DNA from brain tissue, there were no significant differences in BDNF methylation between the study groups. However, data showed significantly reduced DNA methylation of the BDNF region upstream of exon I in blood samples of suicide victims compared to the controls (5.67 ± 0.57 vs 6.83 ± 0.64, P_corr = 0.01). In Brodmann area 9 of the brain of the suicide victims but not in their hippocampus, there was higher expression of BDNF transcript I-IX (NM_170731.4) compared to the controls (0.077 ± 0.024 vs 0.05 ± 0.013, P = 0.042). In blood, expression analysis for the BDNF transcripts was not feasible due to extensive RNA degradation.

CONCLUSION

Despite the limitations of the study, the obtained data further support a role for BDNF in suicidality. However, it should be noted that suicidal behavior is a multifactorial disorder with numerous environmental and genetic risk factors involved.

Hippocampal neuropathology in suicide: Gaps in our knowledge and opportunities for a breakthrough

Suicide is a major global hazard. There is a need for increasing suicide awareness and effective and evidence-based interventions, targeting both suicidal ideation and conduct. However, anti-suicide pharmacological effects are unsatisfactory. The human hippocampus is vulnerable to neuropsychiatric damages and subsequently releases psychobiological signals. Human hippocampal studies of suicide completers have shown mechanistic changes in neurobiology, which, however, could not reflect the neuropathological 'fingerprints' of fatal suicide ideations and suicide attempts. In this review, we provide several leading theories of suicide, including the serotoninergic system, Wnt pathway and brain-derived neurotrophic factor/tropomyosin receptor kinase B signalling, and discuss the evidence for their roles in suicide and treatment. Moreover, the cognitive dysfunctions associated with suicide risk are discussed, as well as the novel evidence on cognitive therapies that decrease suicidal ideation. We highlight the need to apply multi-omics techniques (including single-nucleus RNA sequencing and mass spectrometry histochemistry) on hippocampal samples from donors who died by suicide or legal euthanasia, to clarify the aetiology of suicide and propose novel therapeutic strategies.

Genetic propensity for risky behavior and depression and risk of lifetime suicide attempt among urban African Americans in adolescence and young adulthood

Suicide attempts (SA) among African Americans have increased at a greater rate than any other racial/ethnic group. Research in European ancestry populations has indicated that SA are genetically influenced; however, less is known about the genetic contributors that underpin SA among African Americans. We examined whether genetic propensity for depression and risky behaviors (assessed via polygenic risk scores; PRS) independently and jointly are associated with SA among urban, African Americans and whether sex differences exist in these relations. Participants (N = 1,157, 45.0% male) were originally recruited as part of two first grade universal school-based prevention trials. Participants reported in adolescence and young adulthood on whether they ever attempted suicide in their life. Depression and risky behaviors PRS were created based on large-scale genome-wide association studies conducted by Howard et al. (2019) and Karlson Línner et al. (2019), respectively. There was a significant interaction between the risky behavior PRS and depression PRS such that the combination of high risky behavior polygenic risk and low/moderate polygenic risk for depression was associated with greater risk for lifetime SA among the whole sample and African American males specifically. In addition, the risky behavior PRS was significantly positively associated with lifetime SA among African American males. These findings provide preliminary evidence regarding the importance of examining risky behavior and depression polygenic risk in relation to SA among African Americans, though replication of our findings in other African American samples is needed.

Six-week oral ketamine treatment for chronic suicidality is associated with increased grey matter volume

Chronic suicidality has been associated with neuronal atrophy in cortico-striato-limbic regions and is thought to be mediated via a glutamatergic imbalance. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been posited to exert anti-suicidal effects by promoting neurogenesis via modulation of glutamatergic transmission. This voxel-based morphometry study examined the effect of ketamine on whole brain grey matter in adults with chronic suicidality. Grey matter in the periaqueductal grey, nucleus accumbens, putamen, caudate, and thalamus was significantly increased following 6 weeks of low dose oral ketamine treatment. These results support the notion that ketamine rapidly enhances synaptic plasticity within striato-limbic regions.

Obsessive Thought, Compulsive Behavior, and Their Associations With Suicide Ideation and Attempts and Major Depressive Disorder: A Nationwide Community Sample of Korean Adults

ABSTRACT

In this study, we defined obsessive thoughts (OT) as bothersome, unpleasant thoughts about oneself that keep entering the mind against one's will, and compulsive behavior (CB) as behavior that a person repeats against his or her wishes. The study included 12,532 adults selected randomly through a one-person-per-household method. Each subject selected underwent a face-to-face interview using the Korean version of the Composite International Diagnostic Interview with a questionnaire that examines lifetime suicide attempts (LSAs). Among the participants, 341 (2.74%) had OT and 639 (5.14%) had CB. The highest LSA rate was in subjects with both OT and CB, followed by those with either OT or CB; subjects with neither OT nor CB had the lowest LSA rate. In a multivariate logistic regression analysis of OT and CB, OT, ordering, and rituals of repeating words were significantly associated with LSAs. In subjects with OT and CB, those with MDD had a significantly higher risk of LSAs compared with those without, and MDD with both OT and CB showed odds of approximately 27-fold (adjusted odds ratio, 27.24; 13.29-55.82; p < 0.0001) compared with those without MDD, OT, or CB. OT and CB were associated with increased risk of LSAs, and comorbid MDD further increased LSAs.

Genetic testing for suicide risk assessment: Theoretical premises, research challenges and ethical concerns

We explore ethical premises and practical implications of using genetic testing to predict suicide risk. Twin studies indicate heritable components of suicide risk, intertwined with the heritability of mental disorders, and possibly other traits. Current genetics research has abandoned searching for single gene Mendelian determinants, in favour of complex probabilistic epigenetic models. Genome-Wide Association Studies (GWAS) might identify thousands of single nucleotide polymorphisms (SNPs), each contributing very little to the variance associated with behavioral phenotypes. However, suicide is a behavioral outcome rather than a phenotype, with so many different causal aetiologies, that it is impossible to predict the behaviors of individuals. We analyse practical and ethical issues that would arise if future research were to identify genetic information that will accurately predict suicide. Applying ACCE guidelines that specify when genetic tests should and should not be used, we examine the Analytic Validity, Clinical Validity, Clinical Utility and Ethical, Legal, and Social Implications. Low sensitivity and specificity for predicting suicide diminish potential advantages and exacerbate risks. Key considerations include the likelihood that testing will result in effective preventive interventions, which are not currently available, and unreliable positive results increasing hopelessness, stigma, and psychosocial risks. If the unregulated direct-to-consumer genetic testing services include suicide risk assessments, their use risks negative impacts. In the future, if genetic testing could accurately identify suicide risk in individuals, its use would be contraindicated if we cannot provide effective preventive interventions and mitigate the negative impacts of informing people about their risk level.

The Effect of Brief Mindfulness Meditation on Suicidal Ideation, Stress and Sleep Quality

OBJECTIVES

Suicide is the fourth leading cause of death for individuals aged 15-29 years, and early intervention on suicidal ideation and risk factors should be priortized. Brief mindfulness meditation (BMM) is convenient and cost-effective in improving physical and mental well-being, but less is known about its efficacy for suicidal ideation, stress and sleep quality. We investigated the effects of BMM on suicidal ideation, stress, and sleep quality for individuals with suicide risk.

METHODS

Sixty-four college students with high suicidal ideation (aged 18-30 years) were randomly allocated to either a BMM (n = 32) or control group (n = 32). The BMM was based on Anapanasati and core mindfulness concepts. Sixty participants completed all scheduled sessions including pretest, one month of intervention or waiting, and posttest. Suicidal ideation was measured with the Beck Scale for Suicidal Ideation. Stress was evaluated using the Perceived Stress Scale and salivary cortisol levels. Sleep was measured using the Pittsburgh Sleep Quality Index and actigraphy accompanied with 7-day sleep diaries.

RESULTS

Post-intervention, the BMM group showed significant decrease in suicidal ideation with a large effect size; the decrease showed a medium effect size in the control group. The BMM group, but not the control group, showed significant decrease in morning salivary cortisol and sleep latency, and improved sleep efficiency.

CONCLUSIONS

BMM could help reduce suicidal ideation, stress, and sleep disturbance for individuals with high suicidal ideation and it may implicate effective suicide prevention strategy.