Biomarkers of Suicide Attempt Behavior: Towards a Biological Model of Risk

Clinical correlates, lipid metabolic parameters and thyroid hormones are associated with abnormal glucose metabolism in first-episode and drug-naïve major depressive disorder patients with suicide attempts: A large cross-sectional study

BACKGROUND

The factors associated with glucose disturbances in major depressive disorder (MDD) patients with comorbid suicide attempts remains unclear. To the best of our knowledge, this is the first study with a large sample size to examine risk factors for glucose disturbances, including clinically relevant factors, lipid metabolic parameters, and thyroid hormone levels in first-episode drug-naïve (FEDN) MDD patients with comorbid suicide attempts.

METHODS

A total of 1718 FEDN MDD patients were enrolled. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), and Positive and Negative Syndrome Scale (PANSS) were used to assess the clinical symptoms of the patients. Fasting blood samples were collected and biochemical parameters were measured, including fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), thyroid stimulating hormone (TSH), free thyroxine (FT4, FT3), anti-thyroid autoantibodies (TgAb), and thyroid peroxidase antibody (TPOAb). Statistical analyses were performed using multivariate logistic regression analyses and receptor operating characteristic curves.

RESULTS

The prevalence of glucose disturbances was 24 % in MDD patients with comorbid suicide attempts, which was 1.88 times higher than that in MDD patients without suicide attempts (11 %). Among MDD patients with comorbid suicide attempters, compared with patients without glucose disturbances, patients with glucose disturbances had higher mean scores on the HAMA, HAMD and PANSS positive subscale scores, and higher mean levels of TC, TG, TSH, HDL-C, LDL-C, and TPOAb. The combination of HAMA score, HAMD score, PANSS positive subscale score and TSH distinguished between patients with and without glucose disturbances.

CONCLUSIONS

Our findings suggest a high prevalence of glucose disturbances in FEDN MDD patients with comorbid suicide attempts. Several clinical correlates, lipid metabolism parameters, and thyroid hormone function are associated with glucose disturbances in MDD patients with comorbid suicide attempts.

Development and validation of a neutrophil-lymphocyte ratio-based nomogram for suicidal ideation in first-episode drug-naïve schizophrenia patients: A large-scale cross-sectional study

BACKGROUND

Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and platelet-neutrophil ratio (PNR) play a significant role in the pathophysiology of suicidal ideation (SI) in schizophrenia (SZ). The objective of this research was to create a nomogram that utilizes these markers to forecast the likelihood of SI in patients with first-episode drug-naïve (FEDN) SZ.

METHODS

This research analyzed 582 FEDN SZ patients cross-sectionally. The Positive and Negative Syndrome Scale (PANSS) was utilized to evaluate symptoms, depressive and cognitive factors in patients. The complete blood count was measured to calculate derived inflammatory indicators. Patients were divided into SI and non-SI groups based on the Beck Scale for Suicide Ideation scores and then randomly allocated to a training group (70 %, n = 407) and a validation group (30 %, n = 175). LASSO and binary logistic regression identified SI-associated variables in the training group, and a nomogram was built for SI prediction. The model's discrimination, calibration, and clinical utility were assessed by analyzing the area under the receiver operating characteristic curve (AUC), calibration plots, decision curve analysis (DCA), and internal validation procedures.

RESULTS

We developed a nomogram integrating NLR, PLR, PNR, and depressive factors to predict SI in FEDN SZ patients. AUCs were 0.748 (95 % CI: 0.700-0.796) for the training group and 0.795 (95 % CI: 0.723-0.866) for the validation group. Calibration analysis confirmed the nomogram's accuracy, and DCA supported its clinical utility.

CONCLUSIONS

This study successfully developed and validated a nomogram for early identification of high-risk SI in FEDN SZ patients, facilitating the establishment of effective suicide prevention measures.

Composite lifestyle, genetic risk, blood biomarkers, and risk of suicide attempts: a prospective cohort study

BACKGROUND

Although individual lifestyle factors may be associated with suicide attempts (SA), the prospective association of composite lifestyles with SA remains unknown. Furthermore, whether this association is modulated by genetic risk remains to be elucidated. The study aimed to investigate the association of composite lifestyles and genetic risk with SA risk and to explore the underlying biological mechanisms.

METHODS

435,154 individuals from the UK Biobank without a history of SA at baseline were enrolled. The SA diagnosis was based on the International Classification of Diseases coding system. Composite lifestyles were developed based on seven modifiable lifestyle factors and categorized into favorable, intermediate, and unfavorable groups. According to the polygenic risk score for SA, genetic risk was classified as low, intermediate, or high. Cox proportional hazard models and mediation analyses were conducted to examine the associations and mechanisms, respectively.

FINDINGS

During a mean follow-up of 13.6 years, 1,515 (0.35 %) individuals experienced SA. Compared to individuals with favorable lifestyles, the HR (95 % CI) for SA among those with unfavorable lifestyles was 2.19 (1.93-2.48). The risk of SA was 68 % higher among those with high genetic risk compared with low-risk individuals (HR = 1.68, 95 % CI: 1.48-1.92). The joint test revealed that individuals with unfavorable lifestyles and high genetic risk faced the highest risk of SA (HR = 3.58, 95 % CI: 2.91-4.40), which could be explained by an additive interaction. Several biomarkers in liver function, endocrine, inflammation, and blood cell pathways collectively explained 15.84 % (95 % CI: 7.68 %-27.68 %) of the association.

INTERPRETATION

Adherence to favorable lifestyles was associated with a lower risk of SA, especially among those at high genetic risk. The beneficial association might be partially explained by improvement in key mediating biomarkers.

Absence of nonfatal suicidal behavior preceding suicide death reveals differences in clinical risks

Nonfatal suicidal behavior is the most robust predictor of suicide death. However, only ∼10 % of those who survive an attempt go on to die by suicide. Moreover, ∼50 % of suicide deaths occur in the absence of prior known attempts, suggesting risks other than nonfatal suicide attempt need to be identified to help prevent suicide mortality. We studied data from 4,000 population-ascertained suicide deaths and 26,191 population controls to improve understanding of suicide deaths without prior nonfatal attempts. This study included 2,253 suicide deaths and 3,375 controls with evidence of nonfatal suicidal ideation or behaviors (SUI_SI/SB and CTL_SI/SB) from diagnostic codes and natural language processing of electronic health records notes. Characteristics of these groups were compared to 1,669 suicides with no prior nonfatal SI/SB (SUI_None) and 22,816 controls with no lifetime suicidality (CTL_None). The SUI_None and CTL_None groups had fewer overall diagnoses and were older than SUI_SI/SB and CTL_SI/SB. Mental health diagnoses were far less common in both the SUI_None and CTL_None groups; mental health problems were far less associated with suicide death than with presence of SI/SB. Physical health diagnoses were conversely more often associated with risk of suicide death than with presence of SI/SB. Pending replication, results indicate highly significant clinical differences among suicide deaths with versus without prior nonfatal SI/SB, and suggest that, for a substantial number of individuals at risk for suicide mortality, history of SI/SB does not serve as an effective clinical marker of risk.

Peripheral biological correlates of suicidality in children and adolescents: A systematic review and meta-analysis

A systematic review and meta-analysis were conducted to identify peripheral biological correlates of suicidality in children and adolescents. The review was pre-registered through PROSPERO (CRD42023417128) and included four databases (PubMed, Cochrane Library, Embase, and PsycINFO). From 27,977 non-duplicated articles, 102 full-text studies were selected. Studies investigated suicide attempts (n = 52), suicidal ideation (n = 42), or individuals with suicidal ideation or attempts grouped together (n = 22). Seropositive toxoplasmosis, cortisol, neutrophil, and neutrophil to lymphocyte ratio (NLR) exhibited significant effect size after Bonferroni correction. Effect sizes for biological correlates of suicidality were pooled using Cohen's d (effect size = -0.04, 95% confidence interval [CI]: -1.36 to 1.27) and odds ratio (effect size = -0.31, 95% CI: -1.06 to 0.42). Meta-regression analysis revealed that type of suicidality, type of control, means collected, and sample size significantly impacted the pooled effect size. Analysis showed significant publication bias and heterogeneity, as well as notable moderators and potential biomarkers for future research.

Characterizing suicidal thoughts and behaviours in individuals presenting to a psychiatric emergency department: a protocol for a multimethod approach for suicide prevention research

INTRODUCTION

Identifying individuals at risk of suicide remains an ongoing challenge. Previous research investigating risk factors for suicidal thoughts and behaviours (STB) has been informative for assessing suicide risk. However, the complex biological, psychological and sociocultural factors underlying STB have not been comprehensively captured to date, which has limited our understanding of how these factors interact to influence STB. Moreover, acute care settings, such as emergency departments (EDs), are often first points of contact for individuals with STB, highlighting a need for more research in these settings.

METHODS AND ANALYSIS

We aim to (1) characterize a cohort seeking care for STB and their clinical trajectories; (2) situate the cohort by comparing its characteristics and outcomes to other groups seeking emergency care; (3) explore their experiences of seeking care; and (4) examine blood-based biomarkers modulating risk for STB. Using a multimethod, prospective cohort design, we will follow up to 500 people aged 16 or older presenting to the ED with STB at a psychiatric hospital over 1 year. Analyses will involve descriptive statistics and latent profile analysis to characterize the cohort, hypothesis tests and regression models to situate the cohort, qualitative analysis based on a realist research framework to understand experiences, and within-participant comparisons of proteins, mRNA and epigenetic DNA modifications to examine biomarkers of contrasting states of STB.

ETHICS AND DISSEMINATION

This study was approved by the hospital's Research Ethics Board with safeguards in place to ensure the well-being of participants and research team. An integrated knowledge translation approach will be used for dissemination, wherein patient and family advisors are engaged throughout each study phase. Findings will enhance our understanding of the multifactorial nature of suicide risk, inform strategies for prevention and provide important insights into characteristics, experiences and outcomes of individuals with STB, who are under-represented in mental health research.

Psycho-biological mechanisms involved in suicidal risk, suicide attempts, and aggression: A replication and extension in bipolar disorder

BACKGROUND

Despite studies showing the individual roles of childhood maltreatment, alexithymia, impulsivity, and biological markers in suicide and aggression in bipolar disorder (BD), combined influence of these factors has not been studied yet.

METHODS

This study aimed to explore this issue in 353 individuals with BD completing self-report and clinician-rated measures. Blood samples were also taken to evaluate biological markers.

RESULTS

Higher C-reactive protein (CRP) and triglycerides (TG) and lower total cholesterol (TC) were observed in alexithymic people. Individuals with childhood maltreatment showed elevated CRP and lower TC and high-density lipoprotein cholesterol (HDLC). Those with both alexithymia and maltreatment displayed the most adverse profile regarding CRP and lipids. Depressive and manic symptoms, suicidal ideation, and low TC and HDL-C were associated with suicide attempts, while age, depressive and manic symptoms, childhood maltreatment, alexithymia, impulsivity, CRP, and low HDL-C accounted for suicidal risk. Aggression was linked to gender, impulsivity, and reduced low-density lipoprotein cholesterol (LDL-C).

LIMITATIONS

A cross-sectional design is a limitation of the study.

CONCLUSION

The study underscores the relationships between psychological and altered biomarkers, particularly elevated CRP and decreased lipid levels, and their roles in contributing to suicide and aggression, proposing a psychobiological model in BD.

Neuroinflammation, Stress-Related Suicidal Ideation, and Negative Mood in Depression

Importance

Brain translocator protein 18k Da (TSPO) binding, a putative marker of neuroinflammatory processes (eg, gliosis), is associated with stress and elevated in depressed and suicidal populations. However, it is unclear whether neuroinflammation moderates the impact of daily life stress on suicidal ideation and negative affect, thereby increasing risk for suicidal behavior.

Objective

To examine the association of TSPO binding in participants with depression with real-world daily experiences of acute stress-related suicidal ideation and negative affect, as well as history of suicidal behavior and clinician-rated suicidal ideation.

Design, Setting, and Participants

Data for this cross-sectional study were collected from June 2019 through July 2023. Procedures were conducted at a hospital-based research center in New York, New York. Participants were recruited via clinical referrals, the Columbia University research subject web portal, and from responses to internet advertisements. Of 148 participants who signed informed consent for study protocols, 53 adults aged 18 to 60 years who met DSM-5 diagnostic criteria for current major depressive disorder completed procedures with approved data and were enrolled. Participants were free of schizophrenia spectrum disorders, active physical illness, cognitive impairment, and substance intoxication or withdrawal at the time of scan.

Exposures

All participants underwent positron emission tomography imaging of TSPO binding with 11C-ER176 and concurrent arterial blood sampling.

Main Outcome and Measures

A weighted average of 11C-ER176 total distribution volume (VT) was computed across 11 a priori brain regions and made up the primary outcome measure. Clinician-rated suicidal ideation was measured via the Beck Scale for Suicidal Ideation (BSS). A subset of participants (n = 21) completed 7 days of ecological momentary assessment (EMA), reporting daily on suicidal ideation, negative affect, and stressors.

Results

In the overall sample of 53 participants (mean [SD] age, 29.5 [9.8] years; 37 [69.8%] female and 16 [30.2%] male), 11C-ER176 VT was associated at trend levels with clinician-rated suicidal ideation severity (β, 0.19; 95% CI, -0.03 to 0.39; P = .09) and did not differ by suicide attempt history (n = 15; β, 0.18; 95% CI, -0.04 to 0.37; P = .11). Exploratory analyses indicated that presence of suicidal ideation (on BSS or EMA) was associated with higher 11C-ER176 VT (β, 0.21; 95% CI, 0.01 to 0.98; P = .045). In 21 participants who completed EMA, 11C-ER176 VT was associated with greater suicidal ideation and negative affect during EMA periods with stressors compared with nonstress periods (β, 0.12; SE, 0.06; 95% CI, 0.01 to 0.23; P = .03 and β, 0.19; SE, 0.06; 95% CI, 0.08 to 0.30; P < .001, respectively).

Conclusion and Relevance

TSPO binding in individuals with depression may be a marker of vulnerability to acute stress-related increases in suicidal ideation and negative affect. Continued study is needed to determine the causal direction of TSPO binding and stress-related suicidal ideation or negative affect and whether targeting neuroinflammation may improve resilience to life stress in patients with depression.

Development of a short form of the Geriatric Depression Scale-30 based on item response theory and the RiskSLIM algorithm

Recently, methods of quickly and accurately screening for geriatric depression have attracted substantial attention. Short forms of the 30-item Geriatric Depression Scale have been developed based on classical test theory, such as the GDS-4, GDS-5, and GDS-15, but they have shown low diagnostic accuracy. Therefore, in this study, we developed a new short form of the GDS-30 based on item response theory and the RiskSLIM, a machine learning method, and validated it based on gray matter volume. We found that the short form based on IRT (GDS-9) and the short form based on the RiskSLIM (GDS-14) had higher diagnostic accuracy than other short forms of the scale. In addition, in the Region of Interest based brain analysis, we found that the GDS-9 was significantly negatively correlated with the gray matter volumes of the right hippocampus, the right parahippocampal gyrus, and the right superior temporal gyrus, whereas the other short forms were not significantly associated with the gray matter volumes of any regions. This implies that the GDS-9 has higher empirical validity than other short forms and corresponds with brain structure. Therefore, the GDS-9 can be used to screen for geriatric depression and may improve the efficiency and accuracy of screening.

Cognitive reappraisal improves the social decision-making performance of suicide attempters

A growing body of evidence suggests that emotion regulation (ER) plays a crucial role in the decision-making (DM) process of suicide attempters (SA). Cognitive reappraisal (CR), an emotion regulation strategy that reinterprets emotional situations to alter physiological and emotional responses, has been studied widely. Whereas, its effect on SA is yet to be explored. The present study attempted to use CR to modulate ER in SA to improve their DM performance, and explore the physiological mechanisms underlying this process. Scale scores under natural responses and after using the CR strategy, as well as behavioral and electroencephalographic (EEG) data from subjects were recorded during the classical DM task - ultimatum game (UG) paradigm. 52 patients with psychiatric disorders (including 26 SA and 26 non-suicide attempters) and 22 healthy controls (HC) performed in UG. Scale results showed that negative emotional experience scores decreased in all three groups after CR, but SA showed less improvement compared to HC. The behavioral results showed that acceptance of SA significantly increased after CR in both fair and unfair alternatives in the UG task, suggesting that CR can improve DM performance of SA. Besides, we extracted the late-positive potential (LPP) and theta-gamma coupling (TGC) of EEG for analysis. The LPP of SA was significantly higher when facing unfair alternatives than in fair ones, reflecting the fact that SA showed stronger negative emotions in the face of unfair situations. In addition, SA exhibited TGC diminished in frontotemporal regions when facing unfair allocation schemes, which demonstrated the existence of cognitive impairment in SA. This study verified the feasibility of CR for the moderation of DM ability in SA and provided new ideas for early intervention of suicidal behavior.

The link between endocrine parameters, serum lithium concentrations, and cognitive functions among individuals with affective disorders at risk of suicidal behavior. A study protocol

INTRODUCTION

Suicidal behavior is prevalent among individuals with mental disorders and constitutes a major global, clinical, and public health concern. It is generally accepted that the majority of persons who die by suicide are suffering from psychiatric disorders in most cases and that affective disorders make up the single commonest group. Suicide risk is highest during the years immediately following the onset of affective disorders; therefore, identifying risk factors and successful treatment of initially non-suicidal individuals with affective disorders can prevent developing suicidal behavior, help detecting, and predict it. Clarifying risk factors for individual types of major affective disorders could enhance earlier identification of suicidal risk, support preventive interventions and improve the treatment and prognosis of individuals at risk. We have developed a study protocol with the aim to address the complex interaction of endocrine parameters, lithium trace concentrations and cognitive functions with affective disorders and risk of suicidal behavior.

METHOD

A cross-sectional study will be done among individuals hospitalized after a suicidal attempt for treatment of affective disorders (group 1), hospitalized for the treatment of affective disorders without life time history of suicidal behavior (group 2), and control group individuals without life time history of mental disorders or suicidal behavior (group 3). Based on this study design we calculated the appropriate study sample size (N = 210). Venous blood samples of study participants will be collected for the evaluation of endocrine parameters, serum lithium concentrations, liver and kidney function. Data on sociodemographic factors, cognitive functions, history of mental disorders, and suicidality risk will be evaluated using validated questionnaires and instruments. Associations of endocrine parameters, serum lithium concentrations, cognitive functions, and suicidality risk will be analyzed using descriptive and inferential statistics, including linear and logistic regression. Based on this study design we calculated the appropriate study sample size (N = 210). Power analysis has shown that this sample size is appropriate for detection of significant differences between the groups.

CONCLUSION

The findings of the potential influence of the associations between serum lithium trace concentrations, endocrine parameters, and cognitive functions on suicidality risk in individuals with affective disorders may help clinicians effectively plan suicide prevention and timely implement actions for treatment.

Omics Approaches to Investigate the Pathogenesis of Suicide

Suicide is the second leading cause of death in U.S. adolescents and young adults and is generally associated with a psychiatric disorder. Suicidal behavior has a complex etiology and pathogenesis. Moderate heritability suggests genetic causes. Associations between childhood and recent life adversity indicate contributions from epigenetic factors. Genomic contributions to suicide pathogenesis remain largely unknown. This article is based on a workshop held to design strategies to identify molecular drivers of suicide neurobiology that would be putative new treatment targets. The panel determined that while bulk tissue studies provide comprehensive information, single-nucleus approaches that identify cell type-specific changes are needed. While single-nuclei techniques lack information on cytoplasm, processes, spines, and synapses, spatial multiomic technologies on intact tissue detect cell alterations specific to brain tissue layers and subregions. Because suicide has genetic and environmental drivers, multiomic approaches that combine cell type-specific epigenome, transcriptome, and proteome provide a more complete picture of pathogenesis. To determine the direction of effect of suicide risk gene variants on RNA and protein expression and how these interact with epigenetic marks, single-nuclei and spatial multiomics quantitative trait loci maps should be integrated with whole-genome sequencing and genome-wide association databases. The workshop concluded with a recommendation for the formation of an international suicide biology consortium that will bring together brain banks and investigators with expertise in cutting-edge omics technologies to delineate the biology of suicide and identify novel potential treatment targets to be tested in cellular and animal models for drug and biomarker discovery to guide suicide prevention.

Peripheral blood cellular immunophenotype in suicidal ideation, suicide attempt, and suicide: a systematic review and meta-analysis

Previous meta-analyses have documented the association of immune-inflammatory pathways with the pathophysiology of Major Depressive Episode (MDE), as reflected by alterations in peripheral blood immune cell counts. However, it remains unclear whether these immunological changes are distinct in individuals experiencing suicidal ideation (SI) or suicidal behavior (SB), beyond the context of an MDE. This systematic review and meta-analysis aimed to examine peripheral immune cell profiles across samples with SI/SB and compare them to healthy controls or patients with MDE. A systematic literature search was conducted in MEDLINE, Embase, and PsycINFO for articles published from inception until June 12, 2023. Two independent reviewers screened the articles for inclusion, extracted data, and assessed the risk of bias using the Newcastle-Ottawa scale. Meta-analyses were performed using a random-effects model to calculate standardized mean differences (SMDs) and 95% confidence intervals (CIs) for immune cell counts or ratios between groups with and without SI/SB. Heterogeneity across studies was assessed using the restricted maximum-likelihood estimator for tau statistic and I2-statistic and tested by the Q test. Publication bias was evaluated using the Egger´s test and funnel plots. Meta-regression analyses were conducted to explore the potential moderating effects of age, gender, current or lifetime SI/SB, and the type of self-harming behavior (SI or SB). The study was registered with PROSPERO (CRD42023433089). The systematic review included 30 studies, with data from 19 studies included in the meta-analyses comprising 139 unique comparisons. Eleven different cell populations or ratios were included, comprising 1973 individuals with SI/SB and 5537 comparison subjects. White blood cell (WBC) and neutrophil counts were higher in individuals with SI/SB than in controls (WBC: SMD = 0.458; 95% CI = 0.367-0.548; p value ≤ 0.001; I2 = 0.002% and; Neutrophils: SMD = 0.581; 95% CI = 0.408-0.753; p < 0.001), indicating an inflammatory process. The neutrophil-to-lymphocyte ratio (NLR) emerged as a potential marker, demonstrating a notable elevation in individuals with SI/SB (SMD = 0.695; 95% CI = 0.054-1.335; p value = 0.033; I2 = 94.281%; Q test p value ≤ 0.001). The elevated NLR appears to be primarily driven by the increase in neutrophil counts, as no significant differences were found in lymphocyte counts between groups. Comparisons among participants with and without SI/SB and depression revealed similar trends with increased NLR, monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) observed in depressed individuals with SI/SB compared to those without SI/SB. Broad alteration in the peripheral immune cell populations and their ratios were observed in individuals with SI/SB, indicating an immune activation or dysfunction. Notably, these immunological changes were also evident when comparing MDE individuals with and without SI/SB, suggesting that such immune dysfunction associated with suicidality cannot be solely attributed to or explained by depressive symptoms. The NLR, MLR, and PLR ratios, in combination with novel immune cellular and protein biomarkers, open new avenues in understanding the immunological underpinnings of SI/SB. These findings highlight the potential utility of immune markers as part of a multi-modal approach for risk stratification and therapeutic monitoring in SI/SB.

The ability of peripheral neurophysiological biomarkers to predict future psychological conditions among geriatric populations

OBJECTIVE

Though the association between peripheral neurophysiological biomarkers and psychological conditions is widely discussed, there is still limited evidence about the ability of peripheral biomarkers to predict psychological outcomes, especially among geriatric populations.

METHODS

The study is designed as a prospective cohort study. We collected information from participants aged over 55 years. The participants were evaluated at the start of the study (T0) and 6-9 months later (T1). Information about demographic profiles, peripheral neurophysiological biomarker recordings (including heart rate variability, finger temperature, skin conductance, and electromyogram), and psychological measurements (including Brief Symptom Rating Scale-5, Chinese Happiness Inventory, and Short Portable Mental Status Questionnaire) were collected at T0. At T1, participants reported self-rated questionnaires for psychological outcomes (Patient Health Questionnaire-15, health anxiety questionnaire, Beck Depression Inventory-II, and Beck Anxiety Inventory) and were evaluated with Mini-Mental State Examination by the staff. The association between the peripheral biomarkers and psychological outcomes was evaluated via multiple regression models.

RESULTS

A total of 385 participants were included in the study and the average age was 74.49 ± 7.34 years. Both stepwise multiple linear and logistic models showed a significant association between decreased skin conductance and increased/presence of depression at T1. The receiver operating characteristic (ROC) curve analysis of skin conductance for depression was fair (area under curve = 0.812).

CONCLUSIONS

The ability of skin conductance to predict depression among geriatric populations may facilitate the detection of geriatric depression and future research on the pathophysiology.

C-reactive protein (CRP) level in depressed patients with suicidal behavior: A systematic review and meta-analysis

INTRODUCTION

Suicidal behavior necessitates prompt diagnosis due to its severe consequences. C-reactive protein (CRP) levels may offer insights into its pathophysiology and aid in risk assessment, potentially enhancing preventive interventions and treatment strategies. The aim of this study is to assess the CRP levels in depressed patients with and without suicidal behavior.

METHODS

Our systematic review was registered in Prospero (#CRD42024518477). We searched five databases (PubMed, Scopus, PsycINFO, Web of Science, and CINAHL Complete) for records in English from inception to February 2024. We included observational studies that measured CRP in depressed patients with and without suicidal behavior. We used the Newcastle-Ottawa Scale (NOS) to assess the quality of the included studies. We employed a random-effects model, and the statistical analysis was conducted using Stata software version 17.

RESULTS

Initial 632 articles narrowed to 15 for systematic review. Fifteen studies with 3652 participants included. Fourteen studies involving 3387 depressed patients, 1269 with suicidal behavior, analyzed CRP levels. Suicidal patients exhibited higher CRP levels (SMD: 0.80 [0.37, 1.23]). Analysis of seven studies with 465 participants, including 200 depressed patients with suicidal behavior and 265 healthy controls, showed higher CRP levels in depressed patients (SMD: 1.58 [0.97, 2.19]).

CONCLUSION

In summary, our systematic review and meta-analysis of CRP levels in suicidal patients revealed that those with suicidal behavior exhibited higher CRP levels, suggesting possible implications for treatment approaches.

StressFit: a hybrid wearable physicochemical sensor suite for simultaneously measuring electromyogram and sweat cortisol

This study introduces StressFit, a novel hybrid wearable sensor system designed to simultaneously monitor electromyogram (EMG) signals and sweat cortisol levels. Our approach involves the development of a noninvasive skin patch capable of monitoring skin temperature, sweat pH, cortisol levels, and corresponding EMG signals using a combination of physical and electrochemical sensors integrated with EMG electrodes. StressFit was optimized by enhancing sensor output and mechanical resilience for practical application on curved body surfaces, ensuring accurate acquisition of cortisol, pH, body temperature, and EMG data without sensor interference. In addition, we integrated an onboard data processing unit with Internet of Things (IoT) capabilities for real-time acquisition, processing, and wireless transmission of sensor measurements. Sweat cortisol and EMG signals were measured during cycling exercises to evaluate the sensor suite's performance. Our results demonstrate an increase in sweat cortisol levels and decrease in the EMG signal's power spectral density following exercise. These findings suggest that combining sweat cortisol levels with EMG signals in real-time could serve as valuable indicators for stress assessment and early detection of abnormal physiological changes.

Psychological resilience and suicidality in the general population: A cross-sectional study based on data from the National Mental Health Survey of Korea 2021

BACKGROUND

The relationship between suicidality and resilience is underexplored among the general population. This study aimed to explore the relationship between lifetime, one-year, and one-month prevalence of suicidality (ideation, plan, attempt) and resilience in the general population.

METHODS

Data on suicidality, resilience, prevalence of major mental disorders, and other key psychological factors were collected from the National Mental Health Survey of Korea 2021. Interviewees comprised 5511 South Koreans aged 18-79 years. The contribution of resilience to suicidality was evaluated using Rao-Scot logistic regression, adjusting for possible confounders such as mental disorder prevalence and demographic and psychological characteristics.

RESULTS

Significantly lower resilience levels were noted among participants who reported lifetime, one-year, and one-month suicidal ideation, plan, or attempts. High resilience levels predicted no suicidal ideation, plans, and attempts in the lifetime, and no suicidal ideation and plans in the one-year and one-month time frames.

LIMITATIONS

First, this study's cross-sectional design has limitations for ascertaining a causal relationship between resilience and suicidality. Second, because the number of participants who had attempted suicide in the past year and reported suicidal thoughts/attempts in the past month was small, there were limitations in the analysis of suicidality in these time frames. Third, it was difficult to rule out the mediating effects of personality and temperament on the relationship between resilience and suicidality.

CONCLUSIONS

High resilience levels predicted lower lifetime and current suicidal ideation and suicidal planning in the general population. This study shows that psychological resilience is an important factor in evaluating an individual's current suicidality.

Pediatric suicide: Review of a preventable tragedy

Concepts of suicide are explored in this issue with a focus on suicide in children and adolescents. The epidemiology of pediatric suicide in the United States is reviewed; also, risk and protective factors, as well as prevention strategies, are discussed. Suicide in the pediatric athlete and the potential protective effect of exercise are examined. In addition, this analysis addresses the beneficial role of psychological management as well as current research on pharmacologic treatment and brain stimulation procedures as part of comprehensive pediatric suicide prevention. Though death by suicide in pediatric persons has been and remains a tragic phenomenon, there is much that clinicians, other healthcare professionals, and society itself can accomplish in the prevention of pediatric suicide as well as the management of suicidality in our children and adolescents.

Identifying behaviour-related and physiological risk factors for suicide attempts in the UK Biobank

Suicide is a global public health challenge, yet considerable uncertainty remains regarding the associations of both behaviour-related and physiological factors with suicide attempts (SA). Here we first estimated polygenic risk scores (PRS) for SA in 334,706 UK Biobank participants and conducted phenome-wide association analyses considering 2,291 factors. We identified 246 (63.07%) behaviour-related and 200 (10.41%, encompassing neuroimaging, blood and metabolic biomarkers, and proteins) physiological factors significantly associated with SA-PRS, with robust associations observed in lifestyle factors and mental health. Further case-control analyses involving 3,558 SA cases and 149,976 controls mirrored behaviour-related associations observed with SA-PRS. Moreover, Mendelian randomization analyses supported a potential causal effect of liability to 58 factors on SA, such as age at first intercourse, neuroticism, smoking, overall health rating and depression. Notably, machine-learning classification models based on behaviour-related factors exhibited high discriminative accuracy in distinguishing those with and without SA (area under the receiver operating characteristic curve 0.909 ± 0.006). This study provides comprehensive insights into diverse risk factors for SA, shedding light on potential avenues for targeted prevention and intervention strategies.

Integrative molecular and structural neuroimaging analyses of the interaction between depression and age of onset: A multimodal magnetic resonance imaging study

Depression is a neurodevelopmental disorder that exhibits progressive gray matter volume (GMV) atrophy. Research indicates that brain development is influential in depression-induced GMV alterations. However, the interaction between depression and age of onset is not well understood by the underlying molecular and neuropathological mechanisms. Thus, 152 first-episode depression individuals and matched 130 healthy controls (HCs) were recruited to undergo T1-weighted high-resolution magnetic resonance imaging for this study. By two-way ANOVA, age and diagnosis were used as factors when analyzing the interaction of GMV in the participants. Then, spatial correlations between neurotransmitter maps and factor-related volume maps are established. Results illustrate a pronounced antagonistic interaction between depression and age of onset in the right insula, superior temporal gyrus, anterior cingulate gyrus, and orbitofrontal gyrus. Depression-caused reductions in GMV are mainly distributed in thalamic-limbic-cortical regions, regardless of age. For the main effect of age, adults exhibit brain atrophy in frontal, cerebellum, parietal, and temporal lobe structures. Cross-modal correlations showed that GMV changes in the interactive regions were linked with the serotonergic system and dopaminergic systems. Summarily, our results reveal the interaction between depression and age of onset in neurobiological mechanisms, which provide hints for future treatment of different ages of depression.

Suicide, neuroinflammation and other physiological alterations

Suicide is considered one of the major public health problems worldwide, being the second leading cause of death in the 15-29 age group. It is estimated that every 40s someone in the world commits suicide. The social taboo surrounding this phenomenon as well as the fact that suicide prevention measures currently fail to avoid deaths from this cause, means that more research is needed to understand its mechanisms. The present narrative review on suicide tries to point out several important aspects, such as risk factors or the dynamics of suicide, as well as the current findings in the field of physiology that could offer advances in the understanding of suicide. Subjective measures of risk such as scales and questionnaires are not effective alone, whereas the objective measures can be addressed from physiology. Thus, an increased neuroinflammation in people who take their own lives has been found, with an increase in inflammatory markers such as interleukin-6 and other cytokines in plasma or cerebrospinal fluid. Also, the hyperactivity of the hypothalamic-pituitary-adrenal axis and a decrease in serotonin or in vitamin D levels seems to also be involved. In conclusion, this review could help to understand which factors can trigger an increased risk of dying by suicide, as well as pointing out those alterations that occur in the body when someone attempt to commit suicide or succeeds in taking their own life. There is a need for more multidisciplinary approaches that address suicide to help to raise awareness of the relevance of this problem that causes the death of thousands of people every year.

Functional magnetic resonance imaging alternations in suicide attempts individuals and their association with gene expression

BACKGROUND

Functional Magnetic Resonance Imaging (fMRI) has shown brain activity alterations in individuals with a history of attempted suicide (SA) who are diagnosed with depression disorder (DD) or bipolar disorder (BD). However, patterns of spontaneous brain activity and their genetic correlations need further investigation.

METHODS

A voxel-based meta-analysis of 19 studies including 26 datasets, involving 742 patients with a history of SA and 978 controls (both nonsuicidal patients and healthy controls) was conducted. We examined fMRI changes in SA patients and analyzed the association between these changes and gene expression profiles using data from the Allen Human Brain Atlas by partial least squares regression analysis.

RESULTS

SA patients demonstrated increased spontaneous brain activity in several brain regions including the bilateral inferior temporal gyrus, hippocampus, fusiform gyrus, and right insula, and decreased activity in areas like the bilateral paracentral lobule and inferior frontal gyrus. Additionally, 5,077 genes were identified, exhibiting expression patterns associated with SA-related fMRI alterations. Functional enrichment analyses demonstrated that these SA-related genes were enriched for biological functions including glutamatergic synapse and mitochondrial structure. Concurrently, specific expression analyses showed that these genes were specifically expressed in the brain tissue, in neurons cells, and during early developmental periods.

CONCLUSION

Our findings suggest a neurobiological basis for fMRI abnormalities in SA patients with DD or BD, potentially guiding future genetic and therapeutic research.

Neural activity during inhibitory control predicts suicidal ideation with machine learning

Suicide is a leading cause of death in the US and worldwide. Current strategies for preventing suicide are often focused on the identification and treatment of risk factors, especially suicidal ideation (SI). Hence, developing data-driven biomarkers of SI may be key for suicide prevention and intervention. Prior attempts at biomarker-based prediction models for SI have primarily used expensive neuroimaging technologies, yet clinically scalable and affordable biomarkers remain elusive. Here, we investigated the classification of SI using machine learning (ML) on a dataset of 76 subjects with and without SI(+/-) (n = 38 each), who completed a neuro-cognitive assessment session synchronized with electroencephalography (EEG). SI+/- groups were matched for age, sex, and mental health symptoms of depression and anxiety. EEG was recorded at rest and while subjects engaged in four cognitive tasks of inhibitory control, interference processing, working memory, and emotion bias. We parsed EEG signals in physiologically relevant theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) frequencies and performed cortical source imaging on the neural signals. These data served as SI predictors in ML models. The best ML model was obtained for beta band power during the inhibitory control (IC) task, demonstrating high sensitivity (89%), specificity (98%). Shapley explainer plots further showed top neural predictors as feedback-related power in the visual and posterior default mode networks and response-related power in the ventral attention, fronto-parietal, and sensory-motor networks. We further tested the external validity of the model in an independent clinically depressed sample (n = 35, 12 SI+) that engaged in an adaptive test version of the IC task, demonstrating 50% sensitivity and 61% specificity in this sample. Overall, the study suggests a promising, scalable EEG-based biomarker approach to predict SI that may serve as a target for risk identification and intervention.

Immunological alterations in patients with current and lifetime suicide ideation and attempts: Examining the relationship with depressive symptoms

Background

Suicidal ideation and attempt (SI/SA) have been associated with dysregulation of the immune response and inflammation. However, few studies have explored how innate and acquired cellular immunity impact on the peripheral immune response. Our study addresses this gap by examining the composition of peripheral immune cells and humoral markers among individuals with current SI/SA, individuals with a history of SI/SA, and healthy controls (HC). Additionally, we aim to explore whether depressive symptoms settle the relationship between inflammation and SI/SA.

Methods

This is a multicenter case-control study that included 105 participants. Clinical and demographic characterists together with hemogram parameters, soluble pro and anti-inflamatory factors, and specific innate and adaptive immune cell populations were compared among patients with current SI/SA (n = 21), a history of lifetime SI/SA (n = 42), and HC (n = 42).

Results

Patients with both current and lifetime SI/SA had a significant increase in the absolute count of monocytes and in the monocyte/lymphocyte ratio (MLR). Additionally, patients with current and lifetime SI/SA showed a significant increase in high-sensitivity C- reactive protein (hs-CRP), and patients with lifetime SI/SA also showed higher levels of Erythrocyte Sedimentation Rate (ESR). The cellular inflammatory status of patients with SI/SA was characterized by altered proportions of monocytes with higher levels of nonclassical and intermediate monocytes. No differences were observed in the number of lymphocytes and the proportion of CD4 and CD8 between patients and HC, but we found differences in markers of exhaustion of CD4 lymphocytes, with increased levels of Programmed cell death protein 1 (PD1) in Current SI/SA and Lymphocyte activation gene 3 (LAG3) in Current SI/SA and Lifetime SI/SA compared to HC. The plasmainflammatory status was marked by higher levels of soluble Triggering receptor expressed on myeloid cells 2 (sTREM2) in patients with lifetime SI/SA compared to HC. Finally, the multinomial analysis indicates that inflammation and depressive symptoms are independently associated with SI/SA.

Conclusion

This study highlights the association of immunological alterations with SI/SA. Furthremore, SI/SA is independently influenced by depressive symptoms and inflammation. This may have important therapeutic implications, as in these patients, it may be necessary to treat the inflammatory process beyond treating the depressive symptoms.

Association between peripheral plasma cytokine levels and suicidal ideation in first-episode, drug-naïve major depressive disorder

BACKGROUND

Inflammatory processes could potentially impact both mood and suicide risk, however, the relationship between cytokines and suicidal ideation remains unclear. This study aimed to investigate the association between plasma levels of cytokines and suicidal ideation in population with major depressive disorders (MDD).

METHODS

A cross-sectional study was performed to assess the peripheral plasma levels of interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-10 and tumor necrosis factor-α (TNF-α) in 88 Chinese Han first-episode drug-naïve MDD patients. Suicidal ideation in the past week were identified using the Beck Scale for Suicide Ideation-Chinese Version (BSI-CV). The Hamilton Depression Rating Scale-17 (HAMD-17), the Hamilton Anxiety Rating Scale-14 (HAMA-14) and the Childhood Trauma Questionnaire (CTQ) was used to assess depression, anxiety and childhood trauma. Multivariable logistic regression models were used to estimate the association between cytokines and suicidal ideation. Interaction and stratified analyses were conducted according to age, sex, marital status, education, smoking status, BMI and physical activity.

RESULTS

Among the 88 participants, 42 individuals (47.7%) reported suicidal ideation within the past week. In the fully adjusted model, a statistically significant trend was observed in the association between IL-2 level and suicidal ideation (OR: 1.40, 95% CI: 1.00-1.97). The stratified analysis showed a statistically significant association between IL-6 level and suicidal ideation among younger people (OR: 1.17, 95% CI: 1.01-1.36) and a significant positive association between IL-8 (OR: 1.59, 95% CI: 1.03-2.44) and IL-10 (OR: 2.51, 95% CI: 1.27-4.96) levels and suicide ideation among higher educated populations.

LIMITATIONS

The cross-sectional design, residual confounding effects and small sample size CONCLUSION: Our findings indicate a significant positive association between plasma IL-2 level and suicidal ideation in MDD patients. IL-2 has the potential to be a biomarker of suicidal ideation in patients with depression.

Absence of nonfatal suicidal behavior preceding suicide death reveals differences in clinical risks

Nonfatal suicidality is the most robust predictor of suicide death. However, only ~10% of those who survive an attempt go on to die by suicide. Moreover, ~50% of suicide deaths occur in the absence of prior known attempts, suggesting risks other than nonfatal suicide attempt need to be identified. We studied data from 4,000 population-ascertained suicide deaths and 26,191 population controls to improve understanding of risks leading to suicide death. This study included 2,253 suicide deaths and 3,375 controls with evidence of nonfatal suicidality (SUI_SI/SB and CTL_SI/SB) from diagnostic codes and natural language processing of electronic health records notes. Characteristics of these groups were compared to 1,669 suicides with no prior nonfatal SI/SB (SUI_None) and 22,816 controls with no lifetime suicidality (CTL_None). The SUI_None and CTL_None groups had fewer diagnoses and were older than SUI_SI/SB and CTL_SI/SB. Mental health diagnoses were far less common in both the SUI_None and CTL_None groups; mental health problems were less associated with suicide death than with presence of SI/SB. Physical health diagnoses were conversely more often associated with risk of suicide death than with presence of SI/SB. Pending replication, results indicate highly significant clinical differences among suicide deaths with versus without prior nonfatal SI/SB.

Ventromedial prefrontal cortex activation and neurofeedback modulation during episodic future thinking for individuals with suicidal thoughts and behaviors

Individuals experiencing suicidal thoughts and behaviors (STBs) show less specificity and positivity during episodic future thinking (EFT). Here, we present findings from two studies aiming to (1) further our understanding of how STBs may relate to neural responsivity during EFT and (2) examine the feasibility of modulating EFT-related activation using real-time fMRI neurofeedback (rtfMRI-nf). Study 1 involved 30 individuals with major depressive disorder (MDD; half with STBs) who performed an EFT task during fMRI, for which they imagined personally-relevant future positive, negative, or neutral events. Positive EFT elicited greater ventromedial prefrontal cortex (vmPFC) activation compared to negative EFT. Importantly, the MDD + STB group exhibited reduced vmPFC activation across all EFT conditions compared to MDD-STB; although EFT fluency and subjective experience remained consistent across groups. Study 2 included rtfMRI-nf focused on vmPFC modulation during positive EFT for six participants with MDD + STBs. Results support the feasibility and acceptability of the rtfMRI-nf protocol and quantitative and qualitative observations are provided to help inform future, larger studies aiming to examine similar neurofeedback protocols. Results implicate vmPFC blunting as a promising treatment target for MDD + STBs and suggest rtfMRI-nf as one potential technique to explore for enhancing vmPFC engagement.

Predicting suicidal ideation using multiple serum biomarkers in patients with acute coronary syndrome

BACKGROUND

Biomarkers for suicidal behavior in patients with acute coronary syndrome (ACS) have yet to be elucidated. This study aimed to identify a panel of serum biomarkers associated with suicidal ideation (SI) in patients with ACS.

METHODS

The study evaluated 969 patients within 2 weeks of ACS (acute phase) and 711 patients 12 months later (chronic phase). The evaluation included 14 serum biomarkers covering 7 functional systems, socio-demographic/clinical characteristics, and SI assessed by the "suicidal thoughts" item of the Montgomery-Åsberg Depression Rating Scale. Logistic regression models were used to analyze the data. The results showed that 195 patients (20.1 %) had SI in the acute phase, and 87 patients (12.2 %) had SI in the chronic phase.

RESULTS

A combination of five serum biomarkers (tumor necrosis factor-α, interleukin-1β, folate, troponin I, and creatine kinase-MB) was significantly associated with SI in the acute phase, and a combination of three serum biomarkers (tumor necrosis factor-α, interleukin-1β, and folate) was significantly associated with SI in the chronic phase in a clear dose-dependent manner (all P-values < 0.001) after adjustment for relevant covariates.

DISCUSSION

These findings suggest that the application of a combination of multiple serum biomarkers could improve the predictability of SI in patients with ACS at both acute and chronic phases.

Suicide attempts in the adult Mexican population: an analysis of sociodemographic characteristics and associated factors

OBJECTIVE

Suicide is the culmination of a process or continuum known as suicidal behavior that proceeds from ideation and planning to attempt. The objective was to estimate the prevalence of suicide attempts in the adult Mexican population and to analyze their main associated factors.

METHODS

We conducted an observational, cross-sectional, and descriptive study with information from the National Health and Nutrition Survey (2018). Self-reported lifetime suicide attempt was used in the analysis. We analyzed depression, obesity, tobacco smoking, and alcohol consumption as suicide attempt-associated factors using a multivariate logistic regression model.

RESULTS

The prevalence of adult suicide attempt was 2.0% (95%CI 1.8-2.2) and it was higher among women (2.4%; 95%CI 2.2-2.8) and young people (2.9%; 95%CI 2.4-3.4). Low education (OR=1.6; 95%CI 1.2-2.2), being single (OR=1.3; 95%CI 1.0-1.6), having obesity (OR=1.4; 95%CI 1.1-1.8), consumption of alcohol (OR=2.4; 95%CI 1.7-3.4) or tobacco smoking (OR=1.8; 95%CI 1.4-2.4), and having strong symptoms of depression (OR=10.1; 95%CI 6.2-16.3) were associated with a higher prevalence of suicide attempts.

CONCLUSION

These results help better understand suicidal behavior in Mexico and identify the factors that increase the likelihood of suicide attempts, which is essential to help reduce suicide mortality. This research is crucial for developing early interventions and prevention programs aimed at reducing suicide's public health burden.

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.

A Prospective Multicenter Longitudinal Analysis of Suicidal Ideation among Long-COVID-19 Patients

Long coronavirus disease 19 (COVID-19) is an emerging multifaceted illness with the pathological hallmarks of chronic inflammation and neuropsychiatric symptoms. These pathologies have also been implicated in developing suicidal behaviors and suicidal ideation (SI). However, research addressing suicide risk in long COVID-19 is limited. In this prospective study, we aim to characterize SI development among long-COVID-19 patients and to determine the predictive power of inflammatory markers and long-COVID-19 symptoms-including those of psychiatric origin-for SI. During this prospective, longitudinal, multicenter study, healthy subjects and long-COVID-19 patients will be recruited from the University Hospital of Geneva, Switzerland, the University of Genova, the University of Rome "La Sapienza", and the University of San Francisco. Study participants will undergo a series of clinic visits over a follow-up period of 1 year for SI assessment. Baseline and SI-onset levels of inflammatory mediators in plasma samples, along with 12 long-COVID-19 features (post-exertional malaise, fatigue, brain fog, dizziness, gastrointestinal disturbance, palpitations, changes in sexual desire/capacity, loss/change of smell/taste, thirst, chronic cough, chest pain, and abnormal movements) will be collected for SI risk analysis. The proposed enrollment period is from 15 January 2024 to 15 January 2026 with targeted recruitment of 100 participants for each study group. The anticipated findings of this study are expected to provide important insights into suicide risk among long-COVID-19 patients and determine whether inflammation and psychiatric comorbidities are involved in the development of SI in these subjects. This could pave the way to more effective evidence-based suicide prevention approaches to address this emerging public health concern.

Barriers and facilitators to depression care among Latino men in a primary care setting: a qualitative study

BACKGROUND

In the United States, Latinos face a wide array of cultural and structural barriers to accessing and utilizing mental health care. Latino men specifically are at high risk of receiving inadequate mental health care, possibly due to additional obstacles they experience that are related to masculinity. Among men more generally, greater adherence to emotional control and self-reliance is associated with higher depression severity and less depression help-seeking. Men experience more stigma toward depression and help-seeking and are less likely to be diagnosed with depression than women. However, Latino men's barriers and facilitators to depression care remain largely unexplored. The objective of this study was to examine barriers and facilitators to depression care that are related to masculinity among English- and Spanish-speaking Latino men in a primary care setting.

METHODS

We used convenience and purposive sampling to recruit primary care patients who self-identified as Latino men, spoke English or Spanish, and screened positive for depressive symptoms on the Patient Health Questionnaire-2 or had a history of depression. Semi-structured interviews were conducted between December 2020 and August 2021. The interview guide examined views and experiences of depression, masculinity, and barriers and facilitators to engaging in depression care. Utilizing consensual qualitative research and thematic analysis informed by modified grounded theory, barriers and facilitators to depression care were identified.

RESULTS

We interviewed thirteen participants who varied in English proficiency, education, income, and country of origin. Barriers and facilitators were placed into three domains-Self-Recognition of Depression, Seeking Help for Depression, and Depression Diagnosis and Treatment. Participants described aspects of masculinity as barriers (emotional control and pressure to provide), facilitators (honesty, courage, collaboration, practicality, and responsibility), or both (self-reliance and autonomy).

CONCLUSIONS

Masculinity influences barriers and facilitators for depression care among Latino men at the levels of self-recognition, seeking help, and diagnosis and treatment. Clinicians may promote Latino men's engagement in depression care by understanding patients' values and framing depression care as affirming masculinity. Providing education to primary care physicians and other healthcare professionals on gender and depression and addressing structural barriers are essential to providing access to all who need depression care.

Alcohol use and suicide-related outcomes in people with a diagnosis of schizophrenia: a comprehensive systematic review and meta-analysis

Suicide is the leading cause of unnatural death among people with a diagnosis of schizophrenia. Alcohol use is a prevalent comorbid feature of schizophrenia and a modifiable risk factor for suicide. We conducted a prospectively registered (PROSPERO, CRD42022358214) systematic review and meta-analysis to quantify the relationship between alcohol use and suicide-related outcomes in schizophrenia.We searched Medline, Embase, and PsycINFO for cross-sectional, case-control and longitudinal studies using exhaustive terms from database inception to December 2022 inclusive. Computation of odds ratios (ORs) and hazard ratios (HRs) were performed using a random-effects model with DerSimonian-Laird estimation. We also evaluated publication bias, study quality, and performed subgroup analysis and meta-regression. Fifty studies, comprising 65 samples, met eligibility criteria. Overall, alcohol use was associated with suicide (OR 1.38, 95% CI 1.21-1.58; HR = 1.32, 95% CI 1.00-1.74), attempted suicide (OR 1.69, 95% CI 1.45-1.98), and suicidal ideation (OR 1.69, 95% CI 1.22-2.34). While there was no evidence of publication bias, between-sample heterogeneity was moderate in analyses of attempted suicide (I2 = 39.6%, p = 0.01) and suicidal ideation (I2 = 56.0%, p = 0.01). Summary effects were significant in all subgroups except for longitudinal studies of attempted suicide (OR 1.60, 95% CI 0.86-3.00) and studies of suicidal ideation using gender combined samples (OR 1.63, 95% CI 0.99-2.67). Alcohol use is significantly associated with suicide-related outcomes in schizophrenia. Clinicians should routinely inquire about alcohol use in mental health services to focus preventative treatment efforts.

EEG wakefulness regulation in transdiagnostic patients after a recent suicide attempt

OBJECTIVE

Decades of research have not yet produced statistically reliable predictors of preparatory behavior eventually leading to suicide attempts or deaths by suicide. As the nature of suicidal behavior is complex, it is best investigated in a transdiagnostic approach, while assessing objective markers, as proposed by the Research Domain Criteria (Cuthbert, 2013).

METHODS

A 15-min resting-state EEG was recorded in 45 healthy controls, and 49 transdiagnostic in-patients with a recent (<6 months) suicide attempt. Brain arousal regulation in eyes-closed condition was assessed with the Vigilance Algorithm Leipzig (VIGALL) (Sander et al., 2015).

RESULTS

A significant incline of median vigilance and vigilance slope was observed in patients within the first 3-min of the EEG recording. Additionally, a significant positive correlation of self-reported suicidal ideation with the vigilance slope over 15-min recording time, as well as a significant negative correlation with EEG vigilance stage A1 during the first 3-min was found.

CONCLUSIONS

Transdiagnostic patients with a recent suicide attempt show a distinct vigilance regulation pattern. Further studies including a control group consisting of patients without life-time suicide attempts are needed to increase the clinical utility of the findings.

SIGNIFICANCE

These findings might serve as potential objective markers of suicidal behavior.

Links between psychopathological symptoms and cortical thickness in men with severe alcohol use disorder: A Magnetic Resonance Imaging study

BACKGROUND

Anxiety and depression are psychopathological states frequently co-occurring with severe alcohol use disorder (SAUD). These symptoms generally disappear with abstinence but may persist in some patients, increasing the relapse risk.

METHODS

The cerebral cortex thickness of 94 male patients with SAUD was correlated with symptoms of depression and anxiety, both measured at the end (2-3 weeks) of the detoxification treatment. Cortical measures were obtained using surface-based morphometry implemented with Freesurfer.

RESULTS

Depressive symptoms were associated with reduced cortical thickness in the superior temporal gyrus of the right hemisphere. Anxiety level was correlated with lower cortical thickness in the rostral middle frontal region, inferior temporal region, and supramarginal, postcentral, superior temporal, and transverse temporal regions of the left hemisphere, as well as with a large cluster in the middle temporal region of the right hemisphere.

CONCLUSIONS

At the end of the detoxification stage, the intensity of depressive and anxiety symptoms is inversely associated with the cortical thickness of regions involved in emotions-related processes, and the persistence of the symptoms could be explained by these brain deficits.

Impulsivity in Major Depressive Disorder Patients with Suicidal Ideation: Event-related Potentials in a GoNogo Task

Objective

: Suicidal ideation is one of the strongest predictors of suicide, and its relevance to impulsivity in depressed patients has been accumulated. Furthermore, high impulsivity patients show the attenuation of the Nogo amplitude in the GoNogo event-related potential (ERP). The purpose of the current study is to determine the correlation of Nogo ERP to the suicidal ideation depending on the condition of its presence or absence in major depressive disorder (MDD) patients.

Methods

: A total 162 participants (104 patients with suicidal ideation, 31 patients without suicidal ideation, and 27 healthy controls) were recruited, and performed GoNogo tasks during the electroencephalogram measurement. Depression, anxiety, suicidal ideation and impulsivity were assessed by self-rating scales. The clinical measures, behavioral data and Nogo ERP were compared among groups.

Results

: The MDD with suicidal ideation (SI) group showed significantly decreased Nogo P3 amplitudes compared to MDD without SI (Fz and Cz electrodes) and control group (all electrodes). The MDD with SI group also had significantly low accuracy of both Go and Nogo trails, compared to the MDD without group. The Nogo P3 amplitudes showed the negative relation to the scores of impulsivity, depression, anxiety and SI.

Conclusion

: Our results concluded that the Nogo P3 ERP amplitude was decreased in MDD patients with SI compared to MDD patients without SI and controls. These findings suggest that the decreased Nogo P3 amplitude is the one of the candidate biomarker for impulsivity in MDD patients to evaluating SI.

Immune-related biomarkers and suicidal behaviors: A meta-analysis

Biomarkers that can differentiate between psychiatric disorders with and without suicidal behavior history from each other and from healthy volunteers may explain part of the pathogenesis of suicidal behavior. We conducted the hitherto largest meta-analysis comparing immune biomarkers between subjects with and without suicide attempt history or death by suicide. The study protocol was registered with PROSPERO, CRD42020212841. Standardized mean differences (SMD) were pooled with random-effects models. Heterogeneity between studies was assessed with the I2-statistic and publication bias was evaluated by the Egger test and funnel plots. Data were based on 36 studies including 2679 persons with suicidal behaviors and 6839 comparison subjects, and four immune-related biomarkers (CRP, IL-6, TNF-α and IL-1β). Suicidal behavior was associated with higher CRP blood levels compared with: healthy controls (SMD [95%CI] = 1.42[0.85-1.98]); patients with depression alone (SMD [95%CI] = 1.23[0.20-2.26]); and patients with any psychiatric disorders (SMD [95%CI] = 0.39[0.22-0.55]). IL-6 blood level was higher in patients with suicidal behaviors compared with healthy controls (SMD [95%CI] = 1.13[0.45-1.82]) and when compared with psychiatric patients without suicidal behaviors (SMD [95%CI] = 0.22 [0.11-0.33]). Meta-regression and subgroup analyses revealed that increased CRP in suicidal behavior is primarily driven by recent suicidal behavior. These results implicate the immune system and inflammatory response in suicidal behavior independent of a relationship to major psychiatric disorders, and that these biological measures are predominantly state-dependent markers. Future studies are needed to determine the cause-and-effect relationship of these immune system biomarkers with suicidal behavior, and their potential predictive properties.

Association of interleukin-6 with suicidal ideation in veterans: a longitudinal perspective

Introduction

Studies showing associations between inflammation in suicide are typically cross-sectional. Present study investigated how cytokine levels track with suicidal ideation and severity longitudinally.

Methods

Veterans with a diagnosis of major depressive disorder (MDD) with or without suicide attempt history (MDD/SA n = 38, MDD/NS n = 41) and non-psychiatric non-attempter controls (HC n = 33) were recruited, MDD/SA and HC groups were followed longitudinally at 3 months and 6 months. Blood plasma was collected and processed using Luminex Immunology Multiplex technology.

Results

Significant differences in depression severity (BDI) and suicidal ideation severity (SSI) were observed across all groups at study entry, wherein MDD/SA group had the highest scores followed by MDD/NS and HC, respectively. Cytokines IL-1β, IL-4, TNF-α, IFN-γ, and IL-6 were examined at study entry and longitudinally, with IL6 levels differing significantly across the groups (p = 0.0123) at study entry. Significant differences in changes in cytokine levels between depressed attempters and the control group were detected for IL-6 (interaction F1,91.77 = 5.58, p = 0.0203) and TNF-α (F1,101.73 = 4.69, p = 0.0327). However, only depressed attempters showed a significant change, in IL-6 and TNF-α levels, decreasing over time [IL-6: b = -0.04, 95% CI = (-0.08, -0.01), p = 0.0245 and TNF-α: b = -0.02, 95% CI = (-0.04, -0.01), p = 0.0196]. Although IL-6 levels were not predictive of suicidal ideation presence [OR = 1.34, 95% CI = (0.77, 2.33), p = 0.3067], IL-6 levels were significantly associated with suicidal ideation severity (b = 0.19, p = 0.0422).

Discussion

IL-6 was not associated with presence of suicidal ideation. IL-6 however, was associated with severity of ideation, suggesting that IL-6 may be useful in clinical practice, as an objective marker of heightened suicide risk.

Relationship of stress-reactive cortisol to suicidal intent of prior attempts in major depression

Higher intent suicide attempts carry elevated risk of future suicidal behavior. Abnormal functioning of the hypothalamic-pituitary-adrenal (HPA) axis is both linked to nonfatal suicidal behavior and suicide deaths in major depressive disorder. Few studies, however, have identified biological markers of a high-intent suicidal subgroup. We examined HPA axis output and reactivity to the Trier Social Stress Test (TSST) via salivary cortisol in depressed individuals (N=68) with a suicide attempt (SA) history. A median split of higher and lower suicidal intent scores was used to define groups. Individuals with high intent SA had attenuated total cortisol output (AUCg), F(1,60)=10.04, SE=5.095, p=.003, and lower HPA-axis stress responsivity to the TSST (AUCi), F(1,60)=4.50, SE=4.604, p=.039, compared with the low intent SA group. The high intent group also reported more pronounced negative affect than the low intent group (F[1,61]=6.413, SE=10.55, p=.014) both at baseline (meandiff=22.32, p=.038) and in response to the stressor task (meandiff=37.62, p=.003). Vulnerability to suicidal behavior in high-intent individuals may be related to the combined profile of impaired physiological responses to stress and greater negative affectivity. This clinical and biologic subgroup may benefit from targeted suicide prevention interventions.

Alcohol drinking in male patients with chronic schizophrenia: prevalence and its relationship to clinical symptoms

Background

It is common practice to associate schizophrenia (SCZ) patients with substance use. The most commonly used substances in China are tobacco and alcohol. However, few studies have focused on alcohol consumption itself in patients with SCZ. Thus the purpose of this study was to detect the prevalence of alcohol use and associated clinical factors in Chinese patients with SCZ.

Methods

A total of 616 male inpatients who met the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for SCZ participated in this study. A detailed questionnaire, including data on alcohol consumption was used to collect demographic and clinical information on all patients. The five-factor model of the positive and negative syndrome scale (PANSS) was adopted to assess psychiatric symptoms.

Results

In this study, 31.49% of SCZ inpatients had a history of alcohol use, and 82.9% of these patients abstained from alcohol use after the onset of SCZ. Compared to nondrinkers, patients who drank were more likely to smoke (p = 0.004), more likely to have suicide attempts (p = 0.002) and suicidal ideation (p = 0.001), more severe positive (p < 0.001) and depressive symptoms (p = 0.034), but less severe negative symptoms (p = 0.04).

Conclusion

These findings suggest that alcohol use is common during the lifetime of SCZ patients and that alcohol use may be associated with clinical symptoms in SCZ patients.

Multiple serum biomarkers for predicting suicidal behaviours in depressive patients receiving pharmacotherapy

BACKGROUND

Predictive values of multiple serum biomarkers for suicidal behaviours (SBs) have rarely been tested. This study sought to evaluate and develop a panel of multiple serum biomarkers for predicting SBs in outpatients receiving a 12-month pharmacotherapy programme for depressive disorders.

METHODS

At baseline, 14 serum biomarkers and socio-demographic/clinical characteristics including previous suicidal attempt and present suicidal severity were evaluated in 1094 patients with depressive disorders without a bipolar diagnosis. Of these, 884 were followed for increased suicidal severity and fatal/non-fatal suicide attempt outcomes over a 12-month treatment period. Individual and combined effects of serum biomarkers on these two prospective SBs were estimated using logistic regression analysis after adjustment for relevant covariates.

RESULTS

Increased suicidal severity and fatal/non-fatal suicide attempt during the 12-month pharmacotherapy were present in 155 (17.5%) and 38 (4.3%) participants, respectively. Combined cortisol, total cholesterol, and folate serum biomarkers predicted fatal/non-fatal suicide attempt, and these with interleukin-1 beta and homocysteine additionally predicted increased suicidal severity, with clear gradients robust to adjustment (p values < 0.001).

CONCLUSIONS

Application of multiple serum biomarkers could considerably improve the predictability of SBs during the outpatient treatment of depressive disorders, potentially highlighting the need for more frequent monitoring and risk appraisal.

Fight the Fire: Association of Cytokine Genomic Markers and Suicidal Behavior May Pave the Way for Future Therapies

The fight against suicide is highly challenging as it may be one of the most complex and, at the same time, most threatening among all psychiatric phenomena. In spite of its huge impact, and despite advances in neurobiology research, understanding and predicting suicide remains a major challenge for both researchers and clinicians. To be able to identify those patients who are likely to engage in suicidal behaviors and identify suicide risk in a reliable and timely manner, we need more specific, novel biological and genetic markers/indicators to develop better screening and diagnostic methods, and in the next step to utilize these molecules as intervention targets. One such potential novel approach is offered by our increasing understanding of the involvement of neuroinflammation based on multiple observations of increased proinflammatory states underlying various psychiatric disorders, including suicidal behavior. The present paper overviews our existing understanding of the association between suicide and inflammation, including peripheral and central biomarkers, genetic and genomic markers, and our current knowledge of intervention in suicide risk using treatments influencing inflammation; also overviewing the next steps to be taken and obstacles to be overcome before we can utilize cytokines in the treatment of suicidal behavior.

Unlocking the Secrets: Exploring the Biochemical Correlates of Suicidal Thoughts and Behaviors in Adults with Autism Spectrum Conditions

Involving 1 million people a year, suicide represents one of the major topics of psychiatric research. Despite the focus in recent years on neurobiological underpinnings, understanding and predicting suicide remains a challenge. Many sociodemographical risk factors and prognostic markers have been proposed but they have poor predictive accuracy. Biomarkers can provide essential information acting as predictive indicators, providing proof of treatment response and proposing potential targets while offering more assurance than psychological measures. In this framework, the aim of this study is to open the way in this field and evaluate the correlation between blood levels of serotonin, brain derived neurotrophic factor, tryptophan and its metabolites, IL-6 and homocysteine levels and suicidality. Blood samples were taken from 24 adults with autism, their first-degree relatives, and 24 controls. Biochemical parameters were measured with enzyme-linked immunosorbent assays. Suicidality was measured through selected items of the MOODS-SR. Here we confirm the link between suicidality and autism and provide more evidence regarding the association of suicidality with increased homocysteine (0.278) and IL-6 (0.487) levels and decreased tryptophan (-0.132) and kynurenic acid (-0.253) ones. Our results suggest a possible transnosographic association between these biochemical parameters and increased suicide risk.

Association between cortical gyrification and white matter integrity in spinocerebellar ataxia type 3

Gray matter volume and thickness reductions have been reported in patients with spinocerebellar ataxia type 3 (SCA3), whereas cortical gyrification alterations of this disease remain largely unexplored. Using local gyrification index (LGI) and fractional anisotropy (FA) from structural and diffusion MRI data, this study investigated the cortical gyrification alterations as well as their relationship with white matter microstructural abnormalities in patients with SCA3 (n = 61) compared with healthy controls (n = 69). We found widespread reductions in cortical LGI and white matter FA in patients with SCA3 and that changes in these 2 features were also coupled. In the patient group, the LGI of the left middle frontal gyrus, bilateral insula, and superior temporal gyrus was negatively correlated with the severity of depressive symptoms, and the FA of a cluster in the left cerebellum was negatively correlated with the Scale for the Assessment and Rating of Ataxia scores. Our findings suggest that the gyrification abnormalities observed in this study may account for the clinical heterogeneity in SCA3 and are likely to be mediated by the underlying white matter microstructural abnormalities of this disease.

Hypothalamic-prolactin axis regulation in major depressed patients with suicidal behavior

BACKGROUND

So far, little is known about the control of hypothalamic-prolactin axis activity by dopamine (DA) and thyrotropin-releasing hormone (TRH) in depressed patients with suicidal behavior disorder (SBD).

METHODS

We evaluated prolactin (PRL) responses to apomorphine (APO; a DA direct receptor agonist) and 0800 h and 2300 h protirelin (TRH) tests in 50 medication-free euthyroid DSM-5 major depressed inpatients with SBD (either current [n = 22], or in early remission [n = 28]); and 18 healthy hospitalized controls (HCs).

RESULTS

Baseline (BL) PRL levels were comparable across the three diagnostic groups. SBDs in early remission did not differ from HCs regarding PRL suppression to APO (PRLs), PRL stimulation to 0800 h and 2300 h TRH tests (∆PRL), and ∆∆PRL values (difference between 2300 h-∆PRL and 0800 h-∆PRL values). Current SBDs showed lower PRLs and ∆∆PRL values than HCs and SBDs in early remission. Further analyses revealed that current SBDs with a history of violent and high-lethality suicide attempts were more likely to exhibit co-occurrence of low ∆∆PRL and PRL_S values.

CONCLUSIONS

Our results suggest that regulation of the hypothalamic-PRL axis is impaired in some depressed patients with current SBD, particularly those who have made serious suicide attempts. Considering the limitations of our study, our findings support the hypothesis that decreased pituitary D2 receptor functionality (possibly adaptive to increased tuberoinfundibular DAergic neuronal activity) together with decreased hypothalamic TRH drive might be a biosignature for high-lethality violent suicide attempts.

Metabolic parameters and thyroid hormones in relation to suicide attempts in patients with first-episode and drug-naive major depressive disorder with comorbid glucose disturbances: a large cross-sectional study

The factors associated with suicide attempts in major depressive disorder (MDD) patients with comorbid glucose disturbances remain unclear. To the best of our knowledge, this is the first study with a large sample size to examine risk factors of suicide attempts in first-episode drug-naïve (FEDN) MDD patients with comorbid glucose disturbances, including clinically relevant factors, metabolic parameters, and thyroid hormone levels. A total of 1718 FEDN MDD patients were enrolled. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), and Positive and Negative Syndrome Scale (PANSS) were used to assess the clinical symptoms of patients. Fasting blood glucose, metabolic parameters, and thyroid hormone levels were measured. After controlling for HAMA and HAMD scores, the suicide attempt rate was 1.88 times higher in MDD patients with glucose disturbances than in MDD patients without glucose disturbances. Compared to non-suicide attempters, suicide attempters among the MDD patients with glucose disturbances had higher scores on HAMD and HAMA, PANSS positive symptoms, as well as higher levels of systolic and diastolic blood pressure, TC, LDL-C, thyroid stimulating hormone (TSH), TgAb, and thyroid peroxidases antibody (TPOAb). The combination of positive symptom score, HDL-C, systolic blood pressure, and marital status distinguished suicide attempters from non-suicide attempters. In addition, HAMA score, HAMD score, and TPOAb were associated with the number of suicide attempts in MDD patients with comorbid glucose disturbances. Our results suggest a high incidence of suicide attempts in MDD patients with comorbid glucose disturbances. Several clinically relevant factors, metabolic parameters, and thyroid hormone function have an impact on suicide attempts in MDD patients with comorbid glucose disturbances.

Suicide: An Overview for Clinicians

Most suicides have a diagnosable psychiatric disorder, most frequently, a mood disorder. Psychosocial issues and neurobiological abnormalities such as dysregulation in stress response systems contribute to suicidal behavior. All psychiatric patients need to be screened for the presence of suicidal ideation. Clinicians are expected to gather information about patient's clinical features and to formulate decisions about patient's dangerousness to self and the treatment plan. As psychiatric disorders are a major risk factor for suicide their pharmacologic and psychological treatment is of utmost importance to prevent suicide. Restriction of access to lethal means is important for suicide prevention.

Aberrant degree centrality of functional brain networks in subclinical depression and major depressive disorder

BACKGROUND

As one of the most common diseases, major depressive disorder (MDD) has a significant adverse impact on the li of patients. As a mild form of depression, subclinical depression (SD) serves as an indicator of progression to MDD. This study analyzed the degree centrality (DC) for MDD, SD, and healthy control (HC) groups and identified the brain regions with DC alterations.

METHODS

The experimental data were composed of resting-state functional magnetic resonance imaging (rs-fMRI) from 40 HCs, 40 MDD subjects, and 34 SD subjects. After conducting a one-way analysis of variance, two-sample t-tests were used for further analysis to explore the brain regions with changed DC. Receiver operating characteristic (ROC) curve analysis of single index and composite index features was performed to analyze the distinguishable ability of important brain regions.

RESULTS

For the comparison of MDD vs. HC, increased DC was found in the right superior temporal gyrus (STG) and right inferior parietal lobule (IPL) in the MDD group. For SD vs. HC, the SD group showed a higher DC in the right STG and the right middle temporal gyrus (MTG), and a smaller DC in the left IPL. For MDD vs. SD, increased DC in the right middle frontal gyrus (MFG), right IPL, and left IPL, and decreased DC in the right STG and right MTG was found in the MDD group. With an area under the ROC (AUC) of 0.779, the right STG could differentiate MDD patients from HCs and, with an AUC of 0.704, the right MTG could differentiate MDD patients from SD patients. The three composite indexes had good discriminative ability in each pairwise comparison, with AUCs of 0.803, 0.751, and 0.814 for MDD vs. HC, SD vs. HC, and MDD vs. SD, respectively.

CONCLUSION

Altered DC in the STG, MTG, IPL, and MFG were identified in depression groups. The DC values of these altered regions and their combinations presented good discriminative ability between HC, SD, and MDD. These findings could help to find effective biomarkers and reveal the potential mechanisms of depression.

Detection of Suicide Risk Using Vocal Characteristics: Systematic Review

BACKGROUND

In an age when telehealth services are increasingly being used for forward triage, there is a need for accurate suicide risk detection. Vocal characteristics analyzed using artificial intelligence are now proving capable of detecting suicide risk with accuracies superior to traditional survey-based approaches, suggesting an efficient and economical approach to ensuring ongoing patient safety.

OBJECTIVE

This systematic review aimed to identify which vocal characteristics perform best at differentiating between patients with an elevated risk of suicide in comparison with other cohorts and identify the methodological specifications of the systems used to derive each feature and the accuracies of classification that result.

METHODS

A search of MEDLINE via Ovid, Scopus, Computers and Applied Science Complete, CADTH, Web of Science, ProQuest Dissertations and Theses A&I, Australian Policy Online, and Mednar was conducted between 1995 and 2020 and updated in 2021. The inclusion criteria were human participants with no language, age, or setting restrictions applied; randomized controlled studies, observational cohort studies, and theses; studies that used some measure of vocal quality; and individuals assessed as being at high risk of suicide compared with other individuals at lower risk using a validated measure of suicide risk. Risk of bias was assessed using the Risk of Bias in Non-randomized Studies tool. A random-effects model meta-analysis was used wherever mean measures of vocal quality were reported.

RESULTS

The search yielded 1074 unique citations, of which 30 (2.79%) were screened via full text. A total of 21 studies involving 1734 participants met all inclusion criteria. Most studies (15/21, 71%) sourced participants via either the Vanderbilt II database of recordings (8/21, 38%) or the Silverman and Silverman perceptual study recording database (7/21, 33%). Candidate vocal characteristics that performed best at differentiating between high risk of suicide and comparison cohorts included timing patterns of speech (median accuracy 95%), power spectral density sub-bands (median accuracy 90.3%), and mel-frequency cepstral coefficients (median accuracy 80%). A random-effects meta-analysis was used to compare 22 characteristics nested within 14% (3/21) of the studies, which demonstrated significant standardized mean differences for frequencies within the first and second formants (standardized mean difference ranged between -1.07 and -2.56) and jitter values (standardized mean difference=1.47). In 43% (9/21) of the studies, risk of bias was assessed as moderate, whereas in the remaining studies (12/21, 57%), the risk of bias was assessed as high.

CONCLUSIONS

Although several key methodological issues prevailed among the studies reviewed, there is promise in the use of vocal characteristics to detect elevations in suicide risk, particularly in novel settings such as telehealth or conversational agents.

TRIAL REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews CRD420200167413; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020167413.