Toward a biosignature for suicide

Proposition of Two Subtypes of Patients at Risk of Suicide: Pain Hypersensitive Vs. Dissociative

PURPOSE OF REVIEW

The pain-suicide relationship is one of the most debated in recent literature, but theories and clinical evidence have often reached contrasting conclusions. Through a critical overview of theoretical, meta-analytical and empirical contributions, we aimed at advancing the conversation on the pain-suicide relationship by integrating research on related concepts, specifically inflammation and dissociation, and their effects on interoceptive processes and pain perception.

RECENT FINDINGS

Ideation-to-action theories consider increased pain tolerance a key risk factor for the transition from suicidal ideation to attempt. However, several meta-analytical findings suggest that suicidal thoughts and behaviors are associated with inflammation-induced pain sensitization. On the one hand, inflammation contributes to the development and maintenance of chronic pain conditions and mood disorders, and is associated with interoceptive hypervigilance and pain hypersensitivity. Moreover, a trait of increased pain tolerance does not seem to distinguish the individuals attempting suicide among those living with suicidal thoughts. On the other, temporary hypoalgesia is often activated by dissociative experiences. Highly dissociative individuals can indeed be exposed to frequent disintegration of interoceptive processes and transitory hyposensitivity to pain. In light of this, two different patterns of responses to stress (i.e. inflammation vs. dissociation) may characterize different kinds of patients at risk of suicide, associated with specific patterns of interoceptive functioning, pain sensitivity and possibly suicidal ideation. This proposition is partially supported by neuroimaging studies on post-traumatic stress disorder and psychodynamic perspectives on neurodevelopment, as well as alternative clustering models of suicidal behavior. Theoretical, meta-analytical and neurobiological evidence highlight two opposite directions in the pain-suicide relationship: hyper- vs. hyposensitivity. Such contrasts may be explained by the existence of two tendencies in stress-response, namely inflammation and dissociation, defining two different subtypes of patients at risk of suicide. We thus propose the existence of a hypersensitive subtype, defined by underlying neuroinflammatory processes, increased vulnerability to chronic pain and mood disorders, interoceptive hypervigilance, pain hypersensitivity and potentially more persistent suicidal ideation. We further hypothesize a dissociative subtype, characterized by greater trait dissociation, vulnerability to depersonalization and derealization, frequent disintegration of interoceptive processes, transient pain hyposensitivity and abrupt peaks in suicidal ideation.

Genetically informed disassortative brain morphometric similarities revealing suicide risk in bipolar disorder

BACKGROUND

Cortical structure alterations in bipolar disorder (BD) have consistently been reported in association with suicide with high heritability. Currently, multifaceted genetic landscape responsible for replicable neuroanatomical alterations with suicidal effects is poorly explored to develop personalized risk assessments in clinic.

METHODS

Anatomically informed suicidal effects quantified with morphometric similarity network (MSN) upon structural MRI was evaluated in two independent BD cohorts consisted of patients with or without suicide attempt (SA and NSA) (discovery: 63 BD-SAs\72 BD-NSAs with 6 potential suicide-related SNPs examined in 46 BD-SAs\55 BD-NSAs; replication: 23 BD-SAs\23 BD-NSAs) and 119 healthy controls. In discovery study, transcriptomic and neurotransmitter correlates of suicide-relevant MSN deficits were examined by partial least squares regression on Allen Human Brain Atlas and dominance analysis on 9 distinct neurotransmitter systems. Molecularly informed MSN deficits were orthogonally validated by estimating genetic risks from targeted SNP genotyping utilizing a multi-level mediation analysis. Reproducible pattern of genetically decoding suicide-relevant MSN changes was validated in replication study.

RESULTS

Opioid receptor was consistently suggested to be responsible for the reproducible suicide-relevant MSN alterations identified in entorhinal and left lateral occipital cortices. MSN deficits of entorhinal cortex positively mediated the effects of genetic risks of OPRM1 on suicide attempted (portion of mediated = 61.3%, β=6.99e-2, p=.02, 95% CI = [3.34e-2, 0.11]).

CONCLUSION

Abnormal cytoarchitecture communities, especially maladaptive changes in neuronal communication between entorhinal cortex and reward circuit regulated by opioid receptors reflected by enhanced morphometric similarities could mediate the effect on increased suicidal tendencies involved in OPRM1 gene variants in BD.

Suicide in adults within 30 days of discharge from hospital emergency department

Suicide remains a frequent cause of death in adults, often overlooked despite known risk factors like mental disorders, older age, and chronic illness. Emergency department visits offer critical opportunities to identify suicidal ideation and provide preventive care. This study reviewed deaths within 30 days of discharge from the emergency department of a major public hospital in Alicante, Spain, focusing on deaths by suicide. Over five years, 529,312 emergency visits were recorded, with 453,599 patients (85.7%) discharged home. Of the 356 patients (0.078%) who died within 30 days post-discharge, 7 (1.97%) died by suicide. Among these, four had a psychiatric history, and one had a history of substance abuse, both established risk factors. The overall suicide rate among adults discharged from the emergency department was 1.54 per 100,000. Compared with those who died from other causes within 30 days of discharge, patients who died by suicide were younger (median age 72 vs. 83 years; p = 0.037, adjusted OR: 0.59, 95% CI: 0.34-1.03; p = 0.06), had a lower Charlson Comorbidity Index (median 3 vs. 6; p = 0.003), and were more often male (6/7 vs. 50.1%; p = 0.1). The presence of psychiatric history was the most significant risk factor for suicide within 30 days of discharge from the emergency department among patients aged 15 and older. Men were more likely than women to die by suicide, with the majority between the ages of 65 and 79. Notably, only one individual had a prior suicide attempt.

Repetitive transcranial magnetic stimulation frequency effects on suicidal ideation in adolescents with major depressive disorder

Previous research has explored Transcranial Magnetic Stimulation (TMS) interventions for suicidal thoughts and behaviors. However, the optimal dose parameters for TMS interventions targeting suicidal ideation in adolescents remain unknown. This exploratory study examined the impact of 1 Hz and 10 Hz TMS treatment on suicidal ideation in adolescents with major depressive disorder. Participants (N = 41) aged 12-18 years were randomized to TMS treatments with 1 Hz or 10 Hz frequency over 6 weeks and included in the exploratory analyses. The change in the intensity of suicidal ideation throughout treatment was estimated with ordinal logistic regression models with and without adjustments for the change in depressive symptom severity. The predicted odds of intensity of suicidal ideation significantly decreased over six-weeks of acute TMS treatment for both the 10 Hz TMS group (OR = 0.754, 95 % CI = 0.634 to 0.897, p = 0.0015) and the 1 Hz TMS group (OR = 0.780, 95 % CI = 0.668 to 0.909, p = 0.0016). However, after adjustment for the change in depression severity as a time-varying covariate in the ordinal logistic regression model, the magnitude of the decrease (or predicted odds) in intensity of suicidal ideation was attenuated and rendered non-significant for both the 10 Hz and 1 Hz TMS groups. TMS treatment suicidal ideation outcomes were not significantly different between the 10 Hz and 1 Hz TMS groups. Low-frequency TMS may be as effective as high-frequency TMS in treating suicidal ideation in adolescents with depression. Notably, 1 Hz TMS may have a favorable tolerability and safety profile for adolescents.

Machine learning based identification of suicidal ideation using non-suicidal predictors in a university mental health clinic

Suicide causes over 700,000 deaths annually worldwide. Mental disorders are closely linked to suicidal ideation, but predicting suicide remains complex due to the multifaceted nature of contributing factors. Traditional assessment tools often fail to capture the interactions that drive suicidal thoughts, underscoring the need for more sophisticated predictive approaches. This study aimed to predict suicidal and self-harm ideation among university students using machine learning models without relying on suicidal behavior related predictors. The goal was to uncover less obvious risk factors and provide deeper insights into the complex relationships between psychiatric symptoms and suicidal ideation. Data from 924 university students seeking mental health services were analyzed using seven machine learning algorithms. Suicidal ideation was assessed through the 9th item of the Patient Health Questionnaire-9. Three predictive models were developed, with the final model utilizing only subdomains from the DSM-5 Level 1 Self Rated Cross-Cutting Symptom Measure. Feature importance was assessed using SHAP and Integrated Gradients techniques. To ensure model generalizability, the best-performing model was externally validated on a separate dataset of 361 individuals. Machine learning models achieved strong predictive accuracy, with logistic regression and neural networks reaching AUC values of 0.80. The final model achieved an AUC of 0.80 on the training data and 0.79 on external validation data. Key predictors of suicidal ideation included personality functioning and depressed mood (both increasing the likelihood), while anxiety and repetitive thoughts were associated with a decreased likelihood. The use of non-suicidal predictors across datasets highlighted psychiatric dimensions relevant to early intervention. This study demonstrates the effectiveness of machine learning in predicting suicidal ideation without relying on suicide-specific inputs. The findings emphasize the critical roles of personality functioning, mood, and anxiety in shaping suicidal ideation. These insights can enhance early detection and personalized interventions, especially in individuals reluctant to disclose suicidal thoughts.

Toxoplasma gondii, suicidal behaviour and suicide risk factors in US Veterans enrolled in mental health treatment

Markers of chronic infection Toxoplasma gondii (Nicolle et Manceaux, 1908) have been associated with suicidal self-directed violence (SSDV). We present the results of the first study relating T. gondii IgG serology with suicide attempts and suicidal ideation in United States Veterans, known to have higher suicide rates than members of the general population. We also related T. gondii serology to SSDV risk factors, including valid and reliable measures of trait impulsivity, aggression, self-reported depression, and sleep disturbance. We recruited 407 Veterans enrolled at three Veterans Affairs Medical Centers with mean (S.D.) age = 45.6 (11.6) years; 304 men (74.7%); 203 with a history of SSDV and 204 with no history of any self-directed violence (SDV). Seropositivity and serointensity, categorised as high (top quartile) or low (lower three quartiles), were analysed in relationship to SSDV, suicidal ideation and clinical risk factors using age and gender-adjusted linear and logistic methods, after transformations and nonparametric tests when appropriate. Associations between seropositivity and SSDV and its risk factors were not significant in all groups. High serointensity, while not associated with SSDV or repeat suicide attempts, was positively associated with suicidal ideation, depression, impulsivity, and daytime dysfunction due to sleepiness (p < 0.05), but only in Veterans with a history of SSDV. In Veterans without a history of SDV, no associations were significant. These associations remained significant after adjustment for certain socioeconomic factors (i.e., income, homelessness, military rank). Including education in the model downgraded the statistical significance of suicidal ideation and depression to statistical trends, but the significance of associations with impulsivity and daytime dysfunction due to sleepiness remained. Major limitations include the cross-sectional design, overall low seropositivity within the sample, and potentially spurious results due to multiple comparisons. Thus, the results of this report need to be replicated in larger samples, ideally longitudinally.

Analyses of GWAS signal using GRIN identify additional genes contributing to suicidal behavior

Genome-wide association studies (GWAS) identify genetic variants underlying complex traits but are limited by stringent genome-wide significance thresholds. We present GRIN (Gene set Refinement through Interacting Networks), which increases confidence in the expanded gene set by retaining genes strongly connected by biological networks when GWAS thresholds are relaxed. GRIN was validated on both simulated interrelated gene sets as well as multiple GWAS traits. From multiple GWAS summary statistics of suicide attempt, a complex phenotype, GRIN identified additional genes that replicated across independent cohorts and retained biologically interrelated genes despite a relaxed significance threshold. We present a conceptual model of how these retained genes interact through neurobiological pathways that may influence suicidal behavior, and identify existing drugs associated with these pathways that would not have been identified under traditional GWAS thresholds. We demonstrate GRIN's utility in boosting GWAS results by increasing the number of true positive genes identified from GWAS results.

Sleep Disturbance and Subsequent Suicidal Behaviors in Preadolescence

Importance

Suicide is a leading cause of death among adolescents, who demonstrate high rates of sleep disturbance. Poor sleep appears to confer risk for suicide, but longitudinal investigation of suicidal behaviors remains rare, particularly in the transition from childhood to early adolescence.

Objective

To evaluate sleep disturbances in preadolescent children (aged 9 and 10 years) in association with longitudinal risk for suicidal ideation and suicide attempts at the 2-year follow-up.

Design, Setting, and Participants

This cohort study used data from the Adolescent Brain Cognitive Development Study between June 2016 and January 2021. This dataset included children aged 9 or 10 years at baseline and their parents or caregivers who were recruited at 21 sites across the US. Data were analyzed July 2023 to June 2024.

Exposures

The Sleep Disturbance Scale for Children, a 26-item parent-reported inventory, was administered at baseline, generating a total score and 6 subscales. Central covariates included the Child Behavior Checklist Anxiety and Depression subscale and demographic variables.

Main Outcomes and Measures

The computerized Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS-COMP) assessed parent- and youth-reported suicidal behaviors and outcomes (none; passive, active nonspecific, and active specific suicidal ideation; and suicide attempt) at the 2-year follow-up. Sleep disturbance was further grouped by symptom severity (minimal, moderate, elevated, high, and severe).

Results

Of the 10 136 youths who reported no baseline suicidal ideation or behavior, 8807 youths (mean [SD] age, 9.9 [0.6] years; 4507 males [51.2%]; 197 Asian individuals [2.2%], 1273 Black individuals [14.5%], and 5775 White individuals [65.6%]) completed the K-SADS-COMP assessment at the 2-year follow-up and were included in the analysis. At the follow-up, 8044 participants (91.3%) had no suicidal behavior, 317 (3.6%) had passive suicidal ideation, 258 (2.9%) had active nonspecific suicidal ideation, 130 (1.5%) had active specific suicidal ideation, and 58 (0.7%) had a first-time suicide attempt. Baseline sleep disturbance was associated with increased incidence risk for suicidal behavior at age 12 years (odds ratio, 2.68; 95% CI, 1.44-4.98; P = .002), adjusting for covariates. Individual subscales or items demonstrating associations with risk included disorders of excessive somnolence and frequency of nightmares.

Conclusions and Relevance

Results of this longitudinal cohort study revealed that disturbed sleep at age 10 years was associated with risk for suicidal thoughts and behaviors in the next 2 years. The findings highlight the potential importance of sleep as a visible risk factor and intervention target in the prevention of youth suicide.

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.

The Progression of Lethality Across Multiple Suicide Attempts: A Systematic Review

OBJECTIVE

Suicide is a major global public health concern. While some progress has been made in understanding risk factors for suicidal behavior, other relevant questions have received less attention. One such question relates to the longitudinal course of suicidal behavior amongst individuals with multiple suicide attempts. This systematic review investigated whether there is an increase in the lethality across multiple suicide attempts.

METHOD

This systematic review followed PRISMA 2020 reporting guidelines. A literature search was conducted in MEDLINE, Embase and PsycINFO electronic databases from inception to August 2023 to identify studies with key terms related to multiple suicide attempts and lethality. The review included longitudinal studies with data on multiple suicide attempts, and any rating of their lethality. Covidence was used to guide the screening and extraction process. A narrative synthesis approach was used to descriptively summarize included studies.

RESULTS

After identifying 828 unique abstracts for screening, 11 studies were included for narrative synthesis. Suicide attempt assessment methods and definitions were heterogenous, often indirectly inferring lethality based on suicide attempt method. Individuals with repeat attempts may be more likely to continue using the same method.

CONCLUSIONS

There was no evidence to support increasing lethality across repeat suicide attempts. However, this should be interpreted along with the fact that the evidence base is scarce, heterogenous, and methodologically limited.

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.

Validity, Reliability, and Factor Structure of the Suicide Crisis Scale in Turkish

Objective

In our study, we aimed to adapt the Suicide Crisis Inventory (SCI), which can be used specifically to assess the acute phase of suicide, to the Turkish population by examining its Turkish validity and reliability in a non-clinical sample.

Methods

In this cross-sectional study, a total of 300 university students aged 18-24 years were evaluated online using the Socio-demographic and Clinical Data Form, the SCI, and the Suicide Behavior Questionnaire (SBQ). Criterion validity, discriminative validity, and factor analyses (exploratory and confirmatory) were conducted for the validity of the SCI, and internal consistency and item-total correlations were examined for reliability analyses. Additionally, a linear regression model was constructed to assess the predictive validity of the SCI. The predictive validity of past SCI scores was evaluated using a simple regression model.

Results

When the linear regression model was tested with SCI scores as the independent variable and SBQ scores as the dependent variable [F(1-298) = 203.625; P = .000], it was found that the independent variable explained 41% of the variance in the dependent variable (r = 0.637; r 2 = 0.406). SCI scores significantly predicted SBQ scores (t = 14.270; B = 0.047; Bsth = 0.003; β = 0.647; P = .000). In the validity analysis, the items removed from the scale could be evaluated for the total score, as they did not belong to any factor as originally specified. When items were removed, the total item reliability was Cronbach's alpha = 0.981.

Conclusion

We believe that the SCI will be a useful tool in assessing short-term suicide risk in a Turkish sample and in conducting scientific research. The SCI was found to be sufficient for use in a Turkish sample for the evaluation of short-term suicide risk, considering some limitations.

Perception of social inclusion/exclusion and response inhibition in adolescents with past suicide attempt: a multidomain task-based fMRI study

The occurrence of suicidal behaviors increases during adolescence. Hypersensitivity to negative social signals and deficits in cognitive control are putative mechanisms of suicidal behaviors, which necessitate confirmation in youths. Multidomain functional neuroimaging could enhance the identification of patients at suicidal risk beyond standard clinical measures. Three groups of adolescents (N = 96; 78% females, age = 11.6-18.1) were included: patients with depressive disorders and previous suicide attempts (SA, n = 29); patient controls with depressive disorders but without any suicide attempt history (PC, n = 35); and healthy controls (HC, n = 32). We scanned participants with 3T-MRI during social inclusion/exclusion (Cyberball Game) and response inhibition (Go-NoGo) tasks. Neural activation was indexed by the blood-oxygenation-level dependent (BOLD) of the hemodynamic response during three conditions in the Cyberball Game ("Control condition", "Social Inclusion", and "Social Exclusion"), and two conditions in Go-NoGo task ("Go" and "NoGo" blocks). ANCOVA-style analysis identified group effects across three whole-brain contrasts: 1) NoGo vs. Go, 2) Social inclusion vs. control condition, 3) Social exclusion vs. control condition. We found that SA had lower activation in the left insula during social inclusion vs. control condition compared to PC and HC. Moreover, SA compared to PC had higher activity in the right middle prefrontal gyrus during social exclusion vs. control condition, and in bilateral precentral gyri during NoGo vs. Go conditions. Task-related behavioral and self-report measures (Self-reported emotional reactivity in the Cyberball Game, response times and number of errors in the Go-NoGo Task) did not discriminate groups. In conclusion, adolescent suicidal behaviors are likely associated with neural alterations related to the processing of social perception and response inhibition. Further research, involving prospective designs and diverse cohorts of patients, is necessary to explore the potential of neuroimaging as a tool in understanding the emergence and progression of suicidal behaviors.

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.

Genetic factors associated with suicidal behaviors and alcohol use disorders in an American Indian population

American Indians (AI) demonstrate the highest rates of both suicidal behaviors (SB) and alcohol use disorders (AUD) among all ethnic groups in the US. Rates of suicide and AUD vary substantially between tribal groups and across different geographical regions, underscoring a need to delineate more specific risk and resilience factors. Using data from over 740 AI living within eight contiguous reservations, we assessed genetic risk factors for SB by investigating: (1) possible genetic overlap with AUD, and (2) impacts of rare and low-frequency genomic variants. Suicidal behaviors included lifetime history of suicidal thoughts and acts, including verified suicide deaths, scored using a ranking variable for the SB phenotype (range 0-4). We identified five loci significantly associated with SB and AUD, two of which are intergenic and three intronic on genes AACSP1, ANK1, and FBXO11. Nonsynonymous rare and low-frequency mutations in four genes including SERPINF1 (PEDF), ZNF30, CD34, and SLC5A9, and non-intronic rare and low-frequency mutations in genes OPRD1, HSD17B3 and one lincRNA were significantly associated with SB. One identified pathway related to hypoxia-inducible factor (HIF) regulation, whose 83 nonsynonymous rare and low-frequency variants on 10 genes were significantly linked to SB as well. Four additional genes, and two pathways related to vasopressin-regulated water metabolism and cellular hexose transport, also were strongly associated with SB. This study represents the first investigation of genetic factors for SB in an American Indian population that has high risk for suicide. Our study suggests that bivariate association analysis between comorbid disorders can increase statistical power; and rare and low-frequency variant analysis in a high-risk population enabled by whole-genome sequencing has the potential to identify novel genetic factors. Although such findings may be population specific, rare functional mutations relating to PEDF and HIF regulation align with past reports and suggest a biological mechanism for suicide risk and a potential therapeutic target for intervention.

Association study of a single nucleotide polymorphism in the hypoxia response element of the macrophage migration inhibitory factor gene promoter with suicide completers in the Japanese population

BACKGROUND

More than 800 000 people die by suicide annually. The heritability of suicide is 30%-50%. We focused on the hypoxia response element (HRE), which promotes the expression of macrophage migration inhibitory factor (MIF) via the hypoxia-inducible factor (HIF) pathway, important in neurogenesis and neuroprotection. We examined a genetic polymorphism of rs17004038, a single-nucleotide polymorphism (SNP), in suicide completers and controls.

METHODS

The study population included 1336 suicide completers and 814 unrelated healthy controls. All participants were Japanese. We obtained peripheral blood, extracted DNA, and genotyped the patients for SNP rs17004038 (C > A).

RESULTS

No significant differences were observed between the two groups in either the allele or genotype analyses. Subgroup analyses by sex, age (<40 or ≥40), and suicide method (violent or nonviolent suicide) were performed with similar results.

CONCLUSION

No association was observed between SNP rs17004038 and suicide completion. Although it is challenging to collect a large number of samples from suicide completers, further MIF-related genetic studies, including those of rs17004038, are necessary with larger sample sizes.

Impact of Toxoplasma gondii and Human Microbiome on Suicidal Behavior: A Systematic Review

BACKGROUND

Suicide remains a persistent global health challenge, resisting widespread prevention efforts. According to previous findings, toxoplasmosis is particularly associated with altered decision making, which could lead to risk-taking behavior, thereby increasing the likelihood for suicidal behavior (SB). In addition, discussion about the role of microbiome in psychiatric disorders has emerged lately, which also makes it relevant to investigate its role in the context of SB. Therefore, two systematic reviews are integrated in this paper, and the existing knowledge is comprehensively summarized regarding the association between microbial pathogens and SB.

METHODS

We conducted a systematic search with keywords including SB and Toxoplasma gondii (Suicid* AND Toxoplasm*) and microbiome (Suicid* AND Microbiome AND Microbiota) throughout PubMed and Scopus to retrieve related studies up to 9 November 2023, identifying 24 eligible records. The subjects of the included studies had to have fulfilled the criteria of an SB disorder as defined by DSM-5, and death cases needed to have been defined as suicide.

RESULTS

Most studies reported significant association between toxoplasmosis and SB, suggesting a higher likelihood of SB in the infected population. Regarding the microbiome, only very few studies investigated an association between SB and alterations in the microbiome. Based on six included studies, there were some indications of a link between changes in the microbiome and SB.

CONCLUSION

The cognitive aspects of decision making in T. gondii-infected individuals with SB should be further investigated to unravel the underlying mechanisms. Further sufficiently powered studies are needed to establish a link between SB and alterations in the microbiome.

Phenols and GABAA receptors: from structure and molecular mechanisms action to neuropsychiatric sequelae

γ-Aminobutyric acid type A receptors (GABAARs) are members of the pentameric ligand-gated ion channel (pLGIC) family, which are widespread throughout the invertebrate and vertebrate central nervous system. GABAARs are engaged in short-term changes of the neuronal concentrations of chloride (Cl-) and bicarbonate (HCO3 -) ions by their passive permeability through the ion channel pore. GABAARs are regulated by various structurally diverse phenolic substances ranging from simple phenols to complex polyphenols. The wide chemical and structural variability of phenols suggest similar and different binding sites on GABAARs, allowing them to manifest themselves as activators, inhibitors, or allosteric ligands of GABAAR function. Interest in phenols is associated with their great potential for GABAAR modulation, but also with their subsequent negative or positive role in neurological and psychiatric disorders. This review focuses on the GABAergic deficit hypotheses during neurological and psychiatric disorders induced by various phenols. We summarize the structure-activity relationship of general phenol groups concerning their differential roles in the manifestation of neuropsychiatric symptoms. We describe and analyze the role of GABAAR subunits in manifesting various neuropathologies and the molecular mechanisms underlying their modulation by phenols. Finally, we discuss how phenol drugs can modulate GABAAR activity via desensitization and resensitization. We also demonstrate a novel pharmacological approach to treat neuropsychiatric disorders via regulation of receptor phosphorylation/dephosphorylation.

Association between suicidal ideation and burnout: A meta-analysis

Approximately 700,000 people die by suicide annually worldwide. Researchers have explored a spectrum of experiences that involve stress in academic or work environments and potentially intensify suicidal thoughts or behaviors. However, no meta-analysis has examined the relationship between suicidal ideation (SI) and burnout. This study consisted of a meta-analysis to examine the association between SI and burnout syndrome, utilizing the WoS Core Collection, Scopus, PubMed, PsycINFO, DIALNET, and Google Scholar databases. Twenty-one samples met the study's eligibility criteria for inclusion in the analysis. The results revealed a significant relationship between SI and burnout, with the type of burnout (occupational, academic, and parental) emerging as the most significant moderating variable. Occupational burnout exhibited the lowest correlation, followed by academic and parental burnout. These findings suggest the importance of developing tools to assess SI within the context of the work environment, parenting and academics, and psychoeducational programs for managing stress.

Understanding suicide

Suicide remains a significant public health challenge globally, requiring comprehensive approaches for prevention and treatment. Almost 90% of individuals who commit suicide suffer from mental health disorders at the time of death, emphasizing the central role of psychiatry in understanding and preventing suicide. Suicidal thoughts, planning, attempts, and completed suicides exist on a continuum, with the highest suicide rates occurring within six months after an attempt and more severe attempts increasing the risk of future suicide. History plays a significant role in shaping the perception of suicide, from considering it a sin to recognizing it as a mental illness. Emile Durkheim's ground-breaking work on suicide as a social phenomenon furthered our understanding. Knowledge regarding the complexities surrounding suicide is paramount to developing effective strategies. Early detection through clinical interviews and screening tools and creating safe spaces for discussion are critical prevention measures. Pharmacological and non-pharmacological interventions are essential for addressing underlying psychiatric disorders and reducing suicidal thoughts and behaviors. While significant progress has been made in understanding suicide risk factors and implementing prevention strategies, continued research and community engagement are imperative. Destigmatizing mental health discourse and fostering supportive environments are essential steps toward reducing the incidence of suicide and supporting individuals in distress. By embracing a holistic approach that integrates pharmacological and non- pharmacological interventions, along with societal engagement, we can strive towards a future where suicide is increasingly rare, and individuals feel valued, supported, and connected.

Peripheral Markers of Suicidal Behavior: Current Findings and Clinical Implications

Biomarkers of suicidal behavior (SB), particularly peripheral biomarkers, may aid in the development of preventive and intervention strategies. The peripheral biomarkers of SB should be easily accessible, cost-effective, and minimally invasive. To identify peripheral biomarkers of SB, we summarized the current knowledge related to SB biomarkers with a focus on suicidal outcomes (suicidal ideation [SI], suicide risk [SR], suicide attempt [SA], and suicide death [SD]), measured site (center or periphery), and study design (cross-sectional or longitudinal). We also evaluated the central findings to validate the findings of peripheral biomarkers of SB. We found reduced peripheral interleukin (IL)-2 levels in individuals with a recent SA, higher cerebrospinal fluid (CSF) IL-6 levels in patients with a current SR and future SD, higher CSF tumor necrosis factor-α levels for current and future SRs, higher high-sensitivity C-reactive protein levels and lower peripheral total cholesterol levels for recent SAs, lower peripheral 5-HT levels for present SR, and a lower folate level for future SR and SA within 1 year. Previous studies have shown inconsistent associations of low peripheral leptin levels with SR and recent SA; therefore, further study is required. Given the multiple determinants of SB and weak associations with single biological markers, combinations of potential biological markers rather than single markers may improve the screening, diagnosis, and prediction of SB.

Comorbidity of anxiety/affective, conduct/antisocial, attention deficit, and alcohol use disorders with suicidal behaviors in an American Indian community sample of adults and adolescents

AIMS

To study the associations of anxiety/affective disorders, conduct/antisocial disorders (ASPD/CD), attention deficit disorders (ADHD), and alcohol use disorders (AUD) with suicidal behaviors in an American Indian (AI) community sample of adolescents and adults.

METHODS

Participants were AI (360 adolescents, 925 adults) recruited from reservations who were assessed with the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA).

RESULTS

Among AI adults (mean age = 33 years), 17% percent reported lifetime experiences of suicidal thoughts (ideation and/or plans) and 14% reported suicidal acts (including either a suicide attempt history or verified death by suicide; n = 19 deaths). Among AI adolescents (mean age = 15 years), 20% experienced suicidal thoughts and 9% experienced suicidal acts (including 3 deaths). In logistic regression analyses, suicidal thoughts were significantly associated with lifetime diagnoses of affective disorder, CD and ADHD in adolescents, and with anxiety disorder, affective disorder, and ASPD/CD in adults. Suicidal acts were associated with affective disorder, ADHD, and alcohol drinking in adolescents and with anxiety disorder, ASPD/CD and AUD in adults. The number of comorbid disorders greatly increased the risk of both suicidal thoughts and acts among both adolescents and adults.

CONCLUSIONS

In addition to affective disorders, both ADHD and CD in adolescents, and ASPD in adults, demonstrated an association with suicidal thoughts. Alcohol use by adolescents and AUD among adults also were associated with suicidal attempts in this AI sample. These findings suggest need for additional research and potential integration of alcohol in screening and intervention programs focused on the prevention of suicide among AI.

User Feedback on the Use of a Natural Language Processing Application to Screen for Suicide Risk in the Emergency Department

Suicide is the 10th leading cause of death in the USA and globally. Despite decades of research, the ability to predict who will die by suicide is still no better than 50%. Traditional screening instruments have helped identify risk factors for suicide, but they have not provided accurate predictive power for reducing death rates. Over the past decade, natural language processing (NLP), a form of machine learning (ML), has been used to identify suicide risk by analyzing language data. Recent work has demonstrated the successful integration of a suicide risk screening interview to collect language data for NLP analysis from patients in two emergency departments (ED) of a large healthcare system. Results indicated that ML/NLP models performed well identifying patients that came to the ED for suicide risk. However, little is known about the clinician's perspective of how a qualitative brief interview suicide risk screening tool to collect language data for NLP integrates into an ED workflow. This report highlights the feedback and observations of patient experiences obtained from clinicians using brief suicide screening interviews. The investigator used an open-ended, narrative interview approach to inquire about the qualitative interview process. Three overarching themes were identified: behavioral health workflow, clinical implications of interview probes, and integration of an application into provider patient experience. Results suggest a brief, qualitative interview method was feasible, person-centered, and useful as a suicide risk detection approach.

Effect Modification of Cortisol on the Associations Between Obsessive-Compulsive Symptoms on Suicidality in Patients With Acute Coronary Syndrome

OBJECTIVE

Obsessive-compulsive symptoms (OCS) and suicidal ideation (SI) are common in patients with acute coronary syndrome (ACS). This study investigated the associations of OCS and serum cortisol levels with SI, and further evaluated the possible modifying effects of cortisol on the associations between OCS and SI in acute and chronic phases of ACS.

METHODS

In total, 969 ACS patients were recruited from a tertiary university hospital in Korea within 2 weeks of disease onset and evaluated in terms of OCS (using the OCS dimension of the Symptom Checklist-90-Revised), serum cortisol levels, and SI (using the "suicidal thoughts" item of the Montgomery-Åsberg Depression Rating Scale). Covariates included sociodemographics, depression, vascular risk factors, and disease severity. After 1 year, 711 patients were re-evaluated in terms of SI. Logistic regression analysis was performed with adjustment for covariates.

RESULTS

Higher OCS was significantly associated with SI both at baseline and follow-up. Serum cortisol showed no such association, but modified the association between OCS and SI. That was the associations were significant only in the higher but not in the lower serum cortisol levels, with significant interaction terms after adjusted for relevant covariates.

CONCLUSION

Evaluating OCS and serum cortisol levels at the acute phase could improve the accuracy of clinical predictions of SI both in the acute and chronic phases of ACS.

The amplitude of low-frequency fluctuation characteristics in depressed adolescents with suicide attempts: a resting-state fMRI study

Background

The amplitude of low-frequency fluctuation (ALFF) is a measure of spontaneous brain activity derived from resting-state functional magnetic resonance imaging (rs-fMRI). Previous research has suggested that abnormal ALFF values may be associated with major depressive disorder (MDD) and suicide attempts in adolescents. In this study, our aim was to investigate the differences in ALFF values between adolescent MDD patients with and without a history of suicide attempts, and to explore the potential utility of ALFF as a neuroimaging biomarker for aiding in the diagnosis and prediction of suicide attempts in this population.

Methods

The study included 34 adolescent depression patients with suicide attempts (SU group), 43 depression patients without suicide attempts (NSU group), and 36 healthy controls (HC group). Depression was diagnosed using a threshold score greater than 17 on the Hamilton Depression Rating Scale (HDRS). The rs-fMRI was employed to calculate zALFF values and compare differences among the groups. Associations between zALFF values in specific brain regions and clinical variables such as emotion regulation difficulties were explored using Pearson partial correlation analysis. Receiver-Operating Characteristics (ROC) analysis assessed the ability of mean zALFF values to differentiate between SU and NSU groups.

Results

Significant differences in zALFF values were observed in the left and right inferior temporal gyrus (l-ITG, r-ITG) and right fusiform gyrus (r-FG) among the three groups (GRF corrected). Both SU and NSU groups exhibited increased zALFF values in the inferior temporal gyrus compared to the HC group. Furthermore, the SU group showed significantly higher zALFF values in the l-ITG and r-FG compared to both the NSU group and the HC group. Partial correlation analysis revealed a negative correlation between zALFF values in the left superior and middle frontal gyrus (l-SFG, l-MFG) and the degree of emotional dysregulation in the SU group (R = -0.496, p = 0.003; R = -0.484, p = 0.005). Combining zALFF values from the l-ITG and r-FG achieved successful discrimination between depressed adolescents with and without suicide attempts (AUC = 0.855) with high sensitivity (86%) and specificity (71%).

Conclusion

Depressed adolescents with suicidal behavior exhibit unique neural activity patterns in the inferior temporal gyrus and fusiform gyrus. These findings highlight the potential utility of these specific brain regions as biomarkers for identifying suicide risk in depressed adolescents. Furthermore, associations between emotion dysregulation and activity in their frontal gyrus regions were observed. These findings provide preliminary yet pertinent insights into the pathophysiology of suicide in depressed adolescents.

Hill L, Kline A, Stanley BH, Interian A. Improving the prospective prediction of a near-term suicide attempt in veterans at risk for suicide, using a go/no-go task

BACKGROUND

Neurocognitive testing may advance the goal of predicting near-term suicide risk. The current study examined whether performance on a Go/No-go (GNG) task, and computational modeling to extract latent cognitive variables, could enhance prediction of suicide attempts within next 90 days, among individuals at high-risk for suicide.

METHOD

136 Veterans at high-risk for suicide previously completed a computer-based GNG task requiring rapid responding (Go) to target stimuli, while withholding responses (No-go) to infrequent foil stimuli; behavioral variables included false alarms to foils (failure to inhibit) and missed responses to targets. We conducted a secondary analysis of these data, with outcomes defined as actual suicide attempt (ASA), other suicide-related event (OtherSE) such as interrupted/aborted attempt or preparatory behavior, or neither (noSE), within 90-days after GNG testing, to examine whether GNG variables could improve ASA prediction over standard clinical variables. A computational model (linear ballistic accumulator, LBA) was also applied, to elucidate cognitive mechanisms underlying group differences.

RESULTS

On GNG, increased miss rate selectively predicted ASA, while increased false alarm rate predicted OtherSE (without ASA) within the 90-day follow-up window. In LBA modeling, ASA (but not OtherSE) was associated with decreases in decisional efficiency to targets, suggesting differences in the evidence accumulation process were specifically associated with upcoming ASA.

CONCLUSIONS

These findings suggest that GNG may improve prediction of near-term suicide risk, with distinct behavioral patterns in those who will attempt suicide within the next 90 days. Computational modeling suggests qualitative differences in cognition in individuals at near-term risk of suicide attempt.

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.

Suicidal behavior across a broad range of psychiatric disorders

Suicide is a leading cause of death worldwide. In 2020, some 12.2 million Americans seriously contemplated suicide, 3.2 million planned suicide attempts, and 1.2 million attempted suicide. Traditionally, the approach to treating suicidal behavior (SB) has been to treat the "underlying" psychiatric disorder. However, the number of diagnoses associated with SB is considerable. We could find no studies describing the range of disorders reported to be comorbid with SB. This narrative review summarizes literature documenting the occurrence of SB across the lifespan and the full range of psychiatric diagnoses, not only BPD and those that comprise MDE, It also describes the relevance of these observations to clinical practice, research, and nosology. The literature searches contained the terms "suicid*" and each individual psychiatric diagnosis and identified 587 studies. We did not include case reports, case series, studies only addressing suicidal ideation or non-suicidal self-injury (NSSI), studies on self-harm, not distinguishing between SB and NSSI and studies that did not include any individuals that met criteria for a specific DSM-5 diagnosis (n = 366). We found that SB (suicide and/or suicide attempt) was reported to be associated with 72 out of 145 diagnoses, although data quality varied. Thus, SB is not exclusively germane to Major Depressive Episode (MDE) and Borderline Personality Disorder (BPD), the only conditions for which it is a diagnostic criterion. That SB co-occurs with so many diagnoses reinforces the need to assess current and past SB regardless of diagnosis, and supports the addition of charting codes to the DSM-5 to indicate current or past SB. It also comports with new data that specific genes are associated with SB independent of psychiatric diagnoses, and suggests that SB should be managed with specific suicide prevention interventions in addition to treatments indicated for co-occurring diagnoses. SB diagnostic codes would help researchers and clinicians document and measure SB's trajectory and response to treatment over time, and, ultimately, help develop secondary and tertiary prevention strategies. As a separate diagnosis, SB would preclude situations in which a potentially life-threatening behavior is not accounted for by a diagnosis, a problem that is particularly salient when no mental disorder is present, as is sometimes the case.

Suicide prevention and ketamine: insights from computational modeling

Suicide is a pressing public health issue, with over 700,000 individuals dying each year. Ketamine has emerged as a promising treatment for suicidal thoughts and behaviors (STBs), yet the complex mechanisms underlying ketamine's anti-suicidal effect are not fully understood. Computational psychiatry provides a promising framework for exploring the dynamic interactions underlying suicidality and ketamine's therapeutic action, offering insight into potential biomarkers, treatment targets, and the underlying mechanisms of both. This paper provides an overview of current computational theories of suicidality and ketamine's mechanism of action, and discusses various computational modeling approaches that attempt to explain ketamine's anti-suicidal effect. More specifically, the therapeutic potential of ketamine is explored in the context of the mismatch negativity and the predictive coding framework, by considering neurocircuits involved in learning and decision-making, and investigating altered connectivity strengths and receptor densities targeted by ketamine. Theory-driven computational models offer a promising approach to integrate existing knowledge of suicidality and ketamine, and for the extraction of model-derived mechanistic parameters that can be used to identify patient subgroups and personalized treatment approaches. Future computational studies on ketamine's mechanism of action should optimize task design and modeling approaches to ensure parameter reliability, and external factors such as set and setting, as well as psychedelic-assisted therapy should be evaluated for their additional therapeutic value.

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.

Genetic Factors Associated with Suicidal Behaviors and Alcohol Use Disorders in an American Indian Population

American Indians (AI) demonstrate the highest rates of both suicidal behaviors (SB) and alcohol use disorders (AUD) among all ethnic groups in the US. Rates of suicide and AUD vary substantially between tribal groups and across different geographical regions, underscoring a need to delineate more specific risk and resilience factors. Using data from over 740 AI living within eight contiguous reservations, we assessed genetic risk factors for SB by investigating: (1) possible genetic overlap with AUD, and (2) impacts of rare and low frequency genomic variants. Suicidal behaviors included lifetime history of suicidal thoughts and acts, including verified suicide deaths, scored using a ranking variable for the SB phenotype (range 0-4). We identified five loci significantly associated with SB and AUD, two of which are intergenic and three intronic on genes AACSP1, ANK1, and FBXO11. Nonsynonymous rare mutations in four genes including SERPINF1 (PEDF), ZNF30, CD34, and SLC5A9, and non-intronic rare mutations in genes OPRD1, HSD17B3 and one lincRNA were significantly associated with SB. One identified pathway related to hypoxia-inducible factor (HIF) regulation, whose 83 nonsynonymous rare variants on 10 genes were significantly linked to SB as well. Four additional genes, and two pathways related to vasopressin-regulated water metabolism and cellular hexose transport, also were strongly associated with SB. This study represents the first investigation of genetic factors for SB in an American Indian population that has high risk for suicide. Our study suggests that bivariate association analysis between comorbid disorders can increase statistical power; and rare variant analysis in a high-risk population enabled by whole-genome sequencing has the potential to identify novel genetic factors. Although such findings may be population specific, rare functional mutations relating to PEDF and HIF regulation align with past reports and suggest a biological mechanism for suicide risk and a potential therapeutic target for intervention.

Suicidal ideation among people with Parkinson's disease and comparison with a control group

BACKGROUND

Detection of suicidal ideation (SI) is key for trying to prevent suicide. The aim of this study was to analyze the frequency of SI and related factors in Spanish people with Parkinson's Disease (PwPD) and to compare them with a control group.

METHODS

PD patients and controls recruited from the Spanish cohort COPPADIS from January 2016 to November 2017 were included. Two visits were conducted: V0 (baseline); V2 (2-year ± 1 month follow-up). SI was defined as a score ≥1 on item nine of the Beck Depression Inventory-II (BDI-II). Regression analyses were conducted to identify factors related to SI.

RESULTS

At baseline, 693 PwPD (60.2% males; 62.59 ± 8.91 years old) and 207 controls (49.8% males; 60.99 ± 8.32 years old) were included. No differences between PwPD and controls were detected in SI frequency at either V0 (5.1% [35/693] vs. 4.3% [9/207]; p = 0.421) or at V2 (5.1% [26/508] vs. 4.8% [6/125]; p = 0.549). Major depression (MD) and a worse quality of life were associated with SI at both visits in PwPD: V0 (MD, OR = 5.63; p = 0.003; PDQ-39, OR = 1.06; p = 0.021); V2 (MD, OR = 4.75; p = 0.027; EUROHIS-QOL8, OR = 0.22; p = 0.006). A greater increase in the BDI-II total score from V0 to V2 was the only factor predicting SI at V2 (OR = 1.21; p = 0.002) along with an increase in the total number of non-antiparkinsonian drugs (OR = 1.39; p = 0.041).

CONCLUSION

The frequency of SI (5%) in PwPD was similar to in controls. Depression, a worse quality of life, and a greater comorbidity were related to SI.

Sequential bilateral accelerated theta burst stimulation in adolescents with suicidal ideation associated with major depressive disorder: Protocol for a randomized controlled trial

BACKGROUND

Suicide is a leading cause of death in adolescents worldwide. Previous research findings suggest that suicidal adolescents with depression have pathophysiological dorsolateral prefrontal cortex (DLPFC) deficits in γ-aminobutyric acid neurotransmission. Interventions with transcranial magnetic stimulation (TMS) directly address these underlying pathophysiological deficits in the prefrontal cortex. Theta burst stimulation (TBS) is newer dosing approach for TMS. Accelerated TBS (aTBS) involves administering multiple sessions of TMS daily as this dosing may be more efficient, tolerable, and rapid acting than standard TMS.

MATERIALS AND METHODS

This is a randomized, double-blind, sham-controlled trial of sequential bilateral aTBS in adolescents with major depressive disorder (MDD) and suicidal ideation. Three sessions are administered daily for 10 days. During each session, continuous TBS is administered first to the right DPFC, in which 1,800 pulses are delivered continuously over 120 seconds. Then intermittent TBS is applied to the left DPFC, in which 1,800 pulses are delivered in 2-second bursts and repeated every 10 seconds for 570 seconds. The TBS parameters were adopted from prior research, with 3-pulse, 50-Hz bursts given every 200 ms (at 5 Hz) with an intensity of 80% active motor threshold. The comparison group will receive 3 daily sessions of bilateral sham TBS treatment for 10 days. All participants will receive the standard of care for patients with depression and suicidal ideation including daily psychotherapeutic skill sessions. Long-interval intracortical inhibition (LICI) biomarkers will be measured before and after treatment. Exploratory measures will be collected with TMS and electroencephalography for biomarker development.

DISCUSSION

This is the first known randomized controlled trial to examine the efficacy of sequential bilateral aTBS for treating suicidal ideation in adolescents with MDD. Results from this study will also provide opportunities to further understand the neurophysiological and molecular mechanisms of suicidal ideation in adolescents.

TRIAL REGISTRATION

Investigational device exemption (IDE) Number: G200220, ClinicalTrials.gov (ID: NCT04701840). Registered August 6, 2020. https://clinicaltrials.gov/ct2/show/NCT04502758?term=NCT04701840&draw=2&rank=1.

Altered gray matter volumes and plasma IL-6 level in major depressive disorder patients with suicidal ideation

BACKGROUNDS

Suicidal ideation (SI) is one of the most serious consequences of major depressive disorder (MDD). Understanding the unique mechanism of MDD with SI (MDD + S) is crucial for treatment development. While abundant research has studied MDD, past studies have not reached a consensus on the mechanism of MDD + S. The study aimed to investigate the abnormalities of the gray matter volumes (GMVs) and plasma IL-6 level in MDD + S to further reveal the mechanism of MDD + S.

METHODS

We tested the plasma IL-6 level using Luminex multifactor assays and collected the Structural Magnetic Resonance Imaging (SMRI) data from 34 healthy controls (HCs), 36 MDD patients without SI (MDD - S) and 34 MDD + S patients. We performed a partial correlation between the GMVs of the brain regions with significant differences and plasma IL-6 level with age, sex, medication, scores of HAMD-17 and HAMA as the covariates.

RESULTS

Compared with HCs and MDD - S, MDD + S had significantly decreased GMVs in the left cerebellum Crus I/II and significantly increased plasma IL-6 level; compared with HCs, both the MDD + S and MDD - S had significantly decreased GMVs in right precentral and postcentral gyri. No significant correlation was found between the GMVs and the plasma IL-6 level in the MDD + S and MDD - S, respectively. While the GMVs of the right precentral and postcentral gyri negatively correlated with the level of IL-6 in the whole MDD (r = -0.28, P = 0.03). The GMVs of the left cerebellum Crus I/II (r = -0.47, P = 0.02), and the right precentral and postcentral gyri (r = -0.42, P = 0.04) negatively correlated with the level of IL-6 in HCs.

CONCLUSION

The altered GMVs and the plasma IL-6 level may provide a scientific basis to understand the pathophysiological mechanisms of MDD + S.

Mapping the genetic architecture of suicide attempt and suicide death using polygenic risk scores for clinically-related psychiatric disorders and traits

BACKGROUND

Suicidal behavior is moderately heritable and a consequence of a combination of the diathesis traits for suicidal behavior and suicide-related major psychiatric disorders. Here, we sought to examine shared polygenic effects between various psychiatric disorders/traits and suicidal behavior and to compare the shared polygenic effects of various psychiatric disorders/traits on non-fatal suicide attempt and suicide death.

METHODS

We used our genotyped European ancestry sample of 260 non-fatal suicide attempters, 317 suicide decedents and 874 non-psychiatric controls to test whether polygenic risk scores (PRSs) obtained from large GWASs for 22 suicide-related psychiatric disorders/traits were associated with suicidal behavior. Results were compared between non-fatal suicide attempt and suicide death in a sensitivity analysis.

RESULTS

PRSs for major depressive disorder, bipolar disorder, schizophrenia, ADHD, alcohol dependence, sensitivity to environmental stress and adversity, educational attainment, cognitive performance, and IQ were associated with suicidal behavior (Bonferroni-corrected p < 2.5 × 10^-4). The polygenic effects of all 22 psychiatric disorders/traits had the same direction (p for binomial tests = 4.8 × 10^-7) and were correlated (Spearman's ρ = 0.85) between non-fatal suicide attempters and suicide decedents.

CONCLUSIONS

We found that polygenic effects for major psychiatric disorders and diathesis-related traits including stress responsiveness and intellect/cognitive function contributed to suicidal behavior. While we found comparable polygenic architecture between non-fatal suicide attempters and suicide decedents based on correlations with PRSs of suicide-related psychiatric disorders/traits, our analyses are limited by small sample size resulting in low statistical power to detect difference between non-fatal suicide attempt and suicide death.

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.

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.

Retrospective data analysis to determine the effectiveness of intravenous ketamine therapy on patients suffering from depression with suicidal ideation

Background

Depression is often a debilitating and recurrent psychiatric disorder. Depression with suicidal ideation, being a psychiatric emergency, often needs intensive intervention such as Electro-Convulsive Therapy (ECT). ECT may be refused because of stigma and perceived risk. Intravenous ketamine therapy, being an alternative to ECT for quick response compared to routine pharmaco-therapy, is analyzed to determine its effectiveness.

Methods

Among patients suffering from depression with suicidal ideation, intravenous ketamine therapy is routinely offered as an alternative to ECT to the needy in the Department of Psychiatry affiliated with a teaching institute. There is a standard operative procedure laid down for ketamine therapy. Baseline and periodical assessment of depression by Hamilton Depression Rating Scale and suicidality by Columbia Suicide Severity Rating Scale is a part of it. Taking advantage of it, retrospective data analysis was done to determine the effectiveness of the therapy.

Result

Significant improvement of depression and suicidality found at all the evaluation points after intravenous ketamine therapy.

Conclusion

Intravenous ketamine therapy is an effective alternative to ECT among patients suffering from depression with suicidal ideation.

Suicidal Ideation and Obsessive-Compulsive Disorder: Links and Knowledge

Suicidal ideation (SI) is understudied in obsessive-compulsive disorder (OCD). Nonetheless, evidence suggests increased risk for SI in individuals with OCD compared to the general population. Understanding the relationship between SI and OCD involves investigating risk factors associated with SI. Furthering knowledge of links is essential for enhancing outcomes and decreasing experiences of SI through improving treatment interventions. Additionally, increasing awareness of factors that lead SI to suicide attempts (SA) is vital. To best illustrate the current state of knowledge, this scoping review examines risk factors for SI, including symptom profiles or phenotypes, comorbid diagnoses, sociodemographic and lifestyle factors, childhood trauma, and genetic and familial contributions. Important treatment considerations for targeting SI within the context of OCD are detailed with respect to the current evidence for psychotherapy, pharmacology, brain stimulation, and neurosurgery. Gaps in the literature and future directions are identified, broadly with respect to studies examining the treatment of SI within the context of OCD, particular OCD phenotypes, and factors influencing SI in pediatric OCD. Due to the relative novelty of this area of exploration, many unknowns persist regarding onset of SI in OCD, factors contributing to the maintenance of SI in OCD, and relevant treatment protocols. Findings suggest that individuals with previous SI or SA, history of childhood trauma, significant life stress, and psychiatric comorbidities, particularly depression, should be closely monitored and screened for SI.

Predictors of future suicide attempts in individuals with high suicide risk admitted to an acute psychiatry suicide intervention unit in India. A survival analysis study

OBJECTIVE

Determination of suicide vulnerability remains challenging in mental illness. Variability in risk factors identified compound its poor predictability. Longitudinal studies, offering more reliable indices of risk, from developing countries are conspicuously limited. Furthermore, research advances allude to inherent vulnerability. This study, the first of its kind from India, consequently aimed to delineate factors influencing subsequent attempts in mental illness and acute suicidality.

METHOD

Baseline and follow-up information (up to five years) was obtained from medical records of individuals (n = 130) with acute suicidality [recent attempt (first attempt/ reattempt) and high-risk ideators]. Variables were compared between individuals with, and without subsequent suicide attempts. Time to attempt and factors influencing the same was determined using survival analysis, and Cox proportional hazard for estimating the likelihood of a subsequent suicide attempt.

RESULTS

Median duration of follow up of the sample (n = 130) was 23 months. The sample comprised of individuals with a recent attempt (first-time attempt), recent reattempt and recent high-risk ideators. Subsequent suicide attempts were noted in 30 (23.1 %) patients. Baseline sociodemographic and clinical variables, including suicidality, could not differentiate individuals with a subsequent suicide attempt. Survival analysis indicated that 65 % of subsequent attempts occurred within 9 months of discharge. Family history of suicide and the presence of impulsive-aggressive traits were associated with both, reduced survival time and overall increased risk of a subsequent suicide attempt.

CONCLUSION

This study delineates both, the time frame associated with greatest risk, as well as individuals most likely to reattempt suicide. It thereby offers insights into potential windows of opportunity to mitigate prospective suicide risk. Strategies such as enhanced after-care and integrating specific interventions to attenuate impulsive-aggressive behaviors could be a focus to prevent future attempts, thereby decreasing rates of suicide amongst those with mental illness. Furthermore, the findings of this study reaffirm the role of factors that independently confer vulnerability to suicide. Traversing noted regional variations, the findings importantly reinforce the distinct pathophysiological underpinnings of suicide in mental illness.

Comparison of lithium levels between suicide and non-suicide fatalities: Cross-sectional study

Ecological studies have suggested the protective effect of micro-dose lithium in drinking water against suicide, however, the association between body lithium level and suicide is unknown. We aimed to compare body lithium levels between suicide and non-suicide fatalities. This cross-sectional study included 12 suicides and 16 non-suicides who were examined or dissected at the Tokyo Medical Examiner's Office from March 2018 to June 2021. The aqueous humor lithium concentration was measured twice using inductively coupled plasma mass spectrometry. Analysis of covariance (ANCOVA) was used to compare the lithium concentration between suicides and non-suicides. Mixed-effects model was conducted to account for all lithium concentration data. The aqueous humor lithium concentration did not change after death (t(7) = -0.70, [Formula: see text], SE = 0.03, 95% CI = [-0.09, 0.05], P = 0.51, Cohen's d = 0.01). The aqueous humor lithium concentration was lower in suicides (mean 0.50 μg/L (variance s² 0.04)) than in non-suicides (mean 0.9² μg/L (s² 0.07)) (t(26) = 4.47, [Formula: see text], SE = 0.09, 95% CI = [0.22 to 0.61], P < 0.001, Cohen's d = 1.71). The ANCOVA showed that death by suicide was significantly associated with lower lithium concentration (F(1, 24) = 8.57, P = 0.007), and the effect size was large (η_p² = 0.26). The random intercept model showed a significant effect of suicide on aqueous humor lithium concentration (b = -0.261, SE = 0.102, 95% CI = [-0.471 to -0.051], t(24) = -2.568, P = 0.017). The results of this study demonstrate that even micro-dose lithium is associated with suicide death. Clinical studies are warranted to examine the effects of micro-dose lithium on suicide prevention.

Network science approach elucidates integrative genomic-metabolomic signature of antidepressant response and lifetime history of attempted suicide in adults with major depressive disorder

Background: Individuals with major depressive disorder (MDD) and a lifetime history of attempted suicide demonstrate lower antidepressant response rates than those without a prior suicide attempt. Identifying biomarkers of antidepressant response and lifetime history of attempted suicide may help augment pharmacotherapy selection and improve the objectivity of suicide risk assessments. Towards this goal, this study sought to use network science approaches to establish a multi-omics (genomic and metabolomic) signature of antidepressant response and lifetime history of attempted suicide in adults with MDD. Methods: Single nucleotide variants (SNVs) which associated with suicide attempt(s) in the literature were identified and then integrated with a) p180-assayed metabolites collected prior to antidepressant pharmacotherapy and b) a binary measure of antidepressant response at 8 weeks of treatment using penalized regression-based networks in 245 'Pharmacogenomics Research Network Antidepressant Medication Study (PGRN-AMPS)' and 103 'Combining Medications to Enhance Depression Outcomes (CO-MED)' patients with major depressive disorder. This approach enabled characterization and comparison of biological profiles and associated antidepressant treatment outcomes of those with (N = 46) and without (N = 302) a self-reported lifetime history of suicide attempt. Results: 351 SNVs were associated with suicide attempt(s) in the literature. Intronic SNVs in the circadian genes CLOCK and ARNTL (encoding the CLOCK:BMAL1 heterodimer) were amongst the top network analysis features to differentiate patients with and without a prior suicide attempt. CLOCK and ARNTL differed in their correlations with plasma phosphatidylcholines, kynurenine, amino acids, and carnitines between groups. CLOCK and ARNTL-associated phosphatidylcholines showed a positive correlation with antidepressant response in individuals without a prior suicide attempt which was not observed in the group with a prior suicide attempt. Conclusion: Results provide evidence for a disturbance between CLOCK:BMAL1 circadian processes and circulating phosphatidylcholines, kynurenine, amino acids, and carnitines in individuals with MDD who have attempted suicide. This disturbance may provide mechanistic insights for differential antidepressant pharmacotherapy outcomes between patients with MDD with versus without a lifetime history of attempted suicide. Future investigations of CLOCK:BMAL1 metabolic regulation in the context of suicide attempts may help move towards biologically-augmented pharmacotherapy selection and stratification of suicide risk for subgroups of patients with MDD and a lifetime history of attempted suicide.

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

Suicide is the 14th 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.

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.

Childhood adversity, adulthood adversity and suicidal ideation in Chinese patients with major depressive disorder: in line with stress sensitization

The stress sensitization model indicates that early adversity (e.g., childhood stress) sensitizes individuals to subsequent proximal stress (e.g., stressful life events in adult life), thereby increasing their vulnerability to psychiatric disorders. However, the effect of stress sensitization on suicidality in patients with major depressive disorder (MDD) has not been previously investigated. Data for the present study were derived from the Objective Diagnostic Markers and Personalized Intervention in MDD Patients (ODMPIM) study. The psychiatric diagnosis and suicidal ideation were evaluated by the Mini-International Neuropsychiatric Interview (M.I.N.I.). We used a multiple logistic analysis to examine the association among childhood adversity (CA), adulthood adversity (AA) and suicidal ideation. Among 1084 MDD patients, 48.6% had suicidal ideation and 65.6% experienced life adversity during their childhood or adulthood. Patients who reported suicidal ideation were more likely to report CA (46.7% vs. 38.7%, P = 0.008) or AA (49.5% vs. 40.9%, P = 0.004) than patients without suicidal ideation. Patients who experienced two waves of adversity (both CA and AA) were associated with higher rates of suicidal ideation (odds ratio = 1.68, 95% CI = 1.19-2.37, P = 0.003); however, neither CA nor AA alone was associated with suicidal ideation. This study first verifies the hypothesis of stress sensitization on suicidal ideation in patients with MDD. Focusing on stress sensitization may enhance the early identification of MDD patients at suicidal risk and the ability to provide timely and appropriate intervention. Clinicaltrials.gov identifier: NCT02023567.

Examining Risk Factors in the Cannabis–Suicide Link: Considering Trauma and Impulsivity among University Students

Cannabis is a commonly used substance among university students that may have several negative health repercussions, including suicidal ideation (SI) and suicide attempts (SA). The factors that contribute to or help explain this relation remain uncertain. Earlier negative experiences, especially trauma encountered during early life, have been associated with the development of psychopathology upon later stressor encounters. In the current study, we examined the associations between SI and SA with problematic cannabis use among young adults and the role of earlier trauma experiences and trait impulsiveness in understanding this link. Among university students (N = 539), problematic cannabis use was moderately related to lifetime and past-12-months suicidal ideation and attempts. Impulsiveness mediated the relationship between problematic cannabis use and lifetime SI and SA. Moreover, previous life trauma moderated the relationship between problematic cannabis use and SA, such that the association between problematic cannabis use and SA was stronger among those who experienced high levels of trauma. These findings highlight behavioral and environmental factors that could predict suicide ideation and attempts among young cannabis users. Accordingly, trait impulsiveness and early trauma experiences should be considered, alongside problematic cannabis use, in suicide-risk detection and prevention strategies among young adults.

Factor structure and validity of the Revised Suicide Crisis Inventory (SCI-2) among Indian adults

BACKGROUND

There is a dearth of cross-cultural data on the psychometric properties of the revised Suicide Crisis Inventory (SCI)- 2. Our objective was to examine the factor structure, reliability, and validity of the SCI-2 among Indian adults.

METHODS

Using an online survey method, between August 20, 2020 and January 31, 2021, an anonymous questionnaire containing general sociodemographic information and self-report measures was circulated over email and social media. Confirmatory factor analyses (CFA) of the SCI-2 was carried out. We also examined the internal consistency of the SCI-2 and tested its convergent validity against the Suicide Narrative Inventory (SNI) and the Perceived Stress Scale (PSS-10).

RESULTS

A total of 302 participants (Mean age = 43.5 ± 17.9 years, 53.6% female) were obtained. Results of the one-factor CFA indicated good model fit (χ2[1769] = 5368.75, p < 0.001, Comparative Fit Index [CFI] =0.99, Root mean square error of approximation [RMSEA] =0.08). Similarly, the five-factor CFA also exhibited strong model fit (χ2[1759] = 4215.54, p < 0.001, CFI = 1.00, RMSEA =0.07). Comparison of these models indicated that the five-factor model demonstrated superior model fit (Δχ2[10] = 278.88, p < 0.001). The SCI-2 total and subscale scores showed excellent internal consistency and good convergent validity against most domains of the SNI and PSS-10.

CONCLUSION

Among Indian adults, the SCI-2 demonstrated good psychometric properties with the proposed five-factor solution providing the best fit. These findings provide support for the SCI construct and its assessment with the SCI-2 in an Asian setting.

NAA/Glu Ratio Associated with Suicidal Ideation in Pilot Sample of Autistic Youth and Young Adults

Suicidality is increased in autism spectrum disorder (ASD), yet effective interventions are lacking. Developing biologically based approaches for preventing and treating suicidality in ASD hinges on the identification of biomarkers of suicidal ideation (SI). Here, we assessed magnetic resonance spectroscopy (MRS) markers of glutamatergic neurotransmission in ASD youth and young adults. Twenty-eight ASD participants (16-33 years) underwent 1H-MRS, and metabolites were quantified using LCModel. N-acetylaspartate (NAA), glutamate (Glu), and the NAA/Glu ratio from the left dorsolateral prefrontal cortex were compared between ASD SI+ (n = 13) and ASD SI- (n = 15) participants. We found that ASD SI+ participants had a higher NAA/Glu ratio compared ASD SI- participants. The NAA/Glu ratio also predicted SI and significantly discriminated between ASD SI+/SI- participants. All analyses including NAA and Glu alone were non-significant. Here, we provide preliminary evidence for the importance of NAA/Glu in ASD with SI, with implications for biomarker discovery. Further mechanistic research into risk and interventional approaches to address SI in ASD are needed.

Prevalence and Correlational Factors of Suicidal Ideation and Suicide Attempts Among Chinese Adolescents

This study’s purpose was to (1) determine the prevalence of suicidality (i.e., suicidal ideation or suicide attempts) among adolescents in a city in Northeast China and (2) identify the correlational factors among adolescents with suicidality. A total of 69,519 adolescents from grades 5 to 12 in a city in Northeast China participated in the online investigation. Students completed a structured questionnaire to report their demographic information, psychological characteristics, and suicidality. Univariable and multivariable logistic regressions were applied to determine significant correlational factors associated with suicidal ideation (SI) and suicide attempts (SA). The prevalence of SI and SA among adolescents in the past 12 months was 13 and 4.8%, respectively. Multivariable logistic regression analyses found that the potential risk factors for SI and SA included female, non-nuclear family, higher subjective socioeconomic status, meaningless in life, depression, bullying perpetrator, negative parental rearing styles, lower self-esteem scores, hopelessness, and stressful life events. In order to improve the accuracy of suicide risk identification, a cumulative risk index was used. With the increase in the number of cumulative risks, the risk of SI and SA also increased. So the cumulative risk index was very valuable. The total prevalence of SI and SA among primary and middle school students was high. Preventive measures could be implemented according to the risk factors.