Association between C-reactive protein and suicidal behavior in an adult inpatient population

Brain-derived neurotrophic factor and C-reactive protein (CRP) biomarkers in suicide attempter and non-attempter major depression disorder (MDD) patients

BACKGROUND

In the available literature, levels of BDNF and CRP have been reported to correlate with suicide in depressive patients but there are inconsistencies in the results. We aimed to evaluate and compare BDNF and CRP concentrations in MDD patients with(MDD + SA) and without suicide attempts (MDD-SA) and healthy controls.

METHODS

30 (MDD + SA) patients, 30 (MDD-SA) patients, and 26 healthy controls were enrolled in the study. Age, sex, and BMI of patients were recorded. Blood sample was obtained for measurement of BDNF and CRP. Smoking and drug history, family history of suicide, and history of self-harm were also documented. Data were analyzed with SPSS version 22 and R version 4.1.1.

RESULTS

86 patients in three groups were evaluated (mean age: 28.45 ± 9.27 years, 56.71% female). Baseline and demographic parameters except for self-harm (40%, 3.3%, and 0% for MDD + SA, MDD-SA, and healthy controls, respectively, p = 0.001) did not differ between groups. CRP level was not significantly different between groups. BDNF showed a significant difference between groups (17.35, 16.45, and 19.43 for three groups, respectively, p < 0.001). An increase in BDNF decreased the odds of both depression and suicide. Roc curve showed excellent power for BDNF in discriminating MDD groups With healthy group.Roc can notdicrimiate MDD + SA and MDD-SA.

CONCLUSION

In our study, the concentration of BDNF differed significantly between depressed patients with/without suicide attempts and healthy controls which shows the association of BDNF with depression development and not suicide attempts. We could not find any association between CRP level and suicide attempt but still larger cohorts are needed for a definite conclusion.

Prevalence and risk factors of suicide attempts among Chinese elderly patients over 50 years with schizophrenia

BACKGROUND

Several research efforts have found that older schizophrenia patients are at higher risk for suicide. Related risk factors for suicide attempts in the elderly with schizophrenia are poorly understood. This study sought to assess the prevalence of suicide attempts and related risk variables in schizophrenia patients over the age of 50.

METHODS

We recruited 591 elderly patients over the age of 50. Demographic, clinical and blood parameters of all patients were collected. Patients with schizophrenia were evaluated for psychopathological symptoms using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

The rate of suicide attempts among elderly Chinese schizophrenia patients was 15.2%. In these elderly schizophrenia patients, those who with suicide attempts had significantly higher scores for insomnia, depression and smoking addiction, and higher levels of red blood cells, Hc1 glycosylated hemoglobin and free T3, but significantly lower levels of hypersensitive C-reactive protein and -globulin. Binary logistic regression analysis showed that higher depression scores and smoking addiction were risk factors for suicide attempts in these patients. Additionally, multiple regression analyses showed that higher BMI and insomnia scores were associated with suicide risk scores in elderly schizophrenia patients.

CONCLUSIONS

Our research shows that there is a high incidence of suicide attempts in people over 50 years of age with schizophrenia. A number of clinically relevant factors and metabolic markers are associated with suicide attempts among elderly patients with schizophrenia.

Decreased beta 1 (12-15 Hertz) power modulates the transfer of suicidal ideation to suicide in major depressive disorder

BACKGROUND

Suicide prevention for major depressive disorder (MDD) is a worldwide challenge, especially for suicide attempt (SA). Viewing suicide as a state rather than a lifetime event provided new perspectives on suicide research.

OBJECTIVE

This study aimed to verify and complement SAs biomarkers of MDD with a recent SA sample.

METHODS

This study included 189 participants (60 healthy controls; 47 MDD patients with non-suicide (MDD-NSs), 40 MDD patients with suicide ideation (MDD-SIs) and 42 MDD patients with SA (MDD-SAs)). MDD patients with an acute SA time was determined to be within 1 week since the last SA. SUICIDALITY Part in MINI was applied to evaluate suicidality. Absolute powers in 14 frequency bands were extracted from subject's resting-state electroencephalography data and compared within four groups. The relationship among suicidality, the number of SA and powers in significant frequency bands were investigated.

RESULTS

MDD-SIs had increased powers in delta, theta, alpha and beta band on the right frontocentral channels compared to MDD-NSs, while MDD-SAs had decreased powers in delta, beta and gamma bands on widely the right frontocentral and parietooccipital channels compared to MDD-SIs. Beta 1 power was the lowest in MDD-SAs and was modulated by the number of SA. The correlation between suicidality and beta 1 power was negative in MDD-SAs and positive in MDD-SIs.

CONCLUSION

Reduced beta 1 (12-15 Hz) power could be essential in promoting suicidal behaviour in MDD. Research on recent SA samples contributes to a better understanding of suicide mechanisms and preventing suicidal behaviour in MDD.

Associations of potential plasma biomarkers with suicide attempt history, current suicidal ideation and subsequent suicidal events in patients with depression: A discovery study

A growing body of evidences suggests that suicidal ideation (SI) and suicidal behaviors have biological bases. However, no biological marker is currently available to evaluate the suicide risk in individuals with SI or suicide attempt (SA). Moreover, the current risk assessment techniques poorly predict future suicidal events. The aim of this study was to examine the association of 39 new and already described peripheral cells and proteins (implicated in the immune system, oxidative stress and plasticity) with lifetime SA, past month SA, current SI, and future suicidal events (visit to the Emergency Department for SI or SA) in 266 treatment-seeking individuals with mood disorders. Equal parts of patients with and without past history of SA were recruited. All individuals at inclusion gave blood, were evaluated for SA recency, current SI, and were followed for two years afterwards. The 39 peripheral blood cellular and protein markers were entered separately for each outcome in Elastic Net models with 10-fold cross-validation, followed by single-analyte covariate-adjusted regression analyses for pre-selected analytes. Past month SA was associated with increased plasma levels of thrombospondin-2 and C-reactive protein, whereas current SI was associated with lower plasma serotonin levels. These associations were robust to adjustments for key covariates and corrections for multiple testing. The Cox proportional hazards regression showed that higher levels of thrombospondin-1 and of platelet-derived growth factor-AB predicted a future suicidal event. These two associations remained after adjustment for sex, age, and SA history, and outperformed the predictive value of past SA. Thrombospondins and platelet-derived growth factors have never been investigated in the context of suicide. Altogether, our results highlight the involvement in the suicidal process of platelet biological response and plasticity modifiers and also of inflammatory factors. They also suggest that SI and SA may have different biological correlates and that biomarkers associated with past SA or current SI do not automatically also predict future events.

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.

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.

Significantly elevated phosphatidylethanol levels in recent suicide attempters, but not in depressed controls and healthy volunteers

INTRODUCTION

Suicide is a complex transdiagnostic phenomenon. It is strongly associated with, but not exclusive to major depressive disorder (MDD). Hazardous alcohol drinking has also been linked to an increased risk of suicidal behaviours, however, it is often underreported. The study aimed to evaluate whether an objective measure of chronic alcohol use, phosphatidylethanol (PEth) could be useful as a biomarker in clinical practice.

METHOD

ology. The present case-control multi-centric study recruited 156 participants into three study groups: 52 patients treated for major depressive disorder (MDD), 51 individuals immediately following a suicide attempt (SA), and 53 volunteers. Sociodemographic data, medical history, and laboratory data, including PEth concentrations and C-reactive protein levels, were collected from study participants.

RESULTS

PEth concentrations were the highest in suicide attempters (232,54 ± 394,01 ng/ml), followed by patients with MDD (58,39 ± 135,82 ng/ml), and the control group (24,45 ± 70,83 ng/ml) (Kruskall Wallis χ2 = 12.23, df = 2, p = .002). In a multinomial logistic regression model with adjustments, PEth concentration was able to predict belonging to suicide attempters' group, but not to depression group (p = .01). Suicide attempters were also more likely to underreport their recent alcohol consumption.

LIMITATIONS

We did not analyze SA methods, psychiatric comorbidity and several other factors that might be associated with PEth levels, such as body mass index, race, and haemoglobin levels. Sample recruited in hospital settings may not be representative of the whole population. The results of this adult-only study cannot be generalized to adolescents.

CONCLUSIONS

PEth levels in recent suicide attempters significantly exceeded those of patients with MDD and controls. Suicide attempters also were more likely to underreport their alcohol consumption when questioned about their consuption. PEth might be an interesting biomarker to evaluate individuals at risk of SA.

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.

Suicide and Inflammation

Suicide is a leading cause of death worldwide. Although the neurobiological dysfunction underlying suicidal behavior remains unclear, recent work suggests that the immune system may play a role in the pathophysiology of suicide. In this chapter, we discuss a nascent body of literature suggesting that peripheral and central nervous systems (CNS) inflammation are associated with suicidal behavior. Because early-life stress is a major risk factor for suicidal behavior and is also associated with immune dysregulation, we hypothesize that such immune dysregulation may be the mechanism by which childhood maltreatment leads to an increased risk of suicidal behavior and suicide. Targeting inflammatory processes may be a novel treatment strategy, especially in populations that have experienced childhood trauma and exhibit elevated inflammation. Future work should directly test the hypothesis that reducing inflammation would result in a reduction in suicidal behavior.

Inflammation, cognitive dysfunction, and suicidal ideation among patients with major depression

BACKGROUND

Dysregulated proinflammatory cytokines have been shown to be associated with suicidal behavior. Cognitive deficits in working memory and inhibitory control have been demonstrated in depressed patients and people with suicidal ideation (SI). However, the association between proinflammatory cytokines, SI, and cognitive deficits in patients with major depressive disorder (MDD) remains unclear.

METHODS

A total of 77 patients with MDD and age-/sex-matched 60 healthy individuals were recruited. MDD patients were divided into two groups: with SI (n = 36) and no SI (n = 41). SI was defined by a score of ≥2 in item 3 of the 17-item Hamilton Rating Scale for Depression. Levels of proinflammatory cytokines, including soluble interleukin-6 receptor, soluble tumor necrosis factor-α receptor type 1, and C-reactive protein (CRP), were measured, and cognitive function was assessed using 2-back task and Go/No-Go task.

RESULTS

Patients with SI had higher levels of CRP than those without SI and controls (P = .007). CRP was positively associated with SI (β = 0.21, P = .037), independent of cognitive function and depressive symptoms. Furthermore, SI was associated with cognitive deficits in working memory and inhibitory control after adjusting for confounding factors (P < .05).

CONCLUSION

Our findings suggest that higher levels of serum CRP and deficits in working memory and inhibitory control may be associated with higher SI among patients with MDD.

Neutrophil to-lymphocyte and platelet-to-lymphocyte ratios as biomarkers for suicidal behavior in children and adolescents with depression or anxiety treated with selective serotonin reuptake inhibitors

BACKGROUND

Both the neutrophil/lymphocyte ratio (NLR) and the platelet/lymphocyte ratio (PLR) have been proposed as biomarkers of suicidal risk in adults with depression. We examined whether these ratios may be considered biomarkers for suicidal behavior in young patients with major depressive or anxiety disorders before treatment with selective serotonin reuptake inhibitors (SSRIs), or as biomarkers for the adverse event of SSRI-associated suicidality.

METHODS

Children and adolescents meeting criteria for major depressive or anxiety disorder were recruited. Serum levels of three pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) were assessed; and NLR and PLR calculated, from blood samples collected at baseline and after 8 weeks treatment with SSRI. A Mann-Whitney test was performed to evaluate differences in NLR and PLR between children with and without a history of a suicide attempt prior to treatment. We compared hematological parameters before and after treatment, and between children who developed SSRI-associated suicidality versus children without treatment emergent suicidality.

RESULTS

Among 91 children and adolescents (aged 13.9 ± 2.4 years), baseline NLR and PLR were significantly higher among those with a history of a suicide attempt versus those without such history. Statistically significant correlations were found for the suicide ideation subscale in the Columbia suicide severity rating scale with both baseline NLR and PLR. Baseline NLR and PLR were similar in children who did and did not develop SSRI-associated suicidality after 8 weeks. In the final logistic regression model (χ2 = 18.504, df = 4, p value = 0.001), after controlling for sex, depression severity and IL-6 levels, NLR was significantly associated with a past suicide attempt (β = 1.247, p = 0.019; OR [95% CI] = 3.478 [1.230-9.841]), with a NLR cut-off value of = 1.76 (area under the curve = 0.75 (95% CI = 0.63-0.88, sensitivity = 73%, and specificity = 71%, p value = 0.003).

CONCLUSIONS

High NLR and PLR values may be associated with suicidal behavior in depressed and anxious children and adolescents. NLR appears as a better predictor of suicide attempt than PLR, and thus may be a useful biomarker of suicidality in young patients with depression or anxiety.

Associations of three major physiological stress systems with suicidal ideation and suicide attempts in patients with a depressive and/or anxiety disorder

BACKGROUND

People with depressive and/or anxiety disorders are at increased risk of suicidal ideation and suicide attempts, but biological correlates signaling such risk remain unclear. Independent and cumulative dysregulations in physiological stress systems, in particular the hypothalamic-pituitaryadrenal axis (HPA-axis), immune-inflammatory system, and autonomous nervous system (ANS), may contribute to this risk. However, findings have either been heterogeneous or absent thus far.

METHODS

Associations between individual markers and cumulative indices of the HPA-axis (cortisol awakening response and evening cortisol), immune-inflammatory system (C-reactive protein, interleukin-6 (IL-6), and tumor necrosis factor-α), and the ANS (heart rate, respiratory sinus arrhythmia, and pre-ejection period) and the outcomes no suicide ideation with suicide attempt (SI-SA+), suicide ideation without suicide attempt (SI+SA-) and suicide ideation with suicide attempt (SI+SA+) were investigated in 1749 persons with depressive and/or anxiety disorders from the Netherlands Study of Depression and Anxiety (NESDA).

RESULTS

High levels of CRP and IL-6 were associated with SI-SA+ and SI+SA+ respectively when compared to non-suicidal patients after adjusting for confounders and multiple testing. Also, cumulative immune-inflammatory dysregulations were positively associated with SI+SA+, suggesting a dose-response effect. No significant associations were found between HPA-axis or ANS indicators and suicide-outcomes and between immune-inflammatory system markers or cumulative stress system dysregulations and SI+SA-.

CONCLUSION

Although stress system markers could not differentiate between SI+SA- and non-suicidal patients, findings indicate that dysregulations of individual and cumulative immune-inflammatory markers are associated with suicide attempts in depressive and/or anxiety patients. Thus, immune-inflammatory system dysregulation may be involved in the pathophysiology of suicidal behavior, supporting further examination of the effects of anti-inflammatory interventions on suicidality.

Suicide Biomarkers to Predict Risk, Classify Diagnostic Subtypes, and Identify Novel Therapeutic Targets: 5 Years of Promising Research

BACKGROUND

Suicide is a global health crisis. However, no objective biomarkers of suicide risk currently exist, and self-reported data can be unreliable, which limits prediction, diagnostic, and treatment efforts. Reliable biomarkers that can differentiate between diagnostic subgroups, predict worsening symptoms, or suggest novel therapeutic targets would be extremely valuable for patients, researchers, and clinicians.

METHODS

MEDLINE was searched for reports published between 2016 and 2021 using search terms (suicid*) AND (biomarker*) OR (indicat*). Reports that compared biomarkers between suicidal ideation, suicide attempt, death from suicide, or any suicide subgroup against other neuropsychiatric disorders were included. Studies exclusively comparing suicidal behavior or death from suicide with healthy controls were not included to ensure that biomarkers were specific to suicide and not other psychopathology.

RESULTS

This review summarizes the last 5 years of research into suicide-associated biomarkers and provides a comprehensive guide for promising and novel biomarkers that encompass varying presentations of suicidal ideation, suicide attempt, and death by suicide. The serotonergic system, inflammation, hypothalamic-pituitary-adrenal axis, lipids, and endocannabinoids emerged as the most promising diagnostic, predictive, and therapeutic indicators.

CONCLUSIONS

The utility of diagnostic and predictive biomarkers is evident, particularly for suicide prevention. While larger-scale studies and further in-depth research are required, the last 5 years of research has uncovered essential biomarkers that could ultimately improve predictive strategies, aid diagnostics, and help develop future therapeutic targets.

Inflammation and nitro-oxidative stress in current suicidal attempts and current suicidal ideation: a systematic review and meta-analysis

A meta-analysis showed a significant association between activated immune-inflammatory and nitro-oxidative (IO&NS) pathways and suicide attempts (SA). There is no data on whether recent suicidal ideation (SI) is accompanied by activated IO&NS pathways and whether there are differences between recent SA and SI. The current study searched PubMed, Google Scholar, and Web of Science, for articles published from inception until May 10, 2021, and systematically reviewed and meta-analysed the association between recent SA/SI (<3 months) and IO&NS biomarkers. We included studies which compared psychiatric patients with and without SA and SI and controls (either healthy controls or patients without SA/SI) and used meta-analysis (random-effect model with restricted maximum-likelihood) to delineate effect sizes with 95% confidence intervals (CI). Our search included 59 studies comprising 4.034 SA/SI cases and 12.377 controls. Patients with SA/SI showed activated IO&NS pathways (SMD: 0.299; CI: 0.200; 0.397) when compared to controls. The immune profiles were more strongly associated with SA than with SI, particularly when compared to healthy controls, as evidenced by activated IO&NS (SMD: 0.796; CI: 0.503; 1.089), immune (SMD: 1.409; CI: 0.637; 1.462), inflammatory (SMD: 1.200; CI: 0.584; 1.816), and neurotoxic (SMD: 0.904; CI: 0.431; 1.378) pathways. The effects sizes of the IO&NS, immune and inflammatory profiles were significantly greater in SA than in SI. In conclusion: activated IO&NS pathways are associated with recent SA and SI, and inflammation, T helper-1 activation, nitro-oxidative stress, lowered neuroprotection, and increased neurotoxicity explain at least in part why psychiatric patients show increased suicidal behaviours, especially SA.

Suicide attempts are associated with activated immune-inflammatory, nitro-oxidative, and neurotoxic pathways: A systematic review and meta-analysis

BACKGROUND

Suicide attempts (SA) frequently occur in patients with mood disorders and schizophrenia, which are both accompanied by activated immune-inflammatory and nitro-oxidative (IO&NS) pathways.

METHODS

We searched PubMed, Google Scholar, and Web of Science, for articles published from inception until February 1, 2021. We included studies that compared blood biomarkers in psychiatric patients with (SA+) and without SA (SA-) and heathy controls and we combined different IO&NS biomarkers into immune, inflammatory, and neurotoxic profiles and used meta-analysis (random-effect model with restricted maximum-likelihood) to delineate effect sizes with 95% confidence interval (CI).

FINDINGS

Our search included 51 studies comprising 4.945 SA+ patients and 24.148 controls. We stratified the control group into healthy controls and SA- patients. SA+ patients showed significantly (p<0.001) increased immune activation (SMD: 1.044; CI: 0.599, 1.489), inflammation (SMD: 1.109; CI: 0.505, 1.714), neurotoxicity (SMD: 0.879; CI: 0.465, 1.293), and lowered neuroprotection (SMD: 0.648; CI: 0.354, 0.941) as compared with healthy controls. When compared with SA- patients, those with SA+ showed significant (p<0.001) immune activation (SMD: 0.290; CI: 0.183, 0.397), inflammation (SMD: 0.311; CI: 0.191, 0.432), and neurotoxicity (SMD: 0.315; CI: 0.198, 0.432), and lowered neuroprotection (SMD: 0.341; CI: 0.167, 0.515). Patients with current, but not lifetime, SA showed significant (p<0.001) levels of inflammation and neurotoxicity as compared with controls.

CONCLUSIONS

Patients with immune activation are at a higher risk of SA which may be explained by increased neurotoxicity due to inflammation and nitro-oxidative stress. This meta-analysis discovered new biomarkers of SA and therapeutic targets to treat individuals with SA.

Increased C-reactive protein concentration and suicidal behavior in people with psychiatric disorders: A systematic review and meta-analysis

OBJECTIVE

Suicide is a leading cause of death worldwide. Identifying factors associated with suicidality (suicidal ideation [SI]/suicidal behavior) could increase our understanding of the pathophysiological underpinnings of suicide and improve its prevention.

METHODS

We conducted a systematic review (PubMed/PsycInfo/Cochrane databases, up to September 2020) and random-effect meta-analysis including observational studies comparing peripheral C-reactive protein (CRP) levels in suicidal versus non-suicidal patients affected by any psychiatric disorder and healthy controls (HC). Primary outcome was the CRP standardized mean difference (SMD) between patients with high suicidality versus those with absent or low suicidality. Secondary outcomes were SMD of CRP levels between those with suicide attempt versus no suicide attempt, as well as between those with (high) versus low or absent SI. Quality of included studies was measured with Newcastle-Ottawa scale.

RESULTS

Out of initial 550 references, 21 observational studies involving 7682 subjects (7445 with mood disorders or first-episode psychosis, 237 HC) were included. A significant association of CRP levels with suicidality (SMD 0.688, 95% CI 0.476-0.9, p < 0.001) emerged. CRP levels were higher in individuals with high SI (SMD 1.145, 95% CI 0.273-2.018, p = 0.010) and in those with suicide attempt (SMD 0.549, 95%CI 0.363-0.735, p < 0.001) than non-suicidal individuals (either patients or HC). Main analyses were confirmed in sensitivity analysis (removing HC), and after adjusting for publication bias. The cross-sectional design of included studies, and the high heterogeneity of diagnosis and treatment limit the generalizability of these results. Median quality of included studies was high.

CONCLUSION

CRP is associated with higher suicidality in patients with mental disorders. Large cohort studies longitudinally monitoring CRP levels are needed to explore its longitudinal association with suicidality.

Comparison Between Inflammatory Biomarkers (High-Sensitivity C-Reactive Protein and Neutrophil-Lymphocyte Ratio) and Psychological Morbidity in Suicide Attempt Survivors Brought to Medicine Emergency

Objectives: This study aimed to compare inflammatory biomarkers (high-sensitivity {hs} C-reactive protein, neutrophil-lymphocyte ratio) and psychological morbidity in suicide attempt survivors.

Methods: One hundred ninety-eight poisoning cases screened, 40 age-matched suicide attempt survivors (SAS), 40 healthy controls (HC) between the age of 18 years and 60 years were included. Complete hemogram, neutrophil-lymphocyte ratio (NLR), hsCRP values obtained, compared with Hospital Anxiety and Depression Scale (HADS), suicide intent scale, presumptive stressful life events scale (PSLES), general health questionnaire 12-item (GHQ-12) (Hindi version), and Hindi Mental State Examination (HMSE).

Results: A statistically significant difference was observed in hsCRP (p=0.016) and NLR (p=0.029) of depressed-suicidal participants vs healthy controls. hsCRP values of anxious-suicidal subjects vs healthy controls showed a statistically significant difference (p=0.001). There was a statistically significant difference between patients, healthy controls in HADS anxiety and HADS depression mean scores (p<0.001). The PSLES items were ranked according to the mean stress scores of all the items (mean±SD), highest four were excessive alcohol use by the family member 47.50 (±27.03), conflicts with in-laws 50 (±27.73), family conflict 50 (±29.42), marital conflict 50.63 (±32.76). There was a statistically significant difference in hemoglobin (p<0.001), red blood cells count (p<0.001), hematocrit (p<0.001) between suicide attempt survivors and healthy controls.

Conclusion: Both hsCRP and NLR have emerged as potential inflammatory biomarkers for depressive patients with suicidal attempts. Additionally, there may be a link between anemia and suicide risk in patients with depression.

Neutrophil-to-lymphocyte ratio and C-reactive protein in non-fatal suicidal attempts: A cross-sectional pilot study in Bangladesh

BACKGROUND

Precise identification of risk factors for suicide has been found as fundamentally challenging for the stakeholders. In search of that, the determination of potential biological markers of suicide has been scrutinizing in recent days. However, replicative studies across the culture and time are warranted to utilize the biomarkers in decision-making while considering suicide prevention.

OBJECTIVES

We aimed to measure the neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) in non-fatal suicidal attempts.

METHODS

This cross-sectional study was conducted from August 2020 to May 2021. Data were collected from 26 hospitalized patients after an immediate non-fatal suicidal attempt. We collected blood samples and assessed the complete blood count, NLR, and CRP. Data were analyzed by Statistical Package for the Social Science version 24.0 and Microsoft Excel software. We performed the independent Mann-Whitney U test to determine the variations between the groups. A value <.05 was considered as the level of significance.

RESULTS

The mean age of the study population was 24.1 (±7.3), more than half of them (n = 19, 73.1%) were female. The mode of attempt was either hanging (n = 13, 50.0%) or poisoning (n = 13, 50.0%). The previous attempt was noted in 12 (46.2%) cases. The mean CRP level was 16.8 (±30.2) mg/L and the mean NLR level was 8.3 (±6.8) for the total sample. Both the CRP and NLR were significantly higher among those who attempted hanging (P = .019 and .001).

CONCLUSIONS

The current study revealed preliminary findings on CRP and NLR among non-fatal suicides in Bangladesh where both of the parameters were significantly higher in non-fatal hanging.

Raised C-reactive protein in medication overdose: A report of two cases

Studies have been coming out focusing on the biological markers of suicide. Here, we present two cases with raised C-reactive protein who were admitted after attempts of suicide by overdose. There is a need to study the neuro-immuno-endocrinal changes in suicide systematically that will give insight into the biological underpinning.

Association between high-sensitivity C-reactive protein levels and depression: Moderation by age, sex, obesity, and aerobic physical activity

BACKGROUND

Low-grade systemic inflammation evidenced by elevated serum high-sensitivity C-reactive protein (hsCRP) levels can be a biomarker for depression. This study aimed to investigate the association between serum hsCRP levels and depressive symptoms and to explore the potential moderating effects of age, sex, body mass index (BMI), and aerobic physical activity on the association.

METHODS

Data of 10,702 adults (≥ 19 years) were obtained from the nationwide cross-sectional Korea National Health and Nutrition Examination Surveys of 2016 and 2018. Significant depressive symptoms were defined as ≥ 10 on the Patient Health Questionnaire-9, and high hsCRP level was defined as > 3.0 mg/L.

RESULTS

Adults with high hsCRP levels were more likely to have depressive symptoms (odds ratio [OR]: 1.41, 95% confidence interval [CI]: 1.07-1.84) and suicidal ideation (OR: 1.39, 95% CI: 1.07-1.80) than those with low hsCRP levels. In the age- and sex-stratified analysis, high hsCRP levels were associated with depressive symptoms in the non-geriatric population (age ≤ 64 years) alone, with a higher OR in males than females. In subgroup analyses, the association between them was observed only among obese adults and adults without aerobic physical activity.

LIMITATIONS

Causal interpretation is limited due to the cross-sectional design.

CONCLUSIONS

Our results replicate previous findings of an association between high hsCRP levels and depressive symptoms in adults using a large nationally representative sample. The association between them was more prominent in the non-geriatric population, males, obese adults, and those without aerobic physical activity.

The GSK3-NRF2 Axis in Suicide

Mutations in the genes coding for tryptophan-hydrolase-2 and the scaffold protein FKBP5 are associated with an increased risk of suicide. The mutation in both cases enhances the enzymatic activity of glycogen synthase kinase-3 (GSK3). Conversely, anti-suicidal medications, such as lithium, clozapine, and ketamine, indirectly inhibit the activity of GSK3. When GSK3 is active, it promotes the metabolic removal of the transcription factor NRF2 (nuclear factor erythroid 2-related factor-2), which suppresses the transcription of multiple genes that encode anti-oxidative and anti-inflammatory proteins. Notably, several suicide-biomarkers bear witness to an ongoing inflammatory process. Moreover, alterations in serum lipid levels measured in suicidal individuals are mirrored by data obtained in mice with genetic deletion of the NRF2 gene. Inflammation is presumably causally related to both dysphoria and anger, two factors relevant for suicide ideation and attempt. Preventing the catabolism of NRF2 could be a strategy to obtain novel suicide-prophylactic medications. Possible candidates are minocycline and nicotinic-α7 agonists. The antibiotic minocycline indirectly activates NRF2-transcriptional activity, whereas the activation of nicotinic-α7 receptors indirectly inhibits GSK3.

Examination of structural brain changes in recent suicidal behavior

We aimed to identify brain structural changes in cortical and subcortical regions linked to recent suicidal behavior. We performed secondary analyses of structural MRI data of two independent studies, namely the Establishing Moderators/Biosignatures of Antidepressant Response - Clinical Care (EMBARC) study and a Little Rock study on acute suicidal behavior. Study 1 (EMBARC, N = 187), compared individuals with remote suicide attempts (Remote-SA), individuals with lifetime suicide ideation but no attempts (Lifetime-SI only), and depressed individuals without lifetime suicide ideation or attempts (non-suicidal depressed). Study 2 (Little Rock data, N = 34) included patients recently hospitalized for suicide ideation or attempt constituted by: patients who recently attempted suicide (Recent-SA), individuals with remote suicide attempts (Remote-SA), and Lifetime-SI only. Study 3 combined the EMBARC and Little Rock datasets including Recent-SA, Remote-SA, Lifetime-SI only and non-suicidal depressed individuals. In Study 1 and Study 2, no significant differences were observed between groups. In Study 3, significantly lower middle temporal gyrus thickness, insular surface area, and thalamic volume and higher volume in the nucleus accumbens were observed in Recent-SA. This pattern of structural abnormalities may underlie pain and emotion dysregulation, which have been linked to the transition from suicidal thoughts to action.

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

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

Sex-dependent grades of haematopoietic modulation in patients with major depressive episodes are associated with suicide attempts

Suicide is the leading cause of non-natural death worldwide, and major depressive disorder (MDD) is the mood disorder with the highest prevalence among individuals with suicidal behaviour (SB). The role of inflammation and immunomodulation in mood disorders has raised interest in recent years, as inflammation biomarkers have been reported to be increased in mood disorder patients, suggesting a role of inflammation in their pathogenesis. The influence of inflammation on the haematopoietic production is well known; however, a comprehensive study of the haematopoietic production in patients with major depressive episodes (MDE) is lacking. We examined global haematopoietic parameters from complete blood counts (CBC) of patients with MDE, in search of prognostic patterns. MDE patients presented differences in several CBC parameters, differences that were clearly pronounced and/or significant in concurrence with suicide attempts (SA). Red and white blood cell lineage parameters were affected, suggesting general haematopoietic modulation or imbalance. We observed distinct haematological parameter changes in women versus men, with men presenting milder alterations than women. Interestingly, we found that the List of Threatening Experiences (LTE) score, but not the Childhood Trauma Questionnaire (CTQ), was associated with the haematopoietic alterations observed exclusively in women and, more importantly, served as a parameter to stratify female MDE patients based on concurrence or non-concurrence with SA. In conclusion, grades of haematopoietic modulation in MDE patients are associated with absence or presence of SA. Haematopoietic manifestations differ between men and women and, in the latter, are markedly influenced by late, and not early, traumatic events.

Slower perception of time in depressed and suicidal patients

Effective suicide prevention is hindered by a limited understanding of the natural progression and neurobiology of the suicidal process. Our objective was to characterize the duration of the suicidal process and its relation to possible determinants: time judgment and cognitive impulsivity. In four groups of adults of both sexes including recent suicide attempters (n = 57), suicidal ideators (n = 131), non-suicidal depressed controls (n = 51) and healthy controls (n = 48) we examined time estimation and production, impulsivity and other cognitive variables. Duration of the suicidal process was recorded in suicide attempters. The suicide process duration, suicide contemplation and action intervals, had a bimodal distribution, ∼40% of attempters took less than 5 min from decision to attempt. Time slowing correlated negatively with the suicidal action interval (time from the decision to kill oneself to suicide attempt) (p = .003). Individuals with suicide contemplation interval shorter than three hours showed increased time slowing, measured as shorter time production at 35 s (p = .011) and 43 s (p = .036). Delay discounting for rewards correlated with time estimation at 25 min (p = .02) and 90 s (p = .01). Time slowing correlated positively with suicidal ideation severity, independently of depression severity (p < .001). Perception of time slowing may influence both the intensity and the duration of the suicidal process. Time slowing may initially be triggered by intense psychological pain, then worsen the perception of inescapability in suicidal patients.

Neutrophil-to-lymphocyte ratio: A potential new peripheral biomarker of suicidal behavior

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) have emerged as important peripheral inflammatory biomarkers. Recent data suggest a possible role of the immune system in the pathophysiology of suicidal behavior (SB). The aim of this study is to evaluate the association among NLR, MLR, and PLR and SB in patients with major depressive disorder (MDD), and to test its validity as a biomarker for suicidality.

METHODS

We evaluated 538 patients with MDD (mean age [standard deviation] = 43.87 [14.36] years; females: 68.8%). A logistic regression model was estimated to determine the independent factors associated with suicide risk in patients with and without a history of suicide attempt (SA).

RESULTS

Three hundred ninety-three patients (74.7%) had a personal history of SA. Patients with a previous SA were more frequently female (71.9% vs. 59.6%; p = 0.007), significantly younger (41.20 vs. 51.77 years; p < 0.001), had lower depression severity at enrolment (15.58 vs. 18.42; p < 0.000), and significantly higher mean NLR and PLR ratios (2.27 vs. 1.68, p = 0.001; 127.90 vs. 109.97, p = 0.007, respectively). In the final logistic regression model, after controlling for age, sex, and depression severity, NLR was significantly associated with SB (β = 0.489, p = 0.000; odds ratio [95% confidence intervals] = 1.631 [1.266-2.102]). We propose a cut-off value of NLR = 1.30 (sensitivity = 75% and specificity = 35%).

CONCLUSIONS

Our data suggest that NLR may be a valuable, reproducible, easily accessible, and cost-effective strategy to determine suicide risk in MDD.

Effects of chronic physical disease and systemic inflammation on suicide risk in patients with depression: a hospital-based case-control study

BACKGROUND

Few studies have examined the concurrent effects of physical disease and systemic inflammation on suicide risk in patients with depression. The authors investigated the independent contributions of chronic physical disease and systemic inflammation as indexed by C-reactive protein (CRP), on risk of suicide attempt.

METHODS

In this case-control study, 1468 cases of suicide attempters and 14 373 controls, both aged 18-65 years with a diagnosis of depression during 2011-2015, were identified from the hospital-wide database. Regression models were implemented to identify separate effects of physical diseases and systemic inflammation indexed by CRP, on risk of suicide attempt.

RESULTS

Compared with having no physical disease, having one, two, and three or more physical diseases was associated with a 3.6-, 6.4-, and 14.9-fold increase in odds of making a suicide attempt, respectively, after adjusting for age, sex, and race/ethnicity. In a sub-sample of cases and controls with available CRP values, patients with high CRP (>3 mg/L) had 1.9 times the odds of suicide attempt compared with patients with low CRP (<1 mg/L). This association was no longer significant when controlling for the effect of physical disease.

CONCLUSIONS

The presence of physical disease is an important risk factor for suicide attempt among patients with depression. Systemic inflammation is likewise associated with increased risk for suicide attempt, however, this association appears to be accounted for by the presence of physical disease among patients receiving care in a medical center setting. Healthcare providers should consider the risk of suicide attempt in depressed patients burdened with multiple comorbidities.

Examination of pain threshold and neuropeptides in patients with acute suicide risk

INTRODUCTION

One of the main challenges in suicide prevention is the limited understanding of the biological mechanisms underlying suicide. Recent findings suggest impairments in pain processing in acutely suicidal patients. However, little is known about the biological factors that may drive these discrete physiological abnormalities. In this study, we examined plasma peptides involved in analgesic and inflammatory responses and physical pain threshold in acutely suicidal patients.

METHODS

Thirty-seven depressed patients of both sexes hospitalized for severe suicidal ideation or a recent suicide attempt were characterized clinically including history of suicidal ideation and behavior. Psychological and physical pain, and pressure pain threshold was also measured. Plasma levels of β-endorphin, neurotensin, agouti-related protein (AgRP), C-reactive protein (CRP), adrenocorticotropic hormone (ACTH), and brain-derived neurotrophic factor (BDNF) were run in Milliplex multiplex assays.

RESULTS

The number of lifetime suicide attempts was positively correlated with β-endorphin (r = 0.702; p = 0.007), and neurotensin (r = 0.728, p = 0.007) plasma levels. Higher pain threshold was measured in the suicide attempt group as compared to the suicidal ideation group. Pain threshold was strongly and negatively associated with CRP plasma levels (r = -0.548; p < 0.001). In patients reporting chronic pain, lower AgRP levels and lower pain threshold were observed (t = 4.472; p = 0.001).

CONCLUSION

Our results suggest that abnormalities in the opioid and neurotensin systems may underlie the increase in pain threshold found in suicide attempters, and possibly risk for suicidal behavior. Targeting pain circuits and systems may provide therapeutic mechanisms for suicide prevention.

An inflammatory profile linked to increased suicide risk

BACKGROUND

Suicide risk assessments are often challenging for clinicians, and therefore, biological markers are warranted as guiding tools in these assessments. Suicidal patients display increased cytokine levels in peripheral blood, although the composite inflammatory profile in the subjects is still unknown. It is also not yet established whether certain inflammatory changes are specific to suicidal subjects. To address this, we measured 45 immunobiological factors in peripheral blood and identified the biological profiles associated with cross-diagnostic suicide risk and depression, respectively.

METHODS

Sixty-six women with mood and anxiety disorders underwent computerized adaptive testing for mental health, assessing depression and suicide risk. Weighted correlation network analysis was used to uncover system level associations between suicide risk, depression, and the immunobiological factors in plasma. Secondary regression models were used to establish the sensitivity of the results to potential confounders, including age, body mass index (BMI), treatment and symptoms of depression and anxiety.

RESULTS

The biological profile of patients assessed to be at increased suicide risk differed from that associated with depression. At the system level, a biological cluster containing increased levels of interleukin-6, lymphocytes, monocytes, white blood cell count and polymorphonuclear leukocyte count significantly impacted suicide risk, with the latter two inferring the strongest influence. The cytokine interleukin-8 was independently and negatively associated with increased suicide risk. The results remained after adjusting for confounders.

LIMITATIONS

This study is cross-sectional and not designed to prove causality.

DISCUSSION

A unique immunobiological profile was linked to increased suicide risk. The profile was different from that observed in patients with depressive symptoms, and indicates that granulocyte mediated biological mechanisms could be activated in patients at risk for suicide.

Self-criticism, interpersonal conditions, and biosystemic inflammation in suicidal thoughts and behaviors within mood disorders: A bio-cognitive-interpersonal hypothesis

We review the theoretical and empirical literature on the role of self-concept in suicidal behavior in the context of mood disorders (i.e., unipolar depression and bipolar spectrum disorders). The main themes emanating from this review are then juxtaposed against (a) the Interpersonal-Psychological Theory of Suicide and (b) biological research on the role of inflammatory processes in suicidality. Such a juxtaposition paves the way for a bio-cognitive-interpersonal hypothesis. Pathologies of the self-concept-primarily self-criticism-propel mood disorder sufferers to generate interpersonal stress that culminates in two proximal causes of suicidality: thwarted belongingness and perceived burdensomeness. In turn, these two interpersonal conditions set in motion systemic biosystemic inflammation, serving as a proximal cause for suicidality in mood disorders. We conclude by describing a research project aimed at testing this hypothesis, and by outlining pertinent implications for assessment, treatment, and prevention.

Prevalence and correlates of low-grade systemic inflammation in adult psychiatric inpatients: An electronic health record-based study

Low-grade inflammation is a risk factor for depression, psychosis and other major psychiatric disorders. It is associated with poor response to antidepressant and antipsychotics, and could potentially be a treatment target. However, there is limited data on the prevalence of low-grade inflammation in major psychiatric disorders, and on the characteristics of patients who show evidence of inflammation. We examined the prevalence of low-grade inflammation and associated socio-demographic and clinical factors in acute psychiatric inpatients. An anonymised search of the electronic patient records of Cambridgeshire and Peterborough NHS Foundation Trust was used to identify patients aged 18-65 years who were hospitalised between 2013 and 2016 (inclusive). We excluded patients on antibiotics or oral steroids, or with missing data. Inflammation was defined using serum C-reactive protein (>3 mg/L) or total white cell count (>9.4 × 10⁹/L) as measured within 14 days of admission. Out of all 599 admissions, the prevalence of inflammation (serum CRP >3 mg/L) in the ICD-10 diagnostic groups of psychotic disorders (F20-29), mood disorders (F30-39), neurotic disorders (F40-48) and personality disorders (F60-69) was 32%, 21%, 22% and 42%, respectively. In multivariable analyses, low-grade inflammation was associated with older age, black ethnicity, being single, self-harm, diagnoses of schizophrenia, bipolar disorder, current treatments with antidepressants, benzodiazepines, and with current treatment for medical comorbidities. A notable proportion of acutely unwell psychiatric patients from all ICD-10 major diagnostic groups show evidence of low-grade inflammation, suggesting inflammation may be relevant for all psychiatric disorders.

A probe in the connection between inflammation, cognition and suicide

BACKGROUND

Increased inflammation is linked to suicide risk. However, it is unclear whether increased inflammation drives suicidal crises or is a trait associated with lifetime suicidal behavior. Limited data exist on the sources of increased inflammation observed in suicidal patients and on its downstream effects.

AIMS

To examine factors associated with inflammation and with suicidal ideation severity in acutely suicidal depressed patients.

METHODS

Fifty-two adult depressed patients of both sexes hospitalized for severe suicidal ideation were characterized for suicidality, depression, anxiety, medical comorbidity, psychological and physical pain, impulsivity, verbal fluency, C-reactive protein (CRP) and interleukin (IL) 6. Two generalized linear models were performed with either CRP or suicidal ideation severity as dependent variables.

RESULTS

CRP levels were positively associated with age, body mass index (BMI), IL6, current physical pain and number of lifetime suicide attempts. Suicidal ideation severity was not significantly correlated with either CRP or IL6. Suicidal ideation severity was positively associated with female sex, presence of an anxiety disorder, current physical pain, number of lifetime suicide attempts and with delay discounting for medium and large losses.

CONCLUSIONS

Increased inflammation is not associated with acute suicidal risk, but seems to represent a trait associated with lifetime suicidal behavior.

The connections among suicidal behavior, lipid profile and low-grade inflammation in patients with major depressive disorder: a specific relationship with the neutrophil-to-lymphocyte ratio

OBJECTIVES

The role of inflammation and lipid metabolism in the pathophysiology of suicidal behavior has received particular attention in recent years. The neutrophil-to-lymphocyte ratio (NLR) has been suggested as a new and more reliable indicator of low-grade inflammation. NLR has been found to be altered in major depressive disorder (MDD) and has been related to various factors, including chronic stress and impulsivity that were previously reported to be related to suicidal behavior. We aimed to explore the roles of NLR, C-reactive protein (CRP) and serum lipid levels on suicidal behavior in patients with MDD.

METHODS

The study group consisted of 139 inpatients diagnosed with MDD [37 suicide attempters (SA); 102 suicide non-attempters (NSA)], 50 healthy controls and matched according to age, gender and education. NLR, PLR, CRP and lipid values were obtained from digital inpatient records.

RESULTS

CRP levels and NLR were substantially higher in patients with SA than in subjects with NSA and healthy comparison subjects after adjusting the confounding factors. The logistic regression included two predictive variables for suicide status in patients with depressive disorder (A) previous suicidal history; (B) NLR.

CONCLUSIONS

This is the first study suggesting that NLR may be a trait marker for suicidal vulnerability via a relationship between NLR and a recent suicide attempt in depressed inpatients. Future prospective studies are needed to determine the exact roles of NLR, and other inflammatory markers on suicidality in MDD.

Association between high sensitivity CRP and suicidal ideation in the Korean general population

Inflammation has been linked with a potential critical role in suicide. The purpose of this study is to examine the relation of CRP with suicidal behavior in the Korean population. We conducted a cross-sectional study in 4693 Korean adults aged 20-81 years who participated in the 2015 Korea National Health and Nutrition Examination Survey. High sensitivity CRP levels were measured by immunoturbidimetric method. Suicidal ideation and suicide attempt were assessed by using a questionnaire. Data were analyzed in 2017. Multiple logistic regression analysis was used to compute odds ratios (ORs) and 95% confidence intervals (CIs). The prevalence of suicidal ideation was 4.9% and that of suicide attempt was 0.4%. Suicidal ideation was more prevalent in the highest compared with the lowest serum CRP quartile (OR, 1.79; 95% CI, 1.11-2.89) after adjustment for age, sex, household income, educational level, marital status, employment status, alcohol dependency, current smoking, physical activity, BMI, sleep duration, number of chronic diseases, restriction on activity, subjective health status, perceived stress, depression and depressive mood (p for trend<0.05). In conclusion, elevated levels of CRP were associated with an increased risk of suicidal ideation among South Korean adults.

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

PURPOSE OF REVIEW

The rising suicide rate in the USA will not be reversed without improved risk assessment and prevention practices. To date, the best method for clinicians to assess a patient's risk for suicide is screening for past suicide attempts in the patient and their family. However, neuroimaging, genomic, and biochemical studies have generated a body of findings that allow description of an initial heuristic biological model for suicidal behavior that may have predictive value.

RECENT FINDINGS

We review studies from the past 3 years examining potential biological predictors of suicide attempt behavior. We divide findings into two major categories: (1) structural and functional brain imaging findings and (2) biochemical and genomic findings encompassing several systems, including major neurotransmitters (serotonin, catecholamines, GABA, and glutamate), the hypothalamic pituitary adrenal (HPA) axis, the inflammasome, lipids, and neuroplasticity. The biomarkers that appear promising for assessing suicide risk in clinical settings include indices of serotonergic function, inflammation, neuronal plasticity, and lipids.