CSF 5-HIAA and DST non-suppression -independent biomarkers in suicide attempters?

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.

Plasma Apolipoprotein-AIV Downregulated in Patients with Major Depressive Disorder having Suicidal Ideation Compared to those without Suicidal Ideation

Background:

Identification of a peripheral biological marker might aid in identifying patients at high risk of attempting suicide and might help in effective early intervention.

Objective:

In the present study, we extend the findings of our previous multidimensional proteomics study by examining the levels of plasma Apolipoprotein-AIV in patients diagnosed with major depression with and without suicidal ideation compared to age and gender-matched controls.

Methods:

Using the mass spectrometry platform, we quantified the levels of plasma Apolipoprotein-AIV in patients with major depressive disorder with and without suicidal ideation compared to matched controls with isotope-labelled peptides-based quantitative proteomics approach.

Results:

The targeted quantitative proteomics approach with isotope-labelled peptides showed that plasma Apolipoprotein-AIV was significantly downregulated in depressed patients having suicidal ideation 1.45 (CI:1.11–1.90) compared to those without suicidal ideation 0.88 (CI:0.77–1.003).

Conclusion:

These findings extend our earlier observation of downregulation of plasma Apolipoprotein-AIV in patients with suicidal attempts to depressed patients with suicidal ideation. The consistent downregulation of plasma Apolipoprotein-AIV observed in both the proteomics studies suggests Apolipoprotein-AIV might be a plasma-based biomarker for suicidal behaviour.

The effect of oral dexamethasone administration on testosterone levels in combat veterans with or without a history of suicide attempt

Combat exposure has been linked to increased risk of suicidal ideation, suicide attempts, and death by suicide, and suicidality has been linked with altered testosterone levels. In this study, we examined morning baseline free and total testosterone levels and the effect of dexamethasone administration on testosterone levels in male combat veterans with or without a history of suicide attempt. Demographic and clinical parameters of the study participants were assessed and recorded. Blood samples were collected between 8:00 and 8:30 a.m. on the day prior to and following dexamethasone (0.5 mg) ingestion. Suicide attempters had higher schedule for suicidal ideation (SSI) scores in comparison to non-attempters. Baseline free and total testosterone levels were lower in suicide attempters compared to non-attempters. In the whole sample, both baseline free and total testosterone levels negatively correlated with SSI scores. Free testosterone levels decreased after dexamethasone administration among non-attempters but not among attempters. Free testosterone post-dexamethasone levels positively correlated with aggression scores among non-attempters but not among suicide attempters. Our findings indicate that there are substantial differences in the testosterone regulation between combat veterans with or without a history of suicide attempt. Studies of the relation between the testosterone function and suicidal behavior among combat veterans may lead to improvement in detection of suicidality and finding new pharmacological targets for prevention of suicide among veterans.

Serum endocannabinoid levels in suicide attempters: A pilot study

The search for a biomarker for suicide risk is a longstanding pursuit in clinical psychiatry. Literature addressing the role of endocannabinoids in suicide attempters (SA) is sparse. This cross-sectional study is aimed at comparing 8 AM serum concentrations of 4 endogenous cannabinoids (anandamide, AEA; 2-arachidonoylglycerol, 2-AG; N-palmitoiletanolamida, PEA; and oleoylethanolamide, OEA) in 30 suicide attempters (SA) and 12 psychiatric controls (PC). 8 AM AEA and PEA serum levels were higher in SA compared to PC without controlling for cannabis use (n = 42) (3.58 ± 5.77 vs. 1.62 ± 2.49, F = 3.04, P = 0.089; and 3.31 ± 4.82 vs. 1.21 ± 1.20, F = 6.22, p = 0.017, respectively). Serum ACTH was higher in PC compared to SA (32.11 ± 21.60 vs. 20.05 ± 9.96, F = 9.031, p = 0.0.005). After controlling for cannabis use in the urine test (n = 28), 8 AM AEA and PEA serum levels remained higher in SA compared to PC (4.57 ± 6.38 vs. 0.64 ± 1.11, F = 4.852, P = 0.037; and 4.35 ± 5.46 vs. 1.21 ± 1.25, F = 4.125, p = 0.053, respectively). The present study offers preliminary evidence about the role of AEA and PEA in suicidal behavior (SB). Furthermore, in the context of the mental pain model of SB, our findings suggest that some endocannabinoids may play a role in the pathophysiology of SB. Our pilot study deserves replication by other studies with bigger sample sizes.

Serum β-endorphin levels are associated with addiction to suicidal behavior: A pilot study

The literature provides partial support for the hypothesis that some suicide attempters develop a behavioral addiction to suicidal behavior (SB). We hypothesized that major suicide repeaters (MR) (≥5 lifetime suicide attempts) are addicted to suicide attempts as measured by modified DSM-IV criteria for substance dependence. In this cross-sectional study with 13 psychiatric controls (PC), 55 non-major suicide attempters (NMR), and 9 MR we found that MR are characterized by emotional abuse and neglect, as well as higher scores on the Personality and Life Event scale (short version). The levels of 8 AM serum ACTH, cortisol and β-endorphin were elevated in all three groups. Serum β-endorphin (pg/mL) was particularly high in PC diagnosed with schizophrenia 220.34 (±56.30). The level of 8 AM serum β-endorphin rose with increased numbers of criteria met for addiction to SB from 130.31 (±88.16) (≥ 3 criteria met for addiction to SB) to 174.84 (±114.93) (≥ 6 criteria met for addiction to SB) whereas serum ACTH and cortisol did not change. SB addicts (≥ 6 criteria) displayed higher serum β-endorphin concentrations than non-addicts (174.84 ± 114.93 vs. 116.93 ± 61.70, FET p = 0.09). The present study brings some support to the addictive hypothesis of SB. Our results delineate β-endorphin as a promising biomarker of SB addiction, and offer a good basis for future studies that test whether buprenorphine can be used to prevent repetitive suicide attempts, non-suicidal-self-injury (NSSI), and the development of an addiction to SB.

Leptin, Anxiety Symptoms, and Hypothalamic-Pituitary-Adrenal Axis Activity among Drug-Free, Female Suicide Attempters

BACKGROUND

Dysregulation of leptin secretion and functioning of the hypothalamic-pituitary-adrenal (HPA) axis may be involved in the pathophysiology of suicide. Preclinical and clinical studies have shown interactions between the HPA axis and leptin. There is also evidence for a negative relationship between leptin and anxiety in humans. However, these possible associations have not been studied in individuals with attempted suicide.

OBJECTIVES

To examine the relationship between leptin, HPA axis activity, and anxiety in individuals with a recent suicide attempt.

METHOD

Sixty-nine individuals with a recent suicide attempt (n = 37 females; n = 32 males) were recruited and subjected to the Dexamethasone Suppression Test (DST), lumbar puncture, and evaluation with the Comprehensive Psychopathological Rating Scale from which the Brief Scale for Anxiety (BSA) was derived. Leptin was analyzed in cerebrospinal fluid (CSF) and cortisol in serum. Leptin was corrected for body mass index (BMI) by dividing CSF-leptin by BMI (CSF-leptin/BMI). Due to gender-related differences in leptin secretion and HPA axis activity, calculations were made for males and females separately.

RESULTS

Significant differences were only found among females; CSF-leptin/BMI levels correlated significantly and negatively with BSA (p < 0.05), pre-DST cortisol, and post-DST serum cortisol at 8 a.m. and 3 p.m. (all p < 0.05). Furthermore, CSF-leptin/BMI was significantly lower in nonsuppressors of dexamethasone as compared to suppressors (p < 0.05).

CONCLUSIONS

These findings suggest that in females with a recent suicide attempt, low CSF leptin may be related to symptoms of anxiety and a hyperactive HPA axis.

Dexamethasone Suppression Test May Predict More Severe/Violent Suicidal Behavior

INTRODUCTION

Several studies demonstrated that the hypothalamic-pituitary-adrenal (HPA) axis is dysregulated in suicide attempters. Prospective studies found that people with an abnormal response at the dexamethasone suppression test (DST) are more likely to commit suicide. However, whether DST may predict suicide attempts remains less clear. A possible strategy to address this question is to consider the suicide attempt lethality.

OBJECTIVES

(1) To compare the pre- and post-DST cortisol levels in serious/violent suicide attempters and in non-serious/non-violent suicide attempters, and (2) to investigate whether cortisol level can predict new suicide attempts or their lethality.

METHODS

The study included 70 recent suicide attempters (25 with a serious or violent attempt) who were followed for two years. Three saliva samples for cortisol measurement were obtained at 8a.m., 3p.m., and 9p.m. before the DST (pre-DST). Then, at 11 p.m., 1 mg of dexamethasone was given orally. The following day (post-DST), three saliva samples were collected at the same hours as before. The post-DST-pre-DST salivary cortisol Δ index was calculated for each collection time. The Risk-Rescue Ratio Scale (RRRS) and the Suicidal Intent Scale (SIS) were used to characterize the suicide attempt at inclusion and those occurring during the follow-up.

RESULTS

Post-DST cortisol level at 9 p.m. was higher in patients with an initial violent or serious suicide attempt than in non-violent/non-serious attempters (p < .010). Higher post-DST cortisol at 9p.m. was associated with lower RRRS rescue score and higher clinical impression of suicide severity at inclusion. Among the 66 patients who completed the follow-up, 26 attempted suicide again at least once. Higher pre-DST cortisol at 8a.m. predicted new suicide attempts during the follow-up (OR = 2.15 [1.11, 4.15]), and higher cortisol Δ index at 9p.m. was associated with higher suicide intent during the follow-up.

CONCLUSIONS

Our results suggest that HPA axis hyper-reactivity monitored with the DST is a marker of violent/serious suicide attempt with lower rescue possibility. Furthermore, higher changes between pre-DST and post-DST cortisol levels may predict higher suicide intent. These findings might help to characterize the biological features of nearest suicide phenotypes.

Association of polymorphisms in HTR2A, TPH1, and TPH2 genes with attempted suicide in rural China

OBJECTIVE

We aimed to test the association of polymorphisms in HTR2A, TPH1, and TPH2 genes with attempted suicide in rural China.

PARTICIPANTS AND METHODS

On the basis of a case-control study, we recruited 1200 pairs of participants from Shandong Province, China. The blood samples of 712 suicide attempters and 739 nonsuicide attempters were collected finally. We tested seven single nucleotide polymorphisms: rs6313 and rs6311 in HTR2A, rs4537731, rs1800532, and rs1799913 in TPH1, and rs4448731 and rs4641527 in TPH2.

RESULTS

In univariate analysis, allele C of rs4537731 was associated negatively with attempted suicide among total and male samples; however, the association was not statistically significant in multivariate analysis after adjusting for other potential confounding factors. No association between other six single nucleotide polymorphisms and attempted suicide was found in the total, male, or female samples.

CONCLUSION

This study did not support the effect of these seven serotonergic gene polymorphisms on attempted suicide in rural China.

Research on potential biomarker correlates for suicidal behavior: A review

Suicide is a world health priority. Studies over the last few decades have revealed the complexity underlying the neurobiological mechanisms of suicide. Researchers have found dysregulations in the serotonergic system, the stress system, neural plasticity, lipid metabolism, and cell signaling pathways in relation to suicidal behaviors. These findings have provided more insight into the final path leading to suicide, at which medical intervention should be applied to prevent the action. However, because these molecular mechanisms have been implicated in both depression and suicide, the specificity of the mechanisms has been obscured. In this review, we summarize the main findings of studies on molecular mechanisms of suicidal behavior from the last 2 decades, with particular emphasis on the potential, independent role of each mechanism that is not contingent upon an underlying psychopathology, such as depression. The act of suicide is multifactorial; no single molecular mechanism is sufficient to fully account for the act. Knowledge of the reciprocal interactions among these molecular mechanisms and studying them in the context of brain circuitry by using neuroimaging techniques will provide a better understanding of the neurobiology of suicide.

Association, haplotype, and gene-gene interactions of the HPA axis genes with suicidal behaviour in affective disorders

Family twin and adoption studies have noted the heritability of specific biological factors that influence suicidal behaviour. Exposure to stress is one of the factors that strongly contribute to suicide attempts. The biological response to stress involves the hypothalamic-pituitary-adrenal axis (HPA). Therefore, we found it interesting to study polymorphisms of genes involved in the HPA axis (CRHR1, NR3C1, and AVPBR1). The study was performed on 597 patients, 225 of whom had a history of suicide attempts. We did not observe any significant differences in the studied polymorphisms between the group of patients with a history of suicide attempts and the control subjects. Our haplotype analysis of the AVPR1b gene revealed an association between the GCA haplotype and suicide attempts; however, this association was not significant after correcting for multiple testing. We did not observe any other association in haplotype and MDR analysis. We report here a comprehensive analysis of the HPA axis genes and a lack of association for genetic variations regarding the risk of suicide attempts in affective disorder patients. Nonetheless, the inconsistencies with the previously published results indicate the importance of the further investigation of these polymorphisms with respect to the risk of suicide attempts.

Biological indicators of suicide risk in youth with mood disorders: what do we know so far?

Suicidal behaviour in youth is a major public health concern worldwide, and youth in the early stages of a primary mood disorder are an identifiable high-risk population. Neurobiological research in youth at risk for suicidality has sought to investigate the most promising parameters from research in adults. The present paper provides an overview of the current findings of neurobiological research in children and adolescents with mood disorders and suicidality including genetic/epigenetic findings, neuro-hormonal and immunological investigations. Longitudinal research in high-risk youth is a powerful way to investigate the influences and their pathways in determining suicidal risk in the context of a developing mood disorder. In the meantime, there are clear clinical indicators of risk to help identify youth who would benefit from close surveillance and early intervention.

Does perceived burdensomeness erode meaning in life among older adults?

BACKGROUND

Identification of risk factors for the loss of meaning in life among older adults is needed. In this article, we test hypotheses derived from the Interpersonal Theory of Suicide concerning the role of perceptions that one is a burden on others as a risk factor for lower meaning in life.

METHODS

A prospective design was used to examine the temporal associations between perceptions of burdensomeness on others and perceived meaning in life among older adults (n=65) seeking mental health treatment (primarily for depression and/or anxiety) at an outpatient geriatric mental health clinic. Participants completed self-report questionnaires within a month following intake. Follow-up questionnaires were completed over the phone two months later.

RESULTS

Perceived burdensomeness predicted lack of meaning in life two months later, while accounting for depression severity. In contrast, baseline levels of meaning in life did not significantly predict the levels of burdensomeness at two months.

CONCLUSION

The findings suggest that burdensomeness may contribute to suicide morbidity and mortality in late-life by eroding meaning in life. Empirically supported treatments for late-life depression could be adapted to focus on perceptions of burdensomeness and its connections with meaning in life.

Suicidality and epilepsy: a neuropsychobiological perspective

People with epilepsy (PWE) are at increased risk of experiencing suicidal ideation, displaying suicidal behavior, and committing suicide than the general population. The relationship between suicidality and epilepsy is complex and multifactorial in which operant pathogenic mechanisms include epilepsy-related variables, personal and familial psychiatric history, and iatrogenic effects. Furthermore, a bidirectional relationship between suicidality and epilepsy has suggested the existence of common neurobiological pathogenic mechanisms operant in both conditions and including disturbances of several neurotransmitters, in particular, serotonin (5HT), norepinephrine (NE), glutamate (GTE), and γ-aminobutyric acid (GABA), and disturbances of the hypothalamic-pituitary-adrenal axis (HPAA), which, in turn, can result in abnormal secretion of some of these neurotransmitters. The purpose of this article is to review these common neurobiological pathogenic mechanisms.

Potential peripheral biological predictors of suicidal behavior in major depressive disorder

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

The hypothalamic-pituitary-adrenal axis and serotonin abnormalities: a selective overview for the implications of suicide prevention

Suicidal behavior and mood disorders are one of the world's largest public health problems. The biological vulnerability for these problems includes genetic factors involved in the regulation of the serotonergic system and stress system. The hypothalamic-pituitary-adrenal (HPA) axis is a neuroendocrine system that regulates the body's response to stress and has complex interactions with brain serotonergic, noradrenergic and dopaminergic systems. Corticotropin-releasing hormone and vasopressin act synergistically to stimulate the secretion of ACTH that stimulates the biosynthesis of corticosteroids such as cortisol from cholesterol. Cortisol is a major stress hormone and has effects on many tissues, including on mineralocorticoid receptors and glucocorticoid receptors in the brain. Glucocorticoids produce behavioral changes, and one important target of glucocorticoids is the hypothalamus, which is a major controlling center of the HPA axis. Stress plays a major role in the various pathophysiological processes associated with mood disorders and suicidal behavior. Serotonergic dysfunction is a well-established substrate for mood disorders and suicidal behavior. Corticosteroids may play an important role in the relationship between stress, mood changes and perhaps suicidal behavior by interacting with 5-HT1A receptors. Abnormalities in the HPA axis in response to increased levels of stress are found to be associated with a dysregulation in the serotonergic system, both in subjects with mood disorders and those who engage in suicidal behavior. HPA over-activity may be a good predictor of mood disorders and perhaps suicidal behavior via abnormalities in the serotonergic system.

CSF 5-HIAA and DST non-suppression--orthogonal biologic risk factors for suicide in male mood disorder inpatients

Two biomarkers of suicide risk; non-suppression in the dexamethasone suppression test (DST) and low 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF) have been reported to be predictors of suicide in mood disorders. The interrelation of the two systems seems to be different in suicide attempters compared with depressed inpatients who have not made a suicide attempt, indicating that the two biomarkers may be seen as independent. This investigation examined the interrelation of low CSF 5-HIAA and DST non-suppression in suicide victims with mood disorder. Fifty-eight mood disorder inpatients not receiving any treatment with antidepressants underwent lumbar puncture and the DST. Plasma cortisol levels at 8:00 a.m., 4:00 p.m. and 11:00 p.m. were analysed in relation to CSF 5-HIAA. All patients were followed up for causes of death and suicides were verified with death certificates. During follow-up (mean 21 years), 11 (19%) patients had committed suicide. In male suicide victims (n=6), the serum cortisol level at 4:00 p.m. showed a significant positive correlation with CSF 5-HIAA. Low CSF 5-HIAA predicted all early suicides (within 1 year), whereas all males who committed suicide after 1 year were DST non-suppressors. In female suicide victims (n=5), the post-DST serum cortisol did not correlate with CSF 5-HIAA. Low CSF 5-HIAA and DST non-suppression are orthogonal biologic risk factors for suicide in male mood disorder inpatients. CSF 5-HIAA is associated with short-term suicide risk; dysregulation of the hypothalamic-pituitary-adrenal axis seems to be a long-term suicide predictor.