Differentiating suicide attempts and suicidal ideation using neural markers of emotion regulation

Pain tolerance and threshold in suicide attempters: A systematic review and meta-analysis

It has been hypothesized that individuals less sensitive to pain could be at higher risk of suicide. However, data on pain sensitivity in suicide attempters (SA) obtained using experimental procedures are heterogeneous. The aim of this systematic review and meta-analysis was to investigate and compare pain tolerance and threshold in SA (patients with lifetime history of suicide attempt), non-attempters (psychiatric controls, PC), and healthy controls (HC). A random effects meta-analysis was used to estimate the standardized mean differences using data from 16 studies that compared physical pain tolerance and threshold in SA and PC or HC. Pain tolerance and threshold were not significantly different in SA and PC. However, pain tolerance, but not threshold, was higher in SA than HC. Our findings do not support the hypothesis of an altered pain perception related as a trait for suicidal vulnerability, but rather suggest altered pain perception related to psychiatric vulnerability.

The interactive effects of AS and trauma exposure on suicide capability and suicide risk

BACKGROUND

Trauma exposure has been linked with heightened suicide risk purportedly through habituation to threatening stimuli, thereby reducing fear of suicide. However, no research has examined variables that may influence this process. Anxiety sensitivity (AS) is one cognitive-affective factor that may strengthen the relationship between trauma exposure and reduced fear of suicide by amplifying traumatic reactivity. The present study evaluated this by examining the interaction of AS and trauma exposure type (e.g., direct vs. witnessed) predicting fear of suicide and self-reported suicide risk.

METHODS

Participants (n = 124) were recruited for a long-term (∼3-4 years) follow-up after participation in a clinical trial targeting suicide risk factors and were asked to complete self-report measures of trauma history, AS, fear of suicide, and suicide risk.

RESULTS

Significant interactions emerged such that a greater number of direct traumasexperienced predicted lower fear of suicide and greater suicide risk among those with greater AS. The interactive effect of witnessed traumas and AS predicting suicidality was insignificant. Results remained even after including relevant covariates.

DISCUSSION

The current findings suggest that AS augments the effects of repeated trauma exposure on fear of suicide and suicide risk. It is plausible these painful and provocative events are more potent among those with high AS due to the amplification of traumatic affective responses, though future research examining the longitudinal relations is needed to confirm this process.

Reward-related neural dysfunction in youth with a history of suicidal ideation: The importance of temporal predictability

Abnormal reward processing is an important yet understudied risk factor for suicide. Recent neuroimaging studies have found that suicidality is associated with abnormal reward-related neural reactivity and connectivity across a wide range of brain regions and circuits. The varying, and oftentimes discrepant, findings have hindered progress in elucidating the neurobiological link between reward processing dysfunction and suicide risk. Some of this variability is likely related to different reward-related paradigms that are utilized across studies. The primary aim of the current study was to address these issues by comparing neural reactivity between youth with and without a history of suicidal ideation during direct manipulation of reward parameters. A total of 108 unmedicated youth, ages 17-19, were classified into two groups: 1) history of suicidal ideation (n = 39) and 2) no history of suicidal ideation (n = 69). All participants completed a novel reward anticipation task probing anticipation of predictable (P-reward) and unpredictable (U-reward) monetary reward. Results revealed that compared with controls, youth with a history of suicidal ideation exhibited increased neural activation in the dorsal anterior cingulate cortex (dACC) and right anterior insula (aINS) during anticipation of U-reward. There were no group differences during anticipation of P-reward. These findings suggest that propensity for suicidal ideation may be related to specific abnormalities during anticipation of U-reward, but not P-reward.

Reduced working memory performance in PTSD and suicide among veterans presenting for treatment

Suicide is among the leading causes of death in the United States, underscoring the continued need to understand the mechanisms underlying suicide risk. A growing body of research has examined the role of working memory deficits in suicidal thoughts and behaviors (STBs), yet little research has evaluated putative pathways via which working memory impairments may heighten suicide risk. Elevated posttraumatic stress symptoms (PTSS) represent one plausible mechanism through which poor working memory performance may increase STBs. The present study utilized data from 140 treatment-seeking veterans who presented for an intake evaluation in the PTSD Clinical Team of a large VA Medical Center. Veterans completed self-report measures, a semi-structured PTSD evaluation, and a digit span working memory test. In addition to concurrent suicidal ideation assessed during the intake, additional information regarding past suicide attempts, presence of a safety plan, documentation of past suicidal behaviors, and engagement with suicide crisis lines were collected via electronic medical records. Consistent with hypotheses, a significant indirect path emerged such that poor working memory performance predicted greater suicidal ideation, greater likelihood of a past suicide attempt, and greater latent suicide risk via increased PTSS. However, no direct effect of working memory on STBs or indirect paths of PTSS on STBs via working memory emerged. These findings suggest that the relation between working memory and STBs may be explained by PTSS severity.

Self-injurious thoughts and behaviors and alterations in positive valence systems: A systematic review of the literature

Self-injurious thoughts and behaviors (SITBs), which include suicidal ideation (SI), suicide attempts (SA), and nonsuicidal self-injury (NSSI), are prevalent and associated with impairments in functioning and elevated risk of suicide deaths. Preventing suicide is a complex problem, with numerous systems likely contributing to the onset and maintenance of SITBs, and there is a critical need to identify more precise predictors of risk. Positive valence systems (PVS) are an understudied domain with promise for improving understanding of risk processes underlying SITBs. In this systematic review, we evaluate the evidence for the potential role of altered PVS function in SI, SA, and/or NSSI, including alterations in reward responsiveness, learning, and valuation assessed through behavioral, physiological and circuit measures. Results provide preliminary support for associations between distinct aspects of PVS function and alterations in SITBs. Specifically, SI appears to be characterized by low reward responsiveness, whereas little research has examined reward responsiveness in SA, and NSSI has been characterized by hyper-responsiveness to rewards. Alterations in reward learning and valuation are commonly examined in SA, with some evidence that they may be more strongly associated with attempts than SI or NSSI. At the same time, the literature is limited in that some constructs are commonly examined in one form of SITBs but not others. Further, research is predominantly cross-sectional and focused on adults, raising questions about the role of PVS function in developmental pathways to SITBs. We conclude by integrating the research to date and highlighting promising directions for future research.

Phenome-wide screening of the putative causal determinants of depression using genetic data

Depression is one of the most common mental health disorders and one of the top causes of disability throughout the world. The present study sought to identify putative causal associations between depression and hundreds of complex human traits through a genome-wide screening of genetic data and a hypothesis-free approach. We leveraged genome-wide association studies (GWAS) summary statistics for depression and 1504 complex traits and investigated potential causal relationships using the latent causal variable method. We identified 559 traits genetically correlated with depression risk at FDR < 5%. Of these, 46 were putative causal genetic determinants of depression, including lifestyle factors, diseases of the nervous system, respiratory disorders, diseases of the musculoskeletal system, traits related to the health of the gastrointestinal system, obesity, vitamin D levels, and the use of prescription medications, among others. No phenotypes were identified as potential outcomes of depression. Our results suggest that genetic liability to multiple complex traits may contribute to a higher risk for depression. In particular, we show a putative causal genetic effect of pain, obesity, and inflammation on depression. These findings provide novel insights into the potential causal determinants of depression and should be interpreted as testable hypotheses for future studies to confirm, which may facilitate the design of new prevention strategies to reduce depression's burden.

Electrophysiological Changes Between Patients With Suicidal Ideation and Suicide Attempts: An Event-Related Potential Study

INTRODUCTION

Inhibitory control is regarded as an important ability related to the transition from suicidal ideation to suicide attempts. In event-related potential, patients with dysfunction of inhibitory control demonstrate a reduction in the no-go amplitude. This study aimed to determine the association between the no-go event-related potential component and suicidal behaviors among suicide attempters and ideators who never attempted suicide.

METHODS

Overall, 150 patients who visited the emergency room by suicide attempts or patients who visited the psychiatric department with suicidal ideation were recruited and instructed to perform a go/no-go task during electroencephalography recording. The Beck Depression Inventory, Beck Anxiety Inventory, Barratt Impulsivity Scale, Difficulties in Emotional Regulation Scale, and Acquired Capability for Suicide Scale were used. Individuals were divided into two groups: those with suicide attempt group) and with suicidal ideation (SI group) without SA. The psychological characteristics and event-related potentials of the two groups were compared. Correlation analyses were conducted to test the association between the clinical characteristics and event-related potentials.

RESULTS

The SA group had significantly decreased no-go P3 amplitudes at all electrodes compared to the SI group. In the correlation analysis between the clinical measurements and event-related potentials in all the participants, no-go P3 amplitudes in whole electrode sites were negatively correlated with the scores of the acquired capability for the suicide scale.

CONCLUSIONS

This study revealed that suicide attempters have dysfunction in controlling inhibition compared to suicide ideators reflected in the no-go P3. Our findings suggested that no-go P3 can be a biomarker associated suicide attempts in suicide ideators.

Thwarted belongingness predicts greater neural reactivity to a novel social exclusion image set: Evidence from the late positive potential

INTRODUCTION

Thwarted belongingness (TB) is among the most well-researched risk factors for suicidal ideation (SI). Yet, there is little research examining neural mechanisms underlying this construct. The present study used a novel social exclusion image set in concert with the late positive potential (LPP) to test the role of neural reactivity social exclusion in TB and SI.

METHODS

Participants (n = 243) were recruited based on elevated suicide risk and completed an emotional picture viewing task. The LPP was used to index neural reactivity to a novel set of social exclusion images and international affective picture system (IAPS) neutral, positive, and negative images.

RESULTS

Greater TB predicted a larger social exclusion ΔLPP (social exclusion LPP relative to neutral LPP) and social exclusion LPP even when accounting for SI, biological sex, age, negative affect, and perceived burdensomeness. Moreover, the social exclusion LPP was uniquely related to TB beyond the LPP to other images. Last, a larger social exclusion LPP predicted greater SI via elevations in TB.

CONCLUSION

Reactivity to social exclusion stimuli may play an important role in SI via elevated TB, but not perceived burdensomeness. Future research should further explore the neural mechanisms underlying other IPT constructs.

Suicidal thoughts, behaviors, and event-related potentials: A systematic review and meta-analysis

Suicidal thoughts and behaviors (STBs) are thought to result from, at least in part, abnormalities in various neural systems. Event-related potentials (ERPs) are a useful method for studying neural activity and can be leveraged to study neural deficits related to STBs; however, it is unknown how effective ERPs are at differentiating various STB groups. The present meta-analysis examined how well ERPs can differentiate (a) those with and without suicidal ideation, (b) those with and without suicide attempts, (c) those with different levels of suicide risk, and (d) differences between those with suicide attempts versus those with suicidal ideation only. This meta-analysis included 208 effect sizes from 2,517 participants from 27 studies. We used a random-effects meta-analysis using a restricted maximum likelihood estimator with robust variance estimation. We meta-analyzed ERP-STB combinations that had at least three effect sizes across two or more studies. A qualitative review found that for each ERP and STB combination, the literature is highly mixed. Our meta-analyses largely did not find significant relationships between STBs and ERPs. We also found that the literature is likely severely underpowered, with most studies only being sufficiently powered to detect unrealistically large effect sizes. Our results provided little-to-no support for a reliable relationship between the ERPs assessed and STBs. However, the current literature is severely underpowered, and there are many methodological weaknesses that must be resolved before making this determination. We recommend large-scale collaboration and improvements in measurement practices to combat the issues in this literature.

Emotional Dysregulation, Temperament and Lifetime Suicidal Ideation among Youths with Mood Disorders

Background: Psychopathological dimensions contributing to suicidal ideation in young age are poorly understood. We aimed to investigate the involvement of emotional dysregulation and temperament in suicide risk in a sample of accurately selected young patients with mood disorders and a matched sample of healthy controls (HC). Methods: We assessed 50 young patients (aged 14–25 years) with DSM-5 bipolar or depressive disorders for clinical and psychopathological characteristics and 82 age and sex, educational level, and smoking habits-matched HC. Emotional dysregulation and temperament were assessed using the Difficulties in Emotion Regulation Scale (DERS) and the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Autoquestionnaire (TEMPS-A-39), respectively. We tested their associations with suicidal ideation, using standard univariate/bivariate methods, preceded by overall multivariate analysis. Results: In the group of patients, 24 (48%) reported lifetime suicide ideation (LSI). Patients with LSI scored higher on emotional dysregulation (p < 0.001) and cyclothymic (p < 0.001), irritable (p = 0.01), and hyperthymic temperaments (p = 0.003) than HC. Patients with LSI specifically presented with more emotional dysregulation (p < 0.001) and cyclothymic temperament (p = 0.001), than patients without LSI (N = 26). Conclusions: Temperamental features, in particular cyclothymic temperament, and emotion dysregulation may represent independent factors for increased vulnerability to lifetime suicidal ideation in young adults with mood disorders.

The Frequency and Subjective Impact of Painful and Provocative Events on the Acquired Capability for Suicide

BACKGROUND

Leading theoretical explanations for suicide state that for suicide death to occur, a person must have sufficient capability to enact an attempt. Exposure to painful and provocative events is hypothesized to play an important role in acquiring the capability for suicide over a lifetime. Unfortunately, assessment tools for painful and provocative events have focused solely on the frequency of events, neglecting the potential contributions of perceived impact. Further, past measurements have used predetermined items for painful and provocative events thereby neglecting other relevant events. The current study uses visual analog scales (VAS) to assess both the frequency and impact of painful and provocative events and how these contribute to the capability for suicide.

METHOD

Data were collected from 787 adults via Amazon's online platform.

RESULTS

Findings indicated that the frequency VAS and impact VAS both had a moderate correlation with the original Painful and Provocative Events Scale. Greater scores on the frequency VAS were associated with increased capability, whereas lower scores on the subjective impact VAS were associated with increased capability scores. Both VAS independently predicted capability above and beyond the PPES.

LIMITATIONS

Temporal or causal associations are unable to be drawn due to cross-sectional data. In addition, the sample was largely homogenous (White = 72%, female = 63.5%), limiting generalizability.

CONCLUSIONS

These initial findings demonstrate individuals who perceive painful and provocative events as being less impactful may have increased capability, and that VAS may be appropriate to approximate the impact and frequency of painful and provocative events.

Neurophysiological Markers Related to Negative Self-referential Processing Differentiate Adolescent Suicide Ideators and Attempters

Background

Adolescent suicide is a major public health concern, and presently, there is a limited understanding of the neurophysiological correlates of suicidal behaviors. Cognitive models of suicide indicate that negative views of the self are related to suicidal thoughts and behaviors, and this study investigated whether behavioral and neural correlates of self-referential processing differentiate suicide ideators from recent attempters.

Methods

Adolescents with depression reporting current suicidal ideation and no lifetime suicide attempts (suicide ideators, n = 30) and past-year suicide attempts (recent attempters, n = 26) completed a self-referential encoding task while high-density electroencephalogram data were recorded. Behavioral analyses focused on negative processing bias (i.e., tendency to attribute negative information as being self-relevant) and drift rate (i.e., slope of reaction time and response type that corresponds to how quickly information is accumulated to make a decision about whether words are self-referent). Neurophysiological markers probing components reflecting early semantic monitoring (P2), engagement (early late positive potential), and effortful encoding (late late positive potential) also were tested.

Results

Adolescent suicide ideators and recent suicide attempters reported comparable symptom severity, suicide ideation, and mental disorders. Although there were no behavioral differences, compared with suicide ideators, suicide attempters exhibited greater P2 amplitudes for negative versus positive words, which may reflect enhanced attention and arousal in response to negative self-referential stimuli. There were no group differences for the early or late late positive potential.

Conclusions

Enhanced sensory arousal in response to negative stimuli-that is, attentional orienting to semantic, emotional, and self-relevant features-differentiates adolescent suicide attempters from ideators and thus may signal risk for suicidal behavior.

The processing of angry faces in schizophrenia patients with a history of suicide: An fMRI study examining brain activity and connectivity

BACKGROUND

The high rate of suicidal behaviours (SBs) in psychiatric populations remain an important preoccupation to address. The literature reveals emotional instability as an important risk factor for SBs. However, the neural mechanisms underpinning this risk factor have never been investigated in schizophrenia patients with SBs. The following study implemented a task-based emotional processing functional magnetic resonance imaging (fMRI) paradigm to evaluate the activation and connectivity differences exhibited by schizophrenia patients with a history of suicide attempt (SA).

METHOD

A sample of 62 schizophrenia patients with and without SA and 22 controls completed an fMRI emotional processing task, which included the visualization of dynamic angry facial expressions. Task-based connectivity was assessed using generalized psychophysical interaction analyses.

RESULTS

During the processing of angry faces, suicidal schizophrenia patients displayed increased activation of the left median cingulate gyrus, left middle frontal gyrus, and left precuneus when compared to nonsuicidal schizophrenia patients and healthy controls. Whole-brain connectivity analyses yielded an increased coupling of the right amygdala and right superior frontal gyrus, as well as between the left precuneus and median cingulate gyrus, in suicidal schizophrenia patients. Schizophrenia patients' hostility scores on the Positive and Negative Symptom Scale (PANSS) were significantly and positively correlated with the activity of the left median cingulate gyrus.

CONCLUSION

When exposed to angry faces, suicidal schizophrenia patients demonstrate elevated activation of brain regions associated to executive functioning and self-processing, as well as aberrant fronto-limbic connectivity involved in emotion regulation. Our results highlight the neglected role of anger when investigating the neural alterations underpinning SBs in schizophrenia.

Psychotherapy and youth suicide prevention: An interpretative phenomenological analysis of specialist clinicians' experiences

The study explored psychologists' experiences in delivering short-term psychotherapy for suicidal adolescents and sought to clarify how these experiences fit with empirically supported interventions and the interpersonal psychological theory of suicide. Semistructured interviews were conducted with 12 psychologists' who provided short-term psychotherapy in a suicide prevention programme for youth (12- to 25-year-olds). Interview transcripts were analysed using interpretative phenomenological analysis. Three superordinate themes were identified: (i) understand the experience and context of the suicidality and the importance of a formulation-based approach to engagement and individualized treatment planning; (ii) involve broad support systems, and in particular families, to help the young person reduce feelings of burdensomeness and increase safety, connectedness and belonging; and (iii) improve affect regulation and reflective functioning, important not only for the young person but also for the support system to maximize the positive impact of supports via emotional coregulation and effective problem-solving. Interventions and approaches as well as the potential underlying processes of change being targeted are discussed in light of these findings. As an example, the development of a suicide safety plan was an intervention that traversed these themes. When used as a process tool, it helped foster a collaborative, formulation, dimensional and biopsychosocial approach to treat psychopathology and suicidality and extended beyond the therapist-client dyad. Moreover, treatment needs to be extended beyond the therapist-client dyad to allow therapists to facilitate a systemic treatment response, as this was seen as a major component of interventions for suicidal youth.

The role of psychiatric symptoms and environmental vulnerability factors in explaining the relationship between child maltreatment and suicidality: A prospective investigation

BACKGROUND

Childhood maltreatment has been associated with suicide thoughts and attempts; however, few longitudinal studies have assessed risk of suicidality into adulthood. Fewer have examined potential mediators (psychiatric symptoms and environmental vulnerability factors).

METHODS

Prospective cohort design. Children with documented cases of maltreatment (N = 495, ages 0-11) were matched with non-maltreated children (N = 395) and followed up into adulthood. Psychiatric symptoms (depression, anxiety, dysthymia, post-traumatic stress,antisocial personality,and substance use) and environmental vulnerability (social isolation, physical disability/illness, and homelessness) were assessed at mean age 29 and suicide thoughts and attempts at 39. Structural equation models tested for mediation, controlling for age, sex, race, and IQ.

RESULTS

Childhood maltreatment predicted suicide attempts (Beta = 0.44, p<0.001), but not suicide thoughts only.Individuals with only suicide thoughts differed significantly from those with suicide attempts in psychiatric symptoms, physical disability/ illness, and homelessness. There were significant paths from child maltreatment to suicide attempts through psychiatric symptoms (0.18, p<0.001), ASPD (0.13, p<0.001), substance use (0.07, p<0.01), and homelessness (0.10, p<0.05).

LIMITATIONS

Court cases of child maltreatment may not generalize to middle- or upper- class and non-reported cases.Effect sizes were small but significant.

CONCLUSIONS

Psychiatric risk factors for suicide are well recognized. These new results provide strong evidence that environmental vulnerability factors, particularly homelessness, are associated with increased risk for suicide attempts and warrant attention.Although many people report suicide thoughts, maltreated children with more psychiatric symptoms and experience homelessness are more likely to attempt suicide and warrant targeted interventions.

Differences in Behavioral Inhibitory Control in Response to Angry and Happy Emotions Among College Students With and Without Suicidal Ideation: An ERP Study

Suicidal ideation is one of the strongest predictors of suicide. A large number of studies have illustrated the important effect of impulsivity on suicidal ideation, and behavioral inhibitory control (BIC) is a specific manifestation of impulsivity. The goal of the present study is to evaluate the difference in BIC in response to happy and angry emotions between individuals with or without suicidal ideation to reveal the underlying mechanism of the effect of impulsivity on suicidal ideation when accounting for the effect of emotion. Combining the ERP technique and the two-choice oddball paradigm, a total of 70 college students were recruited to participate in this study. The Beck Scale for Suicidal Ideation–Chinese Version was used to identify whether the participants had suicidal ideation. There were 30 participants in the risky-suicidal ideation (SI) group and 19 participants in the non-suicidal ideation (NSI) group. The results showed that the reaction time of the SI group was longer than that of the NSI group for happy emotions. At the electrophysiological level, the P3 amplitude of the NSI group was larger than that of the SI group regardless of the electrode sites and valence, and the P3 component elicited by angry faces was larger than those elicited by happy faces in the SI group. These findings suggest that individuals without suicidal ideation have better BIC, and the SI group has more difficulty controlling their responses to happy emotions than their responses to angry emotions.