Differential effects of executive functioning on suicide attempts

Neurological, Metabolic, and Psychopathological Correlates of Lifetime Suicidal Behaviour in Major Depressive Disorder without Current Suicide Ideation

INTRODUCTION

Suicidal behaviour (SB) has a complex aetiology. Although suicidal ideation (SI) is considered the most important risk factor for future attempts, many people who engage in SB do not report it.

METHODS

We investigated neurological, metabolic, and psychopathological correlates of lifetime SB in two independent groups of patients with major depression (sample 1: n = 230; age: 18-65 years; sample 2: n = 258; age >60 years) who did not report SI during an index episode.

RESULTS

Among adults (sample 1), SB was reported by 141 subjects (58.7%) and severe SB by 33 (15%). After controlling for interactions, four risk factors for SB emerged: male gender (OR 2.55; 95% CI: 1.06-6.12), negative self-perception (OR 1.76; 95% CI: 1.08-2.87), subthreshold hypomania (OR 4.50; 95% CI: 1.57-12.85), and sexual abuse (OR 3.09; 95% CI: 1.28-7.48). The presence of at least two of these factors had the best accuracy in predicting SB: sensitivity = 57.6% (39.2-74.5); specificity = 75.1% (68.5-82.0); PPV = 27.9% (20.9-37.2); NPV = 91.4% (87.6-94.1). In older patients (sample 2), 23 subjects (9%) reported previous suicide attempts, which were characterized by earlier onset (25 years: OR 0.95: 0.92-0.98), impaired verbal performance (verbal fluency: OR 0.95: 0.89-0.99), higher HDL cholesterol levels (OR 1.04: 1.00-1.07) and more dyskinesias (OR 2.86: 1.22-6.70).

CONCLUSION

Our findings suggest that SB is common in major depressive disorder, even when SI is not reported. In these individuals it is feasible and recommended to investigate both psychiatric and organic risk factors. The predictive power of models excluding SI is comparable to that of models including SI.

Reduced attentional control in individuals with a history of suicide attempts compared to those with suicidal ideation: Results from a systematic review and meta-analysis

BACKGROUND

Neurocognitive profiles may be especially useful to identify factors that facilitate transitioning from contemplating suicide to attempting suicide. Generally, those who attempt suicide show greater disruptions in neurocognitive ability compared to those who think about suicide but do not proceed to attempt. The goal of this systematic review and meta-analysis is to test whether this pattern is observed with attentional control.

METHODS

We systematically searched PubMed, PsychINFO, CINAHL, and Google Scholar to find pertinent studies. All included studies compared attentional functioning using neutral stimuli. Each sample featured adults with a history of suicidal ideation (SI) and no history of suicide attempts (SA) compared to those with a history of SA.

RESULTS

We identified 15 studies with 32 effect sizes (N = 931; n = 506 with SI only; n = 425 with SA). SA groups, compared to SI groups, exhibited worse accuracy yet similar reaction time, suggesting a comparatively blunted speed-accuracy tradeoff. Relative to SI, SA groups performed worse on Stroop-like and Go/NoGo tasks. SA performed better than SI on Trail Making Test B, but not A.

LIMITATIONS

There were few available studies. Most samples were small. We did not differentiate current vs. past SI or high vs. low lethality SA. Only English and Spanish language articles were included.

CONCLUSIONS

Disrupted attentional control may convey risk for transitioning to SA from SI. More work is needed to determine which components of attention are most associated with suicide risk.

Reactive control in suicide ideators and attempters: An examination of the congruency sequence effect in cognitive and emotional Simon tasks

Reactive control is the cognitive ability to adjust thoughts and behaviors when encountering conflict. We investigated how this ability to manage conflict and stress distinguishes suicidal from nonsuicidal individuals. The hypothesis was that suicidal individuals would show poorer reactive control when faced with conflict generated by emotional than neutral stimuli. Hence, individuals with a lifetime history of suicide ideation or attempt and nonsuicidal controls were tested in cognitive and emotional Simon tasks. We examined the congruency sequence effect (CSE) in the Simon tasks as an indication of the efficiency of reactive control in resolving conflict. Whereas controls demonstrated significant CSEs in both tasks, suicide attempters showed a significant CSE in the cognitive task but not in the emotional task. Suicide ideators, on the other hand, displayed marginally significant CSEs in both tasks. Comparing groups with pairwise comparison demonstrated that the difference in CSE was significant only in the emotional task between attempters and controls. Our findings of attempters' inefficiency in adjusting reactive control during the emotional task reflect cognitive inflexibility in coping with conflicting situations during which suicidal individuals become vulnerable to suicide attempts in states of negative emotion.

Sociodemography, pattern, and response inhibition in suicide survivors: A case-control study

Introduction

Suicide is a global phenomenon. Psychiatric disorders are estimated to contribute to a large proportion of suicides; however, impulsive suicide is also common. Among the ages of 15-29 years, suicide was the second leading cause of death worldwide and has been hypothesized to have reduced response inhibition and decision-making abilities as contributing factors, which directly relate to impaired executive functioning and suicidal behavior.

Aim

This study aimed to study sociodemography, method, and pattern of suicide, and response inhibition in suicide survivors.

Material and Methods

A case-control study was designed in a tertiary medical center in Madhya Pradesh using convenient sampling of suicide survivors and controls from the general population over 3 months. Data collection was semi-structured pro forma, and response inhibition was assessed using the Stroop test. Statistical analysis was performed using IBM Statistical Package for the Social Sciences (SPSS) Windows version 25.0. Independent-samples Student's t-test, Chi-square test, and Mann-Whitney U-test were used for analyzing means of continuous data, nominal data, and ordinal data, respectively. The level of significance was at P < 0.05.

Result

A total of 126 suicide survivors and 99 controls were assessed after the end of the study period. Age (mean age for cases 25.4 ± 9.16; controls 23 ± 7.9), gender (F ~ M), and socioeconomic status were used to match cases and controls. 85.7% of suicide survivors had no history of suicide, but the majority had precipitating factors. Anomic suicide was the most common type, and poisoning was the most common method of suicide. Response inhibition between cases and control was significantly different.

Conclusion

The majority of suicide attempts were impulsive in youth, with no gender discrimination. Response inhibition seemed to play a role in a suicide attempt.

Childhood Maltreatment, Executive Function, and Suicide Attempts in Adolescents

Evidence suggests that child maltreatment is a risk factor for adolescent suicidal behavior. However, the differential influence of distinct forms of child maltreatment on adolescent suicide attempts is understudied and the factors that might exacerbate or ameliorate these associations warrant attention. We examined the associations between two distinct forms of child maltreatment (threat and deprivation) and suicide attempt history, and investigated whether executive function domains moderated these associations. Participants were 119 adolescents (M = 15.24, SD = 1.46, 72.3% female) recruited from an inpatient psychiatric hospital during hospitalization for suicidal thoughts and behaviors. Results indicated that the executive function domains of initiation, shifting, and planning/organization moderated the associations between threat and suicide attempt history. Associations between threat and suicide attempt history were significant only when initiation and shifting T-scores were lower (OR = 1.22, p = .03 and OR = 1.32, p = .01, respectively). The association between threat and suicide attempt history trended toward significance when planning/organization T-scores were lower (OR = 1.15, p = .10). None of the executive function domains moderated the link between deprivation and suicide attempt history. Findings highlight the need for research investigating whether initiation, shifting, and planning/organization might be amendable to intervention in the context of threat-related child maltreatment.

Cognitive impairment and factors influencing depression in adolescents with suicidal and self-injury behaviors: a cross-sectional study

BACKGROUND

Non-suicidal self-injury (NSSI) and suicide attempts (SAs) by adolescent patients with depression have become serious public health problems. There is still insufficient research evidence on the effects of NSSI and SAs on neurocognitive functioning in adolescents. Cognitive function alterations may be associated with SAs and self-injury. NSSI and SAs have different influencing factors.

METHODS

Participants were recruited from outpatient clinics and included 142 adolescent patients with depression (12-18 years old). This cohort included the SAs group (n = 52), NSSI group (n = 65), and depression without SAs/NSSI control group (n = 25). All participants underwent a clinical interview and neuropsychological assessment for group comparisons, and post-hoc tests were performed. Finally, partial correlation analysis was used to explore factors related to changes in cognitive function.

RESULTS

The SAs group performed significantly worse than the control group in executive function and working memory. The depression score was directly proportional to the executive function of the SAs group, whereas cognitive functioning in the NSSI group was associated with borderline traits and rumination.

CONCLUSIONS

These findings suggest that impairment of executive function and working memory may be a common pattern in adolescent depressed patients with SAs. However, borderline traits and rumination may be indicative of NSSI but not SAs.

Association between childhood cognitive skills & adult suicidal behavior: A systematic review and meta-analysis

BACKGROUND

It is unclear whether cognitive skill deficits during childhood carry risk for suicide attempt or mortality later in adulthood at the population level. We conducted a systematic review and meta-analysis of population-based studies examining the association between childhood cognitive skills and adult suicidal behavior, namely attempt and mortality.

METHOD

We systematically searched databases for articles then extracted study characteristics and estimates on the association between childhood cognitive skills (i.e., IQ or school performance at age ≤ 18 years) and later suicide attempt and mortality. Random-effect meta-analysis was used to quantify this association across all studies with available data.

RESULTS

Twenty-three studies met the inclusion criteria and suggest an association between lower childhood cognitive skills and increased risk of suicidal behavior. Meta-analysis of the adjusted estimates from 11 studies (N = 2,830,191) found the association to be small but statistically significant. Heterogeneity was significant but moderate, and results were unlikely to be influenced by publication bias. In subgroup analyses, associations were significant only for males. No difference in effect size was found between suicide attempt and suicide mortality.

LIMITATIONS

Cognitive skills were measured with different cognitive subtests. Heterogeneity in the age of cognitive skills assessment. Meta-regression and subgroup analyses were based on a relatively low number of studies.

CONCLUSIONS

Individuals with lower cognitive skills in childhood have a greater risk of suicidal behavior in adulthood, especially males. Although the association was small, interventions improving cognitive skills may yield large effects on suicide prevention at the population level if the association is causal.

Cognitive flexibility in inpatient children and adolescents with a history of suicide attempts

An increase in suicide rates during adolescence has made it the second leading cause of death for this age group. While potential deficits in cognitive flexibility have been thought to contribute to suicidality, this factor has been evaluated in only a few studies among this age group. The current study sought to evaluate cognitive flexibility in 100 psychiatric inpatient children and adolescents (age X=14.39, SD=2.53), with (n=26) and without (n=74) a history of suicide attempts, using the Wisconsin Card Sorting Test (WCST). Results showed no differences between the groups in WCST scores. However, in a small sub-sample with mood disorders only, those with a history of a suicide attempt performed better than those without such history. These findings are contrary to our hypothesis that those who attempted suicide have worse cognitive flexibility, though consistent with earlier data in adults. Further research is needed to shed light on these findings.

Timing of childhood adversities and self-injurious thoughts and behaviors in adolescence

Greater childhood adversity predicts a higher likelihood of later self-injurious thoughts and behaviors (SITB). There is little research focused on whether the timing of childhood adversity predicts SITB. The current research examined whether the timing of childhood adversity predicted parent- and youth-reported SITB at age 12 and 16 years in the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN) cohort (n = 970). We found that greater adversity at age 11-12 years consistently predicted SITB at age 12 years, while greater adversity at age 13-14 years consistently predicted SITB at age 16 years. These findings suggest there may be sensitive periods during which adversity may be more likely to lead to adolescent SITB, which can inform prevention and treatment.

A Systematic Review of Behavior-Outcome Psychological Assessments as Correlates of Suicidality

AIM

Identifying correlates of suicidality is an important goal for suicide researchers because these correlates may predict suicidal behaviors. Psychological tasks that assess sensitivity to the outcomes of actions (i.e., consequence-based learning) have been commonly used by researchers seeking to identify correlates of suicidality. This is likely due to the straightforward integration of the tasks within most theoretical frameworks for understanding suicidality. Contextual factors have been shown to have a substantial effect on responding in behavior-outcome tasks. However, the direct relevance of these factors as determinants of behavior in suicide research is not clear. Thus, the purpose of this review was to assess the role of context in tasks involving behavior-outcome relations in suicide research.

METHODS

Four databases were searched using terms from general learning theory. Articles that featured evaluation of tasks with hypothetical or real outcomes to differentiate suicidality were included.

RESULTS

Eighty-two studies met inclusion criteria. Across studies there were 27 different tasks. Most instances of tasks across studies involved rewards (76.9%), while others emphasized punishment (15.7%), social (5.6%), or virtual suicide (1.8%) outcomes. Differentiation of suicidality was detected by 43.4%, 64.7%, 83.3%, and 50% of tasks featuring reward, punishment, social contexts, and virtual suicide respectively. All but five studies were retrospective.

CONCLUSION

Tasks that more closely mimic contexts and outcomes related to suicide appear to produce more pronounced differentiation of people with suicidality from people without suicidality. The lack of prospective designs is an important limitation of the literature.HIGHLIGHTSTasks that involve punishment or social outcomes better discriminate suicidality.Reward-based tasks are overused in suicide research.The conditioning hypothesis of suicidality is closely aligned with the literature.Only 5 of 82 studies incorporated prospective measures.

Association between neurocognitive functioning and suicide attempts in U.S. Army Soldiers

BACKGROUND

Suicide is a serious public health problem, including among U.S. Army personnel. There is great interest in discovering objective predictors of suicide and non-fatal suicidal behaviors. The current study examined the association between neurocognitive functioning and pre-military history of suicide attempts (SA) and post-enlistment onset of SA.

METHODS

New Soldiers reporting for Basic Combat Training (N = 38,507) completed a comprehensive computerized neurocognitive assessment battery and self-report questionnaires. A subset of Soldiers (n = 6216) completed a follow-up survey, including assessment of lifetime SA, 3-7 years later.

RESULTS

Six hundred eighty-nine Soldiers indicated lifetime SA at baseline and 210 Soldiers indicated new-onset SA at follow-up. Regression analyses, adjusted for demographic variables, revealed significant bivariate associations between neurocognitive performance on measures of sustained attention, impulsivity, working memory, and emotion recognition and lifetime SA at baseline. In a multivariable model including each of these measures as predictors, poorer impulse control and quicker response times on an emotion recognition measure were significantly and independently associated with increased odds of lifetime SA. A second model predicted new-onset SA at follow-up for Soldiers who did not indicate a history of SA at baseline. Poorer impulse control on a measure of sustained attention was predictive of new-onset SA.

LIMITATIONS

Effect sizes are small and of unlikely clinical predictive utility.

CONCLUSIONS

We simultaneously examined multiple neurocognitive domains as predictors of SA in a large, representative sample of new Army Soldiers. Impulsivity most strongly predicted past and future SA over and beyond other implicated cognitive-emotional domains.

A qualitative systematic review of neurocognition in suicide ideators and attempters: Implications for cognitive-based psychotherapeutic interventions

BACKGROUND

Growing evidence suggests cognitive deficits may represent neurocognitive markers with predictive utility in identifying those at risk for suicide. Characterizing these deficits may offer the opportunity to develop targeted interventions.

AIM

The aim of this systematic qualitative review is to provide a synthesis of the published data on neurocognition in suicide ideators and attempters in order to clarify which neurocognitive targets may be most relevant to address using cognitive-based psychotherapeutic strategies in patients at risk for suicide.

RESULTS

A total of 63 studies met criteria for inclusion. The most consistent findings were in depressed suicide attempters, where deficits in executive subdomains of inhibition, selective attention and decision-making, as well as in working memory, were identified. In contrast, no clear pattern of neurocognitive deficits emerged from studies in suicide ideators across diagnoses.

CONCLUSIONS

More studies are needed to clarify the role of cognitive deficits in specific subtypes of individuals at risk for suicide. The findings are discussed in the context of promising research on cognitive remediation and other psychological interventions.

Associations between Suicidal Thoughts and Behaviors and Genetic Liability for Cognitive Performance, Depression, and Risk-Taking in a High-Risk Sample

Background

Suicidal thoughts and behaviors (STBs) and nonsuicidal self-injury (NSSI) behaviors are moderately heritable and may reflect an underlying predisposition to depression, impulsivity, and cognitive vulnerabilities to varying degrees.

Objectives

We aimed to estimate the degrees of association between genetic liability to depression, impulsivity, and cognitive performance and STBs and NSSI in a high-risk sample.

Methods

We used data on 7,482 individuals of European ancestry and 3,359 individuals of African ancestry from the Collaborative Study on the Genetics of Alcoholism to examine the links between polygenic scores (PGSs) for depression, impulsivity/risk-taking, and cognitive performance with 3 self-reported indices of STBs (suicidal ideation, persistent suicidal ideation defined as ideation occurring on at least 7 consecutive days, and suicide attempt) and with NSSI.

Results

The PGS for depression was significantly associated with all 4 primary self-harm measures, explaining 0.6-2.5% of the variance. The PGS for risk-taking behaviors was also associated with all 4 self-harm behaviors in baseline models, but was no longer associated after controlling for a lifetime measure of DSM-IV alcohol dependence and abuse symptom counts. Polygenic predisposition for cognitive performance was negatively associated with suicide attempts (q = 3.8e-4) but was not significantly associated with suicidal ideation nor NSSI. We did not find any significant associations in the African ancestry subset, likely due to smaller sample sizes.

Conclusions

Our results encourage the study of STB as transdiagnostic outcomes that show genetic overlap with a range of risk factors.

Neurocognitive Functioning in Adolescents at Risk for Suicidal Behaviors

Today, little is still known about the neurocognitive functioning of the individual at risk for suicide in a relevant developmental stage like adolescence. Thus, the main goal of the present work was to analyze the neurocognitive performance of adolescents at high risk for suicide. A total of 1509 adolescents from a stratified random cluster sampling were selected. Adolescents at risk for suicidal behaviors included 83 participants. A comparison group of 83 participants matched by age and gender was also randomly selected from the sample. The Paykel Suicide Scale (PSS) and the University of Pennsylvania Computerized Neurocognitive Battery for children (included 14 tasks assessing five neurobehavioral domains: executive functions, episodic memory, complex cognition, social cognition, and sensorimotor speed) were used. Adolescents at risk for suicide revealed statistically significant impairments across different neurocognitive domains including complex cognition, episodic memory and social cognition. No significant differences were found for Sensorimotor and Executive Function domains. Results found in the present study contribute relevant information about the nature of the neurocognitive impairments associated with suicide and add information in order to deeper comprehend the tentative etiology of suicide thoughts and attempts in adolescents with the aim to establish preventive treatments.

A Systematic Review of Neuromodulation Treatment Effects on Suicidality

Introduction: Neuromodulation is an important group of therapeutic modalities for neuropsychiatric disorders. Prior studies have focused on efficacy and adverse events associated with neuromodulation. Less is known regarding the influence of neuromodulation treatments on suicidality. This systematic review sought to examine the effects of various neuromodulation techniques on suicidality. Methods: A systematic review of the literature from 1940 to 2020 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline was conducted. Any reported suicide-related outcome, including suicidal ideation, suicide intent, suicide attempt, completed suicide in reports were considered as a putative measure of treatment effect on suicidality. Results: The review identified 129 relevant studies. An exploratory analysis of a randomized controlled trial comparing the effects of sertraline and transcranial direct-current stimulation (tDCS) for treating depression reported a decrease in suicidal ideation favoring tDCS vs. placebo and tDCS combined with sertraline vs. placebo. Several studies reported an association between repetitive transcranial magnetic stimulation and improvements in suicidal ideation. In 12 of the studies, suicidality was the primary outcome, ten of which showed a significant improvement in suicidal ideation. Electroconvulsive therapy (ECT) and magnetic seizure therapy was also shown to be associated with lower suicidal ideation and completed suicide rates. There were 11 studies which suicidality was the primary outcome and seven of these showed an improvement in suicidal ideation or suicide intent and fewer suicide attempts or completed suicides in patients treated with ECT. There was limited literature focused on the potential protective effect of vagal nerve stimulation with respect to suicidal ideation. Data were mixed regarding the potential effects of deep brain stimulation on suicidality. Conclusions: Future prospective studies of neuromodulation that focus on the primary outcome of suicidality are urgently needed. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=125599, identifier: CRD42019125599.

Investigating cognitive control and cognitive emotion regulation in Iranian depressed women with suicidal ideation or suicide attempts

OBJECTIVE

This study compared cognitive control (working memory, interference control, perseveration) and cognitive emotion regulation among Iranian women with depression who had attempted suicide, had only suicidal ideation, and healthy controls.

METHOD

Participants (N = 75) completed a clinical interview, cognitive control tasks, and the Cognitive Emotion Regulation Questionnaire.

RESULTS

Those with suicidal ideation or previous attempts had poorer cognitive control and cognitive emotion regulation than controls. Furthermore, those who had attempted suicide had poorer cognitive control and reported greater use of self-blame, rumination, and catastrophizing, and less use of acceptance, than those with suicidal ideation only. There was an indirect effect of cognitive control deficits on suicidality through cognitive emotion regulation (self-blame, acceptance, rumination, catastrophizing).

CONCLUSIONS

Exploring these cognitive deficits and difficulties can assist in further understanding the risk factors for suicidality and improve targeted interventions. This is of particular relevance in Iran where the need for policies and interventions targeting the prevention of suicide has been identified.

Visual memory improvement in adolescents at high risk for suicide who are receiving psychotherapy at a community clinic

The current study aims to: 1) investigate cognitive differences among adolescents at risk for suicide versus healthy controls (HC) and 2) identify cognitive changes associated with response to psychotherapy among adolescents at high risk for suicide. Thirty-five adolescents at high risk for suicide (HR), and 14 HC adolescents were recruited. Clinical and cognitive assessments were conducted in both groups at baseline and 16 weeks later (after the patients completed psychotherapy). HR and HC adolescents were compared at baseline and at completion of the study. We also conducted further analysis by separating into two groups the HR adolescents who responded to psychotherapy (n=17) and those who did not (n=11). At baseline, the HR group had significantly lower performance on verbal memory and processing speed than the HC group. At week 16, HR adolescents performed as well as HC adolescents in all cognitive domains. Among patients, better performance on visual memory was observed in those who responded to psychotherapy compared to those who did not. We concluded that lower performance on verbal memory and processing speed may be associated with a high risk for suicide among adolescents. Improvement in visual memory might be related to a lower risk for suicide in adolescents.

Cognitive Control in Suicide Ideators and Suicide Attempters

There is a need to understand more of the risk factors involved in the process from suicide ideation to suicide attempt. Cognitive control processes may be important factors in assessing vulnerability to suicide. A version of the Stroop procedure, Delis-Kaplan Executive Function System (D-KEFS) Color-Word Interference Test (CWIT) and Behavior Rating Inventory of Executive Function (BRIEF-A) were used in this study to test attention control and cognitive shift, as well as to assess everyday executive function of 98 acute suicidal psychiatric patients. The Columbia Suicide History Form (CSHF) was used to identify a group of suicide ideators and suicide attempters. Results showed that suicide attempters scored lower on attention control than suicide ideators who had no history of attempted suicide. The self-report in the BRIEF-A inventory did not reflect any cognitive differences between suicide ideators and suicide attempters. A logistic regression analysis showed that a poorer attention control score was associated with the suicide attempt group, whereas a poorer cognitive shift score was associated with the suicide ideation group. The results found in this study suggest that suicide attempters may struggle with control of attention or inhibiting competing responses but not with cognitive flexibility.

Biological bases of suicidal behaviours: A narrative review

Suicidal behaviour is a multifaceted phenomenon that concerns all human populations. It has been suggested that a complex interaction between the individual genetic profile and environmental factors throughout life underlies the pathophysiology of suicidal behaviour. Although epidemiological and genetic studies suggest the existence of a genetic component, exposure to biological and psychosocial adversities, especially during critical developmental periods, also contributes to altering the biological responses to threat and pleasure. This results in amplified maladaptive cognitive and behavioural traits and states associated with suicidal behaviours. Alterations in the cognitive inhibition and decision-making capacity have been implicated in suicidal behaviours. Structural and functional changes in key brain regions and networks, such as prefrontal cortex, insula and default mode network, may underlie this relationship. Furthermore, the shift from health to suicidal behaviour incorporates complex and dynamic changes in the immune and stress responses, monoaminergic system, gonadal system and neuroplasticity. In this review, we describe the major findings of epidemiological, genetic, neuroanatomical, neuropsychological, immunological and neuroendocrinological studies on suicide behaviours to provide a solid background for future research in this field. This broad overview of the biological bases of suicide should promote neuroscience research on suicidal behaviours. This might lead to improved biological models and to the identification of evidence-based biomarkers, treatment options and preventive strategies.

A qualitative systematic review of suicide behavior using the cognitive systems domain of the research domain criteria (RDoC) framework

Neurocognitive deficits are associated with both suicide behavior (SB) and psychiatric disorders. Application of a transdiagnostic framework to identify neurocognitive commonalities of SB may clarify important risk factors of SB across psychiatric disorders. The aim of this study was to conduct a qualitative systematic literature review of SB using the Research Domain Criteria (RDoC) Cognitive Systems framework to determine if cognitive deficits exist independently of psychiatric disorders in SB. The following six constructs that encompass the Cognitive Systems domain were assessed: 1) Attention, 2) Cognitive Control, 3) Declarative Memory, 4) Language, 5) Perception, and 6) Working Memory. A total of 1386 abstracts were identified and 74 studies met the inclusion criteria for this review. The majority of studies reviewed (65%) had significant differences in cognition between individuals with and without SB. Seventy-nine percent of studies with a patient control group showed significant cognitive deficits in SB groups. Deficits in cognitive control were associated with SB and had the greatest percentage of studies with significant main findings. Use of the RDoC cognitive systems framework to evaluate SB revealed that cognitive deficits may be a transdiagnostic risk factor for SB, especially alterations in cognitive control.

Etiopathogenesis of Suicide: A Conceptual Analysis of Risk and Prevention Within a Comprehensive, Deterministic Model

Suicide is a rising global health concern receiving disproportionate attention in comparison to other health conditions. In spite of substantial technological and scientific advancements, suicide research has continued to move slowly in terms of clinical translation due to the complexity of neural mechanisms, and subjective experiences that seem to underpin this complex human behavior. This paper analyzes the concepts of risk and prevention in the context of suicide in an attempt to bridge the large methodological and theoretical gaps between the biological, psychological, and sociological dimensions. This paper aims to accomplish the following objectives: (1) operationalize the concepts of suicide risk and prevention as they relate to current knowledge and capabilities; (2) synthesize and integrate suicide research across biological, psychological, and sociological dimensions; (3) discuss limitations of each dimension in isolation; (4) suggest a model of etiopathogenesis that incorporates extant literature and bridges unnecessary gaps between dimensions; and (5) suggest future directions for multidimensional research through the inclusion of principles from the physical sciences. Ultimately, this paper provides a basis for a comprehensive model of suicide within a deterministic, chaotic system.

Value-Based Choice, Contingency Learning, and Suicidal Behavior in Mid- and Late-Life Depression

BACKGROUND

Suicidal behavior is associated with impaired decision making in contexts of uncertainty. Existing studies, however, do not definitively address whether suidice attempers have 1) impairment in learning from experience or 2) impairment in choice based on comparison of estimated option values. Our reinforcement learning model-based behavioral study tested these hypotheses directly in middle-aged and older suicide attempters representative of those who die by suicide.

METHODS

Two samples (sample 1, n = 135; sample 2, n = 125) of suicide attempters with depression (n_attempters = 54 and 39, respectively), suicide ideators, nonsuicidal patients with depression, and healthy control participants completed a probabilistic three-choice decision-making task. A second experiment in sample 2 experimentally dissociated long-term learned value from reward magnitude. Analyses combined computational reinforcement learning and mixed-effects models of decision times and choices.

RESULTS

With regard to learning, suicide attempters (vs. all comparison groups) were less sensitive to one-back reinforcement, as indicated by a reduced effect on both choices and decision times. Learning deficits scaled with attempt lethality and were partially explained by poor cognitive control. With regard to value-based choice, suicide attempters (vs. all comparison groups) displayed abnormally long decision times when choosing between similarly valued options and were less able to distinguish between the best and second-best options. Group differences in value-based choice were robust to controlling for cognitive performance, comorbidities, impulsivity, psychotropic exposure, and possible brain damage from attempts.

CONCLUSIONS

Serious suicidal behavior is associated with impaired reward learning, likely undermining the search for alternative solutions. Attempted suicide is associated with impaired value comparison during the choice process, potentially interfering with the consideration of deterrents and alternatives in a crisis.

Mild Traumatic Brain Injury Burden Moderates the Relationship Between Cognitive Functioning and Suicidality in Iraq/Afghanistan-Era Veterans

OBJECTIVES

Suicidal ideation (SI) is highly prevalent in Iraq/Afghanistan-era veterans with a history of mild traumatic brain injury (mTBI), and multiple mTBIs impart even greater risk for poorer neuropsychological functioning and suicidality. However, little is known about the cognitive mechanisms that may confer increased risk of suicidality in this population. Thus, we examined relationships between neuropsychological functioning and suicidality and specifically whether lifetime mTBI burden would moderate relationships between cognitive functioning and suicidal ideation.

METHODS

Iraq/Afghanistan-era Veterans with a history of mTBI seeking outpatient services (N = 282) completed a clinical neuropsychological assessment and psychiatric and postconcussive symptom questionnaires.

RESULTS

Individuals who endorsed SI reported more severe post-traumatic stress disorder (PTSD), depression, and postconcussive symptoms and exhibited significantly worse memory performance compared to those who denied SI. Furthermore, mTBI burden interacted with both attention/processing speed and memory, such that poorer performance in these domains was associated with greater likelihood of SI in individuals with a history of three or more mTBIs. The pattern of results remained consistent when controlling for PTSD, depression, and postconcussive symptoms.

CONCLUSIONS

Slowed processing speed and/or memory difficulties may make it challenging to access and use past experiences to solve current problems and imagine future outcomes, leading to increases in hopelessness and SI in veterans with three or more mTBIs. Results have the potential to better inform treatment decisions for veterans with history of multiple mTBIs. (JINS, 2019, 25, 79-89).

Serotonin receptors and suicide, major depression, alcohol use disorder and reported early life adversity

Serotonin neurotransmitter deficits are reported in suicide, major depressive disorder (MDD) and alcohol use disorder (AUD). To compare pathophysiology in these disorders, we mapped brain serotonin transporter (SERT), 5-HT1A, and 5-HT2A receptor binding throughout prefrontal cortex and in anterior cingulate cortex postmortem. Cases and controls died suddenly minimizing agonal effects and had a postmortem interval ≤24 h to avoid compromised brain integrity. Neuropathology and toxicology confirmed absence of neuropathology and psychotropic medications. For most subjects (167 of 232), a DSM-IV Axis I diagnosis was made by psychological autopsy. Autoradiography was performed in right hemisphere coronal sections at a pre-genual level. Linear model analyses included sex and age with group and Brodmann area as interaction terms. SERT binding was lower in suicides (p = 0.004) independent of sex (females < males, p < 0.0001), however, the lower SERT binding was dependent on MDD diagnosis (p = 0.014). Higher SERT binding was associated with diagnosis of alcoholism (p = 0.012). 5-HT1A binding was greater in suicides (p < 0.001), independent of MDD (p = 0.168). Alcoholism was associated with higher 5-HT1A binding (p < 0.001) but only in suicides (p < 0.001). 5-HT2A binding was greater in suicides (p < 0.001) only when including MDD (p = 0.117) and alcoholism (p = 0.148) in the model. Reported childhood adversity was associated with higher SERT and 5-HT1A binding (p = 0.004) in nonsuicides and higher 5-HT2A binding (p < 0.001). Low SERT and more 5-HT1A and 5-HT2A binding in the neocortex in depressed suicides is dependent on Axis I diagnosis and reported childhood adversity. Findings in alcoholism differed from those in depression and suicide indicating a distinct serotonin system pathophysiology.

The longitudinal association between cognitive control capacities, suicidality, and depression during late adolescence and young adulthood

This study examined the association between cognitive control capacities, suicidal thoughts and attempts, and depressive symptoms during late adolescence and young adulthood. The sample included 4192 participants (55.5% female) from the United States who participated in Waves III (2001-2002; respondent age 18-26 years) and IV (2007-2008; respondent age 24-33 years) of the National Longitudinal Study of Adolescent to Adult Health. Data were analyzed using structural equation modeling. Suicidality in late adolescence predicted depressive symptoms in young adulthood. Depressive symptoms were not predictive of later suicide ideation nor attempts. Working memory was associated with lower depressive symptoms. Higher verbal ability was associated with more suicidal thoughts but not attempts. Internal locus of control was associated with decreased depressive symptoms and suicidal thoughts/attempts in young adulthood. Findings suggest that cognitive control capacities developed in adolescence differentially predict depressive symptoms, suicidal thoughts, and suicide attempts in young adulthood.

The Association Between Suicidal Behavior, Attentional Control, and Frontal Asymmetry

It can be difficult to identify those at risk of suicide because suicidal thoughts are often internalized and not shared with others. Yet to prevent suicide attempts it is crucial to identify suicidal thoughts and actions at an early stage. Past studies have suggested that deficits in attentional control are associated with suicide, with the argument that individuals are unable to inhibit negative thoughts and direct resources away from negative information. The current study aimed to investigate the association of suicidal behavior with neurological and behavioral markers, measuring attentional bias and inhibition in two Stroop tasks. Fifty-four participants responded to the color of color words in a standard Stroop task and the color of positive, negative, and neutral words in an emotional Stroop task. Electroencephalographic (EEG) activity was recorded from frontal areas during each task and at resting. Participants were separated into a low-risk and high-risk group according to their self-reported suicidal behavior. Participants in the high-risk group showed slower response times in the color Stroop and reduced accuracy to incongruent trials, but faster response times in the emotional Stroop task. Response times to the word "suicide" were significantly slower for the high-risk group. This indicates an attentional bias toward specific negative stimuli and difficulties inhibiting information for those with high levels of suicidal behavior. In the emotional Stroop task the high-risk group showed reduced activity in leftward frontal areas, suggesting limitations in the ability to regulate emotional processing via the left frontal regions. The findings support the argument that deficits in attentional control are related to suicidal behavior. The research also suggests that under certain conditions frontal asymmetry may be associated with suicidal behavior.

Event-Related Potential Measures of Attention Capture in Adolescent Inpatients With Acute Suicidal Behavior

Impaired executive functions, modulated by the frontal lobes, have been suggested to be associated with suicidal behavior. The present study examines one of these executive functions, attentional control, maintaining attention to the task-at-hand. A group of inpatient adolescents with acute suicidal behavior and healthy controls were studied using a passively presented auditory optimal paradigm. This "optimal" paradigm consisted of a series of frequently presented homogenous pure tone "standards" and different "deviants," constructed by changing one or more features of the standard. The optimal paradigm has been shown to be a more time-efficient replacement to the traditional oddball paradigm, which makes it suitable for use in clinical populations. The extent of processing of these "to-be-ignored" auditory stimuli was measured by recording event-related potentials (ERPs). The P3a ERP component is thought to reflect processes associated with the capturing of attention. Rare and novel stimuli may result in an executive decision to switch attention away from the current cognitive task and toward a probe of the potentially more relevant "interrupting" auditory input. On the other hand, stimuli that are quite similar to the standard should not elicit P3a. The P3a has been shown to be larger in immature brains in early compared to later adolescence. An overall enhanced P3a was observed in the suicidal group. The P3a was larger in this group for both the environmental sound and white noise deviants, although only the environmental sound P3a attained significance. Other deviants representing only a small change from the standard did not elicit a P3a in healthy controls. They did elicit a small P3a in the suicidal group. These findings suggest a lowered threshold for the triggering of the involuntary switch of attention in these patients, which may play a role in their reported distractibility. The enhanced P3a is also suggestive of an immature frontal central executive and may provide a promising marker for early identification of some of the risk factors for some of the cognitive difficulties linked to suicidality.

Measurement of latent cognitive abilities involved in concept identification learning

INTRODUCTION

We used cognitive and psychometric modeling techniques to evaluate the construct validity and measurement precision of latent cognitive abilities measured by a test of concept identification learning: the Penn Conditional Exclusion Test (PCET).

METHOD

Item response theory parameters were embedded within classic associative- and hypothesis-based Markov learning models and were fitted to 35,553 Army soldiers' PCET data from the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS).

RESULTS

Data were consistent with a hypothesis-testing model with multiple latent abilities-abstraction and set shifting. Latent abstraction ability was positively correlated with number of concepts learned, and latent set-shifting ability was negatively correlated with number of perseverative errors, supporting the construct validity of the two parameters. Abstraction was most precisely assessed for participants with abilities ranging from 1.5 standard deviations below the mean to the mean itself. Measurement of set shifting was acceptably precise only for participants making a high number of perseverative errors.

CONCLUSIONS

The PCET precisely measures latent abstraction ability in the Army STARRS sample, especially within the range of mildly impaired to average ability. This precision pattern is ideal for a test developed to measure cognitive impairment as opposed to cognitive strength. The PCET also measures latent set-shifting ability, but reliable assessment is limited to the impaired range of ability, reflecting that perseverative errors are rare among cognitively healthy adults. Integrating cognitive and psychometric models can provide information about construct validity and measurement precision within a single analytical framework.

Is cognitive impairment associated with suicidality? A population-based study

Suicide is one of the main causes of mortality in young people and in individuals with depression. The impact of impaired cognitive function on suicidal ideation is largely unknown. The aim of this study was to examine how cognitive functioning may influence suicidal thoughts, both in the general population and in a subgroup of individuals with depression. A total of 4583 participants (aged 18 years and older) were interviewed in a cross-sectional study of a representative sample of the non-institutionalized Spanish population. Cognitive functioning was evaluated using five cognitive tests. Participants were also asked to provide information about mental health symptoms and conditions through an adaptation of the Composite International Diagnostic Interview (CIDI 3.0). Logistic regression analysis was performed overall and by age group. Lifetime prevalence of suicidal ideation was 3.7%, whereas prevalence of suicidal ideation in the previous 12 months was 0.9%. Depression was the strongest risk factor for suicidal ideation. Compared with people without suicidal ideation, people with suicidal ideas performed significantly worse on cognitive functioning after adjusting for age, years of education, gender, and the presence of depression. In the age-subgroup analyses, only the youngest group (18-49 years) showed a significant association between cognitive functioning and suicidal ideation. Worse cognitive functioning was also associated with more frequent suicidal ideas in those individuals with depression even when depression severity was taken into account. In conclusion, both cognitive functioning and diagnosis of depression are associated with higher risk of suicide in the Spanish general population, especially in young individuals.

Exploratory associations with tumor necrosis factor-α, disinhibition and suicidal endorsement after traumatic brain injury

PURPOSE

To examine the relationship of Tumor Necrosis Factor (TNF)-α to disinhibition and suicidal endorsement after traumatic brain injury (TBI).

PARTICIPANTS

Adults with moderate to severe TBI (acute serum levels: n=48, n=543 samples; acute CSF levels: n=37, n=389 samples; chronic serum levels: n=48, n=326 samples).

MAIN MEASURES

TNFα levels (CSF, Serum) from time of injury to 12 months post-injury; Frontal Systems Behavior Scale - Disinhibition Subscale at 6 and 12 months post-injury; Patient Health Questionnaire at 6 and 12 months post-injury.

RESULTS

Participants with TBI had significantly higher CSF and serum TNFα levels than healthy controls (p<0.05). Acute and chronic serum TNFα was significantly associated with disinhibition at 6 months post-injury (p=0.009, p=0.029 respectively), and 6 month disinhibition was associated with suicidal endorsement at both 6 and 12 months (p=0.045, p=0.033 respectively) and disinhibition at 12 months post-injury (p<0.001).

CONCLUSION

These preliminary data suggest a biological to behavioral pathway of suicidality after TBI, from TNFα to disinhibition to suicidal endorsement. Future investigation is warranted to validate these findings and clarify what biological mechanisms might underlie these relationships.

Impulsive choice and psychological pain in acutely suicidal depressed patients

OBJECTIVE

Despite identification of several risk factors, suicide prediction and prevention is still a clinical challenge. Suicide can be seen as a consequence of poor decision making triggered by overwhelming psychological pain. We examined the relationship of choice impulsivity and psychological pain in depressed patients with acute suicidality.

METHODS

Impulsive choice (delay discounting), psychological pain, and clinical characteristics were assessed in four groups of adults (N = 20-22): a) depressed patients within 72 hours after a suicide attempt, b) depressed patients with active suicidal ideation, c) nonsuicidal depressed patients, and d) healthy controls.

RESULTS

Impulsive choice was higher in the suicide attempt (0.114 [0.027]) and ideation (0.099 [0.020]) groups compared with nonsuicidal depressed (0.079 [0.020]) and healthy (0.066 [0.019]) individuals (F(3,79) = 3.06, p = .042). Psychological pain data showed a similar profile (F(3,78) = 43.48, p < .001), with 43.4 (2.9) rating of psychological pain for the suicide attempt, 54.3 (2.2) for suicide ideation, 37.0 (3.2) for nonsuicidal depressed, and 13.7 (0.5) for healthy groups. Within the suicide attempt group, persisting suicidal ideation was associated with more severe depression (36.6 [2.9] versus 21.5 [3.1], p = .007) and choice impulsivity (0.134 [0.03] versus 0.078 [0.04], p = .015). Both measures normalized within a week: depression (29.9 [2.6] versus 14.4 [3.0], p = .006) and choice impulsivity (0.114 [0.026] versus 0.066 [0.032], p = .019).

CONCLUSIONS

Transient impulsive choice abnormalities are found in a subset of those who attempt suicide. Both, suicidal ideation and behavior were associated with choice impulsivity and intense psychological pain.

Neuropsychological function and suicidal behavior: attention control, memory and executive dysfunction in suicide attempt

BACKGROUND

Executive dysfunction, distinct from other cognitive deficits in depression, has been associated with suicidal behavior. However, this dysfunction is not found consistently across samples.

METHOD

Medication-free subjects with DSM-IV major depressive episode (major depressive disorder and bipolar type I disorder) and a past history of suicidal behavior (n = 72) were compared to medication-free depressed subjects with no history of suicidal behavior (n = 80) and healthy volunteers (n = 56) on a battery of tests assessing neuropsychological functions typically affected by depression (motor and psychomotor speed, attention, memory) and executive functions reportedly impaired in suicide attempters (abstract/contingent learning, working memory, language fluency, impulse control).

RESULTS

All of the depressed subjects performed worse than healthy volunteers on motor, psychomotor and language fluency tasks. Past suicide attempters, in turn, performed worse than depressed non-attempters on attention and memory/working memory tasks [a computerized Stroop task, the Buschke Selective Reminding Task (SRT), the Benton Visual Retention Test (VRT) and an N-back task] but not on other executive function measures, including a task associated with ventral prefrontal function (Object Alternation). Deficits were not accounted for by current suicidal ideation or the lethality of past attempts. A small subsample of those using a violent method in their most lethal attempt showed a pattern of poor executive performance.

CONCLUSIONS

Deficits in specific components of attention control, memory and working memory were associated with suicidal behavior in a sample where non-violent attempt predominated. Broader executive dysfunction in depression may be associated with specific forms of suicidal behavior, rather than suicidal behavior per se.

Possible association between suicide committed under influence of ethanol and a variant in the AUTS2 gene

Background

rs6943555 in AUTS2 has been shown to modulate ethanol consumption. We hypothesized that rs6943555 might be associated with completed suicide.

Methods

We genotyped rs6943555 in 625 completed suicides and 3861 controls using real-time TaqMan Allelic Discrimination Assay. All individuals were Polish Caucasians.

Results

We detected an association between suicide and rs6943555 A allele (OR = 1.17, P = 0.018 for allelic comparison, OR = 1.24, P = 0.013 for dominant, and OR = 1.18, P = 0.020 for co-dominant model of inheritance). The association remained significant after adjusting for age and gender (co-dominant: P = 0.002 and dominant model: P = 0.001). After stratifying suicides according to blood ethanol concentration (BAC≤ 20 mg/dl and BAC > 20 mg/dl) the association remained significant only for cases who committed suicide under influence of alcohol (co-dominant: OR  =  1.37, P = 0.004 and dominant model: OR = 1.45, P = 0.006). To validate this finding we genotyped another cohort of 132 cases. We reproduced the association between rs6943555 A allele and suicide under influence of ethanol (allelic comparison: OR = 1.55, P = 0.023; co-dominant : OR = 1.54, P = 0.031; dominant model: OR = 1.84, P = 0.015). Analyzing pooled suicides with BAC >20 mg/dl (N = 300) we found the association of rs6943555 A allele not only vs. controls (allelic OR = 1.41, P = 0.00029) but also vs. cases with BAC ≤ 20 mg/dl (N = 449, allelic OR = 1.33, P = 0.019).

Conclusions

In our study rs6943555 A allele is associated with suicide committed after drinking ethanol shortly before death. The rs6943555 A allele may be linked to adverse emotional reaction to ethanol, which could explain the association with lower consumption in general population as well as the predisposition to suicide under influence of ethanol.