First-degree relatives of suicide completers may have impaired decision-making but functional cognitive control

Risks and familial coaggregation of death by suicide, accidental death and major psychiatric disorders in first-degree relatives of individuals who died by suicide

BACKGROUND

Evidence suggests a familial coaggregation of major psychiatric disorders, including schizophrenia, bipolar disorder, major depression (MDD), autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD). Those disorders are further related to suicide and accidental death. However, whether death by suicide may coaggregate with accidental death and major psychiatric disorders within families remains unclear.

AIMS

To clarify the familial coaggregation of deaths by suicide with accidental death and five major psychiatric disorders.

METHOD

Using a database linked to the entire Taiwanese population, 68 214 first-degree relatives of individuals who died by suicide between 2003 and 2017 and 272 856 age- and gender-matched controls were assessed for the risks of death by suicide, accidental death and major psychiatric disorders.

RESULTS

A Poisson regression model showed that the first-degree relatives of individuals who died by suicide were more likely to die by suicide (relative risk RR = 4.61, 95% CI 4.02-5.29) or accident (RR = 1.62, 95% CI 1.43-1.84) or to be diagnosed with schizophrenia (RR = 1.53, 95% CI 1.40-1.66), bipolar disorder (RR = 1.99, 95% CI 1.83-2.16), MDD (RR = 1.98, 95% CI 1.89-2.08) or ADHD (RR = 1.34, 95% CI 1.24-1.44).

CONCLUSIONS

Our findings identified a familial coaggregation of death by suicide with accidental death, schizophrenia, major affective disorders and ADHD. Further studies would be required to elucidate the pathological mechanisms underlying this coaggregation.

Hippocampal neuropathology in suicide: Gaps in our knowledge and opportunities for a breakthrough

Suicide is a major global hazard. There is a need for increasing suicide awareness and effective and evidence-based interventions, targeting both suicidal ideation and conduct. However, anti-suicide pharmacological effects are unsatisfactory. The human hippocampus is vulnerable to neuropsychiatric damages and subsequently releases psychobiological signals. Human hippocampal studies of suicide completers have shown mechanistic changes in neurobiology, which, however, could not reflect the neuropathological 'fingerprints' of fatal suicide ideations and suicide attempts. In this review, we provide several leading theories of suicide, including the serotoninergic system, Wnt pathway and brain-derived neurotrophic factor/tropomyosin receptor kinase B signalling, and discuss the evidence for their roles in suicide and treatment. Moreover, the cognitive dysfunctions associated with suicide risk are discussed, as well as the novel evidence on cognitive therapies that decrease suicidal ideation. We highlight the need to apply multi-omics techniques (including single-nucleus RNA sequencing and mass spectrometry histochemistry) on hippocampal samples from donors who died by suicide or legal euthanasia, to clarify the aetiology of suicide and propose novel therapeutic strategies.

Decision-making and cognitive control in adolescent suicidal behaviors: a qualitative systematic review of the literature

Suicide and suicidal behaviors represent a leading cause of morbidity and mortality during adolescence. While several lines of evidence suggest that suicidal behaviors are associated with risky decisions and deficient cognitive control in laboratory tasks in adults, comparatively less is known about adolescents. Here, we systematically reviewed the literature on the association between these neurocognitive variables and adolescent suicidal behaviors. The online search strategy identified 17 neurocognitive studies examining either cognitive control or decision-making processes in adolescents with past suicidal behaviors. Several studies have reported that adolescents with a history of suicidal behaviors present neuropsychological differences in the cognitive control (using Go/NoGo, suicide Stroop Test, continuous performance test, suicide/death Implicit Association Test), and decision-making (Iowa Gambling Task, Cambridge Gambling Task, cost computation, delay discounting, loss aversion tasks) domains. Due to a lack of replication or conflicting findings, our systematic review suggests that no firm conclusion can be drawn as to whether altered decision-making or poor cognitive control contribute to adolescent suicidal behaviors. However, these results collectively suggest that further research is warranted. Limitations included scarcity of longitudinal studies and a lack of homogeneity in study designs, which precluded quantitative analysis. We propose remediating ways to continue neuropsychological investigations of suicide risk in adolescence, which could lead to the identification of novel therapeutic targets and predictive markers, enabling early intervention in suicidal youth.

Functional network alterations differently associated with suicidal ideas and acts in depressed patients: an indirect support to the transition model

The transition from suicidal ideas to a suicide act is an important topic of research for the identification of those patients at risk of acting out. We investigated here whether specific brain activity and connectivity measures at rest may be differently associated with suicidal thoughts and behaviors. A large sample of acutely depressed patients with major depressive disorder was recruited in three different centers (Montreal/Canada, Stanford/USA, and Jena/Germany), covering four different phenotypes: patients with a past history of suicide attempt (n = 53), patients with current suicidal ideas but no past history of suicide attempt (n = 40), patients without current suicidal ideation nor past suicide attempts (n = 42), and healthy comparison subjects (n = 107). 3-T resting-state functional magnetic resonance imaging (fMRI) measures of the amplitude of low-frequency fluctuation (ALFF) and degree centrality (DC) were obtained and examined in a whole-brain data-driven analysis. Past suicide attempt was associated with a double cortico-subcortical dissociation in ALFF values. Decreased ALFF and DC values mainly in a frontoparietal network and increased ALFF values in some subcortical regions (hippocampus and thalamus) distinguished suicide attempters from suicide ideators, patient controls, and healthy controls. No clear neural differences were identified in relation to suicidal ideas. Suicide attempters appear to be a distinct subgroup of patients with widespread brain alterations in functional activity and connectivity that could represent factors of vulnerability. Our results also indirectly support at the neurobiological level the relevance of the transition model described at the psychological and clinical levels. The brain bases of suicidal ideas occurrence in depressed individuals needs further investigations.

Risky decision-making in suicide attempters, and the choice of a violent suicidal means: an updated meta-analysis

BACKGROUND

Studies showed disadvantageous decision-making in suicide attempters. The present meta-analysis aims to examine the stability of these findings and related questions.

METHODS

EMBASE and Pubmed databases were searched for studies published between 01/01/2000 and 01/01/2020 with an additional search through bibliographical references. English or French articles published in peer-reviewed journals, reporting quantitative task-based measures of decision-making in suicide attempters were included: 3,582 records were identified, 33 full-text articles screened, and 21 articles finally included.

RESULTS

All studies were conducted in mood disorders; 18 used the Iowa Gambling Task (IGT) and 3 the Cambridge Gamble Task (CGT). With the IGT, suicide attempters showed riskier choices than patient controls (Hedges' g=-0.28 95%CI (-0.44 - -0.12)) and healthy controls (g=-0.54 (-0.83 - -0.25)) with no significant difference between control groups. The difference between suicide attempters and patient controls was not related to age group, mood disorder type, author, or research center while an effect of time of publication was found (p=0.006). Poorer performance was also found in suicide attempters compared to patient controls when using the CGT (g=-0.57 95%CI (-0.82 - -0.31)). Suicide attempters who used a violent means showed poorer IGT performance than those who used a non-violent means (3 studies).

LIMITATION

Limited number of studies outside mood disorders. No data to calculate a gender effect.

CONCLUSION

The present meta-analysis confirmed riskier decision-making in suicide attempters. Although group differences appear to be of modest effect size in general, they were particularly marked in the subgroup of those who used a violent suicidal means.

Association between family history of suicide attempt and neurocognitive functioning in community youth

BACKGROUND

Suicidal behavior is highly familial. Neurocognitive deficits have been proposed as an endophenotype for suicide risk that may contribute to the familial transmission of suicide. Yet, there is a lack of research on the neurocognitive functioning of first-degree biological relatives of suicide attempters. The aim of the present study is to conduct the largest investigation to date of neurocognitive functioning in community youth with a family history of a fatal or nonfatal suicide attempt (FH).

METHODS

Participants aged 8-21 years from the Philadelphia Neurodevelopmental Cohort completed detailed clinical and neurocognitive evaluations. A subsample of 501 participants with a FH was matched to a comparison group of 3,006 participants without a family history of suicide attempt (no-FH) on age, sex, race, and lifetime depression.

RESULTS

After adjusting for multiple comparisons and including relevant clinical and demographic covariates, youth with a FH had significantly lower executive function factor scores (F[1,3432] = 6.63, p = .010) and performed worse on individual tests of attention (F[1,3382] = 7.08, p = .008) and language reasoning (F[1,3387] = 5.12, p = .024) than no-FH youth.

CONCLUSIONS

Youth with a FH show small differences in executive function, attention, and language reasoning compared to youth without a FH. Further research is warranted to investigate neurocognitive functioning as an endophenotype for suicide risk. Implications for the prevention and treatment of suicidal behaviors are discussed.

Toxoplasma gondii, Suicidal Behavior, and Intermediate Phenotypes for Suicidal Behavior

Within the general literature on infections and suicidal behavior, studies on Toxoplasma gondii (T. gondii) occupy a central position. This is related to the parasite's neurotropism, high prevalence of chronic infection, as well as specific and non-specific behavioral alterations in rodents that lead to increased risk taking, which are recapitulated in humans by T. gondii's associations with suicidal behavior, as well as trait impulsivity and aggression, mental illness and traffic accidents. This paper is a detailed review of the associations between T. gondii serology and suicidal behavior, a field of study that started 15 years ago with our publication of associations between T. gondii IgG serology and suicidal behavior in persons with mood disorders. This "legacy" article presents, chronologically, our primary studies in individuals with mood disorders and schizophrenia in Germany, recent attempters in Sweden, and in a large cohort of mothers in Denmark. Then, it reviews findings from all three meta-analyses published to date, confirming our reported associations and overall consistent in effect size [ranging between 39 and 57% elevation of odds of suicide attempt in T. gondii immunoglobulin (IgG) positives]. Finally, the article introduces certain links between T. gondii and biomarkers previously associated with suicidal behavior (kynurenines, phenylalanine/tyrosine), intermediate phenotypes of suicidal behavior (impulsivity, aggression) and state-dependent suicide risk factors (hopelessness/dysphoria, sleep impairment). In sum, an abundance of evidence supports a positive link between suicide attempts (but not suicidal ideation) and T. gondii IgG (but not IgM) seropositivity and serointensity. Trait impulsivity and aggression, endophenotypes of suicidal behavior have also been positively associated with T. gondii seropositivity in both the psychiatrically healthy as well as in patients with Intermittent Explosive Disorder. Yet, causality has not been demonstrated. Thus, randomized interventional studies are necessary to advance causal inferences and, if causality is confirmed, to provide hope that an etiological treatment for a distinct subgroup of individuals at an increased risk for suicide could emerge.

Cognition in offspring of parents with psychotic and non-psychotic severe mental illness

BACKGROUND

Cognitive impairment is a feature of severe mental illness (SMI; schizophrenia, bipolar disorder, major depressive disorder). Psychotic forms of SMI may be associated with greater cognitive impairment, but it is unclear if this differential impairment pre-dates illness onset or whether it reflects a consequence of the disorder. To establish if there is a developmental impairment related to familial risk of psychotic SMI, we investigated cognition in offspring of parents with psychotic and non-psychotic SMI.

METHOD

Participants included 360 children and youth (mean age 11.10, SD 4.03, range 6-24), including 68 offspring of parents with psychotic SMI, 193 offspring of parents with non-psychotic SMI, and 99 offspring of control parents. The cognitive battery assessed a range of functions using standardized tests and executive function tasks from the Cambridge Automated Neuropsychological Test Battery.

RESULTS

Compared to controls, offspring of parents with psychotic SMI performed worse on overall cognition (β = -0.32; p < 0.001) and 6 of 15 cognitive domains, including verbal intelligence, verbal working memory, processing speed, verbal learning and memory, verbal fluency, and sustained attention. Offspring of parents with non-psychotic SMI performed worse than controls on 3 of the 15 domain specific cognitive tests, including verbal intelligence, visual memory and decision-making.

CONCLUSIONS

Widespread mild-to-moderate cognitive impairments are present in young offspring at familial risk for transdiagnostic psychotic SMI. Offspring at familial risk for non-psychotic SMI showed fewer and more specific impairments in the domains of verbal intelligence, visual memory and decision-making.

Prevalence and psychopathologic significance of hallucinations in individuals with a history of seizures

OBJECTIVE

A relationship between seizure activity and hallucinations is well established. The psychopathologic significance of hallucinations in individuals with seizures, however, is unclear. In this study, we assessed the prevalence of auditory and visual hallucinations in individuals who reported a seizure history and investigated their relationship with a number of mental disorders, suicidal ideation, and suicide attempts.

METHODS

Data were from the "Adult Psychiatric Morbidity Survey," a population-based cross-sectional survey. Auditory and visual hallucinations were assessed using the Psychosis Screening Questionnaire. Mental health disorders were assessed using the Clinical Interview Schedule. Logistic regressions assessed relationships between hallucinatory experiences and mental disorders, suicidal ideation, and suicide attempts.

RESULTS

A total of 14 812 adults (58% female; mean [standard error of the mean; SEM] age 51.8 [0.15]) completed the study; 1.39% reported having ever had seizures (54% female), and 8% of individuals with a seizure history reported hallucinatory experiences (odds ratio [OR] 2.05, 95% confidence interval [CI] 1.24-3.38). Individuals with seizures had an increased odds of having any mental disorder (OR 2.34, 95% CI 1.73-3.16), suicidal ideation (OR 2.38, 95% CI 1.77-3.20), and suicide attempt (OR 4.15, 95% CI 2.91-5.92). Compared to individuals with seizures who did not report hallucinatory experiences, individuals with seizures who reported hallucinatory experiences had an increased odds of any mental disorder (OR 3.47, 95% CI 1.14-10.56), suicidal ideation (OR 2.58, 95% CI 0.87-7.63), and suicide attempt (OR 4.61, 95% CI 1.56-13.65). Overall, more than half of individuals with a seizure history who reported hallucinatory experiences had at least one suicide attempt. Adjusting for psychopathology severity did not account for the relationship between hallucinatory experiences and suicide attempts.

SIGNIFICANCE

Hallucinatory experiences in individuals with seizures are markers of high risk for mental health disorders and suicidal behavior. There is a particularly strong relationship between hallucinations and suicide attempts in individuals with seizures. Clinicians working with individuals with seizures should routinely ask about hallucinatory experiences.

New directions in behavioral activation: Using findings from basic science and translational neuroscience to inform the exploration of potential mechanisms of change

Interest in behavioral activation treatments for depression has increased over the past two decades. Behavioral activation treatments have been shown to be effective in treating depression across a variety of populations and settings. However, little is known about the mechanisms of change that may bring about symptom improvement in behavioral activation treatments. Recent developments in the theoretical and empirical literature on behavioral activation treatments have coincided with advances in basic science and translational neuroscience regarding the mechanisms underlying individual differences in responsiveness to reward. Attenuated reward responsiveness has been associated with depression and related clinical outcomes at the self-report, behavioral, and neural levels of analysis. Given that behavioral activation treatments are focused on increasing individuals' contact and engagement with sustainable sources of reward in their environment, it is plausible that behavioral activation treatments bring about improvements in depression symptoms by targeting (low) reward responsiveness directly. This paper integrates findings from the clinical research literature on behavioral activation treatments with insights drawn from basic science and translational neuroscience in order to propose hypotheses about potential mechanisms of change in behavioral activation. Conceptual issues and recommendations for future research on behavioral activation treatments are discussed.

Prospective Investigation of the Interaction Between Social Problems and Neuropsychological Characteristics on the Development of Suicide Ideation

OBJECTIVE

Negative social interactions are known to contribute to the development of suicide ideation. However, it is unclear how this risk factor interacts with other predisposing risk factors. The purpose of this study was to determine how social and neuropsychological factors interact as a prospective predictor of the emergence of suicide ideation in adolescents.

METHOD

Data were collected from adolescents (M age = 13.12, SD = 1.48) over 3 years as part of a larger study. Participants completed the MINI-Kid and Youth Self-Report, which were used to assess for suicidality. Negative social interactions were operationalized as the Social Problems scale of the YSR. Additionally, adolescents completed a neuropsychological battery at each wave of data collection.

RESULTS

Logistic moderation analyses demonstrated a significant interaction between task switching and endorsement of negative social interactions in the prediction of suicide ideation one year later, Wald χ² (1) = 4.94, OR = 0.90, p < .05. Distractibility was a significant predictor, Wald χ² (1) = 5.52, OR = 3.45, p < .05, but it did not demonstrate an interaction effect. Perseveration failed to reach statistical significance independently and in the interaction.

CONCLUSIONS

The results indicate that certain neuropsychological characteristics can aid in predicting which adolescents will develop suicide ideation in the presence of negative social interactions, which may have significant clinical implications.

Neural and neurocognitive markers of vulnerability to gambling disorder: a study of unaffected siblings

Psychological and neurobiological markers in individuals with gambling disorder (GD) could reflect transdiagnostic vulnerability to addiction or neuroadaptive consequences of long-term gambling. Using an endophenotypic approach to identify vulnerability markers, we tested the biological relatives of cases with GD. Male participants seeking treatment for GD (n = 20) were compared with a male control group (n = 18). Biological siblings of cases with GD (n = 17, unrelated to the current GD group) were compared with a separate control group (n = 19) that overlapped partially with the GD control group. Participants completed a comprehensive assessment of clinical scales, neurocognitive functioning, and fMRI of unexpected financial reward. The GD group displayed elevated levels of self-report impulsivity and delay discounting, and increased risk-taking on the Cambridge Gamble Task. We did not observe impaired motor impulsivity on the stop-signal task. Siblings of GD showed some overlapping effects; namely, elevated impulsivity (negative urgency) and increased risk-taking on the Cambridge Gamble Task. We did not observe any differences in the neural response to win outcomes, either in the GD or sibling analysis compared with their control group. Within the GD group, activity in the thalamus and caudate correlated negatively with gambling severity. Increased impulsivity and risk-taking in GD are present in biological relatives of cases with GD, suggesting these markers may represent pre-existing vulnerability to GD.

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.

Cognitive Performance in First-Degree Relatives of Individuals With vs Without Major Depressive Disorder: A Meta-analysis

IMPORTANCE

Findings of cognitive impairment in major depressive disorder (MDD), including remitted MDD, raise the question whether impaired cognition is part of preexisting vulnerability rather than a consequence of MDD or its treatment. To our knowledge, no meta-analyses have been published on cognitive impairment in first-degree relatives of individuals with MDD.

OBJECTIVE

To compare cognitive performance between individuals with and without family history of MDD.

DATA SOURCES

Medline/PubMed, PsycINFO, and Embase using combinations of search terms for depression, first-degree relatives, and cognition from January 1, 1980, to July 15, 2018.

STUDY SELECTION

Original articles that reported data on cognition in first-degree relatives of individuals with MDD compared with controls with no family history of major mental illness.

DATA EXTRACTION AND SYNTHESIS

Means and SDs were extracted, and standardized mean differences (SMD) between relatives and controls were calculated for each measure of cognitive performance. The relative-control differences in overall cognition and in specific cognitive domains were synthesized in random-effects meta-analyses with robust variance estimation that allows including multiple correlated measures of cognition within each study. Heterogeneity was quantified with τ2. Publication bias was assessed with funnel plots and Egger intercept.

MAIN OUTCOMES AND MEASURES

Performance on cognitive tests.

RESULTS

Across 284 measures of cognition in 54 nonoverlapping samples including 3246 relatives of people with MDD (mean age 15.38 years, 57.68% females) and 5222 controls (mean age 14.70 years, 55.93% females), relatives of people with MDD performed worse than controls across all measures of cognition (SMD = -0.19; 95% CI, -0.27 to -0.11; P < .001). Domain-specific meta-analyses showed similar size of relative-control difference in most domains of cognition, including Full-Scale IQ (SMD = -0.19), verbal intelligence (SMD = -0.29), perceptual intelligence (SMD = -0.23), memory (SMD = -0.20), academic performance (SMD = -0.40), and language (SMD = -0.29). Study characteristics were not significantly associated with observed between-group differences. There was no evidence of publication bias.

CONCLUSIONS AND RELEVANCE

A general impairment in cognition is a feature of familial disposition for MDD. Cognition may contribute to early identification of risk for depression and may be examined as potential target for early intervention.

Reward systems and cognitions in Major Depressive Disorder

A lack of motivation and anhedonia represent frequent and pervasive symptoms in depression, although with poor specificity. Historically described as a response bias, reward-related impairments in depression may account for the important aspects of the cognitive impairments associated with diagnosis of major depressive disorder. Reward processing is a broad psychological construct that can be parsed into 3 distinct components known as "reinforcement learning" (learning), "reward responsiveness" (liking), and "motivation to obtain a reward" (wanting). Depressed patients respond hyposensitively to reward and maladaptively to punishment: this pattern is related to a dysfunction in the frontostriatal systems modulated by the monoamine systems; seems to be observed in medicated and unmedicated patients with depression and in healthy individuals with high levels of anhedonia; and could be observed in patients with a history of depression, even when in full remission. Considered to be cognitive impairments, reward-related-impairments may also constitute part of an underlying neurobiological vulnerability to major depressive disorder (MDD). For example, the reward-related impairment is state dependent and, more or less, correlated with symptom severity in some studies but has also been proposed as being trait like, with endophenotype characteristics, possibly contributing to the persistence of the disease or treatment resistance. The 3 core aspects of reward processing have specific neurobiological correlates that involve the ventral and dorsal striatum, lateral habenula, ventral tegmental area, orbitofrontal cortex, anterior cingulate cortex, and ventromedial and dorsolateral prefrontal cortex. These structures underline the important role of the dopaminergic mesolimbic pathway, but glutamate and serotonin could also have an important role, at least in some aspects of reward-related impairments.

Understanding suicide: Focusing on its mechanisms through a lithium lens

BACKGROUND

Current intervention strategies have been slow in reducing suicide rates, particularly in mood disorders. Thus, for intervention and prevention, a new approach is necessary. Investigating the effects of a medication known for its anti-suicidal properties on neurobiological and neurocognitive substrates of suicidal thinking may provide a deeper and more meaningful understanding of suicide.

METHOD

A literature search of recognised databases was conducted to examine the intersection of suicide, mood disorders, and the mechanisms of lithium.

RESULTS

This review synthesises the extant evidence of putative suicide biomarkers and endophenotypes and melds these with known actions of lithium to provide a comprehensive picture of processes underlying suicide. Specifically, the central importance of glycogen synthase kinase-3β (GSK3β) is discussed in detail because it modulates multiple systems that have been repeatedly implicated in suicide, and which lithium also exerts effects on.

LIMITATIONS

Suicide also occurs outside of mood disorders but we limited our discussion to mood because of our focus on lithium and extending our existing model of suicidal thinking and behaviour that is contextualised within mood disorders.

CONCLUSIONS

Focusing on the neurobiological mechanisms underpinning suicidal thinking and behaviours through a lithium lens identifies important targets for assessment and intervention. The use of objective measures is critical and using these within a framework that integrates findings from different perspectives and domains of research is likely to yield replicable and validated markers that can be employed both clinically and for further investigation of this complex phenomenon.

Decision-making performance of depressed patients within 72 h following a suicide attempt

BACKGROUND

The significance of decision-making in suicidal behaviour is often highlighted; however, the performance of persons in suicide crisis is unknown. This study aimed to explore the comprehensive decision-making profile of depressed patients following a suicide attempt.

METHODS

Decision-making was measured by reward- ("ABCD") and punishment- ("EFGH") sensitive versions of the Iowa Gambling Task (IGT) in 59 medication-free depressed patients within 72 h after a suicide attempt and in 46 healthy control subjects. Severity of depressive symptoms was assessed in the patient group by the Hamilton Depression Rating Scale.

RESULTS

Performance of the two groups differed significantly on the IGT ABCD, while a trend towards significant differences was seen on the IGT EFGH. Severity of depressive symptoms did not affect the depressed participants' decision-making performance.

LIMITATIONS

Subjects were not matched for years of education. Administration of the IGT ABCD and IGT EFGH was not counterbalanced. Methods of suicide attempts and history of previous attempts were not collected.

CONCLUSIONS

Individuals with a recent suicide attempt showed decision-making dysfunction on both IGT versions. However, on the EFGH, the overall difference between groups was not significant, depressed participants' performance remained poor during all blocks. Their behaviour reflected a focus on best immediate possible outcomes, not regarding future adverse consequences. This could be a result of psychological and cognitive alterations which modulate suicidal behaviour independent from mood. Further longitudinal studies should verify this possibility. Investigation of state-dependent neuropsychological characteristics of suicidal behaviour might be essential for detecting acute suicidal crisis.

Neuroimaging-informed phenotypes of suicidal behavior: a family history of suicide and the use of a violent suicidal means

The identification of brain markers of suicidal risk is highly expected. However, neuroimaging studies have yielded mixed results, possibly due to phenotypic heterogeneity. In the present study, we addressed this issue using structural brain imaging. First, two independent samples of suicide attempters (n = 17 in Montreal, 32 in Jena), patient controls (n = 26/34), and healthy controls (n = 66/34) were scanned with magnetic resonance imaging. Groups were compared with FSL. We then reviewed the literature and run a GingerALE meta-analysis of 12 structural imaging studies comparing suicide attempters and patient controls with whole-brain analyses (n = 693). Finally, we explored the potential contribution of two variables previously associated with biological/cognitive deficits: a family history of suicide (FHoS), and the use of a violent suicidal means (VSM). Here, we added two groups of healthy first-degree biological relatives of suicide victims and depressed patients (n = 32). When comparing all suicide attempters and controls, very limited between-group differences were found in the two samples, and none in the meta-analysis. In contrast, a FHoS was associated with reduced volumes in bilateral temporal regions, right dorsolateral prefrontal cortex, and left putamen, several of these differences being observed across groups. VSM was associated with increased bilateral caudate (and left putamen) volumes. Some morphometric variations in cortico-subcortical networks may therefore be endophenotypes increasing the suicidal vulnerability, while others (notably in striatum) may modulate action selection. These results therefore confirm at the neural level two phenotypes at high lethal risk with a strong biological background, and uncover motives of heterogeneous findings in neuroimaging studies of suicidal behavior.

Outline of a sociology of decisionism

I propose an agenda for empirical research on decision, choice, decision-makers, and decision-making qua social facts. Given society S, group G, or field F, I make a twofold sociological proposal. First, empirically investigate the conditions under which something-call it X-is taken to be a decision or choice, or the outcome of a decision-making process. What must X be like? What doesn't count (besides, presumably, myotatic reflexes and blushing)? Whom or what must X be done by? What can't be a decision-maker (besides, presumably, rocks and apples)? Second, empirically investigate how decision/choice concepts are used in everyday life, politics, business, education, law, technology, and science. What are they used for? To what extent do people understand and represent themselves and others as decision-makers? Where do decision-centric or "decisionist" understandings succeed? These aren't armchair, theoretical, philosophical questions, but empirical ones. Decision/choice concepts' apparent ubiquity in contemporary societies calls for a well-thought-out research program on their social life and uses.

Altered brain processing of decision-making in healthy first-degree biological relatives of suicide completers

Suicidal behavior is heritable, with the transmission of risk being related to the transmission of vulnerability traits. Previous studies suggest that risky decision-making may be an endophenotype of suicide. Here, we aimed at investigating brain processing of decision-making in relatives of suicide completers in order to shed light on heritable mechanisms of suicidal vulnerability. Seventeen healthy first-degree biological relatives of suicide completers with no personal history of suicidal behavior, 16 relatives of depressed patients without any personal or family history of suicidal behavior, and 19 healthy controls were recruited. Functional 3 T magnetic resonance imaging scans were acquired while participants underwent the Iowa Gambling Task, an economic decision-making test. Whole-brain analyses contrasting activations during risky vs safe choices were conducted with AFNI and FSL. Individuals with a family history of suicide in comparison to control groups showed altered contrasts in left medial orbitofrontal cortex, and right dorsomedial prefrontal cortex. This pattern was different from the neural basis of familial depression. Moreover, controls in comparison to relatives showed increased contrast in several regions including the post-central gyrus, posterior cingulate and parietal cortices, and cerebellum (culmen) in familial suicide; and inferior parietal, temporal, occipital, anteromedial and dorsolateral prefrontal cortices, and cerebellum (vermis) in familial depression. These findings most likely represent a complex combination of vulnerability and protective mechanisms in relatives. They also support a significant role for deficient risk processing, and ventral and dorsal prefrontal cortex functioning in the suicidal diathesis.

Animal models to improve our understanding and treatment of suicidal behavior

Worldwide, suicide is a leading cause of death. Although a sizable proportion of deaths by suicide may be preventable, it is well documented that despite major governmental and international investments in research, education and clinical practice suicide rates have not diminished and are even increasing among several at-risk populations. Although nonhuman animals do not engage in suicidal behavior amenable to translational studies, we argue that animal model systems are necessary to investigate candidate endophenotypes of suicidal behavior and the neurobiology underlying these endophenotypes. Animal models are similarly a critical resource to help delineate treatment targets and pharmacological means to improve our ability to manage the risk of suicide. In particular, certain pathophysiological pathways to suicidal behavior, including stress and hypothalamic-pituitary-adrenal axis dysfunction, neurotransmitter system abnormalities, endocrine and neuroimmune changes, aggression, impulsivity and decision-making deficits, as well as the role of critical interactions between genetic and epigenetic factors, development and environmental risk factors can be modeled in laboratory animals. We broadly describe human biological findings, as well as protective effects of medications such as lithium, clozapine, and ketamine associated with modifying risk of engaging in suicidal behavior that are readily translatable to animal models. Endophenotypes of suicidal behavior, studied in animal models, are further useful for moving observed associations with harmful environmental factors (for example, childhood adversity, mechanical trauma aeroallergens, pathogens, inflammation triggers) from association to causation, and developing preventative strategies. Further study in animals will contribute to a more informed, comprehensive, accelerated and ultimately impactful suicide research portfolio.

Neuropsychological Markers of Suicidal Risk in the Context of Medical Rehabilitation

While great strides have been made to advance the understanding of the neurobiology of suicidal behavior (SB), the neural and neuropsychological mechanisms associated with SB are not well understood. The purpose of the current study is to identify neurocognitive markers of SB in the context of medical rehabilitation. The performances of 39 patients at a medical rehabilitation center, aged 21-78, were examined on a series of neurocognitive executive tasks-decision-making (Iowa Gambling Task - IGT), mental flexibility (WCST), response inhibition (SST) and working memory (digit span). Self-report questionnaires were administered, for Suicidal behaviors, depression, Anxiety, and PTSD as well as perceived social support. Suicidal participants performed more poorly on the IGT. A mediation analysis presented a significant direct effect of decision making on suicidal risk (p < 0.14) as well as significant indirect effect of decision making on suicidal risk that was mediated by the depressive symptoms (95% BCa CI [-0.15, -0.018]) with a medium effect size (κ² = 0.20, 95% BCa CI [0.067, 0.381]). Despite the complexity of relationship between decision-making and suicidal risk, these results suggest that clinicians should routinely assess decision-making abilities in adults at risk for suicide due to the fact that impaired decision-making may increase suicidal risk above and beyond that conferred by depression.

Cognitive, Emotional, Temperament, and Personality Trait Correlates of Suicidal Behavior

Suicide is one of the leading causes of violent death in many countries and its prevention is included in worldwide health objectives. Currently, the DSM-5 considers suicidal behavior as an entity that requires further study. Among the three validators required for considering a psychiatric disorder, there is one based on psychological correlates, biological markers, and patterns of comorbidity. This review includes the most important and recent studies on psychological factors: cognitive, emotional, temperament, and personality correlates (unrelated to diagnostic criteria). We included classic factors related to suicidal behavior such as cognitive, inflexibility, problem-solving, coping, rumination, thought suppression, decision-making, autobiographical memory, working memory, language fluency, burdensomeness, belongingness, fearless, pain insensitivity, impulsiveness, aggressiveness, and hopelessness. The personality correlates reported are mainly based on the personality theories of Cloninger, Costa and McCrae, and Eysenck. Moreover, it explores conceptual links to other new pathways in psychological factors, emptiness, and psychological pain as a possible origin and common end path for a portion of suicidal behaviors.

Spectroscopy markers of suicidal risk and mental pain in depressed patients

OBJECTIVE

Suicidal behavior has been associated with structural and functional impairments in neuroimaging studies, mainly localized in the prefrontal cortex. However, little is known of the in vivo biochemical alterations that could be markers of suicidal risk.

METHODS

Proton magnetic resonance spectroscopy was used to measure at-rest levels of 9 metabolites (glutamate, glutamine, glutathione, GABA, N-acetylaspartate (NAA), N-acetylaspartylglutamate, myo-inositol, aspartate, total choline), in the right dorsal prefrontal cortex of 25 unmedicated depressed patients, including 15 with a history of suicidal behavior, and 33 healthy controls. We compared metabolite levels between groups, and run correlations with 9 clinical variables relevant for suicide risk.

RESULTS

We found very significant associations between NAA levels and psychological pain measured by a simple analog scale (r=-0.47, p<10-3), and between choline levels and current suicidal ideas (r=0.53, p<10-3). These associations were independent from group, gender, age or depression level. While psychological pain and suicidal ideas were highly inter-correlated (r=0.61, p<10-3), the above-mentioned associations with compounds were independent. Mental pain was also correlated with Stroop interference, verbal fluency and (indirectly) decision-making, all cognitive measures previously associated with suicidal risk. Lower NAA levels, and higher glutamine levels were found in suicide attempters and in all patients relative to healthy controls, but these differences did not survive co-variation with age or Bonferroni's correction.

CONCLUSION

This preliminary study suggests that markers of impaired neuronal and glial functioning in right dorsal prefrontal cortex underlie cardinal symptoms of the suicidal crisis. Targeting this region may be relevant for the short-term suicidal prevention. This study also supports a dimensional perspective in research on suicidal behavior.

Prefrontal inositol levels and implicit decision-making in healthy individuals and depressed patients

Risky decision-making is found in several mental disorders and is associated with deleterious consequences. Current research aims at understanding the biological underpinnings of this complex cognitive function and the basis of individual variability. We used 3T proton Magnetic Resonance Spectroscopy to measure in vivo glutamate, GABA, N-acetyl-aspartate (NAA), and myo-inositol levels at rest in the right dorsal prefrontal cortex of 54 participants, comprising 24 unmedicated depressed patients and 30 healthy individuals. Participants were also tested with the Iowa Gambling Task (IGT), a classical measure of value-based decision-making. No group differences were found in terms of compound levels or decision-making performance. However, high inositol levels were associated with lower decision-making scores independently from group, notably during the initial stage of the task when explicit rules are still unknown and decisions are largely based on implicit processes (whole sample: F=4.0; p=0.02), with a large effect size (Cohen׳s d=0.8, 95% [0.2-1.5]). This effect was stronger when explicit knowledge was taken into account, with explicit knowledge showing an independent effect on performance. There was no association with other compounds. This study suggests, for the first time, a role for the inositol pathway on the implicit learning component of decision-making, without any direct effect on the explicit component. Hypothesized mechanisms implicate intracellular calcium modulation and subsequent synaptic plasticity. These findings represent a first step in the understanding of the biochemical mechanisms underlying decision-making and the identification of therapeutic targets. They also emphasize a dimensional approach in the study of the neurobiological determinants of mental disorders.

Iowa Gambling Task Performance in Elderly Persons with a Lifetime History of Suicidal Acts

OBJECTIVES

Suicide in the elderly is a major public health problem. In the present study, we aimed to further understand the mechanisms of suicidal vulnerability in the elderly, focusing on high-risk decision-making. This trait-like impairment has been extensively studied in adolescent and middle-aged suicide attempters, but less often in older persons.

DESIGN

Case-control study.

SETTING

Community and university hospital.

PARTICIPANTS

All participants were aged 65 and older. Thirty-five persons with a lifetime history of suicide attempts and depressive disorder were compared with 52 individuals with a past history of depressive disorder but no history suicidal acts, and 43 healthy comparison subjects.

MEASUREMENTS

The Iowa Gambling Task was used as a measure of value-based decision-making.

RESULTS

Taking into account age, sex, and Beck depression scores, no difference in decision-making performance was found between the three groups. The group of suicide attempters exhibited a significant heterogeneity, however, with those using violent means performing worse than non-violent attempters.

CONCLUSIONS

This study does not confirm the hypothesis of a significant role for poor Iowa Gambling Task performance as a general marker of suicidal behavior among the elderly but highlights its association with the specific subtype of violent suicidal attempters. Combined with previous findings among other age groups, it suggests that Iowa Gambling Task impairment may be a risk marker of vulnerability to violent suicidal acts. Future prospective studies should assess if this may represent a risk marker for suicide completion.

Cognitive inhibition in depression and suicidal behavior: a neuroimaging study

BACKGROUND

Cognitive inhibition deficits have previously been found in suicide attempters. This study examined the neural basis for these deficits in depressed patients with and without a history of suicidal behavior.

METHOD

Functional magnetic resonance imaging was used to measure brain activation during the Go/No-Go response inhibition task in 25 unmedicated and depressed middle-aged suicide attempters, 22 unmedicated depressed patient controls with no personal or family history of suicidal behavior, and 27 healthy controls. Whole-brain analyses were conducted with SPM12.

RESULTS

Suicide attempters exhibited an elevated number of commission errors relative to both control groups. However, suicide attempters did not differ from patient controls in terms of brain activation for any contrast. Analyses showed a significant association between depression and brain activation in the left inferior frontal gyrus and medial thalamus during Go v. No-Go, and in the bilateral parietal cortex and left orbitofrontal cortex during No-Go v. baseline. These regions were correlated with psychological pain, suicidal ideation and global functioning. There was no association between brain activation and personal histories of suicidal act.

CONCLUSIONS

Our study suggests that deficits in cognitive inhibition, in relation to the inferior frontal gyrus, thalamus, orbitofrontal cortex and parietal cortex, are related to the depressive state and not specifically to suicide vulnerability. We hypothesize that state-related deficits may add to trait-like cognitive impairments to facilitate suicidal acts. These different types of cognitive impairments may necessitate different therapeutic strategies for the prevention of suicide.

Can We Use Neurocognition to Predict Repetition of Self-Harm, and Why Might This Be Clinically Useful? A Perspective

Over 800,000 people die by suicide each year globally, with non-fatal self-harm 20 times more common. With each episode of self-harm, the risks of future self-harm and suicide increase, as well as personal and healthcare costs. Therefore, early delineation of those at high risk of future self-harm is important. Historically, research has focused on clinical and demographic factors, but risk assessments based on these have low sensitivity to predict repetition. Various neurocognitive factors have been associated with self-harming behavior, but it is less certain if we can use these factors clinically (i) as risk markers to predict future self-harm and (ii) to become therapeutic targets for interventions. Recent systematic reviews and meta-analyses of behavioral tasks and fMRI studies point to an emerging hypothesis for neurocognition in self-harm: an underactive pre-frontal cortex is unable to respond appropriately to non-emotional stimuli, or inhibit a hyperactive emotionally-/threat-driven limbic system. However, there is almost no imaging data examining repetition of self-harm. Extrapolating from the non-repetition data, there may be several potential neurocognitive targets for interventions to prevent repeat self-harm: cognitive training; pharmacological regimes to promote non-emotional neurocognition; or other techniques, such as repetitive transcranial magnetic stimulation. Hence, there is an urgent need for imaging studies examining repetition and to test specific hypotheses. Until we investigate the functional neurocognitive basis underlying repetition of self-harm in a systematic manner using second-generational imaging techniques, we will be unable to inform third-generational imaging and potential future clinical applications.