An examination of environmental and genetic contributions to the determinants of suicidal behavior among male twins

Differential Allelic Expression of HTR1B in Suicide Victims: Genetic and Epigenetic Effect of the Cis-Acting Variants

OBJECTIVES

In the present study, we tested the allelic imbalance of the C861G single nucleotide polymorphism (SNP) of HTR1B in the frontal cortex of suicide victims.

METHODS

The study was conducted using 3 sets of samples. First, C861G allele-specific mRNA levels in the frontal cortex were compared between suicide (n = 13) and nonsuicide controls (n = 13) from the Stanley Medical Research postmortem brain collection. Second, we tested common variants in the HTR1B promoter for linkage disequilibrium (LD) with the C861G variant in an unrelated sample of suicide attempters (SA; n = 38) and non-SA (NSA; n = 42). Finally, we performed a family-based association study of the C861G and promoter variants in 162 nuclear families using suicidal behavior severity scores as phenotype.

RESULTS

We observed no alterations in the C/G expression ratio in suicide victims compared to nonsuicide controls (p = 0.370). When comparing the LD between the C861G and cis-acting SNPs, we did not find any differences in SA and NSA. There was no association between preferential transmission of cis-acting SNPs and suicidal behavior severity scores in both maternal and paternal meiosis.

CONCLUSIONS

We found several promoter variants in LD that may potentially influence the allelic imbalance in the C861G variant. However, no evidence of allelic imbalance nor parent-of-origin effects of the C861G variant was observed in suicidal behavior. Further research is required to assess this marker in larger cohorts.

Military personnel compared to multiple suicide attempters: Interpersonal theory of suicide constructs

The current study aimed to address the discrepancy between suicide rates in the military and general population by comparing facets of the interpersonal theory of suicide between civilians with multiple suicide attempts and U.S. military personnel. Military personnel exhibited higher levels of capability for suicide but lower levels of perceived burdensomeness and thwarted belongingness than civilian multiple attempters. When comparing only personnel endorsing ideation and civilian multiple attempters, the significant difference for capability remained, but the differences for perceived burdensomeness and thwarted belongingness became nonsignificant. Results suggest the emergence of ideation places personnel at a greater risk for suicide than many civilian multiple attempters.

The role of emotion dysregulation: A longitudinal investigation of the interpersonal theory of suicide

Emotion dysregulation is considered to be transdiagnostic in nature, given its association with a variety of problem behaviors. Of concern, emotion dysregulation also may be associated with key components of the Interpersonal Theory of Suicide (ITS), namely suicidal desire and acquired capability for suicide (ACS; heightened fearlessness toward death and pain tolerance). ITS suggests that experiencing suicidal desire in conjunction with ACS leads to greater risk for suicide attempts. The present 4-wave longitudinal study tested bidirectional associations among emotion dysregulation, NSSI, ACS, and suicidal desire. Emotion dysregulation was associated with both desire and capability for suicide over time. Specifically, emotion dysregulation was associated with (1) higher levels of suicidal desire, (2) higher levels of NSSI, which in turn predicted higher ACS, and (3) lower ACS, suggesting that individuals with emotion dysregulation may find thoughts of death and pain more aversive. Thus, there are two separate paths for how emotion regulation leads to ACS, one path in which emotion dysregulation indirectly leads to ACS through NSSI, and one path in which emotion dysregulation protects against the development of ACS (note that higher levels of ACS alone are not sufficient to lead to a suicide attempt - suicidal desire also is required).

Suicidality and Other Health Risk Behaviors among Female Youth in Juvenile Detention

This study investigates suicidality and health-risk behaviors among female juvenile detainees and identifies the extent to which suicidal behaviors are correlated with other risky activities. This study also explores 12 health risk behaviors, their prevalence, and relative associations to suicidal behaviors within the sample-population. Researchers collected data from 104 female adolescents, ages 12 to 20, residing in a long-term, detention center in the southeastern region of the United States. Descriptive statistics and regression analysis were utilized. Suicidal ideations (40%) and suicide attempts (34%) were highly prevalent among female juvenile detainees. Results also suggest that the persistence of suicidal ideations was significantly influenced by exposure to various forms of interpersonal violence. Despite increased exposure to psychosocial factors strongly correlated to suicidal and high risk behaviors, little attention has been given to this particular population. Research recommendations are also discussed.

Non-suicidal self-injury and suicidal thoughts and behaviors: A study of the explanatory roles of the interpersonal theory variables among military service members and veterans

OBJECTIVE

Research has identified non-suicidal self-injury (NSSI) as a robust correlate of suicidal thoughts and behaviors; however, little is known regarding why these constructs may be related. Consistent with the interpersonal theory of suicide, this study investigated thwarted belongingness (TB), perceived burdensomeness (PB), and capability for suicide (CS) as explanatory links in the association between NSSI, ideation, and suicide attempt history.

METHOD

Military service members and veterans (N = 973; agemean = 29.9 years, 78.8% male, 63.8% Caucasian/White) completed measures of lifetime NSSI and suicide attempts; current suicidal ideation; TB, PB, and CS; and related psychiatric symptoms. Bootstrap moderated mediation analyses were employed to examine whether (a) TB moderated the mediating effect of PB on NSSI and ideation, (b) PB moderated the mediating effect of TB on NSSI and ideation, and (c) CS moderated the mediating effect of TB and PB on NSSI and attempts.

RESULTS

TB and PB significantly accounted for the relationship between lifetime NSSI and current ideation. TB did not moderate the mediating effect of PB on NSSI and ideation, and PB did not moderate the mediating effect of TB. However, CS significantly moderated the mediating effects of TB and PB on NSSI and attempt history.

CONCLUSIONS

The interpersonal theory of suicide hypotheses were partially supported. Consistent with the theory, the interaction of TB and PB only explained NSSI and attempt history among service members with high levels of CS. TB and PB only individually explained the association between lifetime NSSI and recent suicidal ideation. Prospective studies are warranted to replicate these findings across other military samples. (PsycINFO Database Record

A Social Exclusion Manipulation Interacts with Acquired Capability for Suicide to Predict Self-Aggressive Behaviors

The interpersonal theory of suicide posits that individuals who simultaneously experience high levels of thwarted belongingness, perceived burdensomeness, and acquired capability for suicide are at high risk for a lethal or near-lethal suicide attempt. Although supported by self-report studies, no study has examined facets of the theory experimentally. The present study aimed to examine the belongingness and capability components of the theory by testing whether experimentally manipulated social exclusion interacts with self-reported acquired capability to predict higher self-administered shock levels on a self-aggression paradigm. A sample of 253 students completed self-report measures and were then randomly assigned to a social exclusion manipulation condition (future alone, future belonging, no feedback). Participants then participated in the self-aggression paradigm. The positive association between acquired capability and self-aggression was strongest among participants in the future alone social exclusion condition. In those assigned to the future belonging or no feedback conditions, the association between acquired capability and self-aggression was non-significant. These findings provide modest experimental support for the interpersonal theory of suicide and highlight a potential mechanism through which social exclusion may impact suicide risk. Limitations and future research directions are discussed.

The interpersonal theory of suicide: A systematic review and meta-analysis of a decade of cross-national research

Over the past decade, the interpersonal theory of suicide has contributed to substantial advances in the scientific and clinical understanding of suicide and related conditions. The interpersonal theory of suicide posits that suicidal desire emerges when individuals experience intractable feelings of perceived burdensomeness and thwarted belongingness and near-lethal or lethal suicidal behavior occurs in the presence of suicidal desire and capability for suicide. A growing number of studies have tested these posited pathways in various samples; however, these findings have yet to be evaluated meta-analytically. This paper aimed to (a) conduct a systematic review of the unpublished and published, peer-reviewed literature examining the relationship between interpersonal theory constructs and suicidal thoughts and behaviors, (b) conduct meta-analyses testing the interpersonal theory hypotheses, and (c) evaluate the influence of various moderators on these relationships. Four electronic bibliographic databases were searched through the end of March, 2016: PubMed, Medline, PsycINFO, and Web of Science. Hypothesis-driven meta-analyses using random effects models were conducted using 122 distinct unpublished and published samples. Findings supported the interpersonal theory: the interaction between thwarted belongingness and perceived burdensomeness was significantly associated with suicidal ideation; and the interaction between thwarted belongingness, perceived burdensomeness, and capability for suicide was significantly related to a greater number of prior suicide attempts. However, effect sizes for these interactions were modest. Alternative configurations of theory variables were similarly useful for predicting suicide risk as theory-consistent pathways. We conclude with limitations and recommendations for the interpersonal theory as a framework for understanding the suicidal spectrum. (PsycINFO Database Record

Comparisons of the Interpersonal-Psychological Theory of Suicide Constructs Among Individuals Without Suicidality, Ideators, Planners, and Attempters

The Interpersonal-Psychological Theory of Suicide (IPTS) proposes that combinations of thwarted belongingness, perceived burdensomeness, and acquired capability lead to suicide ideation, planning, and attempting. We compared individuals with and without suicidality on thwarted belongingness and perceived burdensomeness, and compared a combined group of planners and attempters to ideators on fearlessness about death (one component of acquired capability). Individuals with suicidality had higher thwarted belongingness and perceived burdensomeness than individuals without suicidality. Planners and attempters did not have higher fearlessness about death than ideators. These findings partially support IPTS hypotheses. Assessing thwarted belongingness and perceived burdensomeness may improve suicide risk determination.

The role of stressful life events preceding death by suicide: Evidence from two samples of suicide decedents

Stressful life events (SLEs) are associated with increased risk for suicidal behavior. Less is known regarding the intensity of SLEs and how this may vary as a function of suicide attempt history. As a large percentage of suicide decedents do not have a history of suicidal behavior, SLEs precipitating suicide may help characterize suicidality in this understudied population. This paper examines the intensity, number, and accumulation of SLEs preceding death by suicide among decedents with varying suicide attempt histories. Suicide attempts, SLEs, and suicide methods were examined in two samples: 62 prison-based and 117 community-based suicide decedents. Regression was used to compare the level of stressor precipitating death by suicide in decedents who died on a first attempt versus multiple previous attempts. A non-significant trend was observed in the prison population which was supported by significant findings in the community-based sample. Decedents who died on a first attempt experienced a stressor of a lower magnitude when compared to decedents with multiple previous suicide attempts. We discuss the implications of these findings in relation to the stress-diathesis model for suicide.

Treating the Capability for Suicide: A Vital and Understudied Frontier in Suicide Prevention

Current efforts at suicide prevention center largely on reducing suicidal desire among individuals hospitalized for suicidality or being treated for related psychopathology. Such efforts have yielded evidence-based treatments, and yet the national suicide rate has continued to climb. We propose that this disconnect is heavily influenced by an unmet need to consider population-level interventions aimed at reducing the capability for suicide. Drawing on lessons learned from other public health phenomena that have seen drastic declines in frequency in recent decades (HIV, lung cancer, motor vehicle accidents), we propose that current suicidality treatment efforts trail current suicidality theories in their lack of focus on the extent to which individuals thinking about suicide are capable of transitioning from ideation to attempt. We summarize extant evidence for specific capability-centered approaches (e.g., means safety) and propose other options for improving our ability to address this largely overlooked variable. We also note that population-level approaches in this regard would represent an important opportunity to decrease risk in individuals who either lack access to evidence-based care or underreport suicidal ideation, as a reduced capability for suicide would theoretically diminish the potency of suicidal desire and, in this sense, lower the odds of a transition from ideation to attempt.

From ideation to action: recent advances in understanding suicide capability

Suicide capability is one of few risk factors associated with suicide attempts among ideators. In the decade since the Interpersonal Psychological Theory of Suicide introduced the concept of acquired capability (i.e. the ability to face the fear and pain associated with death), understanding of the capability to attempt suicide has grown. Acquired (e.g. NSSI), dispositional (e.g. genetic), and practical contributors (e.g. access to firearms) appear to influence suicide capability via mechanisms such as the fear of death, persistence through pain, and familiarity with suicide methods. Self-report methods have shown mixed results, highlighting the importance of developing behavioral measures of suicide capability.

Trait liabilities and specific promotive processes in psychopathology: The example of suicidal behavior

BACKGROUND

The RDoC matrix framework calls for investigation of mental health problems through analysis of core biobehavioral processes quantified and studied across multiple domains of measurement. Critics have raised concerns about RDoC, including overemphasis on biological concepts/measures and disregard for the principle of multifinality, which holds that identical biological predispositions can give rise to differing behavioral outcomes. The current work illustrates an ontogenetic process approach to addressing these concerns, focusing on biobehavioral traits corresponding to RDoC constructs as predictors, and suicidal behavior as the outcome variable.

METHOD

Data were collected from a young adult sample (N=105), preselected to enhance rates of suicidality. Participants completed self-report measures of traits (threat sensitivity, response inhibition) and suicide-specific processes.

RESULTS

We show that previously reported associations for traits of threat sensitivity and weak inhibitory control with suicidal behavior are mediated by more specific suicide-promoting processes-namely, thwarted belongingness, perceived burdensomeness, and capability for suicide.

LIMITATIONS

The sample was relatively small and the data were cross-sectional, limiting conclusions that can be drawn from the mediation analyses.

CONCLUSIONS

Given prior research documenting neurophysiological as well as psychological bases to these trait dispositions, the current work sets the stage for an intensive RDoC-oriented investigation of suicidal tendencies in which both traits and suicide-promoting processes are quantified using indicators from different domains of measurement. More broadly, this work illustrates how an RDoC research approach can contribute to a nuanced understanding of specific clinical problems, through consideration of how general biobehavioral liabilities interface with distinct problem-promoting processes.

Non-violent and violent forms of childhood abuse in the prediction of suicide attempts: Direct or indirect effects through psychiatric disorders?

BACKGROUND

Childhood abuse is linked to suicide. Potential pathways include the increased risk for the development of psychiatric disorders and the contribution of abuse to suicide capability. The current study compared the effects of childhood non-violent and violent abuse in the prediction of suicide attempts, and examined the potential mediated effects of psychiatric disorders.

METHODS

Data from the National Comorbidity Surveys were obtained. At baseline, assessments of childhood non-violent abuse (e.g., parental verbal abuse) and violent abuse (e.g., parental physical abuse, relative rape) were obtained. We also assessed for other adverse childhood experiences, baseline suicidal behaviors, and psychiatric disorders. At the ten-year follow-up, we assessed for psychiatric disorders and suicide attempts that had occurred over time.

RESULTS

Both non-violent and violent abuse predicted attempts, though participants experiencing violent abuse had significantly higher rates. Bootstrapped mediation analyses determined that the influence of non-violent abuse on suicide attempts was indirect, and exerted its influence through the psychiatric disorders that occurred during the ten-year follow-up.

LIMITATIONS

The study relied on retrospective reports of childhood abuse. Further, we could not clearly determine the temporal order of the psychiatric disorders and suicide attempts occurring over follow-up.

CONCLUSION

Different mechanisms may underlie the pathway between violent and non-violent abuse and suicide attempts. Verbal abuse may lead to negative cognitive styles and psychiatric disorders associated with suicidality; violent abuse may contribute to the capacity for suicide. Interventions may need to be specifically tailored to meet the distinct needs of individuals who have experienced past childhood abuse.

Thinking or doing? An examination of well-established suicide correlates within the ideation-to-action framework

Limited research has examined differences in well-established suicide correlates between individuals with various histories of suicidality within the ideation to action framework. We hypothesized that individuals without a history of elevated suicidality would exhibit lowest levels of suicide correlates (perceived burdensomeness, thwarted belongingness, emotion dysregulation, depressive symptoms), and group differences would not be present between those with a history of suicidal ideation relative to those with a history of suicide attempts on variables not theorized to contribute to the capability for suicide. Lastly, we hypothesized that those with a prior history of suicide attempt(s) would exhibit higher levels of lifetime painful and provocative events and fearlessness about death relative to those with a history of ideation only. A community sample of adults (N=378) recruited in part on the basis of a history of suicidality completed self-report questionnaires online. The results were largely consistent with our hypotheses. However, there were no differences in fearlessness about death between those with a history of suicidal ideation and those with a history of attempts. Many variables considered robust correlates of suicide may only directly relate to suicidal ideation rather than suicide attempts, thereby limiting their utility in understanding the transition from ideation to action.

Interaction between Methylation and CpG Single-Nucleotide Polymorphisms in the HTR2A Gene: Association Analysis with Suicide Attempt in Schizophrenia

Dysfunctional mechanisms in the serotonergic system have been implicated in suicidal behavior among patients with schizophrenia. However, previous association analyses of major serotonin genes have provided inconsistent findings regarding their role in suicidal behavior. The goal of the current study was to identify single-nucleotide polymorphisms (SNP) within HTR2A that directly affect CpG methylation sites in schizophrenic patients with suicidal behavior. Furthermore, direct methylation analysis was performed using genomic DNA from peripheral leukocytes employing bisulfite pyrosequencing to assess the contributions of six CpG sites in HTR2A exon I in 67 schizophrenia patients assessed for lifetime suicide attempt. Potential methylation in 25 CpG SNPs across the entire HTR2A gene was analyzed considering their direct contribution to methylation. When we compared direct methylation between attempters and nonattempters, we found that only the polymorphic T102C (rs6313) was significantly different between the two groups (p = 0.02). Furthermore, in the potential methylation analysis, we found a nominal association with suicide attempt for six of the 25 SNPs analyzed, i.e. rs2770293 (p = 0.045), rs6313 (p = 0.033), rs17068986 (p = 0.029), rs4942578 (p = 0.024), rs1728872 (p = 0.014), and rs9534511 (p = 0.003). The results of this investigation provide preliminary evidence that the combined analysis of CpG SNPs and methylation may be useful for investigating the genetic and epigenetic factors involved in suicidal behavior.

The Interactive Effect of Major Depression and Nonsuicidal Self-Injury on Current Suicide Risk and Lifetime Suicide Attempts

This study examined the main and interactive effects of MDD and lifetime nonsuicidal self-injury (NSSI) on current suicide risk and past suicide attempts. We predicted that individuals with a history of NSSI and current MDD would be at greater suicide risk than those with either risk factor alone. An interaction between lifetime MDD and NSSI was hypothesized for past suicide attempts. 204 substance dependent inpatients completed self-report measures and a diagnostic interview. Patients with both a history of NSSI and current MDD, relative to all other groups, had the greatest suicide risk. No support was found for the lifetime MDD by NSSI interaction.

CONCLUSION

Findings suggest the relevance of both NSSI and MDD in suicide risk.

An Aspect of the Capability for Suicide-Fearlessness of the Pain Involved in Dying-Amplifies the Association Between Suicide Ideation and Attempts

The interpersonal theory of suicide posits that individuals who experience suicide ideation will only develop suicidal intent, and subsequently engage in suicidal behavior when they have concomitant fearlessness about death and tolerance for physical pain (i.e., the capability for suicide). The current studies examined the hypothesis that one aspect of the capability for suicide-fearlessness of the pain involved in dying-would amplify the positive association between current suicide ideation and a previous suicide attempt in two samples at high risk for experiencing suicide ideation and suicide attempts. Study 1 examined this relation using self-report methods in a sample of adults entering treatment in a mental health outpatient clinic. Study 2 utilized similar methods in a sample of adults admitted to inpatient psychiatry. Both studies indicated that those individuals who reported suicide ideation were more likely than non-ideators to report having attempted suicide only if they also reported greater fearlessness of the pain involved in dying. The current findings support the theorized role of the capability for suicide in the transition from ideation to attempt and also support assessing the capability for suicide in risk assessment.

Life experiences and the acquired capability for suicide in incarcerated men

Suicide is a leading cause of death in U.S. prisons. Prisoners may be at risk for suicide due to their greater likelihood of experiencing events that promote the acquired capability for suicide. The current study examined the associations of 10 domains of life experiences with the acquired capability for suicide in 399 male prisoners. All life experience domains were associated with acquired capability with certain domains evidencing relatively stronger relations. Results support that aggression, thrill seeking, suicidal thoughts and behaviors, and accidental injury may be particularly important to the development of the acquired capability for suicide in prisoners.

Understanding suicide among older adults: a review of psychological and sociological theories of suicide

OBJECTIVES

Older adults die by suicide at a higher rate than any other age group in nearly every country globally. Suicide among older adults has been an intractable clinical and epidemiological problem for decades, due in part to an incomplete understanding of the causes of suicide, as well as imprecision in the prediction and prevention of suicidal thoughts and behaviors in later life. Theory-driven investigations hold promise in addressing these gaps by systematically identifying testable, and thus falsifiable, mechanisms that may better explain this phenomenon and also point to specific interventions.

METHOD

In this article, we comprehensively review key extant psychological and sociological theories of suicide and discuss each theory's applicability to the understanding and prevention of suicide among older adults.

RESULTS

Despite a modest number of theories of suicide, few have undergone extensive empirical investigation and scrutiny, and even fewer have been applied specifically to older adults.

CONCLUSION

To advance the science and contribute findings with a measurable clinical and public health impact, future research in this area, from conceptual to applied, must draw from and integrate theory.

Understanding the Relationship Between Suicidality and Psychopathy: An Examination of the Interpersonal-Psychological Theory of Suicidal Behavior

A number of studies have reported a bifurcated relationship between psychopathy and suicidality, such that suicidality is positively related to Factor 2 (impulsive-antisocial lifestyle) of psychopathy but negatively related or unrelated to Factor 1 (affective-interpersonal deficits). The present study aims to expand these findings by investigating this relationship through the lens of the interpersonal-psychological theory of suicidal behavior across both undergraduate and forensic samples. We hypothesized that, although both Factors 1 and 2 would be associated with the acquired capability for suicide, Factor 2 would exhibit a unique relationship with suicidal desire (perceived burdensomeness and thwarted belongingness). Results were largely supportive of these hypotheses, although differences were noted across samples and measures. Findings highlight the importance of precision in the assessment of antisociality and suggest potential differences in the construct of psychopathy between non-criminal and criminal samples.

A test of the interpersonal theory of suicide in a large sample of current firefighters

Recent research suggests that firefighters experience elevated rates of suicidal ideation and behaviors. The interpersonal theory of suicide may shed light on this finding. This theory postulates that suicidal desire is strongest among individuals experiencing perceived burdensomeness and thwarted belongingness, and that the combination of suicide desire and acquired capability for suicide is necessary for the development of suicidal behaviors. We tested the propositions of the interpersonal theory in a large sample of current United States firefighters (N=863). Participants completed self-report measures of perceived burdensomeness, thwarted belongingness, fearlessness about death (FAD; a component of acquired capability), and career suicidal ideation and suicide attempt history. Regression models were used to examine the association between interpersonal theory constructs, career suicidal ideation severity, and the presence of career suicide attempts. In line with theory predictions, the three-way interaction between perceived burdensomeness, thwarted belongingness, and FAD was significantly associated with career suicide attempts, beyond participant sex. However, findings were no longer significant after accounting for years of firefighter service or age. Contrary to predictions, the two-way interaction between perceived burdensomeness and thwarted belongingness was not significantly related to career suicidal ideation severity. Applications of the theory to firefighters and future research are discussed.

Subjective pain during NSSI as an active agent in suicide risk

Non-suicidal self-injury (NSSI) has been identified as a correlate and predictor of suicidal ideation and attempts. Given the high-rates of NSSI presence among adolescents and young adults, it is important to identify specific characteristics of NSSI that might place individuals who engage in this behavior at highest risk for suicidal behavior. NSSI is thought to increase the acquired capability for suicide via habituation to self-harm, though the NSSI characteristics most responsible for this relationship are unclear. The current study examined three characteristics of NSSI (frequency, number of methods, and subjective pain) that may help to elucidate this risk relationship. University students (N=997) with a history of NSSI completed measures assessing lifetime NSSI frequency, number of NSSI methods employed, and subjective experience of pain during NSSI, as well as suicide attempt (SA) history. Results indicated that NSSI frequency, number of NSSI methods, and subjective pain experienced during NSSI were each positively associated with SA history. Further, subjective pain experienced during NSSI moderated the relationship between NSSI frequency and SA history, such that the association between NSSI frequency and SA history was stronger for individuals who experienced lower levels of subjective pain.

Suicide, Suicide Attempts, and Suicidal Ideation

Suicidal behavior is a leading cause of death and disability worldwide. Fortunately, recent developments in suicide theory and research promise to meaningfully advance knowledge and prevention. One key development is the ideation-to-action framework, which stipulates that (a) the development of suicidal ideation and (b) the progression from ideation to suicide attempts are distinct phenomena with distinct explanations and predictors. A second key development is a growing body of research distinguishing factors that predict ideation from those that predict suicide attempts. For example, it is becoming clear that depression, hopelessness, most mental disorders, and even impulsivity predict ideation, but these factors struggle to distinguish those who have attempted suicide from those who have only considered suicide. Means restriction is also emerging as a highly effective way to block progression from ideation to attempt. A third key development is the proliferation of theories of suicide that are positioned within the ideation-to-action framework. These include the interpersonal theory, the integrated motivational-volitional model, and the three-step theory. These perspectives can and should inform the next generation of suicide research and prevention.

Suicide as a derangement of the self-sacrificial aspect of eusociality

Building upon the idea that humans may be a eusocial species (i.e., rely on multigenerational and cooperative care of young, utilize division of labor for successful survival), we conjecture that suicide among humans represents a derangement of the self-sacrificial aspect of eusociality. In this article, we outline the characteristics of eusociality, particularly the self-sacrificial behavior seen among other eusocial species (e.g., insects, shrimp, mole rats). We then discuss parallels between eusocial self-sacrificial behavior in nonhumans and suicide in humans, particularly with regard to overarousal states, withdrawal phenomena, and perceptions of burdensomeness. In so doing, we make the argument that death by suicide among humans is an exemplar of psychopathology and is due to a derangement of the self-sacrificial behavioral suite found among eusocial species. Implications and future directions for research are also presented.

Acquired Capability for Suicide, Pain Tolerance, and Fearlessness of Pain-Validation of the Pain Tolerance Scale of the German Capability for Suicide Questionnaire

The interpersonal theory of suicide (Joiner, 2005) postulates that for a serious suicide attempt, one has to possess the acquired capability to commit suicide. Acquired capability includes higher pain tolerance, which is further assumed to comprise both an elevated physical pain tolerance and fearlessness of pain. Recently, the German Capability for Suicide Questionnaire (GCSQ) was validated. The aim of this study is further validation of the GCSQ's Pain Tolerance scale by investigating the scale's association with objective pain tolerance and fearlessness of pain in two undergraduate samples (N = 81; N = 76). Both associations were found indicating a strong criterion validity of the Pain Tolerance scale.

Provocative work experiences predict the acquired capability for suicide in physicians

The interpersonal psychological theory of suicidal behavior (IPTS) offers a potential means to explain suicide in physicians. The IPTS posits three necessary and sufficient precursors to death by suicide: thwarted belongingness, perceived burdensomeness, and acquired capability. The present study sought to examine whether provocative work experiences unique to physicians (e.g., placing sutures, withdrawing life support) would predict levels of acquired capability, while controlling for gender and painful and provocative experiences outside the work environment. Data were obtained from 376 of 7723 recruited physicians. Study measures included the Acquired Capability for Suicide Scale, the Interpersonal Needs Questionnaire, the Painful and Provocative Events Scale, and the Life Events Scale-Medical Doctors Version. Painful and provocative events outside of work predicted acquired capability (β=0.23, t=3.82, p<0.001, f(2)=0.09) as did provocative work experiences (β=0.12, t=2.05, p<0.05, f(2)=0.07). This represents the first study assessing the potential impact of unique work experiences on suicidality in physicians. Limitations include over-representation of Caucasian participants, limited representation from various specialties of medicine, and lack of information regarding individual differences.

The interpersonal theory of suicide and adolescent suicidal behavior

BACKGROUND

Joiner's interpersonal theory of suicide (IPTS) proposes that suicide results from the combination of a perception of burdening others, social alienation, and the capability for self-harm. The theory gained some empirical support, however the overall model has yet to be tested. This study aimed to test the main predictions of IPTS in a large community sample of Israeli adolescents.

METHOD

1196 Israeli Jewish and Arab high-school pupils participating in the SEYLE project completed a self-report questionnaire measuring perceived burdensomeness, thwarted belongingness, health risk behaviors, and non-suicidal self-injury (risk variables), and suicidal ideation and suicide attempts (outcome measures). The data were tested in cross-sectional regression models.

RESULTS

Consistent with IPTS, perceived burdensomeness was found to interact with thwarted belongingness, predicting suicidal ideation. Depression mediated most of the effect of thwarted belongingness and perceived burdensomeness on suicidal ideation. Acquired capability for self-harm, as measured by health risk behaviors and direct non-suicidal self-injurious behaviors, predicted suicide attempt. However, this mechanism operated independently from ideation rather than in interaction with it, at variance with IPTS-based predictions.

LIMITATIONS

The cross-sectional design precludes conclusions about causality and directionality. Proxy measures were used to test the interpersonal theory constructs.

CONCLUSION

The findings support some of the IPTS predictions but not all, and imply two separate pathways for suicidal behavior in adolescents: one related to internalizing psychopathology and the other to self-harm behaviors. This conceptualization has clinical implications for the differential identification of adolescents at risk for suicidal behavior and for the development of prevention strategies.

Five factor model traits as a predictor of suicide ideation and interpersonal suicide risk in a college sample

Research has demonstrated an inconsistent relationship between suicide ideation and personality traits. This is the first study to empirically examine the relationship of the Five Factor Model of personality with current, past and no suicide ideation, and with the two interpersonal risk factors of suicide: thwarted belongingness and perceived burdensomeness (Joiner, T., 2005. Why people die by suicide. Cambridge, MA, US: Harvard University Press). Results indicate that high neuroticism was associated with both current ideation and a history of suicide ideation and extraversion was associated with current ideation. Neuroticism was positively related to thwarted belongingness and perceived burdensomeness, while extraversion was negatively related to these interpersonal predictors of suicide. Agreeableness was negatively related to thwarted belongingness but not perceived burdensomeness, indicating differentiated patterns of relationships between this personality domain and the two suicide constructs. Furthermore, these personality domains predicted 23.82% of variance for thwarted belongingness and 15.07% of the variance for perceived burdensomeness, above and beyond demographic variables associated with suicide ideation. This study, which was conducted with a college sample, demonstrates the potential benefit of identifying predispositional risk factors for suicide ideation and interpersonal predictors of suicide. This may have implications for the development of upstream preventative measures against suicide.

Anhedonia predicts suicidal ideation in a large psychiatric inpatient sample

This study examined the relationship among symptoms of anhedonia and suicidal ideation at baseline, at termination, and over time in 1529 adult psychiatric inpatients. Anhedonia was associated with suicidality cross-sectionally at baseline and at termination. In addition, change in anhedonia from baseline to termination predicted change in suicidality from baseline to termination, as well as level of suicidality at termination; moreover, anhedonia remained a robust predictor of suicidal ideation independent of cognitive/affective symptoms of depression. Symptom-level analyses also revealed that, even after accounting for the physical aspect of anhedonia (e.g., loss of energy), loss of interest and loss of pleasure were independently associated with higher levels of suicidal ideation at baseline, over time, and at discharge. Loss of interest was most highly predictive of suicidal ideation, providing support for recent differential conceptualizations of anhedonia. Taken together, these findings indicate that the manner in which anhedonia is conceptualized is important in predicting suicidal ideation, and that anhedonia symptoms warrant particular clinical attention in the treatment of suicidal patients.

Reconsidering the link between impulsivity and suicidal behavior

It is widely accepted that suicidal behavior often occurs with little planning. We propose, however, that suicidal behavior is rarely if ever impulsive-that it is too frightening and physically distressing to engage in without forethought-and that suicidal behavior in impulsive individuals is accounted for by painful and fearsome behaviors capable of enhancing their capacity for suicide. We conducted a meta-analysis of the association between trait impulsivity and suicidal behavior and a critical review of research considering the impulsiveness of specific suicide attempts. Meta-analytic results suggest the relationship between trait impulsivity and suicidal behavior is small. Furthermore, studies examining a mediating role of painful and provocative behaviors have uniformly supported our model. Results from our review suggest that researchers have been unable to adequately measure impulsivity of attempts and that measures sensitive to episodic planning must be developed to further our understanding of this phenomenon.

Hope and the interpersonal-psychological theory of suicidal behavior: replication and extension of prior findings

The interpersonal-psychological theory of suicidal behavior (IPTS; Joiner, 2005) posits that suicidal behavior occurs when an individual has a desire for death (due to the combination of perceived burdensomeness and thwarted belongingness) in addition to an acquired capacity for suicide, which is present when the individual has a low fear of death and high pain tolerance. Previous research has demonstrated an expected negative relation between trait hope and perceived burdensomeness and thwarted belongingness, as well as a more perplexing finding that hope is positively associated with the acquired capability. In a sample of 230 college students, measures of the three components of the IPTS were administered, along with measures of hope, depression, and painful and/or provocative events. Hierarchical regression analyses replicated the previously found associations between hope and burdensomeness and belongingness while controlling for depression and demographic variables. The positive association between hope and acquired capacity was also replicated, but a mediation analysis demonstrated that the effect was statistically accounted for by distress tolerance. The results further support the incremental validity of hope as a consideration in suicide risk assessments and suggest that hope may serve as a protective factor with respect to suicidal desire.

Psychological models of suicide

Suicidal behavior is highly complex and multifaceted. Consequent to the pioneering work of Durkheim and Freud, theoreticians have attempted to explain the biological, social, and psychological nature of suicide. The present work presents an overview and critical discussion of the most influential theoretical models of the psychological mechanisms underlying the development of suicidal behavior. All have been tested to varying degrees and have important implications for the development of therapeutic and preventive interventions. Broader and more in-depth approaches are still needed to further our understanding of suicidal phenomena.

Means and capacity for suicidal behavior: a comparison of the ratio of suicide attempts and deaths by suicide in the US military and general population

BACKGROUND

There is a discrepancy in the frequency of non-lethal and lethal suicidal behavior. Given the extensive training in firearms within the military and prior research indicating that military personnel exhibit elevated mean levels of the acquired capability, we hypothesized that the ratio between non-lethal and lethal suicidal behavior would be lower in US military personnel than in the general population.

METHOD

We examined publicly available data on non-lethal and lethal suicidal behavior within the US military and US general population.

RESULTS

The ratio of non-lethal to lethal suicidal behavior was lower in military across sex and age. Furthermore, results indicated that a greater proportion of both non-lethal and lethal suicide attempts in military personnel involved firearms. When considering only suicidal behavior unrelated to firearms, the ratio remained significantly lower in the military. The ratio of non-lethal to lethal suicidal behavior involving drugs and alcohol was not significantly lower in the military.

LIMITATIONS

The use of public data precluded analyses directly testing competing theories. Also, level of intent involved in non-lethal self-injury in the general population was unclear. Finally, only active duty personnel were considered in analyses related to the military.

CONCLUSIONS

Suicide attempts in the military are more likely to result in death than in the general population. This appears to be primarily due to the use more lethal means. Clinically, this speaks to the importance of recognizing suicidal desire in military personnel, as it is more likely to be paired with the capacity for suicide than in civilians.

Suicidal Behavior and Neurological Illnesses

OBJECTIVE

Suicidal ideation and behavior have been associated with a variety of neurological illnesses. Studies are ongoing in combat veterans and other groups to examine possible mechanisms and pathways that account for such associations.

METHOD

This article provides a review of the literature on suicide ideation and suicidal behavior in patients with neurological illnesses including publications on veteran's health and military medicine. Studies of suicide attempts and deaths in people with neurological illnesses are also reviewed.

RESULTS

The studies summarized in this review indicate that there are important linkages between suicidal ideation and behavior and neurological conditions, including epilepsy, multiple sclerosis, and amyotrophic lateral sclerosis.

CONCLUSION

Additional studies are needed to further clarify why suicide ideation and suicidal behavior are associated with neurological diseases, in order to improve quality of life, alleviate patient distress, and prevent nonfatal and fatal suicide attempts in veteran and non-veteran populations.