Are suicide attempters more impulsive than suicide ideators?

Substitution of Methods in Suicide Deaths - Firearm Injury and Hanging

Background: Prevention strategies for suicide emphasize restrictions on firearm access. These restrictions may lose efficacy if individuals substitute other lethal suicide methods. Aims: The objective of this study is to determine the extent to which individuals who die by suicide in the United States substitute hanging for firearm injury. Methods: This study is a repeated cross-sectional analysis of suicide deaths in the United States from 2003 to 2021. Multiple regression was used to estimate the effect of firearm access proxies on individual suicide methods (hanging vs. firearm injury). Results: The probability of death by hanging was significantly and negatively associated with proxies of firearm access. Limitations: This study does not compare crude rates of suicide by state, which rise on average with rates of firearm ownership. The National Violent Death Reporting System expanded over the sample period, so early years have incomplete ascertainment. Rates of gun ownership and gun safety law scales are measured as proxies. Conclusions: Although means restriction around firearm access is a critical tool for suicide prevention, complementary strategies for prevention around hanging merit further study.

Potential association between suicide risk, aggression, impulsivity, and the somatosensory system

Aggression and impulsivity are linked to suicidal behaviors, but their relationship to the suicidal crisis remains unclear. This magnetoencephalography (MEG) study investigated the link between aggression, impulsivity, and resting-state MEG power and connectivity. Four risk groups were enrolled: high-risk (HR; n = 14), who had a recent suicidal crisis; lower-risk (LR; n = 41), who had a history of suicide attempts but no suicide attempt or ideation in the past year; clinical control (CC; n = 38), who had anxiety/mood disorders but no suicidal history; and minimal risk (MR; n = 28), who had no psychiatric/suicidal history. No difference in resting-state MEG power was observed between the groups. Individuals in the HR group with high self-reported aggression and impulsivity scores had reduced MEG power in regions responsible for sensory/emotion regulation vs. those in the HR group with low scores. The HR group also showed downregulated bidirectional glutamatergic feedback between the precuneus (PRE) and insula (INS) compared to the LR, CC, and MR groups. High self-reported impulsivity was linked to reduced PRE to INS feedback, whereas high risk-taking impulsivity was linked to upregulated INS to postcentral gyrus (PCG) and PCG to INS feedback. These preliminary findings suggest that glutamatergic-mediated sensory and emotion-regulation processes may function as potential suicide risk markers.

Implicit measures of suicide vulnerability: Investigating suicide-related information-processing biases and a deficit in behavioral impulse control in a high-risk sample and healthy controls

OBJECTIVE

Relevant implicit markers of suicidal thoughts and behaviors (STBs) have only been studied in isolation with mixed evidence. This is the first study that investigated a suicide attentional bias, a death-identity bias and a deficit in behavioral impulsivity in a high-risk sample and healthy controls.

METHOD

We administered the Death Implicit Association Test, the Modified Suicide Stroop Task, and a Go/No-Go Task to inpatient suicide ideators (n = 42), suicide attempters (n = 40), and community controls (n = 61).

RESULTS

Suicide ideators and attempters showed a suicide attentional bias and a death-identity bias compared to healthy controls. Ideators and attempters did not differ in these implicit information-processing biases. Notably, only attempters were more behaviorally impulsive compared to controls; however, ideators and attempters did not significantly differ in behavioral impulsivity. Moreover, implicit scores were positively intercorrelated in the total sample.

CONCLUSION

In line with the Cognitive Model of Suicide, ideators and attempters display suicide-related information processing biases, which can be considered as implicit cognitive markers of suicide vulnerability. Furthermore, attempters have elevated levels of behavioral impulsiveness. These results are highly relevant in the context of crisis intervention strategies and warrant further research.

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

BACKGROUND

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

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

Testing Suicide Ideation-to-Action Theory Differences Among Those With Nonsuicidal Self-Injury

OBJECTIVE

Individuals with recent nonsuicidal self-injury (NSSI) are at elevated risk for suicide but our understanding of the factors that impact the emergence of suicidal ideation and/or suicide attempts in this group is limited. The current study aimed to evaluate whether the processes identified by existing ideation-to-action theories of suicide apply within this subgroup.

METHOD

A sample of 362 university students (77.9% female, 88.5% White) who reported past year engagement in NSSI completed an anonymous online questionnaire assessing past year NSSI, suicidal ideation, and suicide attempts as well as hopelessness, interpersonal, and acquired capability/volitional variables. Participants were divided into NSSI only (controls), NSSI + Ideation, and NSSI + Suicide Attempt groups.

RESULTS

A one-way ANOVA evaluated group differences on the theoretical factors. There were significant differences between NSSI controls and both the ideation and attempt groups, who did not differ from each other, on hopelessness and interpersonal factors. No significant differences were observed across groups for the volitional factors except for impulsivity, which differed between the NSSI controls and ideation group.

CONCLUSION

Results suggest suicide ideation-to-action theories may have applicability to understanding the presence of suicide ideation among those with NSSI but may lack specificity for understanding risk for suicide attempts.

Potential Mechanisms Underlying Suicidality in Autistic People with Attention Deficit/Hyperactivity Disorder: Testing Hypotheses from the Interpersonal Theory of Suicide

Background

Autistic people with co-occurring attention deficit/hyperactivity disorder (ADHD) appear to be at heightened risk of suicide. To understand why, we explored two explanatory mechanisms from the interpersonal theory of suicide: first, that co-occurring ADHD might be associated with greater risk through greater thwarted belongingness and perceived burdensomeness and, secondly, that hyperactive/impulsive features might incur additional risk through their association with painful and provocative events, which are suggested to create "capability" for suicide.

Methods

Autistic adults (n = 314) completed an online survey including measures of thwarted belongingness, perceived burdensomeness, painful and provocative events, acquired capability for suicide, and ADHD features. Creating an overall index of likely ADHD, we examined associations between likely ADHD, suicide ideation, and lifetime suicide attempts through the parallel mediators of thwarted belongingness, perceived burdensomeness, anxiety, and depression. In several models, we then examined hyperactive, impulsive, and inattentive features as predictors of exposure to painful and provocative events and subsequent capability for suicide, and examined whether these two variables, sequentially or individually, mediated an association with lifetime suicide attempts.

Results

Likely ADHD was associated with past-year suicide ideation through greater depression and perceived burdensomeness, which also mediated its association with more suicide attempts. Hyperactive and impulsive features were associated with exposure to painful and provocative events and through this acquired suicide capability. Both features were associated with more numerous suicide attempts through these two mediators sequentially, and through exposure to painful and provocative events alone.

Conclusions

These data suggest that suicidality in autistic people with ADHD may be partially related to perceived burdensomeness and to acquired suicide capability after exposure to painful and provocative events. However, as we observed a pathway to suicidality associated with painful and provocative events alone, it is likely that there are also other explanatory mechanisms for the influence of traumatic events on suicide risk.

Multidimensional Impulsivity and Suicidal Behaviour: A Partial Test of the Integrated Motivational-Volitional (IMV) Model of Suicide

OBJECTIVE

Suicide remains a public health problem within the United Kingdom (UK) and globally. Impulsivity is a key risk factor within the Integrated Motivational-Volitional Model (IMV) of Suicide warranting further study. The current study applied a multi-dimensional impulsivity framework (UPPS-P) to differentiate suicidality subgroups within an IMV framework (i.e., no suicidal behavior, suicidal ideation only, and suicide attempt). Impulsivity subscales were evaluated as moderators of the suicidal ideation-future suicide attempt link.

METHOD

Adults living in the UK (N = 1027) completed an online survey addressing demographics, impulsivity, psychological distress, and lifetime suicidal behavior. We used analysis of variance (ANOVA) and linear regression with simple slopes analyses to investigate study objectives.

RESULTS

Data analyses revealed that: (1) four impulsivity subtypes (negative urgency, positive urgency, lack of premeditation, sensation-seeking) differentially distinguished suicidal behavior groups; (b) negative urgency, positive urgency, and lack of premeditation were meaningfully associated with suicide outcomes, and (c) negative urgency served as a moderator of the suicidal ideation-future attempt link.

CONCLUSIONS

Urgency, regardless of positive or negative valence, is important for understanding differences in lifetime suicidal behavior. Sensation-seeking may play a protective role for direct suicidal behavior. Negative urgency may be the most prominent aspect of impulsivity when considered as an IMV moderator. Findings are contextualized with respect to impulsivity and IMV frameworks. Clinical implications involve accounting for negative urgency in suicide risk assessment and intervention.

Risk and protective factors of suicidal tendencies among freshmen in China revealed by a hierarchical regression model

This study aimed to identify risk and protective factors for suicidal tendencies among college students by exploring current mental health, personal experiences, family environment, and school adaptation. A total of 11,504 freshmen in China were recruited. Suicidal tendencies were assessed using the Adolescents Suicidal Tendencies Scale (ASTS), while explored risk and protective factors included mental health assessed by the Symptom Checklist-90 (SCL-90), campus adaptation using the College Student School Adaptation Scale, and Personal Situation Survey. Single-factor Logistic regression analysis, correlation analysis, and hierarchical regression analysis were used to analyze the risk and protective factors affecting suicidal tendencies. The results showed that in terms of personal experience, self-injury behavior (OR = 3.522, 95% CI [3.256, 3.811]), sexual assault experience (OR = 2.603, 95% CI [2.374, 2.855]) and lack of friendship relationship (OR = 2.249, 95% CI [2.076, 2.436]) were the most significant risk factors. Regarding family environment, parenting style (OR = 2.455, 95% CI [2.272, 2.652]), parent-child relationship (OR = 2.255, 95% CI [2.092, 2.429]) and violent conflict (OR = 2.164, 95% CI [2.015, 2.324]) were the most prominent risk factors. For protective factors, life satisfaction (OR = 0.330, 95% CI [0.304, 0.359]) and rest quality (OR = 0.415, 95% CI [0.386, 0.447]) were the most significant protective factors. In addition, Symptom Checklist-90 was positively correlated with suicidal tendencies (r = 0.541, 95% CI [0.522, 0.560], p < 0.001), while school adaptation was negatively correlated with suicidal tendencies (r = - 0.590, 95% CI [- 0.579, - 0.601], p < 0.001). After considering demographic variables, psychological symptoms, school adaptation and other risk and protective factors, the hierarchical regression model could explain 48.9% of the variance of suicidal tendencies. The study emphasizes a range of multidimensional risk and protective factors for suicidal tendencies. This enhanced understanding is crucial in aiding the design of future intervention studies targeted at improving the mental health of college students.

Effects of sleep and impulsivity on suicidality in shift and non-shift workers

INTRODUCTION

Shift workers are known to have a higher suicide risk than non-shift workers. Sleep disturbance and impulsivity are also risk factors for suicidality. This study investigated the effects of poor sleep and impulsivity on suicidality in shift and non-shift workers.

METHODS

In total, 4572 shift workers (37.0 ± 9.84 years, 2150 males) and 2093 non-shift workers (37.8 ± 9.73 years, 999 males) participated in an online self-report survey. Suicidality was assessed using the Suicidal Behaviors Questionnaire. The Pittsburgh Sleep Quality Index was employed to explore subjective sleep quality, the Insomnia Severity Index to detect insomnia, the Epworth Sleepiness Scale (ESS) to evaluate excessive daytime sleepiness (EDS), the Center for Epidemiological Studies-Depression (CES-D) Scale to assess depressive symptoms, and the Impulsive Behavior Scale (UPPS-P) to explore impulsivity.

RESULTS

Shift workers showed poorer sleep quality, and greater impulsivity and suicidality, than non-shift workers. Impulsivity, sleep duration, sleep quality, and insomnia were significantly associated with suicidality, independent of depression. For both shift and non-shift workers, sleep quality moderated the association between impulsivity and suicidality. However, the moderating effects of sleep duration and EDS on the association between impulsivity and suicidality were apparent only in non-shift workers, while a moderating effect of insomnia was observed only in shift workers.

CONCLUSION

Shift work, sleep disturbances and impulsivity may exacerbate suicide risk. In addition, the interrelationships among insomnia, EDS, impulsivity, and suicidality may differ between shift and non-shift workers.

Cross-phenotype relationship between opioid use disorder and suicide attempts: new evidence from polygenic association and Mendelian randomization analyses

Clinical epidemiological studies have found high co-occurrence between suicide attempts (SA) and opioid use disorder (OUD). However, the patterns of correlation and causation between them are still not clear due to psychiatric confounding. To investigate their cross-phenotype relationship, we utilized raw phenotypes and genotypes from >150,000 UK Biobank samples, and genome-wide association summary statistics from >600,000 individuals with European ancestry. Pairwise association and a potential bidirectional relationship between OUD and SA were evaluated with and without controlling for major psychiatric disease status (e.g., schizophrenia, major depressive disorder, and alcohol use disorder). Multiple statistical and genetics tools were used to perform epidemiological association, genetic correlation, polygenic risk score prediction, and Mendelian randomizations (MR) analyses. Strong associations between OUD and SA were observed at both the phenotypic level (overall samples [OR = 2.94, P = 1.59 ×10-14]; non-psychiatric subgroup [OR = 2.15, P = 1.07 ×10-3]) and the genetic level (genetic correlation rg = 0.38 and 0.5 with or without conditioning on psychiatric traits, respectively). Consistently, increasing polygenic susceptibility to SA is associated with increasing risk of OUD (OR = 1.08, false discovery rate [FDR] =1.71 ×10-3), and similarly, increasing polygenic susceptibility to OUD is associated with increasing risk of SA (OR = 1.09, FDR = 1.73 ×10-6). However, these polygenic associations were much attenuated after controlling for comorbid psychiatric diseases. A combination of MR analyses suggested a possible causal association from genetic liability for SA to OUD risk (2-sample univariable MR: OR = 1.14, P = 0.001; multivariable MR: OR = 1.08, P = 0.001). This study provided new genetic evidence to explain the observed OUD-SA comorbidity. Future prevention strategies for each phenotype needs to take into consideration of screening for the other one.

Suicidal urges and attempted suicide at multiple time scales in borderline personality disorder

BACKGROUND

There is strong evidence for an enduring suicidal diathesis among individuals with a history of suicide attempts, particularly among people diagnosed with borderline personality disorder (BPD). However, the progression of suicidal crises among people predisposed to suicidal behavior remains poorly understood.

METHODS

Via multilevel structural equation modeling we tested the hypothesis that a history of attempted suicide predicts a stronger dynamic link between affect and impulsivity with suicidal ideation (i.e., suicidal urges) - both moment-to-moment and day-to-day. 153 patients diagnosed with BPD, 105 of whom had a history of medically serious suicide attempts completed a 21-day ecological momentary assessment protocol (17,926 total assessments).

RESULTS

Individuals with higher average levels of negative affect reported more suicidal thoughts. Moments characterized by more negative affect, hostility, impulsivity, and less positive affect were also characterized by elevated suicidal ideation. For hostility and positive affect, these significant links generalized to the daily level. At the same time, for negative affect and hostility the within-person coupling was stronger among attempters in comparison to non-attempters, and these effects did not significantly differ across timescales.

LIMITATIONS

Follow-up studies replicating our findings of the dysregulation-suicidality nexus in clinically more diverse samples are needed.

CONCLUSIONS

The diathesis for suicidal behavior manifests in tighter dynamic links between negative affect or hostility and suicidal ideation. Because these within-person links were amplified in attempters compared to non-attempters, differential coupling patterns may index potentially lethal processes that generalize beyond BPD reflecting distinct diathesis components.

Impulsivity, suicidal thoughts, psychological distress, and religiosity in adolescents and young adults

Background

Impulsivity is associated with suicidal acts and ideation, whereas higher religious commitment has been identified as a potential protective factor linked to lower suicidal ideation.

Objectives

We examined the extent to which higher religious commitment is associated with lower suicidal ideation and whether religious commitment modifies the relationship between impulsivity and suicidal ideation.

Methods

Adolescent and young adult males, with a prior history of suicidal act and ideations, completed standardized questionnaires [i.e., Beck Scale for Suicidal Ideation (BSS), Barratt Impulsivity Scale-II (BIS-II), Depression Anxiety Stress Scale (DASS), and Religious Commitment Inventory-10 (RCI-10)], to assess impulsivity, suicidal ideation, distress, and religious commitment. Regression and mediation analyses were performed to investigate the relationships among impulsivity, religious commitment, and suicidal ideation.

Results

Of the 747 study participants (mean age 18.8 years, SD = 4.1), 151 (20.2%) had a history of suicidal acts and 177 (23.7%) had a history of suicidal ideation. Non-planning impulsivity (predictor) was inversely associated with religious commitment (r = -0.33, p < 0.01), and religious commitment (mediator) was inversely related to suicidal ideation (outcome) (r = -0.32, p < 0.01). These findings remained statistically significant when controlling for either religious commitment or non-planning impulsivity, as appropriate. Higher religious commitment reduced the association between non-planning impulsivity and suicidal ideation (p < 0.01).

Conclusion

The findings highlight the potential for cultivating spirituality to buffer against higher suicidal ideation, and thus could be considered as an additional therapeutic strategy for individuals with higher levels of impulsivity and co-morbid suicidal ideation.

Sleep influences daily suicidal ideation through affective reactivity to interpersonal events among high-risk adolescents and young adults

BACKGROUND

Identifying proximal risk factors for suicidal ideation that are modifiable and relevant for adolescents and young adults is critical for suicide prevention. This study used an intensive monitoring approach to examine whether objectively- and subjectively- measured sleep characteristics predict next-day suicidal ideation occurrence and intensity through affective reactivity to interpersonal events in young people at high risk for suicide.

METHODS

Participants included 59 (13-23 years; 76% White; 75% female) adolescents and young adults undergoing intensive outpatient program treatment for depression and suicidality. Participants completed daily ratings of suicidal ideation, sleep quality, and affective reactivity to positive and negative interpersonal events for up to 3 months (M = 56 days, SD = 24.13). Actigraphy captured behavioral sleep duration and timing. Multilevel modeling was used to evaluate within-person fluctuations in sleep and affective reactivity as predictors of suicidal ideation, and multilevel mediation tested the indirect effects of sleep on suicidal ideation via affective reactivity to interpersonal events.

RESULTS

Results indicate significant indirect effects of objectively measured sleep duration and subjective sleep quality on next-day suicidal ideation via affective reactivity to negative and positive interpersonal events, respectively. Shorter-than-usual sleep predicted the presence and intensity of next-day suicidal ideation via heightened affective reactivity to negative interpersonal events. Worse sleep quality than usual predicted next-day suicidal ideation via reduced affective reactivity to positive interpersonal events.

CONCLUSIONS

Affectivity reactivity is a proximal mechanism through which sleep indices may influence risk for suicidal thinking on a daily basis. Findings highlight the utility of targeting sleep and emotion regulation in suicide prevention among adolescents and young adults at high-risk for suicide.

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

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

A Pre-Adolescent and Adolescent Clinical Sample Study about Suicidal Ideation, Suicide Attempt, and Self-Harming

Suicide is the second cause of death among adolescents, and nonsuicidal self-injury (NSSI) is one of the main risk factors for suicidal behavior. However, the possible variables specifically associated with suicidal ideation and suicide attempt, as well as the psychopathological characteristics linked to the concomitant presence of suicidal ideation/attempt and NSSI are still under-investigated in youth. The current study aimed to address these issues in a sample of 174 young Italian inpatients (M_age = 14.3 years ± 1.93, 78.2% girls). Sociodemographic and clinical variables were assessed through psycho-diagnostic interviews and ad hoc questionnaires. A binomial logistic regression was performed to identify the predictors of suicidal ideation and suicide attempt. Then, Kruskal-Wallis tests were run to analyze the psychopathological differences between patients with suicidal ideation and suicide attempt considering the coexistence of NSSI. The results highlighted that previous access to child mental health services and general psychopathological problems significantly predicted suicidal ideation, while previous hospitalizations, borderline personality functioning, and affective disorders significantly predicted suicide attempt. In general, inpatients with also NSSI reported higher levels of internalizing, somatic and total problems, impulsiveness, alexithymia, and emotional dysregulation. The clinical implications of our findings in terms of primary and secondary preventive programs are discussed.

Negative affectivity and disinhibition as moderators of an interpersonal pathway to suicidal behavior in borderline personality disorder

This longitudinal study examined whether personality traits moderate the link between interpersonal dysfunction and suicidal behavior in a high-risk sample of 458 individuals diagnosed with borderline personality disorder (BPD). Participants were assessed annually for up to 30 years (mean number of follow-ups = 7.82). Using multilevel structural equation modeling, we examined i) longitudinal, within-person relationships among interpersonal dysfunction, suicidal ideation, and suicide attempts; and ii) moderation of these relationships by negative affectivity and disinhibition. Negative affectivity predicted a stronger within-person coupling between interpersonal dysfunction and suicidal ideation. Disinhibition predicted a stronger coupling between ideation and suicide attempts. Assessing negative affectivity and disinhibition in a treatment setting may guide clinician vigilance toward those at highest risk for interpersonally triggered suicidal behaviors.

The UPPS Model of Impulsivity and Suicide: A Systematic Literature Review

INTRODUCTION

Suicide is a leading cause of death worldwide. Although inconsistent, impulsivity has been identified as a risk factor for suicidal thoughts and behaviors, and these inconsistent findings can largely be attributed to varying operationalizations of impulsivity. As such, the UPPS model of impulsivity provides a clear definition of impulsivity and its associated features that may provide utility in clarifying unreliable findings between impulsivity and suicide. This review aimed to summarize relevant information pertaining to the UPPS model of impulsivity and suicide.

METHODS

This systematic review followed the a priori guide outlined by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Articles were gathered from PsycINFO, PsycArticles, Scopus, and PubMed.

RESULTS

Twenty-eight articles were reviewed and analyzed. Most articles reviewed reported on indirect (i.e., through mediators and moderators) associations between the UPPS dimensions and suicidal behaviors. Additionally, results noted limited between-group differences in UPPS facets among individuals with a history of suicide attempts and those without a history of suicide attempts, those with a history of suicide attempts and individuals with suicide ideation, and those with suicide ideation and those without suicide ideation, with the exception of lack of premeditation.

DISCUSSION

The results of this review indicate support for the UPPS model of impulsivity as a theoretical starting point when examining the relation between impulsivity and suicide. Further, findings are helpful for clinicians and case conceptualization. Particularly, suicide risk assessment and treatment would be impacted based on impulsivity traits and suicide history.

Suicidal Behavior and Its Relationship with Postmortem Forensic Toxicological Findings

Suicide affects all sociodemographic levels, age groups, and populations worldwide. The factors that can increase the risk of suicidal tendencies are widely studied. The aim of this study was to analyze the types and combinations of toxics found in fatal suicide victims with different suicide mechanisms. A total of 355 autopsies were retrospectively studied, and 26 toxics were determined and related to mechanisms of suicide. Hanging (55%), drug overdose (22.7%), and jumping from a height (17.8%) were most represented suicide mechanisms with positive toxicology. Hanging was the most represented in men (50.3%; p = 0.019), while jumping from a height was more represented in women (29.7%, p = 0.028). Drugs of abuse were the most frequent toxics found in men (55.5%; p < 0.001), while medicines were the most frequent type found in women (70.3%, p < 0.001). Alcohol, nordiazepam, cocaine, and venlafaxine were the most consumed toxics. Benzodiazepines and venlafaxine were found in suicides involving drug overdose, hanging, and jumping from a height. In conclusion, most suicides were associated with drug abuse in men. Hanging was more represented in men and jumping from a height in women. Alcohol was present in combination with other toxics and medicines. The toxicological analysis is fundamental to understanding consumption patterns and establishing strategies and protocols for detecting and preventing suicide.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Applying ideation-to-action theories to predict suicidal behavior among adolescents

BACKGROUND

Although many risk factors for adolescent suicidal behavior have been identified, less is known about distinct risk factors associated with the progression from suicide ideation to attempts. Based on theories grounded in the ideation-to-action framework, we used structural equation modeling to examine risk and protective factors associated with the escalation from suicide ideation to attempts in adolescents.

METHODS

In this cross-sectional study, data from the 2013 and 2015 Hawaii High School Youth Risk Behavior Surveys (N = 8,113) were analyzed. The sample was 54.0% female and racially/ethnically diverse. Risk factors included depression, victimization, self-harm, violent behavior, disinhibition, and hard substance use, and protective factors included adult support, sports participation, academic achievement and school safety.

RESULTS

One in 6 adolescents (16.4%) reported suicide ideation, and nearly 1 in 10 (9.8%) adolescents had made a suicide attempt. Overall, disinhibition predicted the escalation to attempts among adolescents with suicide ideation, and higher academic performance was associated with lower suicide attempt risk. Depression and victimization were associated with suicide ideation.

LIMITATIONS

This study examined data from the Youth Risk Behavior Survey, and other known risk factors such as anxiety and family history of suicide were not available in these data.

CONCLUSIONS

Findings provide guidance for targets for clinical interventions focused on suicide prevention. Programs that incorporate behavioral disinhibition may have the greatest potential for reducing suicide attempt risk in adolescents with suicidal thoughts.

Cultural and interpersonal risk factors for suicide ideation and suicide attempts among Muslim college students from 11 nations

BACKGROUND

Research on suicidality in low to middle-income countries is scarce. We addressed this issue by investigating suicidality in a cross-national college student samples from 11 predominantly low to middle-income majority Muslim countries.

METHODS

The sample consisted of 7427 college students (56% female) who reported to be affiliated with Islam. Data on self-construal, social support, negative life-events, acceptability of suicide, suicidal ideation, and suicide attempts were collected with self-administered questionnaires.

RESULTS

Acceptability of suicide and the experience of negative life-events were positively, and perceived social support was negatively associated with suicidal ideation. Interdependent self-construal was negatively related to the acceptability of suicide and positively associated with perceived social support, implying a negative indirect effect on suicidal ideation although its direct effect was positive. The number of negative life-events was the strongest positive predictor of ever attempting suicide. The interdependent self-construal moderated the association of negative life-events with suicide attempts.

LIMITATIONS

Cross-sectional and self-report nature of the study were its major limitations. Participants may have suppressed their responses about suicide because of religious and legal reasons.

CONCLUSION

Remarkable similarities across 11 country samples emerged in the linkages between cultural and interpersonal factors with suicidality. Our findings highlight the value of a nuanced approach to suicidality, that can recognize the differences in the processes associated with suicidal ideation and suicide attempts, as well as the need to consider the interplay of a broad range of personal, interpersonal, and cultural influences.

Frozen in (e)motion: How reactive motor inhibition is influenced by the emotional content of stimuli in healthy and psychiatric populations

Efficient inhibitory control is vital. However, environmental cues can influence motor control especially in an emotional context. One common task to measure inhibitory control is the stop-signal task (SST), which asks participants to respond to go stimuli knowing that on some trials a stop signal will be presented, requiring them to inhibit their response. This paradigm estimates the ability to inhibit already-initiated responses by calculating participants' stop-signal reaction times (SSRT), an index of inhibitory control. Here, we aim to review the existing, often contradictory, evidence on the influence of emotional stimuli on the inhibitory process. We aim to discuss which factors may reveal an interference as well as an advantage of emotional stimuli on action inhibition performance. Finally, we review the existing evidence that has investigated the effect of such stimuli on action inhibition in the psychiatric population. Important factors are the relevance, the intensity and the valence of the emotional stimulus, as well as the affected component of the motor control. From all this evidence, it is clear that understand precisely how emotion is integrated into core executive functions, such as inhibitory control, is essential not only for cognitive neuroscience, but also for refining neurocognitive models of psychopathology.

Differentiating U.S. military veterans who think about suicide from those who attempt suicide: A population-based study

OBJECTIVE

Several vulnerability factors for suicidal behavior in U.S. veterans have been identified. However, little is known about factors that differentiate veterans who contemplate suicide from those who attempt suicide. This study examined sociodemographic and clinical characteristics that distinguish veterans who think about suicide from those who attempt suicide.

METHOD

Data were analyzed from the 2019-2020 National Health and Resilience in Veterans Study, which surveyed a population-based sample of 4069 veterans. Analyses estimated the lifetime prevalence of suicide ideation (SI) and suicide attempts (SA); and examined differences between veterans with a history of attempt(s), and SI without a history of attempt(s).

RESULTS

A total 25.9% of U.S. veterans reported lifetime SI and 3.9% reported a SA. Several factors distinguished veterans with a history of SA from those with SI only: the strongest were younger age (odds ratio [OR] = 0.97, 95% CI = 0.95-0.98), nonsuicidal self-injury (OR = 1.81, 95% CI = 1.11-3.03), adverse childhood experiences (OR = 1.14; 95% CI = 1.06-1.23), alcohol use disorder (OR = 1.99; 95% CI = 1.28-3.12), lower household income (OR = 0.62; 95% CI = 0.40-0.95), and physical disability (OR = 1.69; 95% CI = 1.07-2.70).

CONCLUSIONS

Although a quarter of U.S. veterans contemplate suicide in their lifetimes, the majority do not attempt suicide. Specific sociodemographic and clinical features may differentiate veterans who contemplate versus attempt suicide.

[Prevention of impulsive suicide with antidepressants in outpatients]

Self-poisoning is a common method of suicide, for which various medications are used, including antidepressants. A non-systematic review of Russian-language and English-language publications, by keywords, in the databases: ELibrary.ru, PubMed, Cochrane Database of Systematic Reviews. The purpose of the review was to analyze the literature on new risk factors and methods of their reduction in suicides with self-poisoning with antidepressants. Every fifth (20%) self-poisoning performed with antidepressants. In self-poisoning attempts, one drug used in 55% of cases, and more than one drug was used in 45% of cases. Impulsive suicides account for up to half of all suicide cases. Risk factors for impulsive suicides include the presence of impulsive character traits, female gender, young age, and the use of psychostimulants. The WHO Regional Office for Europe's mhGAP-IG guidelines recommend limiting access to a patient at risk of suicide to a weekly dose of an antidepressant. Preferably, the use of antidepressants from the group of SSRIs in small forms of release.

Search for solutions, learning, simulation, and choice processes in suicidal behavior

Suicide may be viewed as an unfortunate outcome of failures in decision processes. Such failures occur when the demands of a crisis exceed a person's capacity to (i) search for options, (ii) learn and simulate possible futures, and (iii) make advantageous value‐based choices. Can individual‐level decision deficits and biases drive the progression of the suicidal crisis? Our overview of the evidence on this question is informed by clinical theory and grounded in reinforcement learning and behavioral economics. Cohort and case–control studies provide strong evidence that limited cognitive capacity and particularly impaired cognitive control are associated with suicidal behavior, imposing cognitive constraints on decision‐making. We conceptualize suicidal ideation as an element of impoverished consideration sets resulting from a search for solutions under cognitive constraints and mood‐congruent Pavlovian influences, a view supported by mostly indirect evidence. More compelling is the evidence of impaired learning in people with a history of suicidal behavior. We speculate that an inability to simulate alternative futures using one's model of the world may undermine alternative solutions in a suicidal crisis. The hypothesis supported by the strongest evidence is that the selection of suicide over alternatives is facilitated by a choice process undermined by randomness. Case–control studies using gambling tasks, armed bandits, and delay discounting support this claim. Future experimental studies will need to uncover real‐time dynamics of choice processes in suicidal people. In summary, the decision process framework sheds light on neurocognitive mechanisms that facilitate the progression of the suicidal crisis.

This article is categorized under:

Economics > Individual Decision‐Making

Psychology > Emotion and Motivation

Psychology > Learning

Neuroscience > Behavior

From decision to action: Suicidal history and time between decision to die and actual suicide attempt

A substantial proportion of suicide attempts seem to be realized in a sudden manner. However, it is unclear how suicide attempters showing a rapid transition from the decision to die to acting differ from suicide attempters showing a slower transition regarding their suicidal history. The main aim of this study was to determine the proportion of suicide attempters, who reported a rapid transition (≤5, ≤10, ≤180 min) between their decision to die and their actual attempt. Furthermore, attempter groups (≤ vs. >5, ≤ vs. >10 and ≤ vs. >180 min) were compared regarding suicidal history (ideation, plans, and number of lifetime as well as 12 month suicide attempts) as well as depression, hopelessness and trait impulsivity. In total, 118 inpatients (62.7% female; age: M = 38.71, SD = 14.71) hospitalized due to a recent suicide attempt were assessed using structured clinical interview measures assessing suicidal history and self-report instruments. Thirty-six percent reported a time period of ≤5 min, 44% a time period of ≤10 min and 73% a time period of ≤180 min between their decision to die and their attempt. Participants with a rapid transition (≤5, ≤10, ≤180 min) did not differ from participants with a slower transition (>5, >10, >180 min) regarding suicidal history, depression, hopelessness and trait impulsivity. Taken together, a rapid transition seems common, but nevertheless, rapidly realized suicide attempts cannot necessarily be characterized as impulsive.

Patterns and motivations for method choices in suicidal thoughts and behaviour: qualitative content analysis of a large online survey

BACKGROUND

Choice of suicide method can strongly influence the outcome of suicidal behaviour, and is an important aspect of the process and planning involved in a suicide attempt. Yet, the reasons why individuals consider, choose or discard particular methods are not well understood.

AIMS

This is the first study to explore method choices among people with a history of suicidal behaviour and individuals who have experienced, but not enacted, suicidal thoughts.

METHOD

Via an online survey, we gathered open-ended data about choice of methods in relation to suicidal thoughts and behaviours, including reasons for and against specific means of harm.

RESULTS

A total of 712 respondents had attempted suicide, and a further 686 experienced suicidal thoughts (but not acted on them). Self-poisoning was the most commonly contemplated and used method of suicide, but most respondents had considered multiple methods. Method choices when contemplating suicide included a broader range of means than those used in actual attempts, and more unusual methods, particularly if perceived to be lethal, 'easy', quick, accessible and/or painless. Methods used in suicide attempts were, above all, described as having been accessible at the time, and were more commonly said to have been chosen impulsively. Key deterrents against the use of specific methods were the presence of and impact on other people, especially loved ones, and fears of injury and survival.

CONCLUSIONS

Exploration of method choices can offer novel insights into the transition from suicidal ideation to behaviour. Results underscore the need for preventative measures to restrict access to means and delay impulsive behaviour.

Cingulate white matter volume and associated cognitive and behavioral impulsivity in Veterans with a history of suicide behavior

BACKGROUND

Suicide is one of the leading causes of death for military personnel and Veterans. Neuroimaging studies have revealed abnormalities in white matter tracts and brain connectivity in suicide behavior (SB); however, reports of alterations in white matter volume and its association with related behaviors are limited. The current study examined the relationship between cingulate white matter volume (WMV), impulsivity, and SB in Veterans.

METHODS

Fifty-two Veterans, ages 18 to 65, underwent magnetic resonance imaging on a 3T Siemens Verio scanner. Morphometric analysis of brain images was performed to evaluate differences in WMV in cingulate regions of interest. Participants completed the Columbia Suicide Severity Rating Scale to assess lifetime suicide behavior and the Barratt Impulsivity Scale (BIS) and the Continuous Performance Test (CPT) to assess impulsivity.

RESULTS

Twenty-nine Veterans had a history of suicidal ideation (SI) and 23 had a history of suicide attempts (SA). Controlling for age, sex, handedness and total white matter volume, reduced WMV was observed in the left rostral anterior cingulate cortex (rACC) in Veterans with SA relative to Veterans with SI, p = .008. Additionally, non-planning on the BIS was negatively correlated with left rACC WMV for Veterans with a history of SA, p = .04. Other subregions of the ACC WMV were negatively correlated with planning and attention impulsivity (BIS) and omission and commission errors (CPT) for attempters.

CONCLUSIONS

Reduction in rACC WMV in Veterans with SA was negatively correlated with nonplanning measures. These findings are consistent with ACC involvement in inhibitory processes and build on evidence that SB is associated with neurobiological abnormalities and suggest that white matter changes may be related to actual attempts.

Psychotic Like Experiences are Associated with Suicide Ideation and Behavior in 9 to 10 Year Old Children in the United States

Those experiencing psychotic like experiences (PLEs) are at higher risk for suicide ideation and behavior. However, it is unclear if PLEs are related to suicide ideation and behavior in children, and whether other factors such as impulsivity or emotion dysregulation might moderate the relationship. We hypothesize that PLEs are associated with suicide ideation and behavior, with impulsivity and emotion dysregulation moderating this relationship, in middle childhood. History of PLEs, suicide ideation and behavior, depression, emotion dysregulation, and impulsivity were assessed for 10,624 children aged 9 to 10.9 years (47.8% female, 34.4% minority race, 20.0% Hispanic) as part of the Adolescent Brain Cognitive Development℠ study. Hypotheses about associations between variables were assessed using hierarchical linear modeling. PLEs were associated with suicide ideation and suicide behavior even when controlling for depression severity. Emotion dysregulation and impulsivity were also associated with suicide ideation and moderated the relationship between PLEs and suicide ideation. Variation in suicide ideation due to impulsivity and emotion dysregulation appears to be strongest when people are experiencing low levels to no PLEs. Only impulsivity and PLEs were associated with suicide behavior. Depression was associated with suicide ideation, but not suicide behavior. PLEs may be an important risk factor for suicide ideation and behavior in 9 to 10-year-old children, comparable to adult and adolescent populations. When considering prevention of suicidality, these data suggest that considering the relations between PLEs, impulsivity and emotion dysregulation may be important.

Suicide behavior is associated with childhood emotion dysregulation but not trait impulsivity in first episode psychosis

Historically, research on suicide behavior has not included those experiencing first episode psychosis (FEP), hindering prevention efforts for this population. Emotion dysregulation and impulsivity represent two mechanisms that contribute to suicide, but these have not been examined in FEP. We hypothesize that the combination of trait impulsivity and childhood emotion dysregulation are associated with suicide behavior (SB) and ideation (SI) in those experiencing FEP. Participants were recruited from an Early Psychosis Program (N=80, ages 12-32, 65% male). Clinician ratings of symptoms and history of SI and SB were obtained at baseline. Participants also completed self-report measures of childhood emotion dysregulation and trait impulsivity. Regression analyses examined whether childhood emotion dysregulation and trait impulsivity individually or in combination were associated with SI and SB, and the severity of SI and SB. Childhood emotion dysregulation was significantly associated with a history of SB and its severity, but not SI. Attention impulsivity was associated with the severity of SI. However, other impulsivity types, and interactions were not associated with a history of SI or SB. This suggests childhood emotion dysregulation is a potential target for prevention of SB in FEP, while trait impulsivity may be less important in this effort.

Ventromedial prefrontal value signals and functional connectivity during decision-making in suicidal behavior and impulsivity

Suicide is linked to impaired value-based decision-making and impulsivity, but whether these risk factors share neural underpinnings is unclear. Disrupted ventromedial prefrontal cortex (vmPFC) value signals may underlie this behavioral phenotype. We investigated vmPFC value signals, vmPFC-frontoparietal connectivity, and the impact of impulsivity during decision-making in depressed individuals with and without suicidal behavior. Middle-aged and older adults (n = 116; 35 with a history of suicide attempts, 25 with ideation only, 25 depressed controls with no ideation, and 31 nonpsychiatric controls) completed a decision-making task with drifting reward probabilities during fMRI. Values of choices, estimated by a reinforcement learning model, were regressed against BOLD signal. VmPFC value activation was compared between groups. Moderating effects of impulsivity on vmPFC-frontoparietal connectivity were assessed in nonpsychiatric controls and compared among patient groups. VmPFC value responses in participants with a history of suicide attempts were reduced relative to nonpsychiatric controls (p < 0.05). In nonpsychiatric controls, vmPFC-frontoparietal connectivity was negatively moderated by impulsivity (pFWE corrected < 0.05). This effect was preserved in comparison patient groups but abolished in suicide attempters (p < 0.001). This change in neural connectivity patterns also affected behavior: people with a history of suicide attempts showed a disrupted effect of vmPFC-frontoparietal connectivity, impulsivity, and reinforcement on choice quality (p < 0.001). These effects were specific to vmPFC and not to striatum. In summary, findings from this study largely support disrupted vmPFC value signals in suicidal behavior. In addition, it uncovers an altered pattern of vmPFC-frontoparietal connectivity in impulsive people with suicidal behavior, which may underlie disrupted choice processes in a suicidal crisis.

Caudothalamic dysfunction in drug-free suicidally depressed patients: an MEG study

Major depressive disorder (MDD), characterized by low mood or anhedonia, is commonly associated with a greater suicidal susceptibility. There are numerous suicide-related findings pertaining to the dorsolateral prefrontal cortex (DLPFC), caudate nucleus and thalamus, which form a cortico-striato-thalamo-cortical (CSTC) circuit responsible for executive function and working memory. An aberrant CSTC circuitry is hypothesized to be implicated in depressed patients with a high suicidal risk. 27 MDD patients were assessed with the Nurses Global Assessment of Suicide Risk (NGASR), following which 14 patients were classified into a high suicide risk group (NGASR ≥ 12) and 13 patients were assigned to a low suicide risk group (NGASR < 6). All 27 patients were enrolled with 25 healthy controls for resting-state magnetoencephalography (MEG). Cross-frequency coupling (CFC) measured the phase of alpha-band (8-13 Hz) as it modulated to cortical gamma-band (30-48 Hz). There was a significantly lower alpha-to-gamma phase-amplitude coupling (PAC) between the right caudate and left thalamus in high-risk suicide group compared to both the low-risk suicide group and healthy controls. The presence of a weaker coupling between the right caudate and left thalamus is indicative of a caudothalamic abnormality in suicidally depressed patients. This implies that a disruption of CSTC loop could result in executive dysfunction and working memory impairment, leading to an increased suicidal risk in MDD patients. In the future, this preliminary study has the possibility of being replicated on a larger scale, and hence validates caudothalamic dysfunction as a reliable neuroimaging biomarker for suicide in depression.

A multi factorial model of self-harm behaviors in Anorexia-nervosa and Bulimia-nervosa

BACKGROUND

Co-existence of eating disorders and NSSI, suicide attempts and ideations is well established yet much is not known about the personality traits and behavioral tendencies that maintain this relationship. To this date no empirical work has been produced that offers a multifactorial view on the contributing variables to the occurrence of self-harm behaviors in EDs.

METHOD

Binge eating, depression, impulsivity, ruminations and loss aversion were assessed in a sample of 93 patients diagnosed with Anorexia-Nervosa and Bulimia-Nervosa and other EDs with a history of NSSI and suicide attempts.

RESULTS

Binge eating was found to be a predictor of depression, which in turn was found to be related to NSSI frequency, suicide attempts and suicide ideations. Ruminations were found to mediate a relationship between depression and suicide ideations. Trait impulsivity predicted suicide attempts, while the attentional construct of impulsivity was associated to suicide ideations as well as attempts. Higher loss aversion was positively associated with NSSI frequency and suicide ideations.

CONCLUSION

Our findings suggest that trait and state aspects of impulsivity are related to different self-harm behaviors in EDs. Exploring these differences is potentially of great value in understanding the process of transition from suicidal ideation to suicide attempt and the process of NSSI and may assist clinicians formulate better interventions for patients with EDs at risk. Ways in which individual findings in our model correspond with previous research and future implications are discussed.

Neurocognitive Processes Implicated in Adolescent Suicidal Thoughts and Behaviors: Applying an RDoC Framework for Conceptualizing Risk

Purpose of Review

Identifying risk factors for STBs during adolescence is essential for suicide prevention. In this review, we employ the Research Domain Criteria (RDoC) framework to synthesize studies on key neurocognitive processes-cognitive control, reward responsiveness/valuation, and negative urgency-relevant to adolescent STBs.

Recent Findings

Within subdomains of Cognitive Control, studies of inhibition/suppression and updating/maintenance were mixed, while response selection (i.e., decision-making) deficits were consistently associated with suicide attempts. Fewer studies, by comparison, have probed the Positive Valence Systems. Relative to healthy controls, adolescents with prior STBs may show a blunted neural response to rewards and value rewards less, but findings require replication. Finally, negative urgency, which may span subdomains within both Cognitive Control and the Positive Valence Systems, was associated with recent suicide attempts in the only study to directly test this association.

Summary

Few studies have examined neurocognitive functioning in relation to adolescent STBs, despite the relevance of this research to detecting suicide risk. We recommend that future studies incorporate developmental contexts relevant to both neurocognitive processes and STBs.Broadly, cognitive control is associated with activation of the prefrontal cortex (PFC) and its interaction with other brain areas (e.g., reward and motor regions) [32]. Functional magnetic resonance imaging (fMRI) studies using emotional stimuli have provided evidence of abnormalities in neural regions supporting cognitive control among youth with STBs. [33] computed neural activation corresponding to viewing angry faces (relative to a fixation cross) in a sample of depressed youth. They found that, relative to non-attempters, attempters had: (a) increased activation in the right anterior gyrus and dorsolateral PFC and (b) reduced functional connectivity between the anterior cingulate gyrus and bilateral insulae. Relatedly, youth with bipolar disorder and a history of suicide attempts showed reduced functional connectivity between the amygdala and the left ventral PFC while viewing emotional (happy, fearful) and neutral faces compared to patient non-attempters [34]. The findings indicate that attempters may have problems regulating and appropriately deploying attention, as well as planning and executing behavioral responses, in emotional contexts.

Chronic Testosterone Increases Impulsivity and Influences the Transcriptional Activity of the Alpha-2A Adrenergic Receptor Signaling Pathway in Rat Brain

Testosterone is an anabolic androgenic steroid hormone involved in brain development, reproduction, and social behavior. Several studies have shown that testosterone can cause impulsivity in humans, which in turn, is linked with mood-related psychiatric disorders and higher risk of death by suicide. The mechanisms by which testosterone abuse influences impulsivity are unclear. The present study aims to understand how testosterone influences impulsivity in a rodent model both at behavioral and molecular levels. In this study, rats were either only gonadectomized or gonadectomized and injected with supraphysiological doses of testosterone. Their relative impulsivity levels were assessed using the go/no-go task. Serum level of testosterone was measured using ELISA. Transcript levels of alpha-2A adrenergic receptor (Adra2a), G proteins (stimulatory subunit-G_αs [Gnas], inhibitory subunit-G_iα [Gnai1 and Gnai2]), and catalytic and regulatory subunits of protein kinase A (PKA) were examined using quantitative PCR (qPCR) in brain areas associated with limbic system (prefrontal cortex (PFC), hippocampus, and amygdala). The testosterone-treated (T) group showed significantly higher level of serum testosterone and displayed a lower go/no-go ratio, indicating greater impulsivity compared to the gonadectomized (GDX) group. The transcript levels Adra2a and G_αs genes and PKA subunits encoded by Prkar1a, Prkar1b, Prkar2a, and Prkaca genes were significantly upregulated in PFC of testosterone treated rats. The expression levels of these genes were not significantly altered in hippocampus. On the other hand, amygdala showed changes only in Gnas and Prkar2a. These results suggest that chronic testosterone influences impulsivity possibly via hyperactive alpha-2A adrenergic receptor-PKA signaling axis, specifically in the PFC.