Imaging suicidal thoughts and behaviors: a comprehensive review of 2 decades of neuroimaging studies

Exploring neural changes associated with suicidal ideation and attempts in major depressive disorder: A multimodal study

Suicidal ideation (SI) and suicide attempts (SA) are highly prevalent in individuals with major depressive disorder (MDD). To explore the structural and functional neural changes associated with SI and SA, we analyzed multimodal Magnetic Resonance Imaging (MRI) data from 159 participants, including those with MDD with suicide attempts (SA group, n = 34), those with MDD with suicidal ideation but not attempts (SI group, n = 53), those with MDD without suicidal ideation (NSI group, n = 14), and healthy controls (HC, n = 59). Voxel-based morphometry (VBM) analysis was performed to estimate and compare gray matter volume (GMV) across groups. Subsequently, a seed-based resting-state functional connectivity (rsFC) analysis was conducted to explore the functional networks associated with the structural brain changes related to suicidal ideation and suicide attempts. Compared with the HC and NSI groups, the SI group showed decreased GMV in the left dorsolateral prefrontal cortex (DLPFC), insula, fusiform gyrus, right posterior cerebellum, and right middle temporal gyrus. Additionally, when compared to the HC and SI groups, the SA group demonstrated smaller GMV in the right superior medial frontal gyrus (SFGmed), left superior and inferior occipital gyri, and superior temporal gyrus (STG), and right cuneus, but larger GMV in the right STG. Moreover, GMV in the insula, cerebellum posterior lobe, and SFGmed was negatively correlated with the scores of the Beck Scale for Suicide Ideation (BSSI). The rsFC analysis revealed weaker rsFC between the left insula and the left SFG as well as between the bilateral middle frontal orbital gyrus and the right SFGmed and the left middle occipital gyrus, but stronger rsFC of the right cerebellum posterior lobe with the left precentral gyrus and right parahippocampal gyrus among the SI group compared to the NSI group and HCs. Additionally, the SA group demonstrated weaker rsFC between the right cerebellum posterior lobe and the left cerebellum posterior lobe as well as the right lingual gyrus, but stronger rsFC between the right SFGmed and the left middle temporal gyrus and right inferior parietal lobule compared to the SI group. Our results indicate that structural and functional changes related to insula, DLPFC and cerebellum posterior lobe are associated with the generation and escalation of SI in MDD, while the structural and functional changes related to SFGmed and STG play a crucial role in the transformation from SI to SA in MDD.

The roles of negative mood, impulsivity, and executive dysfunction in non-suicidal self-injury behaviors among Chinese middle school students

BACKGROUND

Previous studies have identified negative mood, impulsivity, and executive dysfunction as potential risk factors for non-suicidal self-injury (NSSI) in adolescents. However, the interplay of these factors and their gender-specific effects on NSSI remain unclear.

METHODS

In 2023, a sample of 1084 middle school students (Mage = 13.33; Nboy=574, Ngirl=510) completed psychological assessments measuring negative mood, impulsivity, executive dysfunction, and NSSI thoughts and behaviors over the past year.

RESULTS

(1) All variables were significantly correlated (all p values < 0.05); (2) Negative mood (β = 0.007, p = 0.002 for boys; β = 0.408, p < 0.001 for girls) and executive dysfunction (β = 0.209, p < 0.001 for boys; β = 0.124, p = 0.041 for girls) significantly predicted NSSI thoughts in both genders, whereas impulsivity showed no predictive effect; (3) Gender differences emerged in NSSI behaviors: negative mood (β = 0.395, p < 0.001) and impulsivity (β = 0.132, p = 0.005) were significant predictors among girls, whereas executive dysfunction (β = 0.200, p < 0.001) was a strong predictor among boys; (4) Impulsivity moderated the association between NSSI thoughts and NSSI behaviors in girls (β = 0.562, p < 0.001), but not in boys (β = -0.079, p = 0.390).

CONCLUSION

The influencing factors of NSSI behaviors exhibit notable gender differences. Tailored interventions should prioritize negative mood and impulsivity in girls, while addressing executive dysfunction in boys. Additionally, girls with high impulsivity and NSSI thoughts warrant closer monitoring, as they may be at a greater risk of engaging in NSSI behaviors.

Genetic Links Between Subcortical Brain Morphometry and Suicide Attempt Risk in Children and Adults

Genome-wide association studies (GWAS) have uncovered genetic variants associated with suicide attempt (SA) risk and regional brain volumes (RBVs). However, the extent of their genetic overlap remains unclear. To address this, we investigated whether the genetic architecture of SA and various RBVs (i.e., caudate nucleus, hippocampus, brainstem, ventral diencephalon, thalamus, globus pallidus, putamen, nucleus accumbens, amygdala and intracranial volume (ICV)) was shared. We leveraged GWAS summary statistics from the largest available datasets on SA (N = 958,896) and intracranial and subcortical RBVs (N = 74,898). Using linkage disequilibrium score regression, we estimated genome-wide genetic correlations between SA and individual RBVs. GWAS-pairwise analyses identified genomic segments associated with both SA and RBVs, followed by functional annotation. Additionally, we examined whether polygenic scores (PGS) for SA were associated with ICV and subcortical brain structure phenotypes in youth of European ancestry (N = 5276) in the Adolescent Brain Cognitive Development (ABCD) study. Linkage disequilibrium score regression results indicated a significant genetic correlation between SA and ICV (rG = -0.10, p-value = 1.9 × 10-3). GWAS-pairwise analyses and functional annotation revealed 10 genomic segments associated with SA and at least one RBV (thalamus, putamen and caudate nucleus). After adjusting for multiple tests, PGS association analysis indicated that a higher PGS for SA was significantly associated with a smaller volume of the right nucleus accumbens (b = -7.05, p = 0.018). Our findings highlight a negative genetic correlation between SA and ICV amongst adults and suggest different neural correlates associated with genetic risk for SA across developmental periods. This study advances our understanding of the shared genetic underpinnings of SA and brain structure, potentially informing future research and clinical interventions.

Multimodal Machine Learning Prediction of 12-Month Suicide Attempts in Bipolar Disorder

INTRODUCTION

Bipolar disorder (BD) patients present an increased risk of suicide attempts. Most current machine learning (ML) studies predicting suicide attempts are cross-sectional, do not employ time-dependent variables, and do not assess more than one modality. Therefore, we aimed to predict 12-month suicide attempts in a sample of BD patients, using clinical and brain imaging data.

METHODS

A sample of 163 BD patients were recruited and followed up for 12 months. Gray matter volumes and cortical thickness were extracted from the T1-weighted images. Based on previous literature, we extracted 56 clinical and demographic features from digital health records. Support Vector Machine was used to differentiate BD subjects who attempted suicide. First, we explored single modality prediction (clinical features, GM, and thickness). Second, we implemented a multimodal stacking-based data fusion framework.

RESULTS

During the 12 months, 6.13% of patients attempted suicide. The unimodal classifier based on clinical data reached an area under the curve (AUC) of 0.83 and balanced accuracy (BAC) of 72.7%. The model based on GM reached an AUC of 0.86 and BAC of 76.4%. The multimodal classifier (clinical + GM) reached an AUC of 0.88 and BAC of 83.4%, significantly increasing the sensitivity. The most important features were related to suicide attempts history, medications, comorbidities, and depressive polarity. In the GM model, the most relevant features mapped in the frontal, temporal, and cerebellar regions.

CONCLUSIONS

By combining models, we increased the detection of suicide attempts, reaching a sensitivity of 80%. Combining more than one modality proved a valid method to overcome limitations from single-modality models and increasing overall accuracy.

Functional connectivity of the default mode network subsystems alterations in suicide attempters with major depressive disorder

Default mode network (DMN) abnormalities are common in patients with major depressive disorder and suicide attempts (MDD-SA). We aimed to investigate the abnormal functional connectivity (FC) patterns of DMN in MDD-SA. Seventeen DMN components were extracted from 55 MDD-SA, 94 patients with MDD but without suicide attempts (MDD-NoSA), and 71 healthy controls (HC). Compared with HC and MDD-NoSA, patients with MDD-SA revealed reduced FC between the dorsomedial prefrontal cortex (dMPFC) seed and middle frontal gyrus (MFG). Patients with MDD-SA also showed specific increased FC between ventral medial prefrontal cortex (vMPFC) seed and medial superior frontal gyrus. MDD-NoSA showed specific increased FC between dMPFC and cerebellum crus Ⅱ. Both patients with MDD-SA and MDD-NoSA demonstrated increased FC between the vMPFC seed and inferior parietal lobule (IPL) and impaired FC between the anterior medial prefrontal cortex and cerebellum crus Ⅱ than HC. Furthermore, the abnormal FC between the vMPFC seed and IPL was correlated with Montgomery-Asberg Depression Scale in the MDD-NoSA group. Our findings highlighted that these abnormal FC patterns of DMN were associated with pathological mechanisms in patients with MDD-SA and MDD-NoSA.

Genetic approach uncovering the pathways between childhood maltreatment and suicide attempt

Childhood maltreatment significantly heightens the risk of suicide attempt, but the causal mechanisms and underlying pathways are not fully understood. Using genetic instruments for both childhood maltreatment (n = 185,414) and suicide attempt (cases = 29,782; controls = 519,961), we performed two-sample Mendelian randomization analyses. Our results show that higher level of childhood maltreatment is causally associated with an increased risk of suicide attempt (OR = 3.40; 95% CI, 2.34-4.96, P = 1.3e-10). We then conducted a two-step Mendelian randomization mediation analysis, identifying 11 out of 58 potential mediators between childhood maltreatment and suicide attempt. These mediators included neurobiological, psychopathological and behavioral factors. The psychopathological factors had the most significant impact, accounting for 10.4-50.2% the mediation. This study confirms the causal relationship between childhood maltreatment and suicide attempt, highlighting specific mediators-especially within the psychopathological dimension-that can guide targeted interventions to alleviate the adverse effects of childhood maltreatment and prevent suicide attempt.

Associations between suicidal ideation and childhood maltreatment as well as inflammatory cytokines in adolescents with major depressive disorder

BACKGROUND

Suicidal ideation (SI) is thought to be associated with childhood maltreatment (CM) and inflammatory processes. Yet, these links are not thoroughly studied in adolescents with major depressive disorder (MDD). So, this study focused on investigating the predictive value of CM and inflammatory cytokines for SI in this population.

METHODS

This study included 156 depressed adolescents. The Center for Epidemiological Studies Depression Scale (CES-D), the Childhood Trauma Questionnaire (CTQ) and the Positive and Negative Suicidal Ideation Scale (PANSI) were used to assess depression, CM and SI, respectively. Additionally, plasma inflammatory cytokines levels were measured, including interleukin (IL)-1β, IL-6, IL-10, IL-17A and tumor necrosis factor-α (TNF-α).

RESULTS

Univariate analyses showed that females had higher levels of SI in adolescents with MDD. Moreover, the level of SI was negatively correlated with age and age at onset, and positively correlated with duration of illness, CES-D score, CTQ score, as well as levels of IL-1β, IL-6 and TNF-α (all p < 0.05). Furthermore, regression analyses revealed that SI was independently associated with age at onset, CES-D score, CTQ score, and Log IL-1β (all p < 0.05). Finally, receiver operating characteristic (ROC) curve analyses revealed that the combination of the CES-D score, CTQ score, and IL-1β (AUC = 0.910, 95% CI = 0.864-0.956, p < 0.001) had a better ability to identify SI in adolescents with MDD, exhibiting higher sensitivity and specificity.

CONCLUSION

SI is associated with depressive symptoms, CM and elevated levels of inflammatory cytokines (especially IL-1β) in adolescents with MDD. In the future, interventions such as cognitive behavioural therapy and the administration of anti-inflammatory drugs, targeting the modulation of CM and inflammatory cytokine levels, may play important roles in preventing suicidal behaviors in depressed adolescents.

Reliable Multimodal Brain Signatures Predict Mental Health Outcomes in Children

BACKGROUND

Interindividual brain differences likely precede the emergence of mood and anxiety disorders; however, the specific brain alterations remain unclear. While many studies focus on a single imaging modality in isolation, recent advances in multimodal image analysis allow for a more comprehensive understanding of the complex neurobiology that underlies mental health.

METHODS

In a large population-based cohort of children from the ABCD (Adolescent Brain Cognitive Development) Study (N > 10,000), we applied data-driven linked independent component analysis to identify linked variations in cortical structure and white matter microstructure that together predict longitudinal behavioral and mental health symptoms. Brain differences were examined in a subsample of twins depending on the presence of at-risk behaviors.

RESULTS

Two multimodal brain signatures at ages 9 to 10 years predicted longitudinal mental health symptoms from 9 to 12 years, with small effect sizes. Cortical variations in association, limbic, and default mode regions linked with peripheral white matter microstructure together predicted higher depression and anxiety symptoms across 2 independent split-halves. The brain signature differed between depression and anxiety symptom trajectories and related to emotion regulation network functional connectivity. Linked variations of subcortical structures and projection tract microstructure variably predicted behavioral inhibition, sensation seeking, and psychosis symptom severity over time in male participants. These brain patterns were significantly different between pairs of twins discordant for self-injurious behavior.

CONCLUSIONS

Our results demonstrate reliable, multimodal brain patterns in childhood, before mood and anxiety disorders tend to emerge, that lay the foundation for long-term mental health outcomes and offer targets for early identification of children at risk.

Towards a neurodevelopmental model of bipolar disorder: a critical review of trait- and state-related functional neuroimaging in adolescents and young adults

Neurodevelopmental mechanisms are increasingly implicated in bipolar disorder (BD), highlighting the importance of their study in young persons. Neuroimaging studies have demonstrated a central role for frontotemporal corticolimbic brain systems that subserve processing and regulation of emotions, and processing of reward in adults with BD. As adolescence and young adulthood (AYA) is a time when fully syndromal BD often emerges, and when these brain systems undergo dynamic maturational changes, the AYA epoch is implicated as a critical period in the neurodevelopment of BD. Functional magnetic resonance imaging (fMRI) studies can be especially informative in identifying the functional neuroanatomy in adolescents and young adults with BD (BDAYA) and at high risk for BD (HR-BDAYA) that is related to acute mood states and trait vulnerability to the disorder. The identification of early emerging brain differences, trait- and state-based, can contribute to the elucidation of the developmental neuropathophysiology of BD, and to the generation of treatment and prevention targets. In this critical review, fMRI studies of BDAYA and HR-BDAYA are discussed, and a preliminary neurodevelopmental model is presented based on a convergence of literature that suggests early emerging dysfunction in subcortical (e.g., amygdalar, striatal, thalamic) and caudal and ventral cortical regions, especially ventral prefrontal cortex (vPFC) and insula, and connections among them, persisting as trait-related features. More rostral and dorsal cortical alterations, and bilaterality progress later, with lateralization, and direction of functional imaging findings differing by mood state. Altered functioning of these brain regions, and regions they are strongly connected to, are implicated in the range of symptoms seen in BD, such as the insula in interoception, precentral gyrus in motor changes, and prefrontal cortex in cognition. Current limitations, and outlook on the future use of neuroimaging evidence to inform interventions and prevent the onset of mood episodes in BDAYA, are outlined.

Frontal Activity of Recent Suicide Attempters: EEG spectrum Power Performing Raven Task

Background: Deficits in problem-solving may be related to vulnerability to suicidal behavior. We aimed to identify the electroencephalographic (EEG) power spectrum associated with the performance of the Raven as a reasoning/problem-solving task among individuals with recent suicide attempts. Methods: This study with the case-control method, consisted of 61 participants who were assigned to three groups: Suicide attempt + Major Depressive Disorder (SA + MDD), Major Depressive Disorder (MDD), and Healthy Control (HC). All participants underwent clinical evaluations and problem-solving abilities. Subsequently, EEG signals were recorded while performing the Raven task. Results: The SA + MDD and MDD groups were significantly different from the HC group in terms of anxiety, reasons for life, and hopelessness. Regarding brain oscillations in performing the raven task, increased theta, gamma, and betha power extending over the frontal areas, including anterior prefrontal cortex, dlPFC, pre-SMA, inferior frontal cortex, and medial prefrontal cortex, was significant in SA + MDD compared with other groups. The alpha wave was more prominent in the left frontal, particularly in dlPFC in SA + MDD. Compared to the MDD group, the SA + MDD group had a shorter reaction time, while their response accuracy did not differ significantly. Conclusions: Suicidal patients have more frontal activity in planning and executive function than the two other groups. Nevertheless, it seems that reduced activity in the left frontal region, which plays a crucial role in managing emotional distress, can contribute to suicidal tendencies among vulnerable individuals. Limitation The small sample size and chosen difficult trials for the Raven task were the most limitations of the study.

Magnetic resonance imaging of regional gray matter volume in persons who died by suicide

In vivo neuroimaging research in suicide attempters has shown alterations in frontal system brain regions subserving emotional regulation, motivation, and self-perception; however, data from living individuals is limited in clarifying risk for suicide death. Postmortem neuroimaging provides an approach to study the brain in persons who died by suicide. Here, whole brain voxel-based analyses of magnetic resonance imaging gray matter volume measures were performed comparing persons confirmed by forensic investigation to have died by suicide (n = 24), versus other causes (n = 24), in a univariate model covarying for age and total brain volume; all subjects were scanned within 24 hours after death. Consistent with the hypothesis that persons who died by suicide would show lower gray matter volume in frontal system brain regions, this study of suicides showed lower gray matter volume in ventral frontal and its major connection sites including insula, striatum, and amygdala.

Joint and distinct neural structure and function deficits in major depressive disorder with suicidality: a multimodal meta-analysis of MRI studies

BACKGROUND

Suicide risk is a major concern for patients with major depressive disorder (MDD). Neuroimaging studies have demonstrated that patients with MDD with suicidal ideation or suicide attempt (MDD-S) are accompanied by neurostructural or functional abnormalities, but there is no consensus of opinion on neural substrate alterations involved in MDD-S.

METHODS

We performed a whole-brain multimodal meta-analysis of existing magnetic resonance imaging (MRI) studies to identify conjoint and separate alterations of grey matter volume (GMV) and spontaneous brain activity characteristics (regional homogeneity and amplitude of low-frequency fluctuations) between patients with MDD-S and patients with MDD without suicidal ideation or suicidal attempt (MDD-NS) via the seed-based d mapping software. We excluded studies that used other modalities, had overlapping data, or had insufficient information.

RESULTS

Our systematic search identified 13 structural MRI studies (471 patients with MDD-S and 508 patients with MDD-NS) and 16 resting-state functional MRI studies (704 patients with MDD-S and 554 patients with MDD-NS) published up to Dec. 5, 2023. Compared with patients with MDD-NS, those with MDD-S showed increased GMV with hypoactivity in the left postcentral gyrus, decreased GMV with hypoactivity in the right inferior parietal gyri, decreased GMV with hyperactivity in the right insula, and separate GMV and functional changes within the bilateral parietal, occipital, and frontal lobes, and the left thalamus.

LIMITATIONS

We were unable to analyze the association between brain features and clinical detail because of a lack of data. Included studies showed considerable heterogeneity and publication bias.

CONCLUSION

These findings provide a comprehensive overview of brain morphological and spontaneous functional impairments linked to impulsivity, impaired positive reward modulation, emotional disturbances, abnormal emotional processing, and cognitive deficits in MDD-S. These results support an understanding of the relationship between neural substrates and clinical symptoms in MDD-S, and these alterations provide useful insight into pathophysiological mechanisms and intervention strategies to decrease suicide risk in MDD.

Cognitive control impairment in suicide behaviors: what do we know? A systematic review and meta-analysis of Stroop in suicide behaviors

BACKGROUND

Suicidal behavior results from a complex interplay between stressful events and vulnerability factors, including cognitive deficits. Poorer performance on the Stroop task, a measure of cognitive control, has been associated with suicidal behavior in numerous studies. The objective was to conduct an updated systematic review of the literature on the Stroop task as a neuropsychological test of vulnerability to suicidal acts in patients with mood and other psychiatric disorders, while also looking at how the type (classic versus emotional) or the version (paper or computerized) of the Stroop task, as well as the characteristics of the patient (clinical population, age, sex) moderated the Stroop effect.

METHODS

A search on Medline, Embase, PsycInfo databases, and article references was performed. 53 studies (6781 participants) met the selection criteria. Interference time and errors of the Stroop Test were assessed in at least 3 studies to be analyzed. Moderators, such as the type (classic versus emotional) of the Stroop task and the characteristics of the patient (clinical population, age, sex) were also assessed.

RESULTS

Interference time on Stroop performance was lower in suicide attempters than in patient controls (g = 0.20; 95%CI [0.10-0.30]) and healthy controls (g = 0.79; 95 % CI [0.29-1.29]), with patient controls scoring lower than healthy controls (g = -0.63; 95%CI [-1.01-0.25]). This was moderated by age and having a mood disorder. In terms of interference errors, suicide attempters performed worse than healthy controls (g = 0.57; 95%CI [0.01-1.15]) but did not perform differently from patient controls (g = 0.20; 95 % CI [-0.06-0.45]). Patient controls also did not score differently than healthy controls (g = -0.18; 95 % CI [-0.54-0.18]). There was a significant moderation effect for the type (i.e., original Stroop task) and version (i.e., paper format) of the Stroop task, and for some characteristics of the patient (i.e., older patients and having a mood disorder).

CONCLUSIONS

Cognitive control impairment was associated with a history of suicidal behavior in patients, especially in older populations and those with mood disorders, however this result was moderated by outcome measure (interference time vs. errors), the type (i.e., original Stroop task) and the version (i.e., paper format) of the Stroop task. Cognitive control processes may be an important factor of suicidal vulnerability. Choosing the right neurocognitive test in the right population to detect suicide vulnerability is important direction for future research.

Impulse control deficits among patients with nonsuicidal self-injury: a mediation analysis based on structural imaging

BACKGROUND

Nonsuicidal self-injury (NSSI) is posited to arise from a complex interaction of biopsychosocial factors, with impulsivity playing a critical role. Given that current research on the neural mechanisms underlying this hypothesis remains inconsistent and limited in scope, we sought to explore how NSSI behaviours are associated with impulsivity resulting from structural brain alterations.

METHODS

We recruited patients with NSSI behaviours and healthy controls from 11 psychiatric hospitals. We assessed the differences in impulse control between the 2 groups using the Barratt Impulsiveness Scale version 11 and the Attention Network Test. We also conducted T 1-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging. Finally, we analyzed the associations among brain structure, psychological characteristics, and self-injurious behaviour among patients with NSSI.

RESULTS

We included 293 patients with NSSI behaviours and 140 healthy controls. Among them, 182 patients with NSSI and 95 controls underwent the T 1-weighted MRI and diffusion tensor imaging. Patients with NSSI showed increased impulsivity and alerting function, with the strongest correlation between NSSI frequency and motor impulsivity. Compared with controls, patients with NSSI exhibited decreased grey matter volume and increased white matter volume, with no significant difference in cortical thickness. Pathway analysis demonstrated that motor impulsivity significantly mediated the association between white matter volume and the NSSI frequency in the right superior frontal gyrus and right inferior parietal lobe. When examining the connecting fibre tracts in the right frontoparietal area, patients with NSSI showed decreased integrity of white matter microstructure in the right cingulum, right superior corona radiata, and the splenium of the corpus callosum.

LIMITATIONS

Accurately measuring executive control linked to NSSI is challenging in cognitive behavioural tasks, as impulsive tendencies during NSSI occurrence are not effectively captured.

CONCLUSION

Our findings suggested that motor impulsivity, a prominent psychopathological characteristic of NSSI, is primarily modulated by the frontoparietal regions. These results provide empirical neuroimaging evidence for the impaired impulse control observed in NSSI.

A moderated mediation model in assessing links between rumination, emotional reactivity, and suicidal risk in alcohol use disorder

Introduction

Suicide is a major public health concern, particularly among people with alcohol use disorders (AUD). Rumination, as a dysfunctional emotion regulation strategy, and increased emotional reactivity may significantly influence suicide risk in this population.

Aim

The aim of this study was to assess whether different emotional reactivity mediate the association between ruminations and suicide risk, and whether AUD or control group (HC) status moderates these relationships.

Methods

A study was conducted with 152 participants, including 86 from AUD and 66 from HC. Self-report questionnaires measuring ruminations, emotional reactivity and suicide risk were used. Structural Equation Modeling, invariance analysis, and moderated mediation estimation were used in the analyses.

Results

The mediation analysis in the full sample revealed a significant indirect effect of rumination on suicide risk via emotional reactivity. Multi-group analysis indicated no significant differences in the mediation effect between the AUD and HC groups, with neither group showing a statistically significant indirect effect.

Conclusions

The findings indicate that emotional reactivity may serve as a key mechanism mediating the relationship between rumination and suicide risk. Therapeutic interventions should focus on reducing ruminations and emotion reactivity to effectively reduce suicide risk in this group. Further research is needed to better understand these mechanisms.

Suicidal Behaviour Prior to First Episode Psychosis: Wider and More Widespread Grey-Matter Alterations

INTRODUCTION

The prodromal phase preceding the onset of First Episode Psychosis (FEP) is associated with an increased risk of Suicidal Behaviors (SBs). The aim of this study was to identify specific structural brain abnormalities linked to SBs that occur prior to the onset of FEP.

METHODS

Voxel-based morphometry analyses were used to investigate differences in brain Grey Matter (GM) volume using the CAT12 toolbox within SPM12. Covariates, including gender, age, handedness, intracranial volume, depression severity, and global cognitive functioning, were controlled for as confounding factors.

RESULTS

Significant reductions in GM were observed in the left superior temporal gyrus, dorsal posterior cingulate cortex, precuneus, cuneus, anterior cerebellum (p-FWE corrected < 0.05, k > 50) as well as in the right amygdala (0.96 ± 0.06 vs. 1.01 ± 0.05; F = 4.78; p < 0.05) and left amygdala (0.97 ± 0.06 vs. 1.02 ± 0.05; F = 8.97; p = 0.01).

CONCLUSIONS

History of SB prior to the onset of the psychotic disorder was related to wider and more widespread brain GM alterations. The regions identified are involved in cognitive and emotional processes such as emotional regulation, social cognition, perseverative thinking, and pain tolerance. These findings suggest that structural brain abnormalities related to SB occurring before FEP onset may serve as early biomarkers for identifying individuals at increased risk of suicide.

Intermittent theta-burst stimulation with adjunctive D-cycloserine rapidly resolves suicidal ideation and decreases implicit association with death/suicide

BACKGROUND

Depressive disorders are the most common diagnosis among individuals who die by suicide, and intermittent theta-burst stimulation (iTBS) is a noninvasive treatment for those with difficult-to-treat depression who are at higher risk for suicide. Previous data suggests that pairing iTBS with D-cycloserine, a partial N-methyl-D-aspartate (NMDA) receptor agonist, improves antidepressant outcomes. However, its impact on suicide risk is not known.

METHODS

We examine suicidal ideation and implicit suicide risk after iTBS+D-cycloserine in two clinical trials (open-label trial [n = 12] and randomized placebo-controlled trial [RCT, n = 50]) involving adults with major depressive disorder and the acute effects of D-cycloserine on implicit suicide risk in a crossover trial (n = 18). Implicit suicide risk was assessed using the computerized death/suicide implicit association test (IAT), and depressive symptoms and suicidal ideation were assessed using the clinician-rated Montgomery-Asberg Depression Rating Scale (MADRS).

RESULTS

Open-label iTBS+D-cycloserine was associated with a rapid reduction in suicidal ideation, and iTBS+D-cycloserine was superior to iTBS+placebo in reducing suicidal ideation. Similarly, open-label iTBS+D-cycloserine was associated with decreased implicit suicide risk as measured by the death/suicide IAT, and iTBS+D-cycloserine was associated with greater decreases in death/suicide IAT scores compared to iTBS+placebo. A single acute dose of D-cycloserine in the absence of iTBS had no effect on implicit suicide risk.

CONCLUSIONS

Adjunctive D-cycloserine with iTBS is a promising strategy to reduce suicidal ideation and implicit suicide risk in depression.

Alterations in orbitofrontal cortex communication relate to suicidal attempts in patients with major depressive disorder

BACKGROUND

Investigating how the interaction between the orbitofrontal cortex (OFC) and various brain regions/functional networks in major depressive disorder (MDD) patients with a history of suicide attempt (SA) holds importance for understanding the neurobiology of this population.

METHODS

We employed resting-state functional magnetic resonance imaging (rs-fMRI) to analyze the OFC's functional segregation in 586 healthy individuals. A network analysis framework was then applied to rs-fMRI data from 86 MDD-SA patients and 85 MDD-Control patients, utilizing seed mappings of OFC subregions and a multi-connectivity-indicator strategy involving cross-correlation, total interdependencies, Granger causality, and machine learning.

RESULTS

Four functional subregions of left and right OFC, were designated as seed regions of interest. Relative to the MDD-Control group, the MDD-SA group exhibited enhanced functional connectivity (FC) and attenuated interaction between the OFC and the sensorimotor network, imbalanced communication between the OFC and the default mode network, enhanced FC and interaction between the OFC and the ventral attention network, enhanced interaction between the OFC and the salience network, and attenuated FC between the OFC and the frontoparietal network.

LIMITATIONS

The medication and treatment condition of patients with MDD was not controlled, so the medication effect on the alteration model cannot be affirmed.

CONCLUSION

The findings suggest an imbalanced interaction pattern between the OFC subregions and a set of cognition- and emotion-related functional networks/regions in the MDD-SA group.

Altered Functional Connectivity of Prefrontal Cortex-Related Circuitry and Trait Impulsivity in Patients With Bipolar Disorder and History of Suicide Attempts

BACKGROUND

The neurobiological basis of impulsivity and its role in suicide attempt (SA) in BD remains underexplored. This study aimed to examine the functional connectivity (FC) within the prefrontal cortex (PFC) in BD patients with and without a history of SA, focusing on the role of trait impulsivity.

METHODS

Seventy-two euthymic BD patients (34 with a history of SA, BDSA; and 38 without, BDNS) and 55 age- and sex-matched healthy controls underwent resting-state functional MRI. FC analyses were conducted on four PFC regions: superior frontal gyrus (SFG), middle frontal gyrus (MFG), inferior frontal gyrus (IFG), and orbitofrontal cortex (OFC). Trait impulsivity was assessed using the Barratt Impulsiveness Scale (BIS-11), and its association with FC was analyzed using a general linear model, adjusting for demographic and clinical variables.

RESULTS

BDSA had higher trait impulsivity than BDNS and the controls. BDSA exhibited reduced FC between the PFC and sensorimotor (postcentral and precentral gyri) and thalamic regions compared to BDNS. These reductions in FC of the fronto-thalamic and fronto-sensorimotor circuits were significantly associated with higher trait impulsivity scores.

CONCLUSION

The findings highlight specific PFC-based FC alterations associated with suicide attempts and trait impulsivity in BD, offering potential neurobiological markers for suicide risk in this population.

Changes in Rates of Suicide by Mass Shooters, 1980-2019

OBJECTIVE

The rate of worldwide mass shootings increased almost 400% over the last 40 years. About 30% are followed by the perpetrator's fatal or nonfatal suicide attempt.

METHOD

We examined the rate of fatal and nonfatal attempts among 528 mass shooters over the last 40 years and their relationship to detected mental illness to better understand this specific context of suicide. We collected information on U.S.-based, personal-cause mass murders that involved one or more firearms, from online sources.

RESULTS

A greater proportion of mass shooters from 2000 to 2019 took or attempted to take their own lives (40.5%) compared with those from 1980 to 1999 (23.2%, p < 0.001). More than double the proportion of perpetrators who made a fatal or nonfatal suicide attempt had a history of non-psychotic psychiatric/neurologic symptoms (38.9%), compared with perpetrators who did not make a fatal or nonfatal suicide attempt (18.1%; p < 0.001). Among mass shooters who made fatal or nonfatal suicide attempts, 77 of 175 (44%) did not have any recorded psychiatric, neurologic, or substance use condition. Of the 98 mass shooters who made fatal or non-fatal suicide attempts and had a psychiatric, substance use, or neurologic condition, 41 had depressive disorders.

CONCLUSION

It is possible that a lack of information about the perpetrators' mental health or suicidal ideation led to an underestimation of their prevalence. These data suggest that suicide associated with mass shootings may represent a specific context for suicide, and approaches such as psychological autopsy can help to ascertain when psychiatric illness mediates the relationship between mass shootings and suicide.

Aberrant glutamatergic systems underlying impulsive behaviors: Insights from clinical and preclinical research

Impulsivity is a broad construct that often refers to one of several distinct behaviors and can be measured with self-report questionnaires and behavioral paradigms. Several psychiatric conditions are characterized by one or more forms of impulsive behavior, most notably the impulsive/hyperactive subtype of attention-deficit/hyperactivity disorder (ADHD), mood disorders, and substance use disorders. Monoaminergic neurotransmitters are known to mediate impulsive behaviors and are implicated in various psychiatric conditions. However, growing evidence suggests that glutamate, the major excitatory neurotransmitter of the mammalian brain, regulates important functions that become dysregulated in conditions like ADHD. The purpose of the current review is to discuss clinical and preclinical evidence linking glutamate to separate aspects of impulsivity, specifically motor impulsivity, impulsive choice, and affective impulsivity. Hyperactive glutamatergic activity in the corticostriatal and the cerebro-cerebellar pathways are major determinants of motor impulsivity. Conversely, hypoactive glutamatergic activity in frontal cortical areas and hippocampus and hyperactive glutamatergic activity in anterior cingulate cortex and nucleus accumbens mediate impulsive choice. Affective impulsivity is controlled by similar glutamatergic dysfunction observed for motor impulsivity, except a hyperactive limbic system is also involved. Loss of glutamate homeostasis in prefrontal and nucleus accumbens may contribute to motor impulsivity/affective impulsivity and impulsive choice, respectively. These results are important as they can lead to novel treatments for those with a condition characterized by increased impulsivity that are resistant to conventional treatments.

Omics Approaches to Investigate the Pathogenesis of Suicide

Suicide is the second leading cause of death in U.S. adolescents and young adults and is generally associated with a psychiatric disorder. Suicidal behavior has a complex etiology and pathogenesis. Moderate heritability suggests genetic causes. Associations between childhood and recent life adversity indicate contributions from epigenetic factors. Genomic contributions to suicide pathogenesis remain largely unknown. This article is based on a workshop held to design strategies to identify molecular drivers of suicide neurobiology that would be putative new treatment targets. The panel determined that while bulk tissue studies provide comprehensive information, single-nucleus approaches that identify cell type-specific changes are needed. While single-nuclei techniques lack information on cytoplasm, processes, spines, and synapses, spatial multiomic technologies on intact tissue detect cell alterations specific to brain tissue layers and subregions. Because suicide has genetic and environmental drivers, multiomic approaches that combine cell type-specific epigenome, transcriptome, and proteome provide a more complete picture of pathogenesis. To determine the direction of effect of suicide risk gene variants on RNA and protein expression and how these interact with epigenetic marks, single-nuclei and spatial multiomics quantitative trait loci maps should be integrated with whole-genome sequencing and genome-wide association databases. The workshop concluded with a recommendation for the formation of an international suicide biology consortium that will bring together brain banks and investigators with expertise in cutting-edge omics technologies to delineate the biology of suicide and identify novel potential treatment targets to be tested in cellular and animal models for drug and biomarker discovery to guide suicide prevention.

A multi-level examination of impulsivity and links to suicide ideation among Native American youth

BACKGROUND

Despite preliminary evidence that links impulsivity to suicide risk among Native American youth, impulsivity has not been directly studied in relation to suicide ideation (SI) or behaviors in this population. We examined indexes of rapid-response impulsivity (RRI) across multiple levels of analysis (self-report, behavioral, neurobiological) and associations with SI among Native American youth ages 9-10 in the Adolescent Brain Cognitive Development Study.

METHODS

Data from the sample (n = 284) included self-report (UPPS-P), behavioral (Stop Signal Task), and neurobiological (right inferior frontal gyrus activation) indicators of RRI. RRI indicators were modeled using variable-centered (i.e., traditional multivariable regression) and person-centered (i.e., clustering analyses) approaches in measuring their association with SI.

RESULTS

Logistic regression analysis demonstrated that higher negative urgency was associated with higher odds of SI (Adjusted Odds Ratio = 1.23, p = 0.015). Latent profile analysis clustered youth into five profiles based on within-individual variation in RRI indicators. Youth with an elevated self-reported negative and positive urgency profile had higher odds of reporting SI than "normative" youth (Adjusted Odds Ratio = 2.38, p = 0.019).

LIMITATIONS

Limitations of this study include the modest sample size particularly regarding SI (14.1 %), potential bias in estimates of lifetime SI, and generalizability to youth from specific Native American communities.

CONCLUSIONS

Negative urgency may increase risk for SI among Native American youth in late childhood. Clinical implications, including the potential for person-centered RRI profiles to act as candidate markers of suicide risk and resilience in adolescence and inform safety assessments and planning, are discussed.

Reverse phase protein array-based investigation of mitochondrial genes reveals alteration of glutaminolysis in the parahippocampal cortex of people who died by suicide

A moderating hub between resting state networks (RSNs) and the medial temporal lobe (MTL) is the parahippocampal cortex (PHC). Abnormal activity has been reported in depressed patients and suicide attempters in this region. Alterations in neuronal mitochondrial function may contribute to depression and suicidal behavior. However, little is known about the underlying molecular level changes in relevant structures. Specifically, expressional changes related to suicide have not been reported in the PHC. In this study, we compared the protein expression levels of genes encoding tricarboxylic acid (TCA) cycle enzymes in the PHC of adult individuals who died by suicide by reverse phase protein array (RPPA), which was corroborated by qRT-PCR at the mRNA level. Postmortem human brain samples were collected from 12 control and 10 suicidal individuals. The entorhinal cortex, which is topographically anterior to the PHC in the parahippocampal gyrus, and some other cortical brain regions were utilized for comparison. The results of the RPPA analysis revealed that the protein levels of DLD, OGDH, SDHB, SUCLA2, and SUCLG2 subunits were significantly elevated in the PHC but not in other cortical brain regions. In accordance with these findings, the mRNA levels of the respective subunits were also increased in the PHC. The subunits with altered levels are implicated in enzyme complexes involved in the oxidative decarboxylation branch of glutamine catabolism. These data suggest a potential role of glutaminolysis in the pathophysiology of suicidal behavior in the PHC.

Transdiagnostic alterations in white matter microstructure associated with suicidal thoughts and behaviours in the ENIGMA Suicidal Thoughts and Behaviours consortium

Previous studies have suggested that alterations in white matter (WM) microstructure are implicated in suicidal thoughts and behaviours (STBs). However, findings of diffusion tensor imaging (DTI) studies have been inconsistent. In this large-scale mega-analysis conducted by the ENIGMA Suicidal Thoughts and Behaviours (ENIGMA-STB) consortium, we examined WM alterations associated with STBs. Data processing was standardised across sites, and resulting WM microstructure measures (fractional anisotropy, axial diffusivity, mean diffusivity and radial diffusivity) for 25 WM tracts were pooled across 40 cohorts. We compared these measures among individuals with a psychiatric diagnosis and lifetime history of suicide attempt (n=652; mean age=35.4±14.7; female=71.8%), individuals with a psychiatric diagnosis but no STB (i.e., clinical controls; n=1871; mean age=34±14.8; female=59.8%), and individuals with no mental disorder diagnosis and no STB (i.e., healthy controls; n=642; mean age=29.6±13.1; female=62.9%). We also compared these measures among individuals with recent suicidal ideation (n=714; mean age=36.3±15.3; female=66.1%), clinical controls (n=1184; mean age=36.8±15.6; female=63.1%), and healthy controls (n=1240; mean age= 31.6±15.5; female=61.0%). We found subtle but statistically significant effects, such as lower fractional anisotropy associated with a history of suicide attempt, over and above the effect of psychiatric diagnoses. These effects were strongest in the corona radiata, thalamic radiation, fornix/stria terminalis, corpus callosum and superior longitudinal fasciculus. Effect sizes were small (Cohen's d < 0.25). Recent suicidal ideation was not associated with alterations in WM microstructure. This large-scale coordinated mega-analysis revealed subtle regional and global alterations in WM microstructure in individuals with a history of suicide attempt. Longitudinal studies are needed to confirm whether these alterations are a risk factor for suicidal behaviour.

The Effect of Forkhead Box O1 Single Nucleotide Polymorphisms on Cortical Thickness and White Matter Integrity in High Suicide Risk Patients

OBJECTIVE

Neuroinflammation's role is increasingly emphasized in the pathology of major depressive disorder (MDD), and its close association with the risk of suicide is being reported. The Forkhead Box O1 (FoxO1) gene is known to play a role in regulating mood and emotion and is associated with susceptibility to suicidality in relation to environmental stress. This research aims to explore the relationship between FoxO1 and the risk of suicide in individuals with MDD.

METHODS

We enrolled 127 healthy controls (HC) and 231 patients diagnosed with MDD, including 119 individuals with high suicide risk (HSR). All participants underwent the Hamilton Rating Scale for Depression Assessment and magnetic resonance imaging. Cortical thickness and white matter integrity were evaluated.

RESULTS

In the HSR group, cortical thinning was observed in the left triangular part of the inferior frontal gyrus and right transverse frontopolar gyrus compared to HC. Additionally, fractional anisotropy (FA) values were decreased in the left posterior thalamic radiation, sagittal stratum, and uncinate fasciculus. Although no differences were observed based on allele variations for the two FoxO1 single nucleotide polymorphisms (SNPs), those with the minor allele of FoxO1 rs34733279, especially in the HSR group, displayed increased cortical thinning and reduced FA values in the left cingulum.

CONCLUSION

Our study reveals close association between the minor allele of the FoxO1 gene rs34733279 and suicide risk in the left cingulum highlights the potential key role of the FoxO1 gene rs34733279 in the context of suicidal vulnerability. Further investigations are warranted to elucidate the underlying biological mechanisms.

EEG oscillations in recent suicide attempters: Assessing responses to positive and negative future imagination tasks

BACKGROUND

Our goal is to uncover Electroencephalography (EEG) power spectrum patterns during imagination tasks in individuals who attempted suicide within the past 1-4 weeks, addressing gaps in understanding the neural correlates of future imagination in suicidal behavior.

METHODS

This case-control study comprised a total of 60 participants, consisting of 47 females and 13 males. The sample comprised three groups: Attempted Suicide + Major Depressive Disorder (SA+MDD), Major Depressive Disorder (MDD), and Healthy Controls (HC). To assess participants' future imagination, a unique approach called the Positive and Negative Future Imagination Task was designed, which involved scenario visualization concurrent with EEG recording. Statistical analyses included ANOVA with post-hoc pairwise comparisons to compare EEG power spectrum between three groups.

RESULTS

It was observed that the SA+MDD group experienced significantly increased theta frequency band in the right frontocentral regions when compared to the MDD group during both positive and negative imagination tasks (P-value < 0.05). Furthermore, increased gamma activity was observed in the SA+MDD group compared to the HC group, predominantly in the right frontocentral areas during both imagination tasks.

CONCLUSION

The results of this study indicate that individuals who have recently attempted suicide exhibit heightened neural activity in the frontocentral regions of the right hemisphere of the brain, specifically in theta and gamma band frequencies, when contemplating both positive and negative aspects of the future. These findings, in the context of behavioral tasks may indicate a decrease in the ability to envision a positive future and an increase in visualizing a negative future.

Neuroimaging studies in major depressive disorder with suicidal ideation or behaviour among Chinese patients: implications for neural mechanisms and imaging signatures

Major depressive disorder (MDD) with suicidal ideation or behaviour (MDSI) is associated with an increased risk of future suicide. The timely identification of suicide risk in patients with MDD and the subsequent implementation of interventions are crucially important to reduce their suffering and save lives. However, the early diagnosis of MDSI remains challenging across the world, as no objective diagnostic method is currently available. In China, the challenge is greater due to the social stigma associated with mental health problems, leading many patients to avoid reporting their suicidal ideation. Additionally, the neural mechanisms underlying MDSI are still unclear, which may hamper the development of effective interventions. We thus conducted this narrative review to summarise the existing neuroimaging studies of MDSI in Chinese patients, including those involving structural magnetic resonance imaging (MRI), functional MRI, neuronal electrophysiological source imaging of the brain dynamics with electroencephalography and magnetoencephalography. By synthesising the current research efforts in neuroimaging studies of Chinese patients with MDSI, we identified potential objective neuroimaging biomarkers, which may aid in the early identification of patients with MDSI who are at high suicide-related risk. Our findings also offer insights into the complex neural mechanisms underlying MDSI and suggest promising therapeutic targets. Furthermore, we propose future directions to discover novel imaging signatures, improve patient care, as well as help psychiatrists and clinical investigators plan their future research.

The neural connectome of suicidality in adults with mood and anxiety disorders

Although suicide risk is a major public health issue, attempts to understand the neural basis of suicidality have been limited by small sample sizes and a focus on specific psychiatric disorders. This sample comprised 579 participants, of whom 428 had a psychiatric disorder (depression, anxiety or stress-related disorder) and 151 were non-psychiatric controls. All participants underwent structured clinical interviews, including an assessment of suicidality in the past month, and completed a functional magnetic resonance imaging scan. There were 238 (41.1%) participants who met criteria for suicidality and 341 (58.9%) were non-suicidal. Task-derived functional connectivity was calculated for 436 brain regions, comprising 8 intrinsic connectivity networks. Participants who were suicidal had decreased connectivity in a network of 143 connections across 86 brain regions. This pattern was characterized primarily by decreased connectivity within the visual, somatomotor and salience networks, between these networks, and also with the default mode and limbic networks. By adopting a transdiagnostic approach with a very large sample of individuals with mood disorders, anxiety and stress and non-psychiatric participants, this study highlights the hypoconnectivity that characterizes suicidality and points to altered connectivity within and between key networks involved in emotional, sensory and cognitive processes that are implicated in suicidal risk.

Transcriptional Patterns of Brain Structural Covariance Network Abnormalities Associated With Suicidal Thoughts and Behaviors in Major Depressive Disorder

BACKGROUND

Although brain structural covariance network (SCN) abnormalities have been associated with suicidal thoughts and behaviors (STBs) in individuals with major depressive disorder (MDD), previous studies have reported inconsistent findings based on small sample sizes, and underlying transcriptional patterns remain poorly understood.

METHODS

Using a multicenter magnetic resonance imaging dataset including 218 MDD patients with STBs, 230 MDD patients without STBs, and 263 healthy control participants, we established individualized SCNs based on regional morphometric measures and assessed network topological metrics using graph theoretical analysis. Machine learning methods were applied to explore and compare the diagnostic value of morphometric and topological features in identifying MDD and STBs at the individual level. Brainwide relationships between STBs-related connectomic alterations and gene expression were examined using partial least squares regression.

RESULTS

Group comparisons revealed that SCN topological deficits associated with STBs were identified in the prefrontal, anterior cingulate, and lateral temporal cortices. Combining morphometric and topological features allowed for individual-level characterization of MDD and STBs. Topological features made a greater contribution to distinguishing between patients with and without STBs. STBs-related connectomic alterations were spatially correlated with the expression of genes enriched for cellular metabolism and synaptic signaling.

CONCLUSIONS

These findings revealed robust brain structural deficits at the network level, highlighting the importance of SCN topological measures in characterizing individual suicidality and demonstrating its linkage to molecular function and cell types, providing novel insights into the neurobiological underpinnings and potential markers for prediction and prevention of suicide.

Neurobiology and medico-legal aspects of suicides among older adults: a narrative review

The task of preventing suicide in older adults is an important social burden as older adults aged above 65 are exposed to singular psychological aspects that increase suicide risks. Moreover, when an older adult corpse is found, the medico-legal inspection represents a fundamental tool to identify the exact cause of death, classifying or excluding it as suicide. In this scenario, this review aims to explore the neurobiological factors that could be related to suicidal behavior in older adults. A further goal of this review is the exploration of the medico-legal aspects surrounding older adult suicides, clarifying the importance of forensic investigation. Particularly, this review examines issues such as neurotransmitter imbalances, cognitive impairment, neuroinflammation, psychosocial factors related to geriatric suicide, and neurodegenerative diseases. Additionally, medico-legal aspects such as policy considerations, legal frameworks, mental health assessments, ethical implications and forensic investigation were explored. Considering the importance of this phenomenon, especially in western countries, a need has emerged for focused screening tools on suicidal behavior among older adults, in order to contain it. Therefore, this review makes an exhaustive appraisal of the literature giving insights into the delicate interplay between neurobiology as well as mental health in relation to older adult suicide within a medico-legal context. The comprehension of different aspects about this complex phenomenon is fundamental to propose new and more effective interventions, supporting tailored initiatives such as family support and improving healthcare, specifically towards vulnerable ageing societies to reduce older adult suicide risks.

Identifying behaviour-related and physiological risk factors for suicide attempts in the UK Biobank

Suicide is a global public health challenge, yet considerable uncertainty remains regarding the associations of both behaviour-related and physiological factors with suicide attempts (SA). Here we first estimated polygenic risk scores (PRS) for SA in 334,706 UK Biobank participants and conducted phenome-wide association analyses considering 2,291 factors. We identified 246 (63.07%) behaviour-related and 200 (10.41%, encompassing neuroimaging, blood and metabolic biomarkers, and proteins) physiological factors significantly associated with SA-PRS, with robust associations observed in lifestyle factors and mental health. Further case-control analyses involving 3,558 SA cases and 149,976 controls mirrored behaviour-related associations observed with SA-PRS. Moreover, Mendelian randomization analyses supported a potential causal effect of liability to 58 factors on SA, such as age at first intercourse, neuroticism, smoking, overall health rating and depression. Notably, machine-learning classification models based on behaviour-related factors exhibited high discriminative accuracy in distinguishing those with and without SA (area under the receiver operating characteristic curve 0.909 ± 0.006). This study provides comprehensive insights into diverse risk factors for SA, shedding light on potential avenues for targeted prevention and intervention strategies.

Brain transcriptomic signatures for mood disorders and suicide phenotypes: an anterior insula and subgenual ACC network postmortem study

Mood disorders affect over ten percent of humans, but studies dissecting the brain anatomical and molecular neurobiological mechanisms underlying mood (dys)functions have not consistently identified the patterns of pathological changes in relevant brain regions. Recent studies have identified pathological changes in the anterior insula (Ant-Ins) and subgenual anterior cingulate (sgACC) brain network in mood disorders, in line with this network's role in regulating mood/affective feeling states. Here, we applied whole-tissue RNA-sequencing measures of differentially expressed genes (DEGs) in mood disorders versus (vs.) psychiatrically unaffected controls (controls) to identify postmortem molecular pathological markers for mood disorder phenotypes. Using data-driven factor analysis of the postmortem phenotypic variables to determine relevant sources of population variances, we identified DEGs associated with mood disorder-related diagnostic phenotypes by combining gene co-expression, differential gene expression, and pathway-enrichment analyses. We found downregulation/under expression of inflammatory, and protein synthesis-related genes associated with psychiatric morbidity (i.e., all co-occurring mental disorders and suicide outcomes/death by suicide) in Ant-Ins, in contrasts to upregulation of synaptic membrane and ion channel-related genes with increased psychiatric morbidity in sgACC. Our results identified a preponderance of downregulated metabolic, protein synthesis, inflammatory, and synaptic membrane DEGs associated with suicide outcomes in relation to a factor representing longevity in the Ant-Ins and sgACC (AIAC) network. Our study revealed a critical brain network molecular repertoire for mood disorder phenotypes, including suicide outcomes and longevity, and provides a framework for defining dosage-sensitive (i.e., downregulated vs. upregulated) molecular signatures for mood disorder phenotypic complexity and pathological outcomes.

Active suicidal ideation associated with dysfunction in default mode network using resting-state EEG and functional MRI - Findings from the T-RAD Study

Suicide in youth and young adults is a serious public health problem. However, the biological mechanisms of suicidal ideation (SI) remain poorly understood. The primary goal of these analyses was to identify the connectome profile of suicidal ideation using resting state electroencephalography (EEG). We evaluated the neurocircuitry of SI in a sample of youths and young adults (aged 10-26 years, n = 111) with current or past diagnoses of either a depressive disorder or bipolar disorder who were enrolled in the Texas Resilience Against Depression Study (T-RAD). Neurocircuitry was analyzed using orthogonalized power envelope connectivity computed from resting state EEG. Suicidal ideation was assessed with the 3-item Suicidal Thoughts factor of the Concise Health Risk Tracking self-report scale. The statistical pipeline involved dimension reduction using principal component analysis, and the association of neuroimaging data with SI using regularized canonical correlation analysis. From the original 111 participants and the correlation matrix of 4950 EEG connectivity pairs in each band (alpha, beta, theta), dimension reduction generated 1305 EEG connectivity pairs in the theta band, 2337 EEG pairs in the alpha band, and 914 EEG connectivity pairs in the beta band. Overall, SI was consistently involved with dysfunction of the default mode network (DMN). This report provides preliminary evidence of DMN dysfunction associated with active suicidal ideation in adolescents. Using EEG using power envelopes to compute connectivity moves us closer to using neurocircuit dysfunction in the clinical setting to identify suicidal ideation.

Functional magnetic resonance imaging alternations in suicide attempts individuals and their association with gene expression

BACKGROUND

Functional Magnetic Resonance Imaging (fMRI) has shown brain activity alterations in individuals with a history of attempted suicide (SA) who are diagnosed with depression disorder (DD) or bipolar disorder (BD). However, patterns of spontaneous brain activity and their genetic correlations need further investigation.

METHODS

A voxel-based meta-analysis of 19 studies including 26 datasets, involving 742 patients with a history of SA and 978 controls (both nonsuicidal patients and healthy controls) was conducted. We examined fMRI changes in SA patients and analyzed the association between these changes and gene expression profiles using data from the Allen Human Brain Atlas by partial least squares regression analysis.

RESULTS

SA patients demonstrated increased spontaneous brain activity in several brain regions including the bilateral inferior temporal gyrus, hippocampus, fusiform gyrus, and right insula, and decreased activity in areas like the bilateral paracentral lobule and inferior frontal gyrus. Additionally, 5,077 genes were identified, exhibiting expression patterns associated with SA-related fMRI alterations. Functional enrichment analyses demonstrated that these SA-related genes were enriched for biological functions including glutamatergic synapse and mitochondrial structure. Concurrently, specific expression analyses showed that these genes were specifically expressed in the brain tissue, in neurons cells, and during early developmental periods.

CONCLUSION

Our findings suggest a neurobiological basis for fMRI abnormalities in SA patients with DD or BD, potentially guiding future genetic and therapeutic research.

Neural activity during inhibitory control predicts suicidal ideation with machine learning

Suicide is a leading cause of death in the US and worldwide. Current strategies for preventing suicide are often focused on the identification and treatment of risk factors, especially suicidal ideation (SI). Hence, developing data-driven biomarkers of SI may be key for suicide prevention and intervention. Prior attempts at biomarker-based prediction models for SI have primarily used expensive neuroimaging technologies, yet clinically scalable and affordable biomarkers remain elusive. Here, we investigated the classification of SI using machine learning (ML) on a dataset of 76 subjects with and without SI(+/-) (n = 38 each), who completed a neuro-cognitive assessment session synchronized with electroencephalography (EEG). SI+/- groups were matched for age, sex, and mental health symptoms of depression and anxiety. EEG was recorded at rest and while subjects engaged in four cognitive tasks of inhibitory control, interference processing, working memory, and emotion bias. We parsed EEG signals in physiologically relevant theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) frequencies and performed cortical source imaging on the neural signals. These data served as SI predictors in ML models. The best ML model was obtained for beta band power during the inhibitory control (IC) task, demonstrating high sensitivity (89%), specificity (98%). Shapley explainer plots further showed top neural predictors as feedback-related power in the visual and posterior default mode networks and response-related power in the ventral attention, fronto-parietal, and sensory-motor networks. We further tested the external validity of the model in an independent clinically depressed sample (n = 35, 12 SI+) that engaged in an adaptive test version of the IC task, demonstrating 50% sensitivity and 61% specificity in this sample. Overall, the study suggests a promising, scalable EEG-based biomarker approach to predict SI that may serve as a target for risk identification and intervention.

Neuroimaging and natural language processing-based classification of suicidal thoughts in major depressive disorder

Suicide is a growing public health problem around the world. The most important risk factor for suicide is underlying psychiatric illness, especially depression. Detailed classification of suicide in patients with depression can greatly enhance personalized suicide control efforts. This study used unstructured psychiatric charts and brain magnetic resonance imaging (MRI) records from a psychiatric outpatient clinic to develop a machine learning-based suicidal thought classification model. The study included 152 patients with new depressive episodes for development and 58 patients from a geographically different hospital for validation. We developed an eXtreme Gradient Boosting (XGBoost)-based classification models according to the combined types of data: independent components-map weightings from brain T1-weighted MRI and topic probabilities from clinical notes. Specifically, we used 5 psychiatric symptom topics and 5 brain networks for models. Anxiety and somatic symptoms topics were significantly more common in the suicidal group, and there were group differences in the default mode and cortical midline networks. The clinical symptoms plus structural brain patterns model had the highest area under the receiver operating characteristic curve (0.794) versus the clinical notes only and brain MRI only models (0.748 and 0.738, respectively). The results were consistent across performance metrics and external validation. Our findings suggest that focusing on personalized neuroimaging and natural language processing variables improves evaluation of suicidal thoughts.

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.

Associations of rumination with suicidal ideation and suicide attempts amongst individuals with major depressive disorder: A 12-month longitudinal study in China

BACKGROUND

This study aimed to explore the longitudinal associations of rumination with suicidal ideation and suicide attempts in individuals with major depressive disorder (MDD).

METHODS

Participants were derived from the Depression Cohort in China study (DCC). Those who completed at least one follow-up visit during the 12 months were included in the analysis. Dimensions of rumination including brooding and reflection were each measured using five items of the Ruminative Responses Scale. Suicidal ideation was assessed using the Beck Scale for Suicide Ideation. Suicide attempts were also assessed and all were analyzed with generalized estimating equations.

RESULTS

Our final sample included 532 participants aged 18 to 59 years (mean [SD], 26.91 [6.94] years) consisting of 148 (27.8%) males and 384 (72.2%) females. After adjusting for temporal trend and potential confounders, individuals with higher levels of reflection were more likely to report suicidal ideation (AOR =1.11, 95% CI:1.01-1.22). However, no statistically significant association was found between brooding and suicidal ideation (AOR =1.06, 95% CI:0.96-1.17). Conversely, individuals with higher levels of brooding were more likely to report suicide attempts (AOR =1.13, 95% CI:1.02-1.24), while no statistically significant association was observed between reflection and suicide attempts (AOR =0.91, 95% CI:0.82-1.01).

CONCLUSION

Rumination reflects a disturbance in cognitive emotional processing and manifests in different dimensions. Our findings suggest that high levels of reflection and brooding may be associated with a higher likelihood of having suicidal ideation and suicide attempts, respectively. However, it should be interpreted with caution, given that effect sizes are small.

Perception of social inclusion/exclusion and response inhibition in adolescents with past suicide attempt: a multidomain task-based fMRI study

The occurrence of suicidal behaviors increases during adolescence. Hypersensitivity to negative social signals and deficits in cognitive control are putative mechanisms of suicidal behaviors, which necessitate confirmation in youths. Multidomain functional neuroimaging could enhance the identification of patients at suicidal risk beyond standard clinical measures. Three groups of adolescents (N = 96; 78% females, age = 11.6-18.1) were included: patients with depressive disorders and previous suicide attempts (SA, n = 29); patient controls with depressive disorders but without any suicide attempt history (PC, n = 35); and healthy controls (HC, n = 32). We scanned participants with 3T-MRI during social inclusion/exclusion (Cyberball Game) and response inhibition (Go-NoGo) tasks. Neural activation was indexed by the blood-oxygenation-level dependent (BOLD) of the hemodynamic response during three conditions in the Cyberball Game ("Control condition", "Social Inclusion", and "Social Exclusion"), and two conditions in Go-NoGo task ("Go" and "NoGo" blocks). ANCOVA-style analysis identified group effects across three whole-brain contrasts: 1) NoGo vs. Go, 2) Social inclusion vs. control condition, 3) Social exclusion vs. control condition. We found that SA had lower activation in the left insula during social inclusion vs. control condition compared to PC and HC. Moreover, SA compared to PC had higher activity in the right middle prefrontal gyrus during social exclusion vs. control condition, and in bilateral precentral gyri during NoGo vs. Go conditions. Task-related behavioral and self-report measures (Self-reported emotional reactivity in the Cyberball Game, response times and number of errors in the Go-NoGo Task) did not discriminate groups. In conclusion, adolescent suicidal behaviors are likely associated with neural alterations related to the processing of social perception and response inhibition. Further research, involving prospective designs and diverse cohorts of patients, is necessary to explore the potential of neuroimaging as a tool in understanding the emergence and progression of suicidal behaviors.

Divergent suicidal symptomatic activations converge on somato-cognitive action network in depression

Individuals with depression have the highest lifetime prevalence of suicide attempts (SA) among mental illnesses. Numerous neuroimaging studies have developed biomarkers from task-related neural activation in depressive patients with SA, but the findings are inconsistent. Empowered by the contemporary interconnected view of depression as a neural system disorder, we sought to identify a specific brain circuit utilizing published heterogeneous neural activations. We systematically reviewed all published cognitive and emotional task-related functional MRI studies that investigated differences in the location of neural activations between depressive patients with and without SA. We subsequently mapped an underlying brain circuit functionally connecting to each experimental activation using a large normative connectome database (n = 1000). The identified SA-related functional network was compared to the network derived from the disease control group. Finally, we decoded this convergent functional connectivity network using microscale transcriptomic and chemo-architectures, and macroscale psychological processes. We enrolled 11 experimental tasks from eight studies, including depressive patients with SA (n = 147) and without SA (n = 196). The heterogeneous SA-related neural activations localized to the somato-cognitive action network (SCAN), exhibiting robustness to little perturbations and specificity for depression. Furthermore, the SA-related functional network was colocalized with brain-wide gene expression involved in inflammatory and immunity-related biological processes and aligned with the distribution of the GABA and noradrenaline neurotransmitter systems. The findings demonstrate that the SA-related functional network of depression is predominantly located at the SCAN, which is an essential implication for understanding depressive patients with SA.

Brain Structural and Functional Damage Network Localization of Suicide

BACKGROUND

Extensive neuroimaging research on brain structural and functional correlates of suicide has produced inconsistent results. Despite increasing recognition that damage in multiple different brain locations that causes the same symptom can map to a common brain network, there is still a paucity of research investigating network localization of suicide.

METHODS

To clarify this issue, we initially identified brain structural and functional damage locations in relation to suicide from 63 published studies with 2135 suicidal and 2606 nonsuicidal individuals. By applying novel functional connectivity network mapping to large-scale discovery and validation resting-state functional magnetic resonance imaging datasets, we mapped these affected brain locations to 3 suicide brain damage networks corresponding to different imaging modalities.

RESULTS

The suicide gray matter volume damage network comprised widely distributed brain areas primarily involving the dorsal default mode, basal ganglia, and anterior salience networks. The suicide task-induced activation damage network was similar to but less extensive than the gray matter volume damage network, predominantly implicating the same canonical networks. The suicide resting-state activity damage network manifested as a localized set of brain regions encompassing the orbitofrontal cortex and middle cingulate cortex.

CONCLUSIONS

Our findings not only may help reconcile prior heterogeneous neuroimaging results, but also may provide insights into the neurobiological mechanisms of suicide from a network perspective, which may ultimately inform more targeted and effective strategies to prevent suicide.

Differentiation between suicide attempt and suicidal ideation in patients with major depressive disorder using cortical functional network

Studies exploring the neurophysiology of suicide are scarce and the neuropathology of related disorders is poorly understood. This study investigated source-level cortical functional networks using resting-state electroencephalography (EEG) in drug-naïve depressed patients with suicide attempt (SA) and suicidal ideation (SI). EEG was recorded in 55 patients with SA and in 54 patients with SI. Particularly, all patients with SA were evaluated using EEG immediately after their SA (within 7 days). Graph-theory-based source-level weighted functional networks were assessed using strength, clustering coefficient (CC), and path length (PL) in seven frequency bands. Finally, we applied machine learning to differentiate between the two groups using source-level network features. At the global level, patients with SA showed lower strength and CC and higher PL in the high alpha band than those with SI. At the nodal level, compared with patients with SI, patients with SA showed lower high alpha band nodal CCs in most brain regions. The best classification performances for SA and SI showed an accuracy of 73.39%, a sensitivity of 76.36%, and a specificity of 70.37% based on high alpha band network features. Our findings suggest that abnormal high alpha band functional network may reflect the pathophysiological characteristics of suicide and serve as a clinical biomarker for suicide.

Unveiling convergent and divergent intrinsic brain network alternations in depressed adolescents engaged in non-suicidal self-injurious behaviors with and without suicide attempts

AIMS

Limited understanding exists regarding the neurobiological mechanisms underlying non-suicidal self-injury (NSSI) and suicide attempts (SA) in depressed adolescents. The maturation of brain network is crucial during adolescence, yet the abnormal alternations in depressed adolescents with NSSI or NSSI+SA remain poorly understood.

METHODS

Resting-state functional magnetic resonance imaging data were collected from 114 depressed adolescents, classified into three groups: clinical control (non-self-harm), NSSI only, and NSSI+SA based on self-harm history. The alternations of resting-state functional connectivity (RSFC) were identified through support vector machine-based classification.

RESULTS

Convergent alterations in NSSI and NSSI+SA predominantly centered on the inter-network RSFC between the Limbic network and the three core neurocognitive networks (SalVAttn, Control, and Default networks). Divergent alterations in the NSSI+SA group primarily focused on the Visual, Limbic, and Subcortical networks. Additionally, the severity of depressive symptoms only showed a significant correlation with altered RSFCs between Limbic and DorsAttn or Visual networks, strengthening the fact that increased depression severity alone does not fully explain observed FC alternations in the NSSI+SA group.

CONCLUSION

Convergent alterations suggest a shared neurobiological mechanism along the self-destructiveness continuum. Divergent alterations may indicate biomarkers differentiating risk for SA, informing neurobiologically guided interventions.

Clinical, behavioral, and electrophysiological profiles along a continuum of suicide risk: evidence from an implicit association task

BACKGROUND

An urgent need exists to identify neural correlates associated with differing levels of suicide risk and develop novel, rapid-acting therapeutics to modulate activity within these neural networks.

METHODS

Electrophysiological correlates of suicide were evaluated using magnetoencephalography (MEG) in 75 adults with differing levels of suicide risk. During MEG scanning, participants completed a modified Life-Death Implicit Association Task. MEG data were source-localized in the gamma (30-58 Hz) frequency, a proxy measure of excitation-inhibition balance. Dynamic causal modeling was used to evaluate differences in connectivity estimates between risk groups. A proof-of-concept, open-label, pilot study of five high risk participants examined changes in gamma power after administration of ketamine (0.5 mg/kg), an NMDAR antagonist with rapid anti-suicide ideation effects.

RESULTS

Implicit self-associations with death were stronger in the highest suicide risk group relative to all other groups, which did not differ from each other. Higher gamma power for self-death compared to self-life associations was found in the orbitofrontal cortex for the highest risk group and the insula and posterior cingulate cortex for the lowest risk group. Connectivity estimates between these regions differentiated the highest risk group from the full sample. Implicit associations with death were not affected by ketamine, but enhanced gamma power was found for self-death associations in the left insula post-ketamine compared to baseline.

CONCLUSIONS

Differential implicit cognitive processing of life and death appears to be linked to suicide risk, highlighting the need for objective measures of suicidal states. Pharmacotherapies that modulate gamma activity, particularly in the insula, may help mitigate risk.Clinicaltrials.gov identifier: NCT02543983, NCT00397111.

Identifying unique subgroups in suicide risks among psychiatric outpatients

BACKGROUND

The presence of psychiatric disorders is widely recognized as one of the primary risk factors for suicide. A significant proportion of individuals receiving outpatient psychiatric treatment exhibit varying degrees of suicidal behaviors, which may range from mild suicidal ideations to overt suicide attempts. This study aims to elucidate the transdiagnostic symptom dimensions and associated suicidal features among psychiatric outpatients.

METHODS

The study enrolled patients who attended the psychiatry outpatient clinic at a tertiary hospital in South Korea (n = 1, 849, age range = 18-81; 61% women). A data-driven classification methodology was employed, incorporating a broad spectrum of clinical symptoms, to delineate distinctive subgroups among psychiatric outpatients exhibiting suicidality (n = 1189). A reference group of patients without suicidality (n = 660) was included for comparative purposes to ascertain cluster-specific sociodemographic, suicide-related, and psychiatric characteristics.

RESULTS

Psychiatric outpatients with suicidality (n = 1189) were subdivided into three distinctive clusters: the low-suicide risk cluster (Cluster 1), the high-suicide risk externalizing cluster (Cluster 2), and the high-suicide risk internalizing cluster (Cluster 3). Relative to the reference group (n = 660), each cluster exhibited distinct attributes pertaining to suicide-related characteristics and clinical symptoms, covering domains such as anxiety, externalizing and internalizing behaviors, and feelings of hopelessness. Cluster 1, identified as the low-suicide risk group, exhibited less frequent suicidal ideation, planning, and multiple attempts. In the high-suicide risk groups, Cluster 2 displayed pronounced externalizing symptoms, whereas Cluster 3 was primarily defined by internalizing and hopelessness symptoms. Bipolar disorders were most common in Cluster 2, while depressive disorders were predominant in Cluster 3.

DISCUSSION

Our findings suggest the possibility of differentiating psychiatric outpatients into distinct, clinically relevant subgroups predicated on their suicide risk. This research potentially paves the way for personalizing interventions and preventive strategies that address cluster-specific characteristics, thereby mitigating suicide-related mortality among psychiatric outpatients.

Neural substrates of affective temperaments: An intersubject representational similarity analysis to resting-state functional magnetic resonance imaging in nonclinical subjects

Previous research has suggested that certain types of the affective temperament, including depressive, cyclothymic, hyperthymic, irritable, and anxious, are subclinical manifestations and precursors of mental disorders. However, the neural mechanisms that underlie these temperaments are not fully understood. The aim of this study was to identify the brain regions associated with different affective temperaments. We collected the resting-state functional magnetic resonance imaging (fMRI) data from 211 healthy adults and evaluated their affective temperaments using the Temperament Evaluation of Memphis, Pisa, Paris and San Diego Autoquestionnaire. We used intersubject representational similarity analysis to identify brain regions associated with each affective temperament. Brain regions associated with each affective temperament were detected. These regions included the prefrontal cortex, anterior cingulate cortex (ACC), precuneus, amygdala, thalami, hippocampus, and visual areas. The ACC, lingual gyri, and precuneus showed similar activity across several affective temperaments. The similarity in related brain regions was high among the cyclothymic, irritable, and anxious temperaments, and low between hyperthymic and the other affective temperaments. These findings may advance our understanding of the neural mechanisms underlying affective temperaments and their potential relationship to mental disorders and may have potential implications for personalized treatment strategies for mood disorders.

Sex modulated the relationship between trait approach motivation and decision-making

It has been observed that one's Behavioral Approach System (BAS) can have an effect on decision-making under uncertainty, although the results have been mixed. To discern the underlying neural substrates, we hypothesize that sex may explain the conflicting results. To test this idea, a large sample of participants was studied using resting state fMRI, utilizing fractional Amplitude of Low Frequency Fluctuations (fALFF) and Resting-State Functional Connectivity (rsFC) techniques. The results of the Iowa Gambling Task (IGT) revealed an interaction between sex and BAS, particularly in the last 60 trials (decision-making under risk). Males with high BAS showed poorer performance than those with low BAS. fALFF analysis showed a significant interaction between BAS group and sex in the left superior occipital gyrus, as well as the functional connectivity between this region and the left ventrolateral prefrontal cortex. Additionally, this functional connectivity was further positively correlated with male performance in the IGT, particularly in the decision-making under risk stage. Furthermore, it was found that the functional connectivity between left ventrolateral prefrontal cortex and left superior occipital gyrus could mediate the relationship between BAS and decision-making in males, particularly in the decision-making under risk stage. These results suggest possible sex-based differences in decision-making, providing an explanation for the inconsistent results found in prior research. Since the research was carried out exclusively with Chinese university students, it is essential to conduct further studies to investigate whether the findings can be generalized.