The neuroscience of suicidal behaviors: what can we expect from endophenotype strategies?

Distinct effects of first-episode and recurrent major depressive disorder on brain changes related to suicidal ideation: Evidence from the REST-meta-MDD Project

BACKGROUND

Significant differences in clinical manifestations between first-episode and recurrent major depression disorder (FE-MDD/R-MDD) have been demonstrated in previous studies, including the degree of suicide attempt. However, the potential brain mechanism underlying the effect of depressive episode frequency on suicidal ideation (SI) remains unclear.

METHODS

In this study, 102 patients with FE-MDD (SI/non-SI: N = 70/32) and 71 matched normal controls (NCs), as well as 75 patients with R-MDD (SI/non-SI: N = 37/38) and 49 matched NCs were screened from the Chinese REST-meta-MDD consortium. T1-weighted and resting-state fMRI images were used to calculate gray matter volume (GMV) and fractional amplitude of low-frequency fluctuations (fALFF), respectively.

RESULTS

Group comparisons revealed that FE-MDD showed changes only in GMV, while R-MDD showed changes in both GMV and fALFF compared to NCs. SI-specific GMV decreases were observed in the right cerebellum, superior marginal gyrus, and left middle temporal gyrus in FE-MDD patients, while SI-specific fALFF decreases in bilateral superior frontal gyrus and increases in bilateral cerebellum and left parahippocampal gyrus were obserevd in R-MDD patients. Moreover, a negative correlation was found between GMV value in right cerebellum and HAMD score.

CONCLUSIONS

These findings suggest that first-episode and recurrent MDD show different effects on brain structure and function in patients with SI, providing a potential explanation for the distinct clinical manifestations of MDD patients from a brain mechanisms perspective.

Gene-environment interaction between HPA-axis genes and trauma exposure in the suicide behavior: A systematic review

Suicide behavior (SB) emerge from complex interactions among traumatic events and multiple genetic factors. We conducted the first systematic review to assess the evidence of a link among trauma exposure, HPA-axis genes, and SB. A systematic search of PubMed, EBSCO, Science Direct, PsychInfo, and Scopus databases on gene-environment interaction, and susceptibility to SB was carried out until February 2022. Our study was prospectively registered in PROSPERO (CRD42022316141). A total of 13 epidemiological studies (11,756 subjects) were included: eight studies focused on traumatic experiences in the childhood and five studies on lifetime trauma exposure. All studies reported a positive association between the trauma exposure with SB. Gene-environment interaction was reported for CRHR1 (n = 6), CRHR2 (n = 2), FKBP5 (n = 2), and CRHBP (n = 1), however, for CRH, NR3C1, MC2R, and POMC genes no found gene-environment effects on SB. Trauma exposure could be one mechanism that links HPA-axis genes activity with the development of SB.

Dissociated deficits of anticipated and experienced regret in at-risk suicidal individuals

Backgrounds

Decision-making deficits have been reported as trans-diagnostic characteristics of vulnerability to suicidal behaviors, independent of co-existing psychiatric disorders. Individuals with suicidal behaviors often regret their decision to attempt suicide and may have impairments in future-oriented processing. However, it is not clear how people with suicidal dispositions use future-oriented cognition and past experience of regret to guide decision-making. Here, we examined the processes of regret anticipation and experience in subclinical youth with and without suicidal ideation during value-based decision-making.

Methods

In total, 80 young adults with suicidal ideation and 79 healthy controls completed a computational counterfactual thinking task and self-reported measures of suicidal behaviors, depression, anxiety, impulsivity, rumination, hopelessness, and childhood maltreatment.

Results

Individuals with suicidal ideation showed a reduced ability to anticipate regret compared to healthy controls. Specifically, suicidal ideators’ experience of regret/relief was significantly different from that of healthy controls upon obtained outcomes, while their disappointment/pleasure experience was not significantly different from healthy controls.

Conclusion

These findings suggest that young adults with suicidal ideation have difficulty predicting the consequences or the future value of their behavior. Individuals with suicidal ideation showed impairments in value comparison and flat affect to retrospective rewards, whereas individuals with high suicidality showed blunted affect to immediate rewards. Identifying the counterfactual decision-making characteristics of at-risk suicidal individuals may help to elucidate measurable markers of suicidal vulnerability and identify future intervention targets.

Association between the number of hours of sleep during weekdays and suicidality among Korean adolescents: Mediating role of depressive and anxiety symptoms

BACKGROUND

Adolescent suicide is a serious concern worldwide. Sleep problems are a risk factor for suicide. Therefore, the aim of this study was to evaluate associations between sleep duration and suicidal ideation/suicide attempts and determine the extent to which depressive and anxiety symptoms mediate these associations.

METHODS

Data from 54,948 middle and high school students in South Korea were collected by the stratified cluster method through the Korea Youth Risk Behavior Web-based Survey.

RESULTS

The weighted prevalences of short and long sleep durations were 19.5 % (95 % confidence interval [CI] = 18.9-20.2) and 4.6 % (95 % CI = 4.3-4.8), respectively. Short sleep duration (<5 h/day) increased the odds of suicidal ideation and suicide attempts by 1.43 (95 % CI = 1.29-1.58) and 1.78 (95 % CI = 1.41-2.25), respectively. Long sleep duration (>9 h/day) increased the odds of suicide attempts by 1.5 (95 % CI = 1.02-2.21). Depressive and anxiety symptoms significantly mediated the relationship between sleep duration and suicidal intensity with a satisfactory goodness of fit.

LIMITATIONS

Causal relationships could not be examined due to the cross-sectional study design. Information on other psychopathologies, besides depression and anxiety, was unavailable.

CONCLUSIONS

Short sleep duration was associated with suicidal ideation and suicide attempts among Korean adolescents. Long sleep duration was associated with suicide attempts only. Both depressive and anxiety symptoms mediated the association between sleep duration and suicidal intensity; therefore, both sleep hour restoration and treatment of depressive/anxiety symptoms should be the goals of suicide prevention strategies.

Suicidal Behaviors in Women With the Hypermobile Ehlers-Danlos Syndrome

BACKGROUND

Hypermobile Ehlers-Danlos syndrome (hEDS) is the most frequent heritable disorder of the connective tissue. This is characterized by a generalized fragility of tissues leading to chronic pain, disability and high levels of psychological distress. Suicidal behaviors in those affected are not uncommon but they have not been well studied. We aimed to explore aspects of suicidality and related factors in a group of patients with hEDS.

METHOD

Thirty-five women with hEDS were included in this cross-sectional study. They were assessed with the Mini-International Neuropsychiatric Interview for Axis 1 DSM-IV mental disorders and suicidality. They also responded to self-questionnaires assessing health (pain, BMI, and diagnosis delay) and psychosocial variables (social support, physical functioning, coping strategies, personality disturbances, and resilience).

RESULTS

Eleven patients (31.4%) had attempted suicide in the past. Fifteen patients (42.9%) had some degree of suicide risk at the time of evaluation, mainly mild risk (60%). Compared with patients without a history of suicide attempt, those who had attempted suicide were younger, scored higher on personality disturbances, especially on depressive, avoidant, antisocial, and borderline trait subscores, and had an increased prevalence of lifetime major depression, mania/hypomanic episodes, and anxiety disorders (p < .05). Binary logistic regression showed that personality disturbances and anxiety disorders increase the probability of belonging to the attempters group.

CONCLUSIONS

Consistent with previous reports, these data highlight the high frequency of suicidal behaviors in hEDS patients as well as the importance to explore psychopathology in those affected in order to identify vulnerable individuals and provide specific support.HIGHLIGHTSAttempted suicide in patients with hEDS is not uncommon.Age and the presence of psychopathology are associated with suicide attempt in hEDS patients.Personality disturbances and lifetime anxiety disorders predicted suicide attempted in this sample.

Increased prefrontal cortex connectivity associated with depression vulnerability and relapse

BACKGROUND

Major depressive disorder (MDD) is a highly prevalent mood disorder, characterized by depressed mood, reduced capabilities to concentrate, impaired cognition, as well as a high risk of relapse. Unaffected siblings who have high risks for MDD development and yet without clinical symptoms may be helpful for understanding the neural mechanisms of MDD traits.

METHODS

We investigated both regional fluctuation and inter-regional synchronization in 31 fully remitted MDD patients, 29 unaffected siblings and 43 age, gender, and educational level matched helathy controls (HCs) using resting-state functional magnetic resonance imaging (rs-fMRI). The 17-item HAMD and neurocognitive scales were performed. Fractional amplitude of low-frequency fluctuation (fALFF) and functional connectivity (FC) strength were investigated.

RESULTS

Compared with healthy control group, patients with remitted MDD and unaffected siblings showed increased fALFF in the left dorsomedial prefrontal cortex (dmPFC) and increased FC between the left dmPFC and the right ventromedial prefrontal cortex (vmPFC). In addition, a negative correlation was observed between the fALFF value in the left dmPFC and the speed of Trail Making Test in the remitted MDD patients. Higher vmPFC-dmPFC FC was positively correlated with Wisconsin Card Sorting Test (WCST) total correct, and negatively correlated with WCST random errors.

CONCLUSIONS

In the absence of clinical symptoms, individuals with remitted MDD and unaffected siblings showed increased fALFF in left dmPFC as well as the vmPFC-dmPFC connectivity. These results suggest a specific trait abnormality in the default mode network associated with vulnerability to MDD, which may have implications for developing effective therapies using this network as a target.

The Effectiveness of Predicting Suicidal Ideation through Depressive Symptoms and Social Isolation Using Machine Learning Techniques

(1) Background: Social isolation is a major risk factor for suicidal ideation. In this study, we investigated whether the evaluation of both depression and social isolation in combination could effectively predict suicidal ideation; (2) Methods: A total of 7994 data collected from community residents were analyzed. Statistical analysis was performed using age, the Patient Health Questionnaire-9, and the Lubben Social Network Scale as predictors as the dependent variables for suicidal ideation; machine learning (ML) methods K-Nearest Neighbors, Random Forest, and Neural Network Classification were used; (3) Results: The prediction of suicidal ideation using depression and social isolation showed high area under the curve (0.643–0.836) and specificity (0.959–0.987) in all ML techniques. In the predictor model (model 2) that additionally evaluated social isolation, the validation accuracy consistently increased compared to the depression-only model (model 1); (4) Conclusions: It is confirmed that the machine learning technique using depression and social isolation can be an effective method when predicting suicidal ideation.

MicroRNAs as novel peripheral markers for suicidality in patients with major depressive disorder

OBJECTIVE

Major depressive disorder (MDD) constitutes a main risk factor for suicide. Suicide risk in psychiatric patients is primarily determined by often unreliable, self-reported information. We assessed serum levels of three microRNAs (miRNAs), previously demonstrated to be dysregulated in post-mortem brain samples of suicide victims, as potential peripheral biomarkers for suicidality.

METHODS

All study participants were diagnosed with MDD according to Diagnostic and Statistical Manual of Mental Disorders, 5th edition criteria. Suicidality, defined as acute suicide risk or suicide attempt within one week prior to study entry, was assessed by clinical interview. Relative serum levels of miR-30a, miR-30e, and miR-200a, normalized to U6, were measured by quantitative real-time PCR in MDD inpatients with (MDD/SI, N = 19) and without (MDD, N = 31) acute suicide risk. Median age and gender distribution were comparable in both groups.

RESULTS

Levels of miR-30a, miR-30e, and miR-200a were significantly elevated in MDD/SI compared to MDD. Subgroup analysis of the MDD/SI group showed that levels of miR-30e and miR-200a were significantly higher and miR-30a was increased by trend in patients admitted following a suicide attempt (N = 7) compared to patients with acute suicide risk but without recent suicide attempt (N = 12). Additionally, use of two databases for in silico transcription factor-miRNA interaction prediction indicated early growth response protein (EGR) 1 as potential transcriptional regulator for all three miRNAs.

CONCLUSION

This study demonstrates suicide risk in MDD patients to be associated with increased levels of miR-30a, miR-30e, and miR-200a. Thus, these miRNAs might constitute potential biomarkers to predict suicidal behavior in MDD patients.

Plasma Apolipoprotein-AIV Downregulated in Patients with Major Depressive Disorder having Suicidal Ideation Compared to those without Suicidal Ideation

Background:

Identification of a peripheral biological marker might aid in identifying patients at high risk of attempting suicide and might help in effective early intervention.

Objective:

In the present study, we extend the findings of our previous multidimensional proteomics study by examining the levels of plasma Apolipoprotein-AIV in patients diagnosed with major depression with and without suicidal ideation compared to age and gender-matched controls.

Methods:

Using the mass spectrometry platform, we quantified the levels of plasma Apolipoprotein-AIV in patients with major depressive disorder with and without suicidal ideation compared to matched controls with isotope-labelled peptides-based quantitative proteomics approach.

Results:

The targeted quantitative proteomics approach with isotope-labelled peptides showed that plasma Apolipoprotein-AIV was significantly downregulated in depressed patients having suicidal ideation 1.45 (CI:1.11–1.90) compared to those without suicidal ideation 0.88 (CI:0.77–1.003).

Conclusion:

These findings extend our earlier observation of downregulation of plasma Apolipoprotein-AIV in patients with suicidal attempts to depressed patients with suicidal ideation. The consistent downregulation of plasma Apolipoprotein-AIV observed in both the proteomics studies suggests Apolipoprotein-AIV might be a plasma-based biomarker for suicidal behaviour.

Sex-based changes in rat brain serotonin and behavior in a model of altitude-related vulnerability to treatment-resistant depression

RATIONALE

Rates of depression and suicide increase with altitude. In our animal model, rats housed at moderate altitude vs. at sea level exhibit increased depressive symptoms in the forced swim test (FST) and lack of response to selective serotonin reuptake inhibitors (SSRIs). Depression and SSRI resistance are linked to disrupted serotonergic function, and hypobaric hypoxia may reduce the oxygen-dependent synthesis of serotonin. We therefore tested brain serotonin in rats housed at altitude.

METHODS

Sprague-Dawley rats were housed at altitude (4,500 ft, 10,000 ft) vs. sea level for 7-36 days. Brain serotonin was measured by ELISA, or behavior evaluated in the FST, sucrose preference (SPT), or open-field tests (OFT).

RESULTS

After 2 weeks at 4,500 ft or 10,000ft vs. sea level, serotonin levels decreased significantly at altitude in the female prefrontal cortex, striatum, hippocampus, and brainstem, but increased with altitude in the male hippocampus and brainstem. Female brain serotonin decreased from 7 to 36 days at 4,500 ft, but males did not vary. At 2 weeks and 24 days, females at altitude exhibit lower brain serotonin and increased depressive symptoms in the FST and SPT, with motor behavior unaltered. In males, serotonin, passive coping in the FST and OFT immobility increased with altitude at 2 weeks, but not at 24 days. Male SPT behavior did not change with altitude.

CONCLUSIONS

Females may be more vulnerable to depressive symptoms at altitude, while males may be resilient. Chronic hypoxic stress at altitudes as low as 4,500 ft may cause a brain serotonin imbalance to worsen vulnerability to depression and SSRI resistance, and potentially worsen suicide risk.

Suicidal Risk in Women with Premenstrual Syndrome and Premenstrual Dysphoric Disorder: A Systematic Review and Meta-Analysis

Purpose: Women with premenstrual dysphoric disorder (PMDD) and premenstrual syndrome (PMS) experience substantial functional impairment and decreased quality of life. While previous research has highlighted a relationship between premenstrual disturbances and suicide risk, no meta-analysis has been conducted to quantitatively assess the findings. Methods: A systematic review and meta-analysis was conducted by searching the literature in three databases (Pubmed, PsycINFO, and EMBASE) on July 15, 2020. Studies that assessed the relationship between suicidality (attempt, ideation, and/or plan) and premenstrual disturbance (PMDD, PMS, and/or premenstrual symptoms) were included. Results: Thirteen studies were included in the qualitative review (n = 10 included in meta-analysis). Results revealed that women with PMDD are almost seven times at higher risk of suicide attempt (OR: 6.97; 95% CI: 2.98-16.29, p < 0.001) and almost four times as likely to exhibit suicidal ideation (OR: 3.95; 95% CI: 2.97-5.24, p < 0.001). Similarly, women with PMS are also at increased risk of suicidal ideation (OR: 10.06; 95% CI: 1.32 to -76.67, p = 0.03), but not for suicide attempt (OR: 1.85; 95% CI: 0.77 to -4.46, p = 0.17). Conclusions: Women with PMDD and PMS are at higher risk of suicidality compared with women without premenstrual disturbances. These findings support routine suicidal risk assessments for women who suffer from moderate-to-severe premenstrual disturbance. Furthermore, psychosocial treatments for women diagnosed with PMS/PMDD should consider and target suicidality to minimize risk and improve well-being.

Detecting suicidal risk using MMPI-2 based on machine learning algorithm

Minnesota Multiphasic Personality Inventory-2 (MMPI-2) is a widely used tool for early detection of psychological maladjustment and assessing the level of adaptation for a large group in clinical settings, schools, and corporations. This study aims to evaluate the utility of MMPI-2 in assessing suicidal risk using the results of MMPI-2 and suicidal risk evaluation. A total of 7,824 datasets collected from college students were analyzed. The MMPI-2-Resturcutred Clinical Scales (MMPI-2-RF) and the response results for each question of the Mini International Neuropsychiatric Interview (MINI) suicidality module were used. For statistical analysis, random forest and K-Nearest Neighbors (KNN) techniques were used with suicidal ideation and suicide attempt as dependent variables and 50 MMPI-2 scale scores as predictors. On applying the random forest method to suicidal ideation and suicidal attempts, the accuracy was 92.9% and 95%, respectively, and the Area Under the Curves (AUCs) were 0.844 and 0.851, respectively. When the KNN method was applied, the accuracy was 91.6% and 94.7%, respectively, and the AUCs were 0.722 and 0.639, respectively. The study confirmed that machine learning using MMPI-2 for a large group provides reliable accuracy in classifying and predicting the subject's suicidal ideation and past suicidal attempts.

Sleep complaints are associated with increased suicide risk independently of psychiatric disorders: results from a national 3-year prospective study

Prior research suggests that sleep disturbances are associated with increased risk of suicide. However, sleep disturbances are associated with a wide range of psychiatric disorders, and it is unknown whether this association is independent of psychopathology. In a large nationally representative prospective survey, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), we used structural equation modeling to examine the shared and specific effects of three sleep complaints (i.e., trouble falling asleep, early morning awakening, and hypersomnia) on the 3-year occurrence of attempting suicide. Because psychiatric disorders increase the risk of suicide attempt almost exclusively through a general psychopathology factor representing their shared effect, covariates included that factor, prior history of suicide attempt, and a wide range of sociodemographic and clinical characteristics. The 3-year prevalence rate of suicide attempt was 0.6% (n = 241). Compared with participants who did not attempt suicide between the two waves, those who did reported significantly more frequently having trouble falling asleep (44.6% vs. 16.6%), early morning awakening (38.9% vs. 12.7%), and hypersomnia (35.0% vs. 10.7%). Following adjustments, effects of sleep complaints on this risk were significant and exerted almost exclusively through a general sleep complaints factor representing the shared effect across all sleep complaints. There were no residual associations of any individual sleep complaint with attempting suicide above that association. Sleep complaints are associated with an increased risk of attempting suicide independently of psychopathology, and should be included in suicide risk assessments as these symptoms may provide targets for reducing the risks of suicidal behaviors.

Auditory evoked potentials and suicidal behaviors in patients with major depressive disorders

Loudness dependence of auditory evoked potentials (LDAEP) has been proposed as a biological marker of central serotonergic activity related to suicides. This study’s objective was to analyze the difference in LDAEP between depressed patients with suicide attempts (SA) and suicidal ideation (SI). It included 130 participants (45 depressed patients with SA, 49 depressed patients with SI, and 36 healthy controls) aged > 18 years who exhibited LDAEP during electroencephalography. Psychological characteristics and event-related potentials of the three groups were compared. There was no significant difference in LDAEP between major depressive disorder (MDD) patients with SA and SI (p = 0.59). MDD patients with SI, who attempted suicide had significantly lower LDAEP than healthy controls (p = 0.01 and p = 0.01, respectively). However, the significance disappeared when psychological characteristics were controlled. Our results suggest that LDAEP might not be possible biomarkers for suicidal behaviors in patients with MDD. Further studies to assess the biological basis of suicide and identify the underlying dimensions that mediate the relationship between the biological basis and suicidal behaviors will be needed.

Modeling endophenotypes of suicidal behavior in animals

Suicide is a major public health concern. One of the common contributors to the increased risk for suicide is the genetic constitution of individuals, which determines certain endophenotypic traits used as quantifiable measure of neurobiological functions. Therefore, a logical deconstruction of the originating endophenotypes associated with suicidal risk could provide a better understanding of this complex disorder. In this regard, non-human animals can be a useful resource to test endophenotypes of suicidal behavior and the neurobiology underlying these endophenotypes. In this review, we have focused on the neurobiological abnormalities, primarily genetic and epigenetic abnormalities, associated with suicidal behavior and the scope of their modeling in animals. This can substantially advance the current understanding of suicidal behavior manifested with certain trait-based endophenotypes and may provide an opportunity to test novel hypotheses as well as aid in the development of treatment opportunities and risk assessment.

Exploring the boundaries between borderline personality disorder and suicidal behavior disorder

OBJECTIVE

To compare clinical traits of suicidal vulnerability among in-patients with suicidal behavior disorder (SBD) with and without borderline personality disorder (BPD).

METHOD

we recruited adult patients with SBD, consecutively and voluntarily hospitalized in a specialized unit for affective disorders and suicidal behavior between July and October 2016. Ninety-two inpatients having attempted suicide within the past 2 years were divided into two subgroups according to the presence or absence of BPD. Clinical vulnerability traits for suicidal behavior were assessed.

RESULTS

Half of the patients with SBD also had BPD. Patients with BPD were nine times more likely to be major suicide repeaters compared to those without. They were also more likely to display clinical and psychological vulnerability traits for suicidal behavior, even after considering potential confounders. Emotional dysregulation, shame-proneness, impulsiveness, preoccupied attachment pattern, and childhood trauma were high in both groups, but significantly increased in those with (vs. without) BPD status. Psychological traits remained stable in SBD-BPD patients, regardless of the time since the last suicide attempt (i.e. SBD in recent vs. early remission).

CONCLUSIONS

Clinical and psychological traits associated with suicidal vulnerability are present in all SBD patients compared to non-suicidal populations, but comorbidity with BPD is associated with particularly high scores. BPD could be considered as a specifier for SBD diagnoses.

Barriers for the Research, Prevention, and Treatment of Suicidal Behavior

Efforts in research, prevention, and treatment of suicidal behavior have produced mixed results. One of the main barriers to combating suicidal behavior lies in the very conceptualization of suicide, a phenomenon that is at once sociological, psychiatric, and even philosophical, and one that has not always been included in the field of health care. There are also many barriers at the social level, ranging from stigma against people with suicidal behavior to stigma towards psychiatric care, as well as the controversial role of the media. The media plays an important role in society and depending on its attitude it can be either beneficial or harmful in our fight against suicidal behavior. Differences between countries - in the provision of resources, in the way of understanding the phenomenon or in the manner of providing official figures - pose an additional challenge to suicide prevention on a global level. In the field of research, predicting suicidal behavior by identifying effective risk markers is severely hampered by the low occurrence of suicide in the population, which limits the statistical power of studies. The authors recommend combining various risk factors to build predictive models. This, in addition to employing increasingly precise machine learning techniques, is a step in the right direction, although there is still a long way to go before the expected results can be obtained. Finally, adequate training of health professionals, both specialized and non-specialized, as well as gatekeeper training, is crucial for implementing suicide prevention strategies in the population.

Biological bases of suicidal behaviours: A narrative review

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

Connectome Analysis of Brain Functional Network Alterations in Depressive Patients with Suicidal Attempt

Our study aimed to clarify the neuroimaging correlates of suicide attempt by comparing differences in functional magnetic resonance imaging (fMRI) among depressed suicide attempters, depressed patients without suicide attempt history, and healthy controls through comprehensive and novel fMRI analyses and methods in the same study population. The association between depression severity and aspects of the brain imaging was also discussed. Our study recruited 109 participants who were assigned to three groups: 33 depressed patients with suicide attempt (SA), 32 depressed patients without suicide attempt (NS), and 44 healthy controls (HC). All participants were scanned using a 3 T MRI imaging system to obtain resting-state functional images. In seed-based correlation analysis, we found altered functional connectivity in some brain regions of the SA compared with the NS or HC, especially in the hippocampus and thalamus. In the voxel-based analysis, our results showed differential activation and regional homogeneity of the temporal lobe and several brain regions in the SA compared with the NS and HC. We also found that some brain areas correlated with the Hamilton Depression Rating Scale (HAM-D), anxiety, and depression scores, especially in the frontal and temporal lobes. Graph theoretical analysis (GTA) and network-based statistical (NBS) analyses revealed different topological organization as well as slightly better global integration and worse local segregation of the brain network (i.e., more like a random network) in depressed participants compared with healthy participants. We concluded that the brain function of major depressive disorders with and without suicide attempts changed compared with healthy participants.

Attenuated prefrontal and temporal neural activity during working memory as a potential biomarker of suicidal ideation in veterans with PTSD

BACKGROUND

Suicide is a significant health concern among veterans, and suicidal ideation is a common and functionally debilitating condition that frequently precedes suicidal behavior. Characterizing neurobiological substrates associated with suicidal ideation in veterans may inform evaluation of risk for this population. Associations between suicidal ideation and functional abnormalities in prefrontal, temporal, and striatal regions supporting cognitive task performance have been documented in individuals with mood and psychotic disorders, suggesting a potential role for neurocognitive vulnerabilities in this condition. To date, however, relatively little research has explored neural correlates of suicidal ideation, particularly among individuals with posttraumatic stress disorder (PTSD).

METHODS

Twenty three combat veterans diagnosed with PTSD completed an adapted Reading Span (Rspan) working memory task during functional magnetic resonance imaging (fMRI). Participants were classified based on presence of current SI. We evaluated differences between these groups on neural activation in response to interference-based working memory demands within the task. Primary analyses were conducted using a voxel-wise between-group t-test.

RESULTS

Task-based activations were observed in regions including the cingulate, middle frontal, parietal, and occipital cortex, striatum, and cerebellum. Relative to individuals without SI, individuals with SI demonstrated less activation in a large region spanning the lateral prefrontal cortex and cingulate cortex, as well as the inferior temporal cortex, in response to interference demands.

CONCLUSIONS

Results are consistent with models proposing that prefrontal neural substrates involved in cognitive regulation are implicated in suicidal ideation. Involvement of temporal functioning may also exist based on current findings. Future research is needed to understand whether disturbances in prefrontal regulatory control reflect a specific profile subtype with distinct neural correlates, and how such neural patterns may be used to improve detection and treatment personalization.

Overlapping genetic effects between suicidal ideation and neurocognitive functioning

BACKGROUND

Suicide is the second leading cause of death among adolescents and young adults. Several studies have indicated significant genetic influences on suicide-related phenotypes and mounting evidence from neurobiological research has linked deficits in neurocognitive abilities to suicide phenotypes. The goal of the present study was to estimate the heritability of suicidal ideation (SI) in a large sample of adolescents and determine if SI is genetically correlated with neurocognitive functioning.

METHODS

Genome-wide data (N = 3564 unrelated individuals of European Ancestry) were drawn from the Philadelphia Neurodevelopment Cohort. Adolescents completed a psychiatric assessment, as well as a computerized neurocognitive battery to assess performance across four domains: memory, executive function, social cognition, and complex cognition. Genomic-relatedness-matrix restricted maximum likelihood (GREML) estimation was used to determine SNP-heritability (h²_SNP) of SI and the genetic correlation (r_G) between SI and neurocognitive domains.

RESULTS

Nearly 17% of adolescents reported SI. The SNP-heritability estimate for SI was marginally significant (h²_SNP = 11%, SE = 8%, p = 0.086). Bivariate analyses indicated a significant r_G between SI and emotion identification (r_G = 0.79, SE = 0.45, p = 0.006; phenotypic correlation r = 0.04, p = 0.017).

LIMITATIONS

It is possible that SI may represent a related, but differentially heritable construct from suicide attempts/completion and other comorbid psychopathology. Additionally, though genetic correlations point to shared genetic factors across traits, direct causal mechanisms cannot be deduced.

CONCLUSIONS

Common heritable factors contribute to variation in SI and neurocognitive functioning. Genetic factors influencing emotion identification have significant genetic overlap with SI.

Low total cholesterol and low-density lipoprotein associated with aggression and hostility in recent suicide attempters

Low cholesterol levels have been correlated with both suicidal and aggressive behavior in psychiatric patients. Few studies have investigated associations between serum lipid profiles and both aggressive state and trait. Fifty-two psychiatric medication-free inpatients were included in this study after a suicide attempt. Composite scores of "State Aggression" and "Trait Aggression" were calculated using relevant items from the Comprehensive Psychopathological Rating Scale and the Karolinska Scales of Personality. State Aggression was significantly and negatively correlated with total cholesterol (TC) and low-density lipoprotein (LDL). Trait Aggression was also significantly and negatively correlated with LDL, but not TC. There were small but significant mediation effects of severity of anxiety symptoms on the relationship between State Aggression and TC as well as LDL. In exploratory analyses we found that low cholesterol was also associated with personality traits of hostility. Moreover, low cholesterol was more robustly associated with personality trait items related to interpersonal aggression, as opposed to items related to irritability or more indirect, non-overt aggression. Our findings suggest that low cholesterol is associated with both state and trait aggression in suicide attempters. Future mechanistic studies are warranted to better understand the relationship between low cholesterol and high aggression in suicide attempters.

5-HTTLPR-brain-derived neurotrophic factor (BDNF) gene interactions and early adverse life events effect on impulsivity in suicide attempters

OBJECTIVES

An expanding body of research suggests that childhood adverse experiences can lead to different negative health outcomes, including attempted suicide. Serotonergic genes such as the promoter region of the serotonin transporter gene (5-HTTLPR) have been associated both with impulsivity in suicide attempts and reactivity to environmental stress exposure. BDNF gene may play an epigenetic role.

METHODS

We studied the influence of childhood stressful events and 5-HTTLPR genotype on impulsivity measured by Barratt Impulsivity Scale (BIS-10) in a multicentre sample of 1,655 suicide attempters (69.4% women, 30.6% men; mean age 40.13 years). A co-dominant additive genetic model was used for the statistical analyses. Interaction between 5-HTTLPR genotype and early trauma exposure was tested using moderated and multiple regression techniques. Interaction plots were used to explore BDNF genotype modulation.

RESULTS

Mildly higher impulsivity scores were found in men with SS compared with SL or LL genotypes, and men with childhood emotional and physical abuse. Interaction analyses showed that combination of 5-HTTLPR-SS genotype and early trauma exposure increase impulsivity scores independently. Impulsivity scores were not affected by the modulation of BDNF genes.

CONCLUSIONS

Childhood trauma and 5-HTTLPR genotype seem to be independently involved in suicide attempts, sharing a common pathway of increasing impulsivity.

Understanding suicide: Focusing on its mechanisms through a lithium lens

BACKGROUND

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

METHOD

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

Gray Matter Volume Reductions Were Associated with TPH1 Polymorphisms in Depressive Disorder Patients with Suicidal Attempts

OBJECTIVE

Structural changes of brain areas have been reported in depressive disorder and suicidal behavior (SB), in which TPH1 also has been known as a promising candidate gene. We investigated gray matter volume (GMV) differences, TPH1 rs1800532 and rs1799913 polymorphisms previously found to be associated with depressive disorder and SB, and the relationship between the two markers.

METHODS

Thirteen depressive disorder patients with suicidal attempts (SA) and twenty healthy controls were included. We examined GMV differences using a voxel-based morphometry and regions of interest analysis. Direct sequencing was used for genotyping.

RESULTS

The patients showed significant GMV reduction in left cerebral region including middle frontal gyrus, inferior frontal gyrus, and anterior cingulate cortex; in right middle temporal gyrus; in left cerebellar tonsil; and in right cerebral region including precentral gyrus and postcentral gyrus (corrected p<0.005). The right precentral and postcentral gyri GMV values of AA and CA genotypes patients were significantly decreased compared to those of CC genotype subjects (corrected p=0.040).

CONCLUSION

These findings show the possibility that both GMV reductions and TPH1 rs1800532/rs1799913 A allele may be involved in the pathogenesis of depressive disorder patients with SA.

Acceptance and Commitment Therapy for the Management of Suicidal Patients: A Randomized Controlled Trial

BACKGROUND

The management of suicidal crisis remains a major issue for clinicians, driving the development of new strategies to improve suicide prevention.

METHODS

We conducted a randomized controlled trial comparing a 7-week acceptance and commitment therapy (ACT) versus relaxation group, as adjunct to treatment as usual for adult outpatients suffering from a current suicidal behavior disorder. The primary outcome was the rate of change in the Columbia Suicide Severity Rating Scale suicidal ideation subscore (adding severity and intensity subscores). Secondary outcomes were the rates of change for depressive symptomatology, psychological pain, anxiety, hopelessness, anger, quality of life, and therapeutic processes. Assessments were performed in the 2 weeks preceding the beginning of the treatment (pretreatment assessment), and within 1 week (posttherapy assessment) and 3 months (follow-up assessment) after therapy completion.

RESULTS

Forty adults were included and randomized. The rate of change in ACT for suicidal ideation at the posttherapy assessment was higher than in the relaxation group (β [SE] = -1.88 [0.34] vs. -0.79 [0.37], respectively; p = 0.03). ACT effectiveness remained stable at the 3-month follow-up. We found a similar pattern of change for depressive symptomatology and anxiety, psychological pain, hopelessness, anger, and quality of life. Therapeutic processes improved more in the ACT group than in the relaxation group. Treatment adherence was high in the ACT group, all participants reported satisfaction with the program.

CONCLUSIONS

Through its effectiveness in reducing suicidal ideation and improving the clinical dimensions associated with suicidal risk in patients suffering from a suicidal behavior disorder, ACT could be developed as an adjunctive strategy in programs for suicide prevention.

Anhedonia is associated with suicidal ideation independently of depression: A meta-analysis

BACKGROUND

Anhedonia is considered a suicide risk factor in patients with major affective disorders. Here, we wanted to quantify the association between anhedonia and current suicidal ideation according to the absence/presence of between-group differences for depressive scores and psychiatric disorders.

METHODS

We performed a meta-analysis of data on studies retrieved from Medline, Web of Science, and PsycINFO from 1965 to 2016 using, among others, the terms (suicid* or depression) and anhedonia.

RESULTS

We identified 15 observational case-control studies that investigated the anhedonia differences in individuals with and without current (i.e., within the past week, independently of the lifetime suicidality status) suicidal ideation (defined as thoughts of killing oneself). Overall, 657 subjects with and 6,690 subjects without current suicidal ideation could be compared. Anhedonia level was higher in the group with current suicidal ideation than in the group without, with a medium effect size (standardized mean difference = 0.57, z = 5.43, P < 0.001, 95% confidence interval, CI = 0.37-0.79). The association between anhedonia and current suicidal ideation remained significant when controlling for depression and psychiatric disorders. The anhedonia scales used in the selected studies did not allow investigating consummatory and motivational anhedonia separately.

CONCLUSION

Our major finding is the robust association between anhedonia and current suicidal ideation, independently of depression. This is highly relevant for the clinicians' daily practice and might help improving suicidal risk detection and the development of new therapeutic strategies for suicide prevention.

Alcohol-induced disinhibition is associated with impulsivity, depression, and suicide attempt: A nationwide community sample of Korean adults

BACKGROUND

Alcohol-induced disinhibition (AID) is defined as a "loss of restraint over some form of behavior after drinking alcohol regardless of its amount". Although many previous studies have investigated on alcohol use disorder and suicide attempt, few studies have focused on AID and suicide.

METHODS

A total of 9461 adults who had a history of drinking completed a face-to-face interview using the Korean version of Composite International Diagnostic Interview (K-CIDI) with the Suicide Module, and Barratt Impulsiveness Scale 11 (BIS-11). In this study, we defined the AID group as those who had been involved with the two antisocial behaviors, including fights, being arrested or dangerous driving, according to the K-CIDI.

RESULTS

Among 9461 subjects, 564 were classified as the AID group (5.96%). The AID group had a significantly higher number of lifetime suicidal ideation, plan, attempt, and multiple attempts, and higher BIS-11 scores than non-AID group. The total scores of BIS-11 of the AID group reported the highest score compared with other psychiatric disorders. The AID group experienced more frequently three types of alcohol withdrawal symptoms, including nervousness, heart beating fast, and feeling weak. Compared with subjects without both AID and MDD, subjects with both AID and MDD showed significant association with a lifetime suicide attempt (AOR = 6.86, p < 0.001) and showed stronger association with multiple attempts (AOR = 10.38, p < 0.001).

CONCLUSION

AID was associated with suicide attempt and impulsivity, and the both AID and MDD showed much stronger association with lifetime suicide attempt and multiple attempts.

Serious suicide attempts in outpatients with multiple substance use disorders

BACKGROUND

Suicide is a major public health concern and suicide attempts (SA) are frequent and burdensome in people suffering from substance use disorders (SUDs). In particular, serious SAs are a preoccupying form of attempt, which remain largely overlooked in these populations, especially regarding basic risk factors such as gender, addictive comorbidity and substance use patterns. Thus, we undertook a gender-specific approach to identify the risk factors for serious SAs in outpatients with multiple SUDs.

MATERIAL AND METHODS

433 Treatment-seeking outpatients were consecutively recruited in specialized care centers and reliably classified as serious, non-serious and non-suicide attempters. We also characterized lifetime exposure to SUDs, including tobacco smoking, with standardized instruments. Current medication, including psychotropic treatments were collected, which informed psychiatric diagnoses. Multinomial regression identified independent factors specifically associated with serious SAs in each gender, separately.

RESULTS

32% Participants (N=139, 47% Women and 27% Men) reported lifetime SA. There were 82 serious attempters (59% of attempters), without significant gender difference. Sedative dependence was an independent risk factor for serious SA compared to non-SA in Women and compared to non-serious SA in Men, respectively. Other risk factors included later onset of daily tobacco smoking in Men and history of psychiatric hospitalizations in Women, whose serious SA risk was conversely lower when reporting opiate use disorder or mood disorder, probably because of treatment issues.

CONCLUSIONS

Despite several study limitations, we identified subgroups for a better-tailored prevention of serious SAs among individuals with SUDs, notably highlighting the need to better prevent and treat sedative dependence.

Neurocognitive Function and Suicide in U.S. Army Soldiers

This prospective cohort study used administrative data from the Army Study to Assess Risk and Resilience in Servicemembers to examine associations between neurocognitive functioning and subsequent suicidal events among Regular Army enlisted soldiers during the years 2004-2009. Cases were all soldiers who completed the Army's Automated Neuropsychological Assessment Metrics (ANAM) computerized testing battery prior to documented suicide attempt (n = 607), ideation (n = 955), or death (n = 57). Controls were an equal-probability sample of 9,893 person-months from other soldiers. Exploratory factor analysis of five ANAM tests identified a general neurocognitive factor that excluded the mathematic processing test (MTH). When examined separately in logistic regression analyses that controlled for sociodemographics and prior mental health diagnosis, both the general neurocognitive factor (logit [β] = -.197 to -.521; p < .01) and MTH (β = -.024 to -.064; p < .05) were associated with all outcomes. When both predictors were examined simultaneously, the general neurocognitive factor continued to be associated with all outcomes (β = -.164 to -.417; p < .05) and MTH continued to be associated with suicide attempt (β = -.015; p = .046) and ideation (β = -.014; p = .018). These small but robust associations suggest that future research must continue to examine the extent to which objective neurocognitive tests may enhance understanding and prediction of suicide risk.

Nine differentially expressed genes from a post mortem study and their association with suicidal status in a sample of suicide completers, attempters and controls

Several lines of evidence indicate that suicidal behaviour is partly heritable, with multiple genes implicated in its aetiology. We focused on nine genes (S100A13, EFEMP1, PCDHB5, PDGFRB, CDCA7L, SCN2B, PTPRR, MLC1 and ZFP36) which we previously detected as differentially expressed in the cortex of suicide victims compared to controls. We investigated 84 variants within these genes in 495 suicidal subjects (299 completers and 196 attempters) and 1513 controls (109 post-mortem and 1404 healthy). We evaluated associations with: 1) suicidal phenotype; 2) possible endophenotypes for suicidal behaviour. Overall positive results did not survive the correction threshold. However, we found a nominally different distribution of EFEMP1 genotypes, alleles and haplotypes between suicidal subjects and controls, results that were partially replicated when we separately considered the subgroup of suicide completers and post-mortem controls. A weaker association emerged also for PTPRR. Both EFEMP1 and PTPRR genes were also related to possible endophenotypes for suicidal behaviour such as anger, depression-anxiety and fatigue. Because of the large number of analyses performed and the low significance values further replication are mandatory. Nevertheless, neurotrophic gene variants, in particular EFEMP1 and PTPRR, may have a role in the pathogenesis of suicidal behaviour.

Animal models to improve our understanding and treatment of suicidal behavior

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

The experience of social exclusion in women with a history of suicidal acts: a neuroimaging study

Suicidal behaviors result from a complex interaction between social stressors and individual vulnerability. However, little is known of the specific neural network supporting the sensitivity to social stressors in patients at risk of suicidal acts. Using functional Magnetic Resonance Imaging, we investigated brain processing of social rejection in suicide attempters. Thirty-six euthymic women with a history of depression and suicidal behavior were compared to 41 euthymic women with a history of depression but no suicidal attempt, and 28 healthy controls. The Cyberball Game was used as a validated social exclusion paradigm. Relative to healthy controls, both patient groups reported higher levels of social distress related to the task, without significant differences according to suicidal status. Compared to patients without any history of suicide attempt and healthy controls, suicide attempters showed decreased contrast in the left insula and supramarginal gyrus during the exclusion vs. inclusion condition, after controlling for number of depressive episodes, medication, mood disorder type or social phobia. Our study highlights impaired brain response to social exclusion in euthymic female suicide attempters in regions previously implicated in pain tolerance and social cognition. These findings suggest sustained brain dysfunctions related to social perception in suicide attempters.

Neuroinflammation in suicide: Toward a comprehensive model

OBJECTIVES

Suicidal behaviour (SB) entered the DSM-5, underlying a specific biological vulnerability. Then, recent findings suggested a possible role of the immune system in SB pathogenesis. The objective of this review is to present these main immune factors involved in SB pathogenesis.

METHODS

We conducted a review using Preferred Reporting Items for Systematic reviews and Meta-Analysis criteria, and combined ("Inflammation") AND ("Suicidal ideation" OR "Suicidal attempt" OR "suicide").

RESULTS

Post mortem studies demonstrated associations between suicide and inflammatory cytokines in the orbitofrontal cortex, a brain region involved in suicidal vulnerability. Also, microgliosis and monocyte-macrophage system activation may be a useful marker of suicide neurobiology. Kynurenine may influence inflammatory processes, and related molecular pathways may be involved in SB pathophysiology. Few recent studies associated inflammatory markers with suicidal vulnerability: serotonin dysfunction, impulsivity and childhood trauma. Interestingly, the perception of threat that leads suicidal individuals to contemplate suicide may activate biological stress responses, including inflammatory responses.

CONCLUSIONS

Translational projects would be crucial to identify a specific marker in SB disorders, to investigate its clinical correlations, and the interaction between inflammatory cytokines and monoamine systems in SB. These researches might lead to new biomarkers and novel directions for therapeutic strategies.

SUICIDAL DEPRESSED PATIENTS RESPOND LESS WELL TO ANTIDEPRESSANTS IN THE SHORT TERM

BACKGROUND

Suicidal thoughts and behaviors could be associated to a poor response to antidepressant treatment, but the exclusion of suicidal patients from randomized clinical trials restricts the available knowledge. In this study, we aimed at defining more precisely the response to antidepressants among suicidal patients and the threshold of suicidality that best predicts a poor response.

METHOD

We investigated the short-term response to a new antidepressant treatment of 4,041 depressed outpatients depending on their suicidal status (passive or active suicidal ideation (SI), history of suicide attempts [SAs]), either self-rated or clinician-rated. Depression outcomes, measured with the Hospital Anxiety and Depression Scale, and remission rates were compared depending on suicidal status at baseline using logistic regression models.

RESULTS

Using either a qualitative or a quantitative approach to measure SI, we found that suicidal patients were less likely to improve or attain remission, but not more likely to worsen, than nonsuicidal patients. In the multivariate analyses, SI (odds ratio [OR] = 1.40; 95% confidence interval [CI]: 1.18-1.65) and a history of SA (OR = 1.39; 95% CI: 1.16-1.66) were the best predictors of nonremission, independently of the class of antidepressant treatment.

CONCLUSION

Antidepressant treatment seems to be less effective among those patients that need it most. Clinical trials including suicidal patients are needed to investigate specific treatment options.

Biological mechanisms underlying evolutionary origins of psychotic and mood disorders

Psychotic and mood disorders are brain dysfunctions that are caused by gene environment interactions. Although these disorders are disadvantageous and involve behavioral phenotypes that decrease the reproductive success of afflicted individuals in the modern human society, the prevalence of these disorders have remained constant in the population. Here, we propose several biological mechanisms by which the genes associated with psychotic and mood disorders could be selected for in specific environmental conditions that provide evolutionary bases for explanations of when, why, and where these disorders emerged and have been maintained in humans. We discuss the evolutionary origins of psychotic and mood disorders with specific focuses on the roles of dopamine and serotonin in the conditions of social competitiveness/hierarchy and maternal care and other potential mechanisms, such as social network homophily and symbiosis.

SKA2 methylation is associated with decreased prefrontal cortical thickness and greater PTSD severity among trauma-exposed veterans

Methylation of the SKA2 (spindle and kinetochore-associated complex subunit 2) gene has recently been identified as a promising biomarker of suicide risk. Based on this finding, we examined associations between SKA2 methylation, cortical thickness and psychiatric phenotypes linked to suicide in trauma-exposed veterans. About 200 trauma-exposed white non-Hispanic veterans of the recent conflicts in Iraq and Afghanistan (91% male) underwent clinical assessment and had blood drawn for genotyping and methylation analysis. Of all, 145 participants also had neuroimaging data available. Based on previous research, we examined DNA methylation at the cytosine-guanine locus cg13989295 as well as DNA methylation adjusted for genotype at the methylation-associated single nucleotide polymorphism (rs7208505) in relationship to whole-brain cortical thickness, posttraumatic stress disorder symptoms (PTSD) and depression symptoms. Whole-brain vertex-wise analyses identified three clusters in prefrontal cortex that were associated with genotype-adjusted SKA2 DNA methylation (methylation(adj)). Specifically, DNA methylation(adj) was associated with bilateral reductions of cortical thickness in frontal pole and superior frontal gyrus, and similar effects were found in the right orbitofrontal cortex and right inferior frontal gyrus. PTSD symptom severity was positively correlated with SKA2 DNA methylation(adj) and negatively correlated with cortical thickness in these regions. Mediation analyses showed a significant indirect effect of PTSD on cortical thickness via SKA2 methylation status. Results suggest that DNA methylation(adj) of SKA2 in blood indexes stress-related psychiatric phenotypes and neurobiology, pointing to its potential value as a biomarker of stress exposure and susceptibility.

Personality Traits of Suicidality Are Associated with Premenstrual Syndrome and Premenstrual Dysphoric Disorder in a Suicidal Women Sample

Objective

Both Premenstrual Syndrome (PMS) and Premenstrual Dysphoric Disorder (PMDD) might increase the risk of suicidal behavior. The aim of this study was to assess the relationship between personality dimensions specifically involved in suicidal vulnerability and PMS/PMDD.

Method

We collected data from 232 women consecutively hospitalized after a suicide attempt. We examined the relationship between impulsivity, aggressiveness/hostility, hopelessness, trait anger, affect intensity, emotional lability, and PMS/PMDD. Notably, we created an algorithm from the shortened Premenstrual Assessment form in order to assess PMDD status.

Results

The proportions of PMS and PMDD among female suicide attempters were 50% and 23% respectively. Women with PMS or PMDD were more likely to endorse most of these personality traits to than those without even after controlling for potential confounders. We found an impulsive-aggressive pattern of personality in women with PMS or PMDD, independently from the time of the menstrual cycle. Interestingly, trait anger remained associated with both PMS and PMDD independently of every other personality traits. The higher the anger level, the higher the risk was to suffer from both PMS and PMDD.

Conclusions

This study demonstrates a strong, independent association between PMS/PMDD and trait anger among a representative sample of female suicide attempters. It is of major interest for clinicians in view of addressing a substantial public health problem among women of reproductive age.

A Neural Basis for the Acquired Capability for Suicide

The high rate of fatal suicidal behavior (SB) in men is an urgent issue as highlighted in the public eye via news sources and media outlets. In this study, we have attempted to address this issue and understand the neural substrates underlying the gender differences in the rate of fatal SB. The Interpersonal-Psychological Theory of Suicide has proposed an explanation for the seemingly paradoxical relationship between gender and SB, i.e., greater non-fatal suicide attempts by women but higher number of deaths by suicide in men. This theory states that possessing suicidal desire (due to conditions such as depression) alone is not sufficient for a lethal suicide attempt. It is imperative for an individual to have the acquired capability for suicide (ACS) along with suicidal desire in order to die by suicide. Therefore, higher levels of ACS in men may explain why men are more likely to die by suicide than women, despite being less likely to experience suicidal ideation or depression. In this study, we used activation likelihood estimation meta-analysis to investigate a potential ACS network that involves neural substrates underlying emotional stoicism, sensation-seeking, pain tolerance, and fearlessness of death, along with a potential depression network that involves neural substrates that underlie clinical depression. Brain regions commonly found in ACS and depression networks for males and females were further used as seeds to obtain regions functionally and structurally connected to them. We found that the male-specific networks were more widespread and diverse than the female-specific ones. Also, while the former involved motor regions, such as the premotor cortex and cerebellum, the latter was dominated by limbic regions. This may support the fact that suicidal desire generally leads to fatal/decisive action in males, while, in females, it manifests as depression, ideation, and generally non-fatal actions. The proposed model is a first attempt to characterize the neural networks underlying gender differences in SB. Future studies should examine the proposed network to better characterize and refine this network using tasks specifically targeted toward constructs underlying ACS.

Processing of decision-making and social threat in patients with history of suicidal attempt: A neuroimaging replication study

Suicidal vulnerability has been related to impaired value-based decision-making and increased sensitivity to social threat, mediated by the prefrontal cortex. Using functional magnetic resonance imaging, we aimed at replicating these previous findings by measuring brain activation during the Iowa Gambling Task and an emotional faces viewing task. Participants comprised 15 euthymic suicide attempters (history of depression and suicidal behavior) who were compared with 23 euthymic patient controls (history of depression without suicidal history) and 35 healthy controls. The following five model-based regions of interest were investigated: the orbitofrontal cortex (OFC), ventrolateral prefrontal cortex (VLPFC), anterior cingulate cortex (ACC), medial (MPFC) and dorsal prefrontal cortex (DPFC). Suicide attempters relative to patient controls showed (1) increased response to angry vs. neutral faces in the left OFC and the VLPFC, as previously reported; (2) increased response to wins vs. losses in the right OFC, DPFC and ACC; (3) decreased response to risky vs. safe choices in the left DPFC; and (4) decreased response to sad vs. neutral faces in the right ACC. This study links impaired valuation processing (here for signals of social threat, sadness and reward) to prefrontal cortex dysfunction in suicide attempters. These long-term deficits may underlie the impaired decision-making and social difficulties found in suicide attempters.

Impaired decision-making in symptomatic anorexia and bulimia nervosa patients: a meta-analysis

BACKGROUND

Impaired decision-making is a potential neurocognitive phenotype of eating disorders. It is therefore important to disentangle the decision-making deficits associated with the eating disorder subtypes and determine whether this putative impairment is a state or trait marker of the disease or more related to starvation. We systematically reviewed the literature on decision-making in eating disorders and conducted a meta-analysis to explore its role in anorexia nervosa (AN), bulimia nervosa (BN) and binge-eating disorder (BED).

METHOD

A search of the Medline and EMBASE databases and article references was performed. A total of 23 studies (2044 participants) met the selection criteria. When the Iowa gambling task (IGT) was used in at least three of the studies, a meta-analysis was run.

RESULTS

IGT performance was significantly worse in patients with an eating disorder diagnosis (AN, BN or BED) compared with healthy controls, indicating that eating disorders have a negative effect on decision-making. Hedges' g effect sizes were moderate to large (-0.72 in AN, -0.62 in BN, and -1.26 in BED). Recovered AN patients had IGT scores similar to those of healthy controls. Restrictive AN patients had significantly lower IGT net scores than purging AN patients, and both AN subtypes had worse performances than healthy controls. Age and body mass index did not explain results.

CONCLUSIONS

Decision-making was significantly altered in patients with eating disorders. Poor decision-making was more pronounced during the acute phase than in the recovered state of AN. Nutritional status during the acute phase of the disease did not seem to influence decision-making skills.

Trait-related decision making impairment in obsessive-compulsive disorder: evidence from decision making under ambiguity but not decision making under risk

This study aimed to investigate whether deficits in decision making were potential endophenotype markers for OCD considering different phases of the disease. Fifty-seven non-medicated OCD patients (nmOCD), 77 medicated OCD patients (mOCD), 48 remitted patients with OCD (rOCD) and 115 healthy controls were assessed with the Iowa Gambling Task (IGT), which measured decision making under ambiguity, and the Game of Dice Task (GDT), which measured decision making under risk. While the three patients groups showed impaired performance on the IGT compared with healthy controls, all patients showed intact performance on the GDT. Furthermore, the rOCD patients showed a preference for deck B, indicating that they showed more sensitivity to the frequency of loss than to the magnitude of loss, whereas the mOCD patients showed a preference for deck A, indicating that they had more sensitivity to the magnitude of loss than to the frequency of loss. These data suggested that OCD patients had trait-related impairments in decision making under ambiguity but not under risk, and that dissociation of decision making under ambiguity and under risk is an appropriate potential neurocognitive endophenotype for OCD. The subtle but meaningful differences in decision making performance between the OCD groups require further study.

Enhancing decision-making and cognitive impulse control with transcranial direct current stimulation (tDCS) applied over the orbitofrontal cortex (OFC): A randomized and sham-controlled exploratory study

BACKGROUND

Decision-making and impulse control (both cognitive and motor) are complex interrelated processes which rely on a distributed neural network that includes multiple cortical and subcortical regions. Among them, the orbitofrontal cortex (OFC) seems to be particularly relevant as demonstrated by several neuropsychological and neuroimaging investigations.

METHODS

In the present study we assessed whether transcranial direct current stimulation (tDCS) applied bilaterally over the OFC is able to modulate decision-making and cognitive impulse control. More specifically, 45 healthy subjects were randomized to receive a single 30-min session of active or sham anodal tDCS (1.5 mA) applied over either the left or the right OFC (coupled with contralateral cathodal tDCS). They were also assessed pre- and post-tDCS with a battery of computerized tasks.

RESULTS

Our results show that participants who received active anodal tDCS (irrespective of laterality), vs. those who received sham tDCS, displayed more advantageous decision-making (i.e., increased Iowa Gambling Task "net scores" [p = 0.04]), as well as improved cognitive impulse control (i.e., decreased "interference" in the Stroop Word-Colour Task [p = 0.007]). However, we did not observe tDCS-related effects on mood (assessed by visual analogue scales), attentional levels (assessed by the Continuous Performance Task) or motor impulse control (assessed by the Stop-Signal Task).

CONCLUSIONS

Our study potentially serves as a key translational step towards the development of novel non-invasive neuromodulation-based therapeutic interventions directly targeting vulnerability factors for psychiatric conditions such as suicidal behaviour and addiction.