Suicidal attempts and increased right amygdala volume in schizophrenia

Association of empathy with clinical symptoms and cognitive function in chronic schizophrenia patients with and without suicide attempts

Cognitive impairment is recognized as a risk factor for suicide in schizophrenia (SZ) patients. Despite empathy being an important aspect of social cognition, the association between suicidal behavior and empathy has received little attention. We aimed to compare empathy and neurocognition in SZ patients with and without suicide attempts (SAs), and to explore the relationship between empathy, neurocognition, and clinical symptoms in SZ patients with and without SAs. Data on SAs and socio-demographic characteristics were collected from 628 chronic SZ patients. The patients' symptomatology was measured by the Positive and Negative Syndrome Scale (PANSS). Empathy and neurocognition were assessed with the Interpersonal Reactivity Index (IRI) and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), respectively. Patients with SAs performed better on all IRI domains (except for Perspective Taking) and total scores. Regression results showed that negative symptoms, positive symptoms, and duration of illness were independently associated with IRI total score in patients without SAs (adjusted R2 = 0.048). In patients without SAs, negative symptoms, general psychopathology, education, age, and sex were independently associated with RBANS total score (adjusted R2 = 0.265), while in patients with SAs, education, PANSS total score, and age at onset were independently associated with RBANS total score (adjusted R2 = 0.456). Our results show that SZ patients with SAs may have better empathic performance than patients without SAs. In chronic SZ patients, negative and positive symptoms may have different effects on cognition in the SAs and non-SAs groups.

Emotion-related impulsivity and suicidal ideation and behavior in schizophrenia spectrum disorder: a pilot fMRI study

Introduction

Suicidal ideation and behavior (SIB) are serious problems in people with schizophrenia spectrum disorders (SSD). Nevertheless, relatively little is known about the circuitry underlying SIB in SSD. Recently, we showed that elevated emotional impulsivity (urgency) was associated with SIB in SSD. Here we examined brain activity in people with SSD and elevated SIB.

Methods

We tested 16 people with SSD who had low SIB and 14 people with high SIB on a task in which emotion regulation in response to affective pictures was implicitly manipulated using spoken sentences. Thus, there were neutral pictures preceded by neutral statements (NeutNeut condition), as well as negative pictures preceded by either negative (NegNeg) or neutral (NeutNeg) statements. After each picture, participants rated how unpleasant each picture was for them. The latter two conditions were compared to the NeutNeut condition. We compared the emotion-regulated condition (NeutNeg) to the unregulated condition (NeutNeut). Statistics were threshold using threshold free cluster enhancement (TFCE).

Results

People in the low SIB group showed higher activation in this contrast in medial frontal gyrus, right rostral anterior cingulate, bilateral superior frontal gyrus/DLPFC, and right middle cingulate gyrus, as well as right superior temporal gyrus.

Discussion

This study provides clues to the neural basis of SIB in SSD as well as underlying mechanisms.

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.

Alterations in the volume and shape of the basal ganglia and thalamus in schizophrenia with auditory hallucinations

Different lines of evidence indicate that the structure and physiology of the basal ganglia and the thalamus is disturbed in schizophrenia. However, it is unknown whether the volume and shape of these subcortical structures are affected in schizophrenia with auditory hallucinations (AH), a core positive symptom of the disorder. We took structural MRI from 63 patients with schizophrenia, including 36 patients with AH and 27 patients who had never experienced AH (NAH), and 51 matched healthy controls. We extracted volumes for the left and right thalamus, globus pallidus, putamen, caudate and nucleus accumbens. Shape analysis was also carried out. When comparing to controls, the volume of the right globus pallidus, thalamus, and putamen, was only affected in AH patients. The volume of the left putamen was also increased in individuals with AH, whereas the left globus pallidus was affected in both groups of patients. The shapes of right and left putamen and thalamus were also affected in both groups. The shape of the left globus pallidus was only altered in patients lacking AH, both in comparison to controls and to cases with AH. Lastly, the general PANSS subscale was correlated with the volume of the right thalamus, and the right and left putamen, in patients with AH. We have found volume and shape alterations of many basal ganglia and thalamus in patients with and without AH, suggesting in some cases a possible relationship between this positive symptom and these morphometric alterations.

History of suicide attempt associated with amygdala and hippocampus changes among individuals with schizophrenia

Abnormalities in subcortical brain structures may reflect higher suicide risk in mood disorders, but less is known about its associations for schizophrenia. This cross-sectional imaging study aimed to explore whether the history of suicide attempts was associated with subcortical changes among individuals with schizophrenia. We recruited 44 individuals with schizophrenia and a history of suicide attempts (SZ-SA) and 44 individuals with schizophrenia but without a history of suicide attempts (SZ-NSA) and 44 healthy controls. Linear regression showed that SZ-SA had smaller volumes of the hippocampus (Cohen's d = -0.72), the amygdala (Cohen's d = -0.69), and some nuclei of the amygdala (Cohen's d, -0.57 to -0.72) than SZ-NSA after adjusting for age, sex, illness phase, and intracranial volume. There was no difference in the volume of the subfields of the hippocampus. It suggests the history of suicide attempts is associated with subcortical volume alterations in schizophrenia.

The neurobiology of misophonia and implications for novel, neuroscience-driven interventions

Decreased tolerance in response to specific every-day sounds (misophonia) is a serious, debilitating disorder that is gaining rapid recognition within the mental health community. Emerging research findings suggest that misophonia may have a unique neural signature. Specifically, when examining responses to misophonic trigger sounds, differences emerge at a physiological and neural level from potentially overlapping psychopathologies. While these findings are preliminary and in need of replication, they support the hypothesis that misophonia is a unique disorder. In this theoretical paper, we begin by reviewing the candidate networks that may be at play in this complex disorder (e.g., regulatory, sensory, and auditory). We then summarize current neuroimaging findings in misophonia and present areas of overlap and divergence from other mental health disorders that are hypothesized to co-occur with misophonia (e.g., obsessive compulsive disorder). Future studies needed to further our understanding of the neuroscience of misophonia will also be discussed. Next, we introduce the potential of neurostimulation as a tool to treat neural dysfunction in misophonia. We describe how neurostimulation research has led to novel interventions in psychiatric disorders, targeting regions that may also be relevant to misophonia. The paper is concluded by presenting several options for how neurostimulation interventions for misophonia could be crafted.

A Computational Model of Hopelessness and Active-Escape Bias in Suicidality

Currently, psychiatric practice lacks reliable predictive tools and a sufficiently detailed mechanistic understanding of suicidal thoughts and behaviors (STB) to provide timely and personalized interventions. Developing computational models of STB that integrate across behavioral, cognitive and neural levels of analysis could help better understand STB vulnerabilities and guide personalized interventions. To that end, we present a computational model based on the active inference framework. With this model, we show that several STB risk markers - hopelessness, Pavlovian bias and active-escape bias - are interrelated via the drive to maximize one's model evidence. We propose four ways in which these effects can arise: (1) increased learning from aversive outcomes, (2) reduced belief decay in response to unexpected outcomes, (3) increased stress sensitivity and (4) reduced sense of stressor controllability. These proposals stem from considering the neurocircuits implicated in STB: how the locus coeruleus - norepinephrine (LC-NE) system together with the amygdala (Amy), the dorsal prefrontal cortex (dPFC) and the anterior cingulate cortex (ACC) mediate learning in response to acute stress and volatility as well as how the dorsal raphe nucleus - serotonin (DRN-5-HT) system together with the ventromedial prefrontal cortex (vmPFC) mediate stress reactivity based on perceived stressor controllability. We validate the model by simulating performance in an Avoid/Escape Go/No-Go task replicating recent behavioral findings. This serves as a proof of concept and provides a computational hypothesis space that can be tested empirically and be used to distinguish planful versus impulsive STB subtypes. We discuss the relevance of the proposed model for treatment response prediction, including pharmacotherapy and psychotherapy, as well as sex differences as it relates to stress reactivity and suicide risk.

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

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

Effects of polygenic risk for suicide attempt and risky behavior on brain structure in young people with familial risk of bipolar disorder

Bipolar disorder (BD) is associated with a 20-30-fold increased suicide risk compared to the general population. First-degree relatives of BD patients show inflated rates of psychopathology including suicidal behaviors. As reliable biomarkers of suicide attempts (SA) are lacking, we examined associations between suicide-related polygenic risk scores (PRSs)-a quantitative index of genomic risk-and variability in brain structures implicated in SA. Participants (n = 206; aged 12-30 years) were unrelated individuals of European ancestry and comprised three groups: 41 BD cases, 96 BD relatives ("high risk"), and 69 controls. Genotyping employed PsychArray, followed by imputation. Three PRSs were computed using genome-wide association data for SA in BD (SA-in-BD), SA in major depressive disorder (SA-in-MDD) (Mullins et al., 2019, The American Journal of Psychiatry, 176(8), 651-660), and risky behavior (Karlsson Linnér et al., 2019, Nature Genetics, 51(2), 245-257). Structural magnetic resonance imaging processing employed FreeSurfer v5.3.0. General linear models were constructed using 32 regions-of-interest identified from suicide neuroimaging literature, with false-discovery-rate correction. SA-in-MDD and SA-in-BD PRSs negatively predicted parahippocampal thickness, with the latter association modified by group membership. SA-in-BD and Risky Behavior PRSs inversely predicted rostral and caudal anterior cingulate structure, respectively, with the latter effect driven by the "high risk" group. SA-in-MDD and SA-in-BD PRSs positively predicted cuneus structure, irrespective of group. This study demonstrated associations between PRSs for suicide-related phenotypes and structural variability in brain regions implicated in SA. Future exploration of extended PRSs, in conjunction with a range of biological, phenotypic, environmental, and experiential data in high risk populations, may inform predictive models for suicidal behaviors.

Anomalous Amygdala Habituation to Unpleasant Stimuli Among Unmedicated Individuals With Borderline Personality Disorder and a History of Self-Harming Behavior

Self-harming behavior (SB) is one of the diagnostic criteria for borderline personality disorder (BPD). However, it is not exhibited by all individuals with BPD. Furthermore, studies examining the neural correlates of SB in BPD are lacking. Given research showing that BPD patients have difficulty habituating to affective stimuli, this study investigated whether anomalous amygdala activation is specific to BPD patients with SB. The authors used fMRI to compare amygdala activation in BPD patients with SB (n = 15) to BPD patients without SB (n = 18) and healthy controls (n = 32) during a task involving pleasant, neutral, and unpleasant pictures, presented twice. BPD patients with SB demonstrated greater amygdala activity during the second presentation of unpleasant pictures. Results highlight neurobiological differences in BPD patients with and without SB and suggest that anomalous amygdala habituation to unpleasant stimuli may be related to SB.

An exploratory magnetic resonance imaging study of suicidal ideation in individuals at clinical high-risk for psychosis

Suicide is a major cause of death in psychosis and associated with significant morbidity. Suicidal ideation (SI) is very common in those at clinical high-risk for psychosis (CHR) and predicts later suicide. Despite substantial work on the pathobiology of suicide in schizophrenia, little is known of its neurobiological underpinnings in the CHR or putatively prodromal state. Therefore, in this pilot study, we examined the neurobiology of SI in CHR individuals using structural MRI. Subjects were aged 14-30 and met criteria for the Attenuated Positive Symptom Psychosis-Risk Syndrome (APSS) delineated in the Structured Interview for Psychosis-Risk Syndromes (SIPS). Suicidality was assessed using the Columbia Suicide Severity Rating Scale (C-SSRS). Volumetric MRI scans were obtained on a 3T Phillips scanner. MRI data were available for 69 individuals (19 CHR without SI, 31 CHR with SI and 19 healthy control subjects). CHR individuals with SI had thicker middle temporal and right insular cortices than CHR individuals without SI and healthy control subjects. The location of these findings is consistent with neurobiological findings regarding suicide in syndromal psychosis. These findings underscore the potential for the use of brain imaging biomarkers of suicide risk in CHR individuals.

The processing of angry faces in schizophrenia patients with a history of suicide: An fMRI study examining brain activity and connectivity

BACKGROUND

The high rate of suicidal behaviours (SBs) in psychiatric populations remain an important preoccupation to address. The literature reveals emotional instability as an important risk factor for SBs. However, the neural mechanisms underpinning this risk factor have never been investigated in schizophrenia patients with SBs. The following study implemented a task-based emotional processing functional magnetic resonance imaging (fMRI) paradigm to evaluate the activation and connectivity differences exhibited by schizophrenia patients with a history of suicide attempt (SA).

METHOD

A sample of 62 schizophrenia patients with and without SA and 22 controls completed an fMRI emotional processing task, which included the visualization of dynamic angry facial expressions. Task-based connectivity was assessed using generalized psychophysical interaction analyses.

RESULTS

During the processing of angry faces, suicidal schizophrenia patients displayed increased activation of the left median cingulate gyrus, left middle frontal gyrus, and left precuneus when compared to nonsuicidal schizophrenia patients and healthy controls. Whole-brain connectivity analyses yielded an increased coupling of the right amygdala and right superior frontal gyrus, as well as between the left precuneus and median cingulate gyrus, in suicidal schizophrenia patients. Schizophrenia patients' hostility scores on the Positive and Negative Symptom Scale (PANSS) were significantly and positively correlated with the activity of the left median cingulate gyrus.

CONCLUSION

When exposed to angry faces, suicidal schizophrenia patients demonstrate elevated activation of brain regions associated to executive functioning and self-processing, as well as aberrant fronto-limbic connectivity involved in emotion regulation. Our results highlight the neglected role of anger when investigating the neural alterations underpinning SBs in schizophrenia.

Suicidality Associated With Deep Brain Stimulation in Extrapyramidal Diseases: A Critical Review and Hypotheses on Neuroanatomical and Neuroimmune Mechanisms

Deep brain stimulation (DBS) is a very well-established and effective treatment for patients with extrapyramidal diseases. Despite its generally favorable clinical efficacy, some undesirable outcomes associated with DBS have been reported. Among such complications are incidences of suicidal ideation (SI) and behavior (SB) in patients undergoing this neurosurgical procedure. However, causal associations between DBS and increased suicide risk are not demonstrated and they constitute a debated issue. In light of these observations, the main objective of this work is to provide a comprehensive and unbiased overview of the literature on suicide risk in patients who received subthalamic nucleus (STN) and internal part of globus pallidum (GPi) DBS treatment. Additionally, putative mechanisms that might be involved in the development of SI and SB in these patients as well as caveats associated with these hypotheses are introduced. Finally, we briefly propose some clinical implications, including therapeutic strategies addressing these potential disease mechanisms. While a mechanistic connection between DBS and suicidality remains a controversial topic that requires further investigation, it is of critical importance to consider suicide risk as an integral component of candidate selection and post-operative care in DBS.

Volumetric MRI Analysis of Brain Structures in Patients with History of First and Repeated Suicide Attempts: A Cross Sectional Study

Structural brain changes are found in suicide attempters and in patients with mental disorders. It remains unclear whether the suicidal behaviors are related to atrophy of brain regions and how the morphology of specific brain areas is changing with each suicide attempt. The sample consisted of 56 patients hospitalized after first suicide attempt (first SA) (n = 29), more than one suicide attempt (SA > 1) (n = 27) and 54 healthy controls (HC). Brain volume was measured using FreeSurfer 6.0 automatic segmentation technique. In comparison to HC, patients with first SA had significantly lower cortical thickness of the superior and rostral middle frontal areas, the inferior, middle and superior temporal areas of the left hemisphere and superior frontal area of the right hemisphere. In comparison to HC, patients after SA > 1 had a significantly lower cortical thickness in ten areas of frontal cortex of the left hemisphere and seven areas of the right hemisphere. The comparison of hippocampus volume showed a significantly lower mean volume of left and right parts in patients with SA > 1, but not in patients with first SA. The atrophy of frontal, temporal cortex and hippocampus parts was significantly higher in repeated suicide attempters than in patients with first suicide attempt.

Common and Specific Alterations of Amygdala Subregions in Major Depressive Disorder With and Without Anxiety: A Combined Structural and Resting-State Functional MRI Study

Anxious major depressive disorder is a common subtype of major depressive disorder; however, its unique neural mechanism is not well-understood currently. Using multimodal MRI data, this study examined common and specific alterations of amygdala subregions between patients with and without anxiety. No alterations were observed in the gray matter volume or intra-region functional integration in either patient group. Compared with the controls, both patient groups showed decreased functional connectivity between the left superficial amygdala and the left putamen, and between the right superficial amygdala and the bilateral anterior cingulate cortex and medial orbitofrontal cortex, while only patients with anxiety exhibited decreased activity in the bilateral laterobasal and superficial amygdala. Moreover, the decreased activity correlated negatively with the Hamilton depression scale scores in the patients with anxiety. These findings provided insights into the pathophysiologic processes of anxious major depressive disorder and may help to develop new and effective treatment programs.

Examination of structural brain changes in recent suicidal behavior

We aimed to identify brain structural changes in cortical and subcortical regions linked to recent suicidal behavior. We performed secondary analyses of structural MRI data of two independent studies, namely the Establishing Moderators/Biosignatures of Antidepressant Response - Clinical Care (EMBARC) study and a Little Rock study on acute suicidal behavior. Study 1 (EMBARC, N = 187), compared individuals with remote suicide attempts (Remote-SA), individuals with lifetime suicide ideation but no attempts (Lifetime-SI only), and depressed individuals without lifetime suicide ideation or attempts (non-suicidal depressed). Study 2 (Little Rock data, N = 34) included patients recently hospitalized for suicide ideation or attempt constituted by: patients who recently attempted suicide (Recent-SA), individuals with remote suicide attempts (Remote-SA), and Lifetime-SI only. Study 3 combined the EMBARC and Little Rock datasets including Recent-SA, Remote-SA, Lifetime-SI only and non-suicidal depressed individuals. In Study 1 and Study 2, no significant differences were observed between groups. In Study 3, significantly lower middle temporal gyrus thickness, insular surface area, and thalamic volume and higher volume in the nucleus accumbens were observed in Recent-SA. This pattern of structural abnormalities may underlie pain and emotion dysregulation, which have been linked to the transition from suicidal thoughts to action.

Neurocognitive Functioning and Suicidal Behavior in Violent Offenders with Schizophrenia Spectrum Disorders

Suicide is one of the main premature causes of death in patients with schizophrenia. However, little is known about the relationship between neurocognitive functioning and suicidality in violent offenders with schizophrenia who have been sentenced to psychiatric treatment after committing violent crimes. We examined the neurocognitive functioning of a sample of 61 violent offenders, most of them murderers with schizophrenia who were classified as suicide attempters (n = 26) and non-attempters (n = 35). We compared the neurocognitive functioning of both groups using a neuropsychological battery. Suicide attempters showed similar performance to non-attempters in a neuropsychological test across all domains of cognitive functioning, memory, attention, verbal fluency, and executive functioning. However, after controlling for demographic and clinical variables, suicide attempters performed better than non-attempters in two planning-related tasks: the Tower of London (p < 0.01) and the Zoo Map (p < 0.01). Suicide attempters were also characterized as having more family histories of suicidality and as displaying more depressive symptoms and negative symptoms of psychopathology on the Positive and Negative Syndrome Scale (PANSS) scale. These results suggest that suicide attempters have a greater ability to formulate plans and initiate goals directed at making a suicide attempt.

Prevalence of suicidal ideation and suicide attempt in patients with migraine: A systematic review and meta-analysis

BACKGROUND

Suicidality is common in patients with migraine. Here, we performed a systematic review and estimated the prevalence of suicidal ideation (SI) and suicide attempt (SA) in patients with migraine.

METHODS

We searched Pubmed, Embase, Web of Science, Cochrane database library, CINAHL, and PsycINFO for relevant publications. A random-effects model was used to pool the estimates of the prevalence of SI and SA, which were also stratified by the geographical location of the research institutions from the studies included in this meta-analysis.

RESULTS

Fifteen studies involving 2,247,648 participants with migraine were selected. Pooled prevalence estimates of SI and SA were 15.5% [95% confidence interval (CI) 10.4-21.3%] and 3.9% (95% CI 0.9-8.8%), respectively, and the prevalence of SI was higher in Asian countries (21.5%, 95%CI 16.8-26.6%) compared with non-Asian countries (11.0%, 95%CI 6.1-17.2%). Measures of heterogeneity between studies were high for all outcomes (I² = 89-100%), indicating that the substantial between-study heterogeneity in estimated proportions was not attributed to sampling error. The leave-one-out analysis showed that no single study significantly affected the final pooled results.

CONCLUSIONS

This meta-analysis indicated a high prevalence of SI and SA in migraine patients. Thus, it is necessary to design targeted preventive measures for the management of migraine-related suicide.

Prefrontal dysfunction associated with a history of suicide attempts among patients with recent onset schizophrenia

Suicide is a major cause of death in patients with schizophrenia, particularly among those with recent disease onset. Although brain imaging studies have identified the neuroanatomical correlates of suicidal behavior, functional brain activity correlates particularly in patients with recent-onset schizophrenia (ROSZ) remain unknown. Using near-infrared spectroscopy (NIRS) recording with a high-density coverage of the prefrontal area, we investigated whether prefrontal activity is altered in patients with ROSZ having a history of suicide attempts. A 52-channel NIRS system was used to examine hemodynamic changes in patients with ROSZ that had a history of suicide attempts (n = 24) or that lacked such a history (n = 62), and age- and sex-matched healthy controls (n = 119), during a block-design letter fluency task (LFT). Patients with a history of suicide attempts exhibited decreased activation in the right dorsolateral prefrontal cortex compared with those without such a history. Our findings indicate that specific regions of the prefrontal cortex may be associated with suicidal attempts, which may have implications for early intervention for psychosis.

Brain grey matter abnormalities in first episode non-affective psychosis patients with suicidal behaviours: The role of neurocognitive functioning

BACKGROUND

Suicide is one of the leading causes of premature death in first-episode psychosis (FEP) patients. The understanding of suicidal behaviour (SB) is limited, and new and integrative approaches focusing on the likely relationship of the biological and cognitive features of SB in the early phases of psychosis are warranted. We aimed to study the relationship of brain grey matter anomalies and cognitive functioning with SB or suicidal risk in a large sample of non-affective FEP patients.

METHODS

We used a voxel-based morphometry analysis in 145 FEP patients to investigate the pattern of structural brain abnormalities related to SB. In addition, bivariate and multivariate analyses were performed to explore the relationship between cognitive functioning and SB.

RESULTS

A reduction in grey matter volume in the frontal area, temporal gyrus, precuneus, uncus, amygdala, left cuneus and subcallosal gyrus as well as a marked regional volume reduction in the right hemisphere was linked with the presence of SB. Additionally, worse global cognitive functioning and living in urban areas were identified as suicide risk factors.

CONCLUSIONS

This study provides some insights about the brain abnormalities associated with SB in FEP patients. Specifically, the areas reported are involved in important functions related to SB, such as impulsivity, problem solving or responses to pain. Thus, the results confirm the relevant role of cognitive functioning on SB.

The neurobiology of suicide in psychosis: A systematic review

The lifetime risk of dying by suicide in schizophrenia and related psychoses has been estimated to be approximately between 5% and 7%, though some have estimated that the number is closer to 10%. The highest risk for suicide occurs within the first year after presentation, when patients have a 12 times greater risk of dying by suicide than the general population, or a 60% higher risk compared with patients in other phases of psychosis, although the risk continues for many years. Some 31% of all deaths in first and early episode samples are due to suicide. Studies in individuals at clinical high-risk for psychosis (CHR) or with attenuated positive symptoms also demonstrate that suicidality is common and problematic in these individuals. Therefore, suicide in psychosis is a particularly severe problem. In order to develop interventions aimed at reducing the risk of suicide in psychotic individuals, it will be critical to understand the neurobiology of suicide in psychosis. In this paper, I report on the results of a systematic review of the work done to date on the neurobiology of suicide in psychosis and on suicidality in the CHR period. I will also identify gaps in knowledge and discuss future strategies for studying the neurobiology of suicidality in psychosis that may help to disentangle the links between suicide and psychosis and, by doing so, allow us to gain a greater understanding of the relationship between suicide and psychosis, which is critical for developing interventions aimed at reducing the risk of suicide in psychotic individuals.

Stratifying major depressive disorder by polygenic risk for schizophrenia in relation to structural brain measures

BACKGROUND

Substantial clinical heterogeneity of major depressive disorder (MDD) suggests it may group together individuals with diverse aetiologies. Identifying distinct subtypes should lead to more effective diagnosis and treatment, while providing more useful targets for further research. Genetic and clinical overlap between MDD and schizophrenia (SCZ) suggests an MDD subtype may share underlying mechanisms with SCZ.

METHODS

The present study investigated whether a neurobiologically distinct subtype of MDD could be identified by SCZ polygenic risk score (PRS). We explored interactive effects between SCZ PRS and MDD case/control status on a range of cortical, subcortical and white matter metrics among 2370 male and 2574 female UK Biobank participants.

RESULTS

There was a significant SCZ PRS by MDD interaction for rostral anterior cingulate cortex (RACC) thickness (β = 0.191, q = 0.043). This was driven by a positive association between SCZ PRS and RACC thickness among MDD cases (β = 0.098, p = 0.026), compared to a negative association among controls (β = -0.087, p = 0.002). MDD cases with low SCZ PRS showed thinner RACC, although the opposite difference for high-SCZ-PRS cases was not significant. There were nominal interactions for other brain metrics, but none remained significant after correcting for multiple comparisons.

CONCLUSIONS

Our significant results indicate that MDD case-control differences in RACC thickness vary as a function of SCZ PRS. Although this was not the case for most other brain measures assessed, our specific findings still provide some further evidence that MDD in the presence of high genetic risk for SCZ is subtly neurobiologically distinct from MDD in general.

The Amygdala in Schizophrenia and Bipolar Disorder: A Synthesis of Structural MRI, Diffusion Tensor Imaging, and Resting-State Functional Connectivity Findings

Frequently implicated in psychotic spectrum disorders, the amygdala serves as an important hub for elucidating the convergent and divergent neural substrates in schizophrenia and bipolar disorder, the two most studied groups of psychotic spectrum conditions. A systematic search of electronic databases through December 2017 was conducted to identify neuroimaging studies of the amygdala in schizophrenia and bipolar disorder, focusing on structural MRI, diffusion tensor imaging (DTI), and resting-state functional connectivity studies, with an emphasis on cross-diagnostic studies. Ninety-four independent studies were selected for the present review (49 structural MRI, 27 DTI, and 18 resting-state functional MRI studies). Also selected, and analyzed in a separate meta-analysis, were 33 volumetric studies with the amygdala as the region-of-interest. Reduced left, right, and total amygdala volumes were found in schizophrenia, relative to both healthy controls and bipolar subjects, even when restricted to cohorts in the early stages of illness. No volume abnormalities were observed in bipolar subjects relative to healthy controls. Shape morphometry studies showed either amygdala deformity or no differences in schizophrenia, and no abnormalities in bipolar disorder. In contrast to the volumetric findings, DTI studies of the uncinate fasciculus tract (connecting the amygdala with the medial- and orbitofrontal cortices) largely showed reduced fractional anisotropy (a marker of white matter microstructure abnormality) in both schizophrenia and bipolar patients, with no cross-diagnostic differences. While decreased amygdalar-orbitofrontal functional connectivity was generally observed in schizophrenia, varying patterns of amygdalar-orbitofrontal connectivity in bipolar disorder were found. Future studies can consider adopting longitudinal approaches with multimodal imaging and more extensive clinical subtyping to probe amygdalar subregional changes and their relationship to the sequelae of psychotic disorders.

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

Identifying brain alterations that contribute to suicidal thoughts and behaviors (STBs) are important to develop more targeted and effective strategies to prevent suicide. In the last decade, and especially in the last 5 years, there has been exponential growth in the number of neuroimaging studies reporting structural and functional brain circuitry correlates of STBs. Within this narrative review, we conducted a comprehensive review of neuroimaging studies of STBs published to date and summarize the progress achieved on elucidating neurobiological substrates of STBs, with a focus on converging findings across studies. We review neuroimaging evidence across differing mental disorders for structural, functional, and molecular alterations in association with STBs, which converges particularly in regions of brain systems that subserve emotion and impulse regulation including the ventral prefrontal cortex (VPFC) and dorsal PFC (DPFC), insula and their mesial temporal, striatal and posterior connection sites, as well as in the connections between these brain areas. The reviewed literature suggests that impairments in medial and lateral VPFC regions and their connections may be important in the excessive negative and blunted positive internal states that can stimulate suicidal ideation, and that impairments in a DPFC and inferior frontal gyrus (IFG) system may be important in suicide attempt behaviors. A combination of VPFC and DPFC system disturbances may lead to very high risk circumstances in which suicidal ideation is converted to lethal actions via decreased top-down inhibition of behavior and/or maladaptive, inflexible decision-making and planning. The dorsal anterior cingulate cortex and insula may play important roles in switching between these VPFC and DPFC systems, which may contribute to the transition from suicide thoughts to behaviors. Future neuroimaging research of larger sample sizes, including global efforts, longitudinal designs, and careful consideration of developmental stages, and sex and gender, will facilitate more effectively targeted preventions and interventions to reduce loss of life to suicide.

Discriminating Suicide Attempters and Predicting Suicide Risk Using Altered Frontolimbic Resting-State Functional Connectivity in Patients With Bipolar II Disorder

Bipolar II disorder (BD-II) major depression episode is highly associated with suicidality, and objective neural biomarkers could be key elements to assist in early prevention and intervention. This study aimed to integrate altered brain functionality in the frontolimbic system and machine learning techniques to classify suicidal BD-II patients and predict suicidality risk at the individual level. A cohort of 169 participants were enrolled, including 43 BD-II depression patients with at least one suicide attempt during a current depressive episode (SA), 62 BD-II depression patients without a history of attempted suicide (NSA), and 64 demographically matched healthy controls (HCs). We compared resting-state functional connectivity (rsFC) in the frontolimbic system among the three groups and explored the correlation between abnormal rsFCs and the level of suicide risk (assessed using the Nurses' Global Assessment of Suicide Risk, NGASR) in SA patients. Then, we applied support vector machines (SVMs) to classify SA vs. NSA in BD-II patients and predicted the risk of suicidality. SA patients showed significantly decreased frontolimbic rsFCs compared to NSA patients. The left amygdala-right middle frontal gyrus (orbital part) rsFC was negatively correlated with NGASR in the SA group, but not the severity of depressive or anxiety symptoms. Using frontolimbic rsFCs as features, the SVMs obtained an overall 84% classification accuracy in distinguishing SA and NSA. A significant correlation was observed between the SVMs-predicted NGASR and clinical assessed NGASR (r = 0.51, p = 0.001). Our results demonstrated that decreased rsFCs in the frontolimbic system might be critical objective features of suicidality in BD-II patients, and could be useful for objective prediction of suicidality risk in individuals.

Quantifying deep grey matter atrophy using automated segmentation approaches: A systematic review of structural MRI studies

The deep grey matter (DGM) nuclei of the brain play a crucial role in learning, behaviour, cognition, movement and memory. Although automated segmentation strategies can provide insight into the impact of multiple neurological conditions affecting these structures, such as Multiple Sclerosis (MS), Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD) and Cerebral Palsy (CP), there are a number of technical challenges limiting an accurate automated segmentation of the DGM. Namely, the insufficient contrast of T1 sequences to completely identify the boundaries of these structures, as well as the presence of iso-intense white matter lesions or extensive tissue loss caused by brain injury. Therefore in this systematic review, 269 eligible studies were analysed and compared to determine the optimal approaches for addressing these technical challenges. The automated approaches used among the reviewed studies fall into three broad categories, atlas-based approaches focusing on the accurate alignment of atlas priors, algorithmic approaches which utilise intensity information to a greater extent, and learning-based approaches that require an annotated training set. Studies that utilise freely available software packages such as FIRST, FreeSurfer and LesionTOADS were also eligible, and their performance compared. Overall, deep learning approaches achieved the best overall performance, however these strategies are currently hampered by the lack of large-scale annotated data. Improving model generalisability to new datasets could be achieved in future studies with data augmentation and transfer learning. Multi-atlas approaches provided the second-best performance overall, and may be utilised to construct a "silver standard" annotated training set for deep learning. To address the technical challenges, providing robustness to injury can be improved by using multiple channels, highly elastic diffeomorphic transformations such as LDDMM, and by following atlas-based approaches with an intensity driven refinement of the segmentation, which has been done with the Expectation Maximisation (EM) and level sets methods. Accounting for potential lesions should be achieved with a separate lesion segmentation approach, as in LesionTOADS. Finally, to address the issue of limited contrast, R2*, T2* and QSM sequences could be used to better highlight the DGM due to its higher iron content. Future studies could look to additionally acquire these sequences by retaining the phase information from standard structural scans, or alternatively acquiring these sequences for only a training set, allowing models to learn the "improved" segmentation from T1-sequences alone.

Classifying suicidal behavior with resting-state functional connectivity and structural neuroimaging

OBJECTIVE

About 80% of patients who commit suicide do not report suicidal ideation the last time they speak to their mental health provider, highlighting the need to identify biomarkers of suicidal behavior. Our goal is to identify suicidal behavior neural biomarkers to classify suicidal psychiatric inpatients.

METHODS

Eighty percent of our sample [suicidal (n = 63) and non-suicidal psychiatric inpatients (n = 65)] was used to determine significant differences in structural and resting-state functional connectivity measures throughout the brain. These measures were used in a random forest classification model on 80% of the sample for training the model.

RESULTS

The model built on 80% of the patients had sensitivity = 79.4% and specificity = 72.3%. This model was tested on an independent sample (20%; n = 32) with sensitivity = 81.3% and specificity = 75.0% for confirming the generalizability of the model. Altered resting-state functional connectivity features from frontal and middle temporal regions, as well as the amygdala, parahippocampus, putamen, and vermis were found to generalize best.

CONCLUSION

This work demonstrates neuroimaging (an unbiased biomarker) can be used to classify suicidal behavior in psychiatric inpatients without observing any clinical features.

Gray matter volumetric study of major depression and suicidal behavior

Structural brain deficits are linked to risk for suicidal behavior. However, there is disagreement about the nature of these deficits, probably due to the heterogeneity of suicidal behavior in terms of the suicidal act's lethality. We hypothesized that individuals with major depressive disorder (MDD) and history of more lethal suicide attempts would have lower gray matter volume (GMV) of the prefrontal regions and insula compared with MDD lower-lethality attempters and MDD non-attempters. We collected structural MRI scans on 91 individuals with MDD; 11 with history of higher-lethality suicide attempts, 14 with lower-lethality attempts, and 66 were non-attempters. Differences in GMV between these three groups were examined using both regions-of-interest (ROI) and brain-wide voxel-based morphometry (VBM) analyses. Both ROI and VBM analyses showed that higher-lethality suicide attempters have greater GMV of the prefrontal cortical regions and insula, compared with the other two groups. Although this contrasts with our hypothesis, the observed larger prefrontal cortex GMV in higher-lethality suicide attempters may underlie the set of attributes observed previously in this suicidal subgroup, including enhanced suicide attempt planning, greater response inhibition, and delayed reward capabilities. Future studies should further examine the role of these brain regions in relation to suicidal intent and planning.

Resting-State Functional Connectivity of the Habenula in Mood Disorder Patients With and Without Suicide-Related Behaviors

The habenula is a small midbrain structure that is important for brain signaling and learning from negative events. Thus, the habenula is strongly connected to both the reward system and motor regions. Increasing evidence suggests a role for the habenula in the etiology of psychiatric disorders, including mood and substance use disorders. However, no studies to date have investigated habenular resting-state functional connectivity (rsFC) in suicide-related behaviors (SB). The authors enrolled 123 individuals with major depressive disorder (MDD) or bipolar disorder and a history of suicide-related behaviors (SB+), 74 individuals with MDD or bipolar disorder and a history of suicidal ideation but no history of SB (SB-), and 75 healthy control subjects (HC). A seed-based approach was used to identify regions showing different rsFC with the habenula followed by region of interest to region of interest post hoc comparisons. Compared with both the SB- and HC groups, the SB+ group showed higher connectivity between the left habenula and the left parahippocampal gyrus, the right amygdala, and the right precentral and postcentral gyri. Patients with mood disorders displayed higher rsFC between the left habenula and left middle temporal gyrus, the left angular gyrus, and the left posterior cingulate cortex, as well as lower rsFC between the right habenula and the left thalamus, when compared with HCs. These findings suggest that the habenula is involved in the neural circuitry of suicide. The higher habenular rsFC found in the SB+ group may mediate a dysfunction in the mechanism that links the habenula with motor activity and contextual associative processing.

Neuroimaging Studies of Suicidal Behavior and Non-suicidal Self-Injury in Psychiatric Patients: A Systematic Review

Background: With around 800,000 people taking their own lives every year, suicide is a growing health concern. Understanding the factors that underlie suicidality and identifying specific variables associated with increased risk is paramount for increasing our understanding of suicide etiology. Neuroimaging methods that enable the investigation of structural and functional brain markers in vivo are a promising tool in suicide research. Although a number of studies in clinical samples have been published to date, evidence about neuroimaging correlates for suicidality remains controversial. Objective: Patients with mental disorders have an increased risk for both suicidal behavior and non-suicidal self-injury. This manuscript aims to present an up-to-date overview of the literature on potential neuroimaging markers associated with SB and NSSI in clinical samples. We sought to identify consistently reported structural changes associated with suicidal symptoms within and across psychiatric disorders. Methods: A systematic literature search across four databases was performed to identify all English-language neuroimaging articles involving patients with at least one psychiatric diagnosis and at least one variable assessing SB or NSSI. We evaluated and screened evidence in these articles against a set of inclusion/exclusion criteria and categorized them by disease, adhering to the PRISMA guidelines. Results: Thirty-three original scientific articles investigating neuroimaging correlates of SB in psychiatric samples were found, but no single article focusing on NSSI alone. Associations between suicidality and regions in frontal and temporal cortex were reported by 15 and 9 studies across four disorders, respectively. Furthermore, differences in hippocampus were reported by four studies across three disorders. However, we found a significant lack of replicability (consistency in size and direction) of results across studies. Conclusions: Our systematic review revealed a lack of neuroimaging studies focusing on NSSI in clinical samples. We highlight several potential sources of bias in published studies, and conclude that future studies should implement more rigorous study designs to minimize bias risk. Despite several studies reporting associations between SB and anatomical differences in the frontal cortex, there was a lack of consistency across them. We conclude that better-powered samples, standardized neuroimaging and analytical protocols are needed to continue advancing knowledge in this field.

Structural and functional alterations of the suicidal brain: An updated review of neuroimaging studies

Brain imaging is a non-invasive and in vivo direct estimation of detailed brain structure, regional brain functioning and estimation of molecular processes in the brain. The main objective of this review was to analyze functional and structural neuroimaging studies of individuals at risk for suicide. We reviewed articles published between 2005 and 2018, indexed in PubMed and Medline, assessing structural and functional alterations of the brain of individuals at high risk for suicide and at low risk for suicide. We reviewed functional and structural neuroimaging studies which included individuals with a history of suicidal ideation or attempt in major depressive disorder (MDD), bipolar disorder (BD), psychosis, and borderline personality disorder (BPD). We selected 45 papers that focused on suicidality in MDD, 17 papers on BD, 11 papers on psychosis, and 5 papers on BPD. The suicidal brain across psychiatric diagnoses seems to heavily involve dysfunction of the fronto-temporal network, primarily involving reductions of gray and white matter volumes in the pre-frontal cortex (PFC), anterior cingulate, and superior temporal gyrus. Nonetheless, there are several ways to define suicidal behaviour and ideation. Therefore, it still remains difficult to combine the evidence from imaging studies that used different definitions of suicidality.

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

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

Resting-state functional connectivity of the amygdala in suicide attempters with major depressive disorder

In this study, we investigated the difference in resting-state functional connectivity (RSFC) of the amygdala between suicide attempters and non-suicide attempters with major depressive disorder (MDD) using functional magnetic resonance imaging (fMRI). This study included 19 suicide attempters with MDD and 19 non-suicide attempters with MDD. RSFC was compared between the two groups and the regression analyses were conducted to identify the correlation between RSFC and Scale for Suicide Ideation (SSI) scores in the suicide attempt group. Statistical significance was set at p-value (uncorrected) <0.005 with k≥28 voxels. Compared with non-suicide attempters, suicide attempters showed significantly increased RSFC of the left amygdala with the right insula and left superior orbitofrontal area, and increased RSFC of the right amygdala with the left middle temporal area. The regression analysis showed a significant correlation between the SSI total score and RSFC of the right amygdala with the right parahippocampal area in the suicide attempt group. The present RSFC findings provide evidence of a functional neural basis and will help reveal the pathophysiology underlying suicidality in subjects with MDD.

Biomarkers of Suicide Attempt Behavior: Towards a Biological Model of Risk

PURPOSE OF REVIEW

The rising suicide rate in the USA will not be reversed without improved risk assessment and prevention practices. To date, the best method for clinicians to assess a patient's risk for suicide is screening for past suicide attempts in the patient and their family. However, neuroimaging, genomic, and biochemical studies have generated a body of findings that allow description of an initial heuristic biological model for suicidal behavior that may have predictive value.

RECENT FINDINGS

We review studies from the past 3 years examining potential biological predictors of suicide attempt behavior. We divide findings into two major categories: (1) structural and functional brain imaging findings and (2) biochemical and genomic findings encompassing several systems, including major neurotransmitters (serotonin, catecholamines, GABA, and glutamate), the hypothalamic pituitary adrenal (HPA) axis, the inflammasome, lipids, and neuroplasticity. The biomarkers that appear promising for assessing suicide risk in clinical settings include indices of serotonergic function, inflammation, neuronal plasticity, and lipids.

The alexithymia, emotion regulation, emotion regulation difficulties, positive and negative affects, and suicidal risk in alcohol-dependent outpatients

The aim of this study was to evaluate the potential contributing factors such as alexithymia, emotion regulation and difficulties in emotion regulation, positive/negative affects and clinical factors including severity of alcohol dependence and depression connected to high suicidality in alcohol-dependent outpatients. 205 alcohol-dependent outpatients and 100 normal controls completed the demographic questionnaire, the Persian version of the Toronto Alexithymia Scale (FTAS-20), the Difficulties in Emotion Regulation Scale (DERS), the Emotion Regulation Questionnaire (ERQ), the Positive/Negative Affect Scales, the Alcohol Use Disorders Identification Test (AUDIT), and the Beck Depression Inventory-II (BDI-II). The suicidal risk was assessed using the Scale for Suicide Ideation (SSI) and history taking. Alcohol-dependent outpatients showed higher means in alexithymia, difficulties in emotion regulation, suppression subscale, negative affect, and suicide ideation than normal controls. Logistic regression analysis revealed that negative affect, duration of alcohol use, externally-oriented thinking, and severity of alcohol dependence explained lifetime suicide attempts. Depression, impulsivity, severity of alcohol dependence, reappraisal (reversely), externally-oriented thinking, difficulties engaging in goal-directed behaviors, and negative affect significantly predicted the suicidal risk. The findings may constitute useful evidence of the relevancies of alexithymia, emotion regulation, emotion regulation difficulties, and affects to suicidality in alcoholic patients.

Subcortical nuclei volumes in suicidal behavior: nucleus accumbens may modulate the lethality of acts

Previously, studies have demonstrated cortical impairments in those who complete or attempt suicide. Subcortical nuclei have less often been implicated in the suicidal vulnerability. In the present study, we investigated, with a specific design in a large population, variations in the volume of subcortical structures in patients with mood disorders who have attempted suicide. We recruited 253 participants: 73 suicide attempters with a past history of both mood disorders and suicidal act, 89 patient controls with a past history of mood disorders but no history of suicidal act, and 91 healthy controls. We collected 1.5 T magnetic resonance imaging data from the caudate, pallidum, putamen, nucleus accumbens, hippocampus, amygdala, ventral diencephalon, and thalamus. Surface-based morphometry (Freesurfer) analysis was used to comprehensively evaluate gray matter volumes. In comparison to controls, suicide attempters showed no difference in subcortical volumes when controlled for intracranial volume. However, within attempters negative correlations between the left (r = -0.35, p = 0.002), and right (r = -0.41, p < 0.0005) nucleus accumbens volumes and the lethality of the last suicidal act were found. Our study found no differences in the volume of eight subcortical nuclei between suicide attempters and controls, suggesting a lack of association between these regions and suicidal behavior in general. However, individual variations in nucleus accumbens structure and functioning may modulate the lethality of suicidal acts during a suicidal crisis. The known role of nucleus accumbens in action selection toward goals determined by the prefrontal cortex, decision-making or mental pain processing are hypothesized to be potential explanations.

Frontal Motor Cortex Activity During Reactive Control Is Associated With Past Suicidal Behavior in Recent-Onset Schizophrenia

BACKGROUND

Suicide is prevalent in schizophrenia (SZ), yet the neural system functions that confer suicide risk remain obscure. Circuits operated by the prefrontal cortex (PFC) are altered in SZ, including those that support reactive control, and PFC changes are observed in postmortem studies of heterogeneous suicide victims.

AIMS

We tested whether history of suicide attempt is associated with altered frontal motor cortex activity during reactive control processes.

METHOD

We evaluated 17 patients with recent onset of DSM-IV-TR-defined SZ using the Columbia Suicide Severity Rating Scale and functional magnetic resonance imaging during Stroop task performance. Group-level regression models relating past suicidal behavior to frontal activation controlled for depression, psychosis, and impulsivity.

RESULTS

Past suicidal behavior was associated with relatively higher activation in the left-hemisphere supplementary motor area (SMA), pre-SMA, premotor cortex, and dorsolateral PFC, all ipsilateral to the active primary motor cortex.

CONCLUSION

This study provides unique evidence that suicidal behavior in patients with recent-onset SZ directly relates to frontal motor cortex activity during reactive control, in a pattern reciprocal to the relationship with proactive control found previously. Further work should address how frontal-based control functions change with risk over time, and their potential utility as a biomarker for interventions to mitigate suicide risk in SZ.

Prefrontal cortex, temporal cortex, and hippocampus volume are affected in suicidal psychiatric patients

Suicide is a leading cause of death in America, with over 40,000 reported suicides per year. Mental illness is a major risk factor for suicidality. This study attempts to validate findings of volumetric differences from studies on suicidality. Psychiatric inpatients classified as having mildly severe or severe depression were separated into two groups: suicide attempted in the past two months (SA; n=20), non-suicidal control group (DA; n=20); these patients were all depressed and not significantly different for age, gender, race, marital status, education level, anxiety level, and substance abuse. Healthy controls (HC; n=20) were not significantly different from the suicidal groups for age and gender. Volunteers underwent MRI to assess volumes of cortical lobes, corpus callosum, and subcortical regions of interest, including the thalamus, insula, limbic structures, and basal ganglia. The right hippocampal volume of the SA group was significantly reduced compared to healthy controls. The frontal and temporal lobe volumes of the SA group were significantly decreased compared to the DA group. These volumetric reductions confirm previous findings and support the hypothesis that fronto-temporal function may be altered in suicidal patients.

Pronounced prefronto-temporal cortical thinning in schizophrenia: Neuroanatomical correlate of suicidal behavior?

Schizophrenia is characterized by increased mortality for which suicidality is the decisive factor. An analysis of cortical thickness and folding to further elucidate neuroanatomical correlates of suicidality in schizophrenia has not yet been performed. We searched for relevant brain regions with such differences between patients with suicide-attempts, patients without any suicidal thoughts and healthy controls. 37 schizophrenia patients (14 suicide-attempters and 23 non-suicidal) and 50 age- and gender-matched healthy controls were included. Suicidality was documented through clinical interview and chart review. All participants underwent T1-weighted MRI scans. Whole brain node-by-node cortical thickness and folding were estimated (FreeSurfer Software) and compared. Additionally a three group comparison for prefrontal regions-of-interest was performed in SPSS using a multifactorial GLM. Compared with the healthy controls patients showed a typical pattern of cortical thinning in prefronto-temporal regions and altered cortical folding in the right medial temporal cortex. Patients with suicidal behavior compared with non-suicidal patients demonstrated pronounced (p<0.05) cortical thinning in the right DLPFC and the superior temporal cortex. Comparing cortical thickness in suicidal patients with non-suicidal patients significant (p<0.05) cortical thinning was additionally found in the right superior and middle temporal, temporopolar and insular cortex. Our findings extend the evidence for neuroanatomical underpinnings of suicidal behaviour in schizophrenia. We identified cortical thinning in a network strongly involved in regulation of impulsivity, emotions and planning of behaviour in suicide attempters, which might lead to neuronal dysregulation in this network and consequently to a higher risk of suicidal behavior.

White matter alterations associated with suicide in patients with schizophrenia or schizophreniform disorder

The risk of suicide is disproportionately high among people diagnosed with schizophrenia or schizophreniform disorder. Brain imaging studies have shown a few relationships between neuroanatomy and suicide. This study examines the relationship between alterations in brain white matter (WM) and suicidal behavior in people with schizophrenia or schizophreniform disorder. The study participants were 56 patients with schizophrenia or schizophreniform disorder, with (n=15) and without (n=41) a history of suicide attempts. Fractional anisotropy (FA) values were compared between suicide attempters and non-attempters using Tract-Based Spatial Statistics (TBSS). Attempters showed significantly higher FA values than non-attempters in the left corona radiata, the superior longitudinal fasciculus, the posterior limb and retrolenticular part of the internal capsule, the external capsule, the insula, the posterior thalamic radiation, the cerebral peduncle, the sagittal stratum, and temporal lobe WM. Scores of the picture arrangement test showed a significant positive correlation with FA values of the right corona radiata, the right superior longitudinal fasciculus, the body of the corpus callosum, and the left corona radiata in attempters but not in non-attempters. These findings suggest that fronto-temporo-limbic circuits can be associated mainly with suicidal behavior in people with schizophrenia or schizophreniform disorder.

Inhibition of glutamine synthetase in the central nucleus of the amygdala induces anhedonic behavior and recurrent seizures in a rat model of mesial temporal lobe epilepsy

The prevalence of depression and suicide is increased in patients with mesial temporal lobe epilepsy (MTLE); however, the underlying mechanism remains unknown. Anhedonia, a core symptom of depression that is predictive of suicide, is common in patients with MTLE. Glutamine synthetase, an astrocytic enzyme that metabolizes glutamate and ammonia to glutamine, is reduced in the amygdala in patients with epilepsy and depression and in suicide victims. Here, we sought to develop a novel model of anhedonia in MTLE by testing the hypothesis that deficiency in glutamine synthetase in the central nucleus of the amygdala (CeA) leads to epilepsy and comorbid anhedonia. Nineteen male Sprague-Dawley rats were implanted with an osmotic pump infusing either the glutamine synthetase inhibitor methionine sulfoximine [MSO (n=12)] or phosphate buffered saline [PBS (n=7)] into the right CeA. Seizure activity was monitored by video-intracranial electroencephalogram (EEG) recordings for 21days after the onset of MSO infusion. Sucrose preference, a measure of anhedonia, was assessed after 21days. Methionine sulfoximine-infused rats exhibited recurrent seizures during the monitoring period and showed decreased sucrose preference over days when compared with PBS-infused rats (p<0.01). Water consumption did not differ between the PBS-treated group and the MSO-treated group. Neurons were lost in the CeA, but not the medial amygdala, lateral amygdala, basolateral amygdala, or the hilus of the dentate gyrus, in the MSO-treated rats. The results suggest that decreased glutamine synthetase activity in the CeA is a possible common cause of anhedonia and seizures in TLE. We propose that the MSO CeA model can be used for mechanistic studies that will lead to the development and testing of novel drugs to prevent seizures, depression, and suicide in patients with TLE.

The co-occurrence of aggression and self-harm: systematic literature review

BACKGROUND

Epidemiological research supports an association between aggression and self-harm through data on the frequency with which individuals exhibit both behaviours. Unbiased evidence, however, is needed to draw conclusions about the nature and extent of co-occurrence.

METHOD

Systematic review of published studies was undertaken to evaluate whether or not the frequency with which aggression and self-harm co-occur is beyond that which would be expected by chance. Outcome measures included: (a) between-group differences on a standardised aggression/self-harm measure - the groups defined by scores on a measure of the other behaviour; (b) correlations between the two behaviours; (c) co-occurrence rates in populations defined by the presence of either behaviour; (d) co-occurrence rates in populations not defined by either behaviour. Odds ratios were calculated for studies presenting complete frequency data.

RESULTS

123 studies, some yielding more than one type of result, met the inclusion criteria. Most case-control studies found elevated levels of aggression in self-harming populations (or self-harm in aggressive populations) compared to controls. The majority of correlational, co-occurrence rate, and odds ratio data found aggression and self-harm to be associated.

LIMITATIONS

Results were subject to descriptive synthesis only and thus, unable to report an overall effect size.

CONCLUSIONS

Evidence suggests that aggression and self-harm frequently co-occur. Such evidence necessitates more theoretical discussion and associated research on the source and nature of co-occurrence. Nonetheless, individuals who present with one behaviour may be considered an 'at-risk' group in terms of exhibiting the other. Such evidence holds implications for practice (e.g. risk assessment).

Depressed suicide attempters have smaller hippocampus than depressed patients without suicide attempts

BACKGROUND

Despite known relationship between hippocampal volumes and major depressive episodes (MDE) and the increased suicidality in MDE, the links between hippocampal volumes and suicidality remain unclear in major depressive disorders (MDD). If the hippocampus could be a biomarker of suicide attempts in depression, it could be useful for prevention matters. This study assessed the association between hippocampal volumes and suicide attempts in MDD.

METHODS

Hippocampal volumes assessed with automatic segmentation were compared in 63 patients with MDD, with (n = 24) or without (n = 39) suicide attempts. Acute (<one month) and past (>one month) suicide attempts were studied.

RESULTS

Although not different in terms of socio-demographic, MDD and MDE clinical features, suicide attempters had lower total hippocampus volumes than non-attempters (4.61 (± 1.15) cm(3) vs 5.22 (± 0.99) cm(3); w = 625.5; p = 0.03), especially for acute suicide attempts (4.19 (± 0.81) cm(3) vs 5.22 (± 0.99) cm(3); w = 334; p = 0.005), even after adjustment on brain volumes, sex, age, Hamilton Depression Rating Scale (HDRS) scores and MDD duration. A ROC analysis showed that a total hippocampal volume threshold of 5.00 cm(3) had a 98.2% negative predictive value for acute suicide attempts.

CONCLUSION

Depressed suicide attempters have smaller hippocampus than depressed patients without suicide attempts, independently from socio-demographics and MDD characteristics. This difference is related to acute suicide attempts but neither to past suicide attempts nor to duration since the first suicide attempt, suggesting that hippocampal volume could be a suicidal state marker in MDE. Further studies are required to better understand this association.

Is there a neuroanatomical basis of the vulnerability to suicidal behavior? A coordinate-based meta-analysis of structural and functional MRI studies

Objective: We conducted meta-analyses of functional and structural neuroimaging studies comparing adolescent and adult individuals with a history of suicidal behavior and a psychiatric disorder to psychiatric controls in order to objectify changes in brain structure and function in association with a vulnerability to suicidal behavior.

Methods: Magnetic resonance imaging studies published up to July 2013 investigating structural or functional brain correlates of suicidal behavior were identified through computerized and manual literature searches. Activation foci from 12 studies encompassing 475 individuals, i.e., 213 suicide attempters and 262 psychiatric controls were subjected to meta-analytical study using anatomic or activation likelihood estimation (ALE).

Result: Activation likelihood estimation revealed structural deficits and functional changes in association with a history of suicidal behavior. Structural findings included reduced volumes of the rectal gyrus, superior temporal gyrus and caudate nucleus. Functional differences between study groups included an increased reactivity of the anterior and posterior cingulate cortices.

Discussion: A history of suicidal behavior appears to be associated with (probably interrelated) structural deficits and functional overactivation in brain areas, which contribute to a decision-making network. The findings suggest that a vulnerability to suicidal behavior can be defined in terms of a reduced motivational control over the intentional behavioral reaction to salient negative stimuli.

Basolateral amygdala volume and cell numbers in major depressive disorder: a postmortem stereological study

Functional imaging studies consistently report abnormal amygdala activity in major depressive disorder (MDD). Neuroanatomical correlates are less clear: imaging studies have produced mixed results on amygdala volume, and postmortem neuroanatomic studies have only examined cell densities in portions of the amygdala or its subregions in MDD. Here, we present a stereological analysis of the volume of, and the total number of, neurons, glia, and neurovascular (pericyte and endothelial) cells in the basolateral amygdala in MDD. Postmortem tissues from 13 subjects with MDD and 10 controls were examined. Sections (~15/subject) taken throughout the rostral-caudal extent of the basolateral amygdala (BLA) were stained for Nissl substance and utilized for stereological estimation of volume and cell numbers. Results indicate that depressed subjects had a larger lateral nucleus than controls and a greater number of total BLA neurovascular cells than controls. There were no differences in the number or density of neurons or glia between depressed and control subjects. These findings present a more detailed picture of BLA cellular anatomy in depression than has previously been available. Further studies are needed to determine whether the greater number of neurovascular cells in depressed subjects may be related to increased amygdala activity in depression.