Periventricular white matter hyperintensities as predictors of suicide attempts in bipolar disorders and unipolar depression

Brain and blood transcriptome profiles delineate common genetic pathways across suicidal ideation and suicide

Human genetic studies indicate that suicidal ideation and behavior are both heritable. Most studies have examined associations between aberrant gene expression and suicide behavior, but behavior risk is linked to the severity of suicidal ideation. Through a gene network approach, this study investigates how gene co-expression patterns are associated with suicidal ideation and severity using RNA-seq data in peripheral blood from 46 live participants with elevated suicidal ideation and 46 with no ideation. Associations with the presence of suicidal ideation were found within 18 co-expressed modules (p < 0.05), as well as in 3 co-expressed modules associated with suicidal ideation severity (p < 0.05, not explained by severity of depression). Suicidal ideation presence and severity-related gene modules with enrichment of genes involved in defense against microbial infection, inflammation, and adaptive immune response were identified and investigated using RNA-seq data from postmortem brain that revealed gene expression differences with moderate effect sizes in suicide decedents vs. non-suicides in white matter, but not gray matter. Findings support a role of brain and peripheral blood inflammation in suicide risk, showing that suicidal ideation presence and severity are associated with an inflammatory signature detectable in blood and brain, indicating a biological continuity between ideation and suicidal behavior that may underlie a common heritability.

Functional Architecture of Brain and Blood Transcriptome Delineate Biological Continuity Between Suicidal Ideation and Suicide

Human genetic studies indicate that suicidal ideation and behavior are both heritable. Most studies have examined associations between aberrant gene expression and suicide behavior, but behavior risk is linked to severity of suicidal ideation. Through a gene network approach, this study investigates how gene co-expression patterns are associated with suicidal ideation and severity using RNA-seq data in peripheral blood from 46 live participants with elevated suicidal ideation and 46 with no ideation. Associations with presence and severity of suicidal ideation were found within 18 and 3 co-expressed modules respectively (p < 0.05), not explained by severity of depression. Suicidal ideation presence and severity-related gene modules with enrichment of genes involved in defense against microbial infection, inflammation, and adaptive immune response were identified, and tested using RNA-seq data from postmortem brain that revealed gene expression differences in suicide decedents vs. non-suicides in white matter, but not gray matter. Findings support a role of brain and peripheral blood inflammation in suicide risk, showing that suicidal ideation presence and severity is associated with an inflammatory signature detectable in blood and brain, indicating a biological continuity between ideation and suicidal behavior that may underlie a common heritability.

Glutamatergic and N-Acetylaspartate Metabolites in Bipolar Disorder: A Systematic Review and Meta-Analysis of Proton Magnetic Resonance Spectroscopy Studies

The exact neurobiological mechanisms of bipolar disorder (BD) remain unknown. However, some neurometabolites could be implicated, including Glutamate (Glu), Glutamine (Gln), Glx, and N-acetylaspartate (NAA). Proton Magnetic Resonance Spectroscopy (¹H-MRS) allows one to quantify these metabolites in the human brain. Thus, we conducted a systematic review and meta-analysis of the literature to compare their levels between BD patients and healthy controls (HC). The main inclusion criteria for inclusion were ¹H-MRS studies comparing levels of Glu, Gln, Glx, and NAA in the prefrontal cortex (PFC), anterior cingulate cortex (ACC), and hippocampi between patients with BD in clinical remission or a major depressive episode and HC. Thirty-three studies were included. NAA levels were significantly lower in the left white matter PFC (wmPFC) of depressive and remitted BD patients compared to controls and were also significantly higher in the left dorsolateral PFC (dlPFC) of depressive BD patients compared to HC. Gln levels were significantly higher in the ACC of remitted BD patients compared to in HC. The decreased levels of NAA of BD patients may be related to the alterations in neuroplasticity and synaptic plasticity found in BD patients and may explain the deep white matter hyperintensities frequently observed via magnetic resonance imagery.

Risk of self-harm in post TIA patients: A population-based cohort study

OBJECTIVE

The purpose of this study was to determine whether individuals who have experienced a transient ischemic attack (TIA) have an increased risk of self-harm behaviors.

METHODS

In this matched cohort study, we reviewed the electronic health records of all patients admitted for any reason to Hong Kong public hospitals between January 1, 1993, and December 31, 2019. We selected a post-TIA cohort consisting of 37,356 patients and a comparison cohort comprising 37,352 subjects. All participants enrolled in this study were followed up until a diagnosis of self-harm, death from other causes, or the end of 2020, whichever occurred first. Univariate Cox proportional hazards regression models were used to calculate the risk of self-harm since the onset of TIA.

RESULTS

Throughout the 27-year study period, the number of individuals exhibiting self-harm behavior in the TIA and comparison groups was 1031 (2.76%) and 512 (1.37%), respectively. The TIA group had a higher proportion of subjects with self-harm (χ² = 178, p < .001). The incidence rates of self-harm were 33.94 and 19.27 per 10,000 person-years in TIA patients and comparators, respectively. Compared with the comparators, the adjusted hazard ratio for self-harm in TIA patients was 1.63 (95% confidence interval, 1.46-1.82).

CONCLUSIONS

TIA is associated with an increased risk of self-harm. Healthcare professionals should help identify patients at heightened risk and provide efficient and targeted prevention strategies for this population.

Insights into myelin dysfunction in schizophrenia and bipolar disorder

Schizophrenia and bipolar disorder are disabling psychiatric disorders with a worldwide prevalence of approximately 1%. Both disorders present chronic and deteriorating prognoses that impose a large burden, not only on patients but also on society and health systems. These mental illnesses share several clinical and neurobiological traits; of these traits, oligodendroglial dysfunction and alterations to white matter (WM) tracts could underlie the disconnection between brain regions related to their symptomatic domains. WM is mainly composed of heavily myelinated axons and glial cells. Myelin internodes are discrete axon-wrapping membrane sheaths formed by oligodendrocyte processes. Myelin ensheathment allows fast and efficient conduction of nerve impulses through the nodes of Ranvier, improving the overall function of neuronal circuits. Rapid and precisely synchronized nerve impulse conduction through fibers that connect distant brain structures is crucial for higher-level functions, such as cognition, memory, mood, and language. Several cellular and subcellular anomalies related to myelin and oligodendrocytes have been found in postmortem samples from patients with schizophrenia or bipolar disorder, and neuroimaging techniques have revealed consistent alterations at the macroscale connectomic level in both disorders. In this work, evidence regarding these multilevel alterations in oligodendrocytes and myelinated tracts is discussed, and the involvement of proteins in key functions of the oligodendroglial lineage, such as oligodendrogenesis and myelination, is highlighted. The molecular components of the axo-myelin unit could be important targets for novel therapeutic approaches to schizophrenia and bipolar disorder.

Altered Levels of Plasma Inflammatory Cytokines and White Matter Integrity in Bipolar Disorder Patients With Suicide Attempts

OBJECTIVE

Bipolar disorder (BD) has a higher lifetime rate of suicide attempts (SA) than other psychiatric disorders. Furthermore, BD patients with SA (BD + S) are prone to a worse quality of life. However, the pathophysiology of BD + S is poorly understood. To further reveal the potential mechanisms of BD + S, abnormalities in peripheral plasma inflammatory cytokines and brain white matter (WM) in BD + S, as well as the correlation between them are investigated.

METHODS

We tested the levels of TNF-α, IL-1β, and IL-6 in peripheral plasma and collected the diffusion tensor imaging (DTI) data from 14 BD + S, 24 BD patients without SA (BD-S), and 26 healthy controls (HCs). The three groups were matched by age and gender. The levels of TNF-α, IL-1β, and IL-6 were detected by Luminex multifactor detection technology, and the fractional anisotropy (FA) values were employed to depict the alterations of WM. Partial correlation analyses were conducted to detect correlations between levels of TNF-α, IL-1β, and IL-6 and changes of WM, and the relationships between severity of clinical symptoms, including scores of HAMD-17 and YMRS, and cytokine levels or FA values in all groups.

RESULTS

For plasma inflammatory cytokines, there was no significant difference in their levels except for IL-6 among the three groups. Post-hoc analyses revealed that increased IL-6 level was only detected in BD + S (p < 0.05, Bonferroni correction). For DTI, BD + S showed specifically decreased FA in the bilateral middle cerebellar peduncle and the left superior corona radiata compared to BD-S and HCs (p < 0.05, Bonferroni correction). Additionally, both BD + S and BD-S groups revealed decreased FA in the bilateral body and genu of corpus callosum (CC) compared to HCs (p < 0.05, Bonferroni correction). No significant correlation between plasma inflammatory cytokines and WM integrity was found. In the BD + S group, we found negative correlation between the scores of YMRS and FA values of the left middle cerebellar peduncle (r = -0.74, p = 0.035).

CONCLUSION

The inflammation and impaired WM integrity may provide a scientific basis to understand the potential mechanisms of BD + S.

Brain Correlates of Suicide Attempt in 18,925 Participants Across 18 International Cohorts

BACKGROUND

Neuroimaging studies of suicidal behavior have so far been conducted in small samples, prone to biases and false-positive associations, yielding inconsistent results. The ENIGMA-MDD Working Group aims to address the issues of poor replicability and comparability by coordinating harmonized analyses across neuroimaging studies of major depressive disorder and related phenotypes, including suicidal behavior.

METHODS

Here, we pooled data from 18 international cohorts with neuroimaging and clinical measurements in 18,925 participants (12,477 healthy control subjects and 6448 people with depression, of whom 694 had attempted suicide). We compared regional cortical thickness and surface area and measures of subcortical, lateral ventricular, and intracranial volumes between suicide attempters, clinical control subjects (nonattempters with depression), and healthy control subjects.

RESULTS

We identified 25 regions of interest with statistically significant (false discovery rate < .05) differences between groups. Post hoc examinations identified neuroimaging markers associated with suicide attempt including smaller volumes of the left and right thalamus and the right pallidum and lower surface area of the left inferior parietal lobe.

CONCLUSIONS

This study addresses the lack of replicability and consistency in several previously published neuroimaging studies of suicide attempt and further demonstrates the need for well-powered samples and collaborative efforts. Our results highlight the potential involvement of the thalamus, a structure viewed historically as a passive gateway in the brain, and the pallidum, a region linked to reward response and positive affect. Future functional and connectivity studies of suicidal behaviors may focus on understanding how these regions relate to the neurobiological mechanisms of suicide attempt risk.

Greater white matter hyperintensities and the association with executive function in suicide attempters with late-life depression

Late-life depression (LLD) is associated with greater risk of suicide and white matter hyperintensities (WMH), which are also found in suicide attempters regardless of age. Greater periventricular WMH are related to worse cognitive function. We investigated the spatial distribution of WMH in suicide attempters with LLD and its association with cognitive function. We recruited 114 participants with LLD (34 with history of suicide attempt and 80 without) and 47 older adult controls (individuals without LLD or history of suicide attempt). WMH were quantified by an automated segmentation algorithm and were classified into different regions. Suicide attempters with LLD had significantly higher global WMH (F3, 150 = 2.856, p = 0.039) and periventricular WMH (F3, 150 = 3.635, p = 0.014) compared to other groups. Suicide attempters with high WMH had significantly lower executive function, which could be an underlying mechanism for cognitive decline in older adults with suicidality.

Brain Functional and Structural Alterations in Women With Bipolar Disorder and Suicidality

Objective: Suicide is the leading cause of death from bipolar disorder (BD). At least 25-50% of the patients with BD will attempt suicide, with suicide rates much higher in women patients than in men. It is crucial to explore the potential neural mechanism underlying suicidality in women with BD, which will lead to understanding and detection of suicidality and prevent death and injury from suicide. Methods: Brain function and structure were measured by amplitude of low-frequency fluctuation (ALFF) and gray matter volume (GMV) in 155 women [30 women with BD and a history of suicidality, 50 women with BD without suicidality, and 75 healthy controls (HC)]. The differences in ALFF and GMV across the BD with suicidality, BD without suicidality, and HC groups were investigated. Results: BD with suicidality showed significantly increased ALFF in the left and right cuneus compared with BD without suicidality and HC groups. Moreover, the GMV in the left lateral prefrontal cortex and left cuneus in BD with suicidality were significantly lower than those in BD without suicidality and HC groups, while the GMV of the right ventral prefrontal cortex was significantly decreased in both BD with and without suicidality groups. Conclusions: This study, combining functional and structural neuroimaging techniques, may help to identify specific pathophysiological changes in women with BD and suicidality. Increased ALFF and less GMV in cuneus might represent the neuroimaging features of suicidality in women with BD. Investigating this potential neuromarker for suicidality in women with BD may lead to the ability to prevent suicidality.

Periventricular White Matter Alterations From Explosive Blast in a Large Animal Model: Mild Traumatic Brain Injury or "Subconcussive" Injury?

The neuropathology of mild traumatic brain injury in humans resulting from exposure to explosive blast is poorly understood as this condition is rarely fatal. A large animal model may better reflect the injury patterns in humans. We investigated the effect of explosive blasts on the constrained head minimizing the effects of whole head motion. Anesthetized Yucatan minipigs, with body and head restrained, were placed in a 3-walled test structure and exposed to 1, 2, or 3 explosive blast shock waves of the same intensity. Axonal injury was studied 3 weeks to 8 months postblast using β-amyloid precursor protein immunohistochemistry. Injury was confined to the periventricular white matter as early as 3-5 weeks after exposure to a single blast. The pattern was also present at 8 months postblast. Animals exposed to 2 and 3 blasts had more axonal injury than those exposed to a single blast. Although such increases in axonal injury may relate to the longer postblast survival time, it may also be due to the increased number of blast exposures. It is possible that the injury observed is due to a condition akin to mild traumatic brain injury or subconcussive injury in humans, and that periventricular injury may have neuropsychiatric implications.

Prevalence of white matter hyperintensities is not elevated in a large sample of adolescents and young adults with bipolar disorder

OBJECTIVE

The increased prevalence rate of white matter hyperintensities is one of the most consistently reported brain abnormalities in adults with bipolar disorder. However, findings in children and adolescents with bipolar disorder are less consistent. Prior studies have been constrained by small sample sizes and/or poor age- and sex-matching of healthy controls. We examined this topic in the largest sample of adolescents with bipolar disorder to date.

METHODS

T2-weighted 3-Tesla magnetic resonance imaging data were acquired for 83 adolescents with bipolar disorder diagnosed via the Kiddie Schedule for Affective Disorders and the Schizophrenia, Present and Lifetime version semi-structured interview and 64 age- and sex-matched healthy controls. All acquired scans were examined by neuroradiologists and the presence or absence of white matter hyperintensities was determined for each participant.

RESULTS

The prevalence of white matter hyperintensities did not differ between adolescents with bipolar disorder (13.3%) and controls (21.9%; χ2 = 1.90; p = 0.168).

CONCLUSION

In contrast to the study hypothesis, the prevalence of white matter hyperintensities was not higher in adolescents with bipolar disorder than controls. The large sample size and good matching for age and sex bolster the reliability of this negative finding. Future studies are warranted to evaluate the prevalence, incidence, and predictors of white matter hyperintensities in early-onset bipolar disorder prospectively.

Bipolar Disorder and Suicide: a Review

PURPOSE OF REVIEW

Bipolar disorder has the highest rate of suicide of all psychiatric conditions and is approximately 20-30 times that of the general population. The purpose of this review is to discuss findings relevant to bipolar disorder and suicide.

RECENT FINDINGS

Risk factors include male gender, living alone, divorced, no children, Caucasian, younger age (< 35 years), elderly age (> 75 years), unemployment, and a personal history of suicide attempt and family history of suicide attempt or suicide completion, as well as predominant depressive polarity. Suicide is associated with the depressed or mixed subtypes, not mania. Although there are emerging treatments for bipolar depression, such as ketamine and TMS, lithium remains the only medication associated with lowered suicide rates in bipolar disorder. Understanding clinical and demographic risk factors for suicide in bipolar disorder remains the best way to prevent suicidal behavior. Early intervention and treatment with anti-suicidal medications, such as lithium, along with close observation and follow-up is the best way to mitigate suicide in patients with bipolar disorder.

White matter hyperintensities in young individuals with bipolar disorder or at high genetic risk

BACKGROUND

Increased white matter hyperintensities (WMHs) is one of the most consistent imaging findings amongst participants with bipolar disorder (BD). This study investigated WMHs in a young population at high genetic risk for bipolar disorder (HR).

METHODS

MRI scans were conducted at baseline in HR individuals (n = 131), patients with BD (n = 47) and controls (CON) (n = 108). Most of the HR (n = 77) and CON (n = 74) group completed scans after two years. Scans were examined for the presence of WMHs.

RESULTS

There were significantly more periventricular WMHs in the BD compared to the CON group at baseline (p = .04). Although the prevalence of periventricular WMHs was intermediate in the HR group, there were no significant differences between the HR and CON or BD participants. Deep WMHs did not differ significantly between the groups. Over time, there was a significant increase in the prevalence of periventricular WMHs in both the HR and CON groups (p = .02).

LIMITATIONS

The use of a visual rating scale to examine WMHs is subjective. As the gradings were collapsed into 'present' or 'absent', we could not ascertain whether the severity of hyperintensities worsened over time.

CONCLUSIONS

Periventricular WMHs are more prevalent in young individuals with BD than controls. As these are not more prevalent in HR individuals, it is possible that these are either secondary to the development of bipolar disorder, its treatment, or resulting changes in lifestyle. In a novel finding, there were similar increases in the prevalence of WMHs in controls and HR youth over the 2-year period.

Gray and white matter differences in adolescents and young adults with prior suicide attempts across bipolar and major depressive disorders

BACKGROUND

Findings regarding brain circuitry abnormalities in suicide attempters (SAs) converge across bipolar disorder (BD) and major depressive disorder (MDD), the most common disorders observed in suicides. These abnormalities appear to be present during adolescence/young adulthood when suicide rates increase steeply, and suicide is a leading cause of death in this age group. Identification of brain circuitry common to adolescent/young adult SAs with BD and MDD is important for generating widely effective early prevention strategies. We examined brain circuitry in SAs in adolescents/young adults across these two disorders.

METHODS

Eighty-three participants (ages 14-25 years), 46 with BD (21 SAs) and 37 with MDD (19 SAs), underwent structural and diffusion-weighted magnetic resonance scanning. Whole-brain analyses compared gray matter (GM) volume and white matter (WM) fractional anisotropy (FA) between SAs and non-suicide attempters (NSAs) across and within BD and MDD (p < 0.005).

RESULTS

Across and within BD and MDD, SAs showed differences compared to NSAs in ventral prefrontal cortex (PFC) GM volume and fronto-limbic (including uncinate fasciculus (UF)) WM FA. Exploratory analyses showed additional within-disorder differences for BD SAs in dorsolateral PFC (dlPFC) and hippocampus GM volume and UF FA, and for MDD SAs dorsomedial and dlPFC GM and dorsal frontal WM. However, there was no significant interaction between suicide attempt status and diagnosis.

LIMITATIONS

Modest sample size.

CONCLUSIONS

Common fronto-limbic gray and white matter alterations in adolescent/young adult SAs are potential targets for suicide prevention strategies across mood disorders. Preliminary findings of disorder-specific regional findings could suggest diagnostic-specific optimal targets may exist.

White matter abnormalities of corpus callosum in patients with bipolar disorder and suicidal ideation

OBJECTIVE

Although many studies have shown that the corpus callosum (CC) may play an important role in bipolar disorder (BD) and suicide, the pathophysiological mechanism of BD underlying suicidal behavior is still unclear. This study aimed to explore the relationship between the CC, and BD and suicidal ideation using diffusion tensor imaging (DTI).

METHOD

A total of 203 participants (47 BD patients with suicidal ideation, 59 with BD without suicidal ideation, and 97 healthy controls [HC]) underwent DTI scanning at a single site. We examined the white matter integrity of the CC in the three groups.

RESULTS

A comparison among groups showed that BD patients with suicidal ideation had significant lower fractional anisotropy (FA) values than those of BD without suicidal ideation and HCs in the body and genu of the CC, and FA values of BD without suicidal ideation were significantly lower than those of HCs. However, in the splenium of corpus callosum, no difference was found between BD without suicidal ideation and HCs.

CONCLUSIONS

Our findings add to the evidence suggesting that the CC plays a key role in BD with suicidal ideation, especially with respect to the role of the genu and body of the CC subserving emotion regulation.

Associations between executive function impairment and biochemical abnormalities in bipolar disorder with suicidal ideation

BACKGROUND

Executive dysfunction and biochemical abnormalities using proton magnetic resonance spectroscopy (¹H-MRS) have been reported in bipolar disorder (BD). Much less is known about the information from BD with suicidal ideation (SI). This study aimed to assess alterations of execution function and biochemical metabolism in BD with SI, in BD without SI, and in healthy controls. The associations between execution function and biochemical metabolism in the two BD patient groups were also been studied.

METHODS

92 patients with bipolar disorder during a depressive episode (50 with current SI, and 42 without SI), as well as, 43 healthy controls were recruited in our study. Executive function was assessed by Wisconsin Card Sorting Test (WCST). Bilateral metabolite levels of prefrontal cortex (PFC), anterior cingulated cortex (ACC), lenticular nucleus (LN) of basal ganglia and thalamus were obtained by ¹H-MRS at 3.0 T, then determined the ratios of N-acetyl aspartate (NAA), choline-containing compounds (Cho), myo-inositol (mI) to creatine (Cr).

RESULTS

Number of categories completed (CC) in BD with SI was significantly less than healthy controls. NAA/Cr ratios of left PFC in the two BD patient groups (with or without SI) were significantly lower than healthy controls, and NAA/Cr ratios of left thalamus were significantly higher than healthy controls. Moreover, NAA/Cr ratio of right LN in BD without SI was higher than BD with SI and healthy controls. For BD with SI, NAA/Cr ratio of left thalamus was negatively correlated with number of CC.

CONCLUSIONS

These results suggested that BD with or without SI may have abnormal NAA metabolism, and NAA/Cr ratio of right LN may distinguish SI from the BD patients. Further, BD with SI may have executive function impairment, which may be associated with the abnormal NAA metabolism in the left thalamus.

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.

Clinical Findings Documenting Cellular and Molecular Abnormalities of Glia in Depressive Disorders

Depressive disorders are complex, multifactorial mental disorders with unknown neurobiology. Numerous theories aim to explain the pathophysiology. According to the “gliocentric theory”, glial abnormalities are responsible for the development of the disease. The aim of this review article is to summarize the rapidly growing number of cellular and molecular evidences indicating disturbed glial functioning in depressive disorders. We focus here exclusively on the clinical studies and present the in vivo neuroimaging findings together with the postmortem molecular and histopathological data. Postmortem studies demonstrate glial cell loss while the in vivo imaging data reveal disturbed glial functioning and altered white matter microstructure. Molecular studies report on altered gene expression of glial specific genes. In sum, the clinical findings provide ample evidences on glial pathology and demonstrate that all major glial cell types are affected. However, we still lack convincing theories explaining how the glial abnormalities develop and how exactly contribute to the emotional and cognitive disturbances. Abnormal astrocytic functioning may lead to disturbed metabolism affecting ion homeostasis and glutamate clearance, which in turn, affect synaptic communication. Abnormal oligodendrocyte functioning may disrupt the connectivity of neuronal networks, while microglial activation indicates neuroinflammatory processes. These cellular changes may relate to each other or they may indicate different endophenotypes. A theory has been put forward that the stress-induced inflammation—mediated by microglial activation—triggers a cascade of events leading to damaged astrocytes and oligodendroglia and consequently to their dysfunctions. The clinical data support the “gliocentric” theory, but future research should clarify whether these glial changes are truly the cause or simply the consequences of this devastating disorder.

White matter tract integrity is associated with antidepressant response to lurasidone in bipolar depression

OBJECTIVES

Patients with bipolar disorder spend the most time in the depressed phase, and that phase is associated with the most morbidity and mortality. Treatment of bipolar depression lacks a test to determine who will respond to treatment. White matter disruptions have been found in bipolar disorder. Previous reports suggest that white matter disruptions may be associated with resistance to antidepressant medication, but this has never been investigated in a prospective study using a Food and Drug Administration (FDA)-approved medication.

METHODS

Eighteen subjects with bipolar disorder who were in a major depressive episode and off all medications were recruited. Magnetic resonance imaging was acquired using a 64-direction diffusion tensor imaging sequence on a 3T scanner. Subjects were treated with 8 weeks of open-label lurasidone. The Montgomrey-Asberg Depression Rating Scale (MADRS) was completed weekly. Tract-Based Spatial Statistics were utilized to perform a regression analysis of fractional anisotropy (FA) data with treatment outcome as assessed by percent change in MADRS as a regressor while controlling for age and sex, using a threshold of P (threshold-free cluster enhancement-corrected) <.05.

RESULTS

FA was positively correlated with antidepressant treatment response in multiple regions of the mean FA skeleton bilaterally, including tracts in the frontal and parietal lobes.

CONCLUSIONS

Greater disruptions in the white matter tracts in bipolar disorder were associated with poorer antidepressant response to lurasidone. The disruptions may potentially indicate treatment with a different antidepressant medication class. These results are limited by the open-label study design, sample size and lack of a healthy control group.

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.

Can neuroimaging disentangle bipolar disorder?

BACKGROUND

Bipolar disorder heterogeneity is large, leading to difficulties in identifying neuropathophysiological and etiological mechanisms and hindering the formation of clinically homogeneous patient groups in clinical trials. Identifying markers of clinically more homogeneous groups would help disentangle BD heterogeneity. Neuroimaging may aid in identifying such groups by highlighting specific biomarkers of BD subtypes or clinical dimensions.

METHODS

We performed a systematic literature search of the neuroimaging literature assessing biomarkers of relevant BD phenotypes (type-I vs. II, presence vs. absence of psychotic features, suicidal behavior and impulsivity, rapid cycling, good vs. poor medication response, age at onset, cognitive performance and circadian abnormalities).

RESULTS

Consistent biomarkers were associated with suicidal behavior, i.e. frontal/anterior alterations (prefrontal and cingulate grey matter, prefrontal white matter) in patients with a history of suicide attempts; and with cognitive performance, i.e. involvement of frontal and temporal regions, superior and inferior longitudinal fasciculus, right thalamic radiation, and corpus callosum in executive dysfunctions. For the other dimensions and sub-types studied, no consistent biomarkers were identified.

LIMITATIONS

Studies were heterogeneous both in methodology and outcome.

CONCLUSIONS

Though theoretically promising, neuroimaging has not yet proven capable of disentangling subtypes and dimensions of bipolar disorder, due to high between-study heterogeneity. We issue recommendations for future studies.

Suicide attempts in bipolar disorders: comprehensive review of 101 reports

OBJECTIVE

Assess reported risk of suicide attempts by patients with bipolar disorder (BD).

METHOD

Systematic searching yielded 101 reports from 22 countries (79 937 subjects). We analyzed for risk (%) and incidence rates (%/year) of attempts, comparing sex and diagnostic types, including by meta-analysis.

RESULTS

Attempt risk averaged 31.1% [CI: 27.9-34.3] of subjects, or 4.24 [3.78-4.70]%/year. In BD-I (43 studies) and BD-II subjects (30 studies), risks (29.9%, 31.4%) and incidence rates (4.01, 4.11%/year) were similar and not different by meta-analysis. Among women vs. men, risks (33.7% vs. 25.5%) and incidence (4.50 vs. 3.21%/year) were greater (also supported by meta-analysis: RR = 1.35 [CI: 1.25-1.45], P < 0.0001). Neither measure was related to reporting year, % women/study, or to onset or current age. Risks were greater with longer exposure, whereas incidence rates decreased with longer time at risk, possibly through 'dilution' by longer exposure.

CONCLUSION

This systematic update of international experience underscores high risks of suicide attempts among patients with BD (BD-I = BD-II; women > men). Future studies should routinely include exposure times and incidence rates by diagnostic type and sex for those who attempt suicide or not.

The impact of periventricular white matter lesions in patients with bipolar disorder type I

INTRODUCTION

White matter hyperintensities (WMHs) are one the most common neuroimaging findings in patients with bipolar disorder (BD). It has been suggested that WMHs are associated with impaired insight in schizophrenia and schizoaffective patients; however, the relationship between insight and WMHs in BD type I has not been directly investigated.

METHODS

Patients with BD-I (148) were recruited and underwent brain magnetic resonance imaging (MRI). Affective symptoms were assessed using Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HDRS17); the presence of impaired insight was based on the corresponding items of YMRS and HDRS17.

RESULTS

Multiple punctate periventricular WMHs (PWMHs) and deep WMHs (DWMHs) were observed in 49.3% and 39.9% of the cases, respectively. Subjects with lower insight for mania had significantly more PWMHs (54.6% vs 22.2%; p < 0.05) when compared to BD-I patients with higher insight for mania. The presence of PWMHs was independently associated with lower insight for mania: patients who denied illness according to the YMRS were 4 times more likely to have PWMHs (95% CI: 1.21/13.42) than other patients.

CONCLUSIONS

Impaired insight in BD-I is associated with periventricular WMHs. The early identification of BD-I subjects with PWMHs and impaired insight may be crucial for clinicians.

DTI and Myelin Plasticity in Bipolar Disorder: Integrating Neuroimaging and Neuropathological Findings

Bipolar disorder (BD) is a major psychiatric illness with a chronic recurrent course, ranked among the worldwide leading disabling diseases. Its pathophysiology is still not completely understood and findings are still inconclusive, though a great interest on the topic has been constantly raised by magnetic resonance imaging, genetic and neuropathological studies. In recent years, diffusion tensor imaging (DTI) investigations have prompted interest in the key role of white matter (WM) abnormalities in BD. In this report, we summarize and comment recent findings from DTI studies in BD, reporting fractional anisotropy as putative measure of WM integrity, as well as recent data from neuropathological studies focusing on oligodendrocyte involvement in WM alterations in BD. DTI research indicates that BD is most commonly associated with a WM disruption within the fronto-limbic network, which may be accompanied by other WM changes spread throughout temporal and parietal regions. Neuropathological studies, mainly focused on the fronto-limbic network, have repeatedly shown a loss in cortical and subcortical oligodendrocyte cell count, although an increased subcortical oligodendrocyte density has been also documented suggesting a putative role in remyelination processes for oligodendrocytes in BD. According to our review, a greater integration between DTI and morphological findings is needed in order to elucidate processes affecting WM, either glial loss or myelin plasticity, on the basis of a more targeted research in BD.

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.

Epidemiology, neurobiology and pharmacological interventions related to suicide deaths and suicide attempts in bipolar disorder: Part I of a report of the International Society for Bipolar Disorders Task Force on Suicide in Bipolar Disorder

OBJECTIVES

Bipolar disorder is associated with elevated risk of suicide attempts and deaths. Key aims of the International Society for Bipolar Disorders Task Force on Suicide included examining the extant literature on epidemiology, neurobiology and pharmacotherapy related to suicide attempts and deaths in bipolar disorder.

METHODS

Systematic review of studies from 1 January 1980 to 30 May 2014 examining suicide attempts or deaths in bipolar disorder, with a specific focus on the incidence and characterization of suicide attempts and deaths, genetic and non-genetic biological studies and pharmacotherapy studies specific to bipolar disorder. We conducted pooled, weighted analyses of suicide rates.

RESULTS

The pooled suicide rate in bipolar disorder is 164 per 100,000 person-years (95% confidence interval = [5, 324]). Sex-specific data on suicide rates identified a 1.7:1 ratio in men compared to women. People with bipolar disorder account for 3.4-14% of all suicide deaths, with self-poisoning and hanging being the most common methods. Epidemiological studies report that 23-26% of people with bipolar disorder attempt suicide, with higher rates in clinical samples. There are numerous genetic associations with suicide attempts and deaths in bipolar disorder, but few replication studies. Data on treatment with lithium or anticonvulsants are strongly suggestive for prevention of suicide attempts and deaths, but additional data are required before relative anti-suicide effects can be confirmed. There were limited data on potential anti-suicide effects of treatment with antipsychotics or antidepressants.

CONCLUSION

This analysis identified a lower estimated suicide rate in bipolar disorder than what was previously published. Understanding the overall risk of suicide deaths and attempts, and the most common methods, are important building blocks to greater awareness and improved interventions for suicide prevention in bipolar disorder. Replication of genetic findings and stronger prospective data on treatment options are required before more decisive conclusions can be made regarding the neurobiology and specific treatment of suicide risk in bipolar disorder.

Apathy and suicide-related ideation 3 months after stroke: a cross-sectional study

BACKGROUND

Both apathy and suicide are common in poststroke patients. However, the association between poststroke apathy and suicide-related ideation (SI) in Chinese stroke patients is not clear and poorly understood. The aim of this study was to examine the association between apathy and SI in stroke.

METHODS

A cross-sectional study was conducted to investigate the association in 518 stroke survivors from Acute Stroke Unit of the Prince of Wales Hospital in Hong Kong. Geriatric Mental State Examination-Version A (GMS) and Neuropsychiatric Inventory-apathy subscale (NPI-apathy) were employed to assess poststroke SI and apathy, respectively. Patients' clinical characteristics were obtained with the following scales: the National Institutes of Health Stroke Scale (NIHSS), the Mini-Mental State Examination (MMSE), and the Geriatric Depression Scale (GDS).

RESULTS

Thirty-two (6.2%) stroke survivors reported SI. The SI group had a significantly higher frequency of NPI-apathy than the non-SI group (31.2% vs 5.3%, p < 0.001). The SI group also had higher GDS scores (10.47 ± 3.17 vs 4.24 ± 3.71, p < 0.001). Regression analysis revealed that NPI-apathy (OR 2.955, 95% CI 1.142-7.647, p = 0.025) was a significant predictor of SI. The GDS score also predicted SI (OR 1.436, 95% CI 1.284-1.606, p < 0.001).

CONCLUSIONS

The current findings show that poststroke apathy is an independent predictor of SI 3 months after stroke. Early screening for and intervention targeting apathy through medication and psychological treatments may be necessary to improve stroke patients' apathy and reduce SI.

Magnetization transfer imaging of suicidal patients with major depressive disorder

Magnetization transfer imaging (MTI) provides a quantitative measure of the macromolecular structural integrity of brain tissue, as represented by magnetization transfer ratio (MTR). In this study, we utilized MTI to identify biophysical alterations in MDD patients with a history of suicide attempts relative to MDD patients without such history. The participants were 36 medication-free MDD patients, with (N = 17) and without (N = 19) a history of a suicide attempt, and 28 healthy controls matched for age and gender. Whole brain voxel-based analysis was used to compare MTR across three groups and to analyze correlations with symptom severity and illness duration. We identified decreased MTR in left inferior parietal lobule and right superior parietal lobule in suicide attempters relative to both non-attempters and controls. Non-attempters also showed significantly reduced MTR in left inferior parietal lobule relative to controls, as well as an MTR reduction in left cerebellum. These abnormalities were not correlated with symptom severity or illness duration. Depressed patients with a history of suicide attempt showed bilateral abnormalities in parietal cortex compared to nonsuicidal depressed patients and healthy controls. Parietal lobe abnormalities might cause attentional dysfunction and impaired decision making to increase risk for suicidal behavior in MDD.

White matter alterations are associated with suicide attempt in patients with panic disorder

BACKGROUND

Panic disorder (PD) is associated with an increased risk of suicide attempt (SA). However, no study has examined the neural correlates of SA in PD. The goal of this study was to evaluate alterations in white matter (WM) and gray matter (GM) in patients with PD with and without a history of SA.

METHODS

Twelve patients with PD and a history of SA (PD+SA) and 24 patients with PD and no history of SA (PD-SA) underwent magnetic resonance imaging (MRI). All patients completed the Scale for Suicide Ideation (SSI), the Panic Disorder Severity Scale (PDSS), and the Beck Depression Inventory (BDI). The groups were matched for age, sex, and BDI and PDSS scores. Voxel-based morphometry and tract-based spatial statistics were used for the imaging analysis.

RESULTS

Although no GM or WM volume differences were observed, increased fractional anisotropy (FA) values were found in the WM tracts of the PD+SA group compared with the PD-SA group. The regions with increased FA included the internal capsule, splenium of the corpus callosum, superior and posterior corona radiata, thalamic radiations, sagittal stratum, and superior longitudinal fasciculus. The FA values for the internal capsule and thalamic radiations were significantly correlated with the SSI scores in the PD+SA group.

LIMITATIONS

The results should be considered preliminary due to the relatively small sample size.

CONCLUSIONS

Our data suggest that the aberrant WM integrity of the internal capsule and thalamic radiations may be the significant neural correlate of SA in patients with PD.

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.

Neurobiological risk factors for suicide: insights from brain imaging

CONTEXT

This article reviews neuroimaging studies on neural circuitry associated with suicide-related thoughts and behaviors to identify areas of convergence in findings. Gaps in the literature for which additional research is needed are identified.

EVIDENCE ACQUISITION

A PubMed search was conducted and articles published before March 2014 were reviewed that compared individuals who made suicide attempts to those with similar diagnoses who had not made attempts or to healthy comparison subjects. Articles on adults with suicidal ideation and adolescents who had made attempts, or with suicidal ideation, were also included. Reviewed imaging modalities included structural magnetic resonance imaging, diffusion tensor imaging, single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging.

EVIDENCE SYNTHESIS

Although many studies include small samples, and subject characteristics and imaging methods vary across studies, there were convergent findings involving the structure and function of frontal neural systems and the serotonergic system.

CONCLUSIONS

These initial neuroimaging studies of suicide behavior have provided promising results. Future neuroimaging efforts could be strengthened by more strategic use of common data elements and a focus on suicide risk trajectories. At-risk subgroups defined by biopsychosocial risk factors and multidimensional assessment of suicidal thoughts and behaviors may provide a clearer picture of the neural circuitry associated with risk status-both current and lifetime. Also needed are studies investigating neural changes associated with interventions that are effective in risk reduction.

White matter abnormalities: Insights into the pathophysiology of major affective disorders

The presence of white matter hyperintensities (WMHs) has been commonly associated with poor outcome in subjects with major affective disorders. Unfortunately, WMHs may be frequently confounded by the use of psychoactive medications and duration of illness. Although findings from the current literature are quite conflicting, we proposed that subjects with WMHs may be at higher suicidal risk when compared to other subgroups without. Based on the Fazekas modified scale, the severity of WMHs may serve as a trait marker of disease. Interestingly, the presence of WMHs may represent a neurobiological marker between the underlying vulnerability and clinical presentation of major affective disorders.

Small vessel disease and memory loss: what the clinician needs to know to preserve patients' brain health

Small vessel disease (SVD) in the brain manifests in the periventricular and deep white matter and radiographically is described as "leukoaraiosis". It is increasingly recognized as a cause of morbidity from middle age onward and this clinical relevance has paralleled advances in the field of neuroradiology. Overall, SVD is a heterogenous group of vascular disorders that may be asymptomatic, or a harbinger of many conditions that jeopardize brain health. Management and prevention focuses on blood pressure control, lifestyle modification, and symptomatic treatment.

The neurobiology of suicide

The stress-diathesis model posits that suicide is the result of an interaction between state-dependent (environmental) stressors and a trait-like diathesis or susceptibility to suicidal behaviour, independent of psychiatric disorders. Findings from post-mortem studies of the brain and from genomic and in-vivo neuroimaging studies indicate a biological basis for this diathesis, indicating the importance of neurobiological screening and interventions, in addition to cognitive and mood interventions, in the prevention of suicide. Early-life adversity and epigenetic mechanisms might explain some of the link between suicide risk and brain circuitry and neurochemistry abnormalities. Results from a range of studies using diverse designs and post-mortem and in-vivo techniques show impairments of the serotonin neurotransmitter system and the hypothalamic-pituitary-adrenal axis stress-response system in the diathesis for suicidal behaviour. These impairments manifest as impaired cognitive control of mood, pessimism, reactive aggressive traits, impaired problem solving, over-reactivity to negative social signs, excessive emotional pain, and suicidal ideation, leading to suicidal behaviour. Biomarkers related to the diathesis might help to inform risk-assessment procedures and treatment choice in the prevention of suicide.

Impaired frontothalamic circuitry in suicidal patients with depression revealed by diffusion tensor imaging at 3.0 T

BACKGROUND

The neurobiology of suicide is largely unknown. Studies of white matter tracts in patients with a history of suicidal behaviour have shown alteration in the left anterior limb of the internal capsule (ALIC). Our aim was to determine whether particular target fields of fibre projections through the ALIC are affected in depressed patients who recently attempted suicide.

METHODS

We studied patients with major depressive disorder (MDD) with and without a history of suicide attempts and healthy controls using diffusion tensor imaging (DTI) and deterministic tractography to generate fibre tract maps for each participant. Tract voxels were coded as being unique to the left ALIC. We compared the mean percentage of fibres projecting to relevant brain regions in the 3 groups using analysis of covariance.

RESULTS

We included 63 patients with MDD (23 with and 40 without a history of suicide attempts) and 46 controls in our study. Both groups of depressed patients had reduced fibre projections through the ALIC to the left medial frontal cortex, orbitofrontal cortex and thalamus. Those with a history of suicide attempts had greater abnormalities than those without suicide attempts in the left orbitofrontal cortex and thalamus.

LIMITATIONS

Diffusion tensor imaging deterministic tracking is unable to distinguish between afferent and efferent pathways, limiting our ability to distinguish the directionality of altered fibre tracts.

CONCLUSION

Frontothalamic loops passing through the ALIC are abnormal in patients with depression and significantly more abnormal in depressed patients with a history of suicide attempts than in those without a history of suicide attempts. Abnormal projections to the orbitofrontal cortex and thalamus may disrupt affective and cognitive functions to confer a heightened vulnerability for suicidal behaviour.

A diffusion tensor imaging study of suicide attempters

BACKGROUND

Few studies have examined white matter abnormalities in suicide attempters using diffusion tensor imaging (DTI). This study sought to identify white matter regions altered in individuals with a prior suicide attempt.

METHODS

DTI scans were acquired in 13 suicide attempters with major depressive disorder (MDD), 39 non-attempters with MDD, and 46 healthy participants (HP). Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were determined in the brain using two methods: region of interest (ROI) and tract-based spatial statistics (TBSS). ROIs were limited a priori to white matter adjacent to the caudal anterior cingulate cortex, rostral anterior cingulate cortex, dorsomedial prefrontal cortex, and medial orbitofrontal cortex.

RESULTS

Using the ROI approach, suicide attempters had lower FA than MDD non-attempters and HP in the dorsomedial prefrontal cortex. Uncorrected TBSS results confirmed a significant cluster within the right dorsomedial prefrontal cortex indicating lower FA in suicide attempters compared to non-attempters. There were no differences in ADC when comparing suicide attempters, non-attempters and HP groups using ROI or TBSS methods.

CONCLUSIONS

Low FA in the dorsomedial prefrontal cortex was associated with a suicide attempt history. Converging findings from other imaging modalities support this finding, making this region of potential interest in determining the diathesis for suicidal behavior.

Frontotemporal White Matter in Adolescents with, and at-Risk for, Bipolar Disorder

Frontotemporal neural systems are highly implicated in the emotional dysregulation characteristic of bipolar disorder (BD). Convergent genetic, postmortem, behavioral and neuroimaging evidence suggests abnormalities in the development of frontotemporal white matter (WM) in the pathophysiology of BD. This review discusses evidence for the involvement of abnormal WM development in BD during adolescence, with a focus on frontotemporal WM. Findings from diffusion tensor imaging (DTI) studies in adults and adolescents are reviewed to explore possible progressive WM abnormalities in the disorder. Intra- and interhemispheric frontotemporal abnormalities were reported in adults with BD. Although evidence in children and adolescents with BD to date has been limited, similar intrahemispheric and interhemispheric findings have also been reported. The findings in youths suggest that these abnormalities may represent a trait marker present early in the course of BD. Functional connectivity studies, demonstrating a relationship between WM abnormalities and frontotemporal dysfunction in BD, and DTI studies of vulnerability in first-degree relatives of individuals with BD, are discussed. Together, findings suggest the involvement of abnormal frontotemporal WM development in the pathophysiology of BD and that these abnormalities may be early trait markers of vulnerability; however, more studies are critically needed.

Differences between suicide attempters and nonattempters in depressed older patients: depression severity, white-matter lesions, and cognitive functioning

OBJECTIVES

The population of older adults with major depressive disorder (MDD) has the highest rate of suicide. White-matter brain lesions (WML) are a potential biologic marker for suicidality in young and middle-aged adults and are correlated with cognitive impairment in older adults. In this study of older patients with MDD, we examined 1) if a history of suicide attempts was associated with a more severe course of MDD; 2) if WML are a biologic marker for suicide; and 3) if suicide attempt history is associated with cognitive impairment mediated by WML.

SETTING

Data from the Neurocognitive Outcomes of Depression in the Elderly study.

PARTICIPANTS

Depressed patients (60+) who had ever attempted suicide (n = 23) were compared with depressed patients (60+) who had not attempted suicide (n = 223).

MEASUREMENTS

Baseline and follow-up assessments were obtained for depressive symptoms (every 3 months) and cognitive functioning (every 6 months) over 2 years. Three magnetic resonance imaging scans were conducted.

RESULTS

At baseline, suicide attempters reported more severe past and present symptoms (e.g., depressive symptoms, current suicidal thoughts, psychotic symptoms, earlier age of onset, and more lifetime episodes) than nonattempters. Suicide attempters had more left WML at baseline, and suicide attempt history predicted a greater growth in both left and right WML. WML predicted cognitive decline; nonetheless, a history of suicide attempt was unrelated to cognitive functioning.

CONCLUSIONS

Severity of depressive symptoms and WML are associated with suicide attempts in geriatric depressed patients. Suicide attempts predicted neurologic changes, which may contribute to poorer long-term outcomes in elder attempters.

The alteration of hypoxia inducible factor-1 (HIF-1) and its target genes in mood disorder patients

Recent studies suggest that the dysfunction of neural plasticity is associated with mood disorders. Hypoxia-inducible factor-1 (HIF-1), which is a transcriptional activator of vascular endothelial growth factor (VEGF), activates the cellular response to hypoxia. HIF-1 is ubiquitously expressed in all cells, including peripheral leukocytes. However, little is known about the role of HIF-1 in mood disorder. In the present study, we investigated the mRNA expression levels of HIF-1 (α and β) and its target genes (VEGF, GLUT1, PGK1, PFKFB3, and LDHA) in the peripheral white blood cells of patients with major depressive disorder (MDD) and bipolar disorder (BPD). We found increased expression of HIF- 1α and HIF-1β mRNA, as well as the target genes, VEGF, and PFKFB3 in both MDD and BPD patients in a depressive state compared to healthy control subjects. Furthermore, the mRNA expression levels of GLUT1, PGK1, and LDHA were increased in MDD patients in a depressive state compared to healthy control subjects. We also found increased expression of HIF-1α and LDHA mRNA in MDD patients in a remissive state, whereas the mRNA expression levels of other genes in a remissive state were comparable to those in healthy control subjects. There was no significant difference in mRNA expression levels of the genes examined among patients receiving any type of antidepressant or mood stabilizer. Our data suggest that altered expression of HIF-1 and its target genes mRNA in peripheral blood cells are associated-mainly in a state-dependent manner-with mood disorders (especially with MDD). In addition, altered expression of HIF-1 and its target genes may be associated with the pathophysiology of depression.

Association of cerebral small vessel disease with delusions in patients with Alzheimer's disease

BACKGROUND

Cerebral small vessel disease (SVD) is frequently observed in patients with Alzheimer's disease (AD). However, the association between SVD and clinical symptoms exhibited by patients with AD remains unclear. This study examined the association of SVD as observed on magnetic resonance imaging (MRI) with behavioural and psychological symptoms of dementia and cognitive function of patients with probable AD.

METHODS

A total of 163 consecutive patients (55 men, 108 women) with probable AD were included in this cross-sectional study of a prospective cohort. Patients were divided into two groups based on the presence or absence of cerebral SVD [white matter hyperintensities (WMH) grade 0/1 (Fazekas scale) and no lacunes: SVD absent, WMH grade 2/3 (Fazekas scale) or the number of lacunes ≥1: SVD present]. Cognitive functions were assessed using the Mini mental state examination, word recall and recognition subtests in the Alzheimer's Disease Assessment Scale-Cognitive Subscale, as well as the letter fluency task and the category fluency task. Psychiatric symptoms were rated according to Neuropsychiatric Inventory.

RESULTS

Patients with probable AD with cerebral SVD had significantly more delusions and depression than those without SVD. No significant differences were observed in other neuropsychiatric symptoms, MMSE or word recall and recognition tests between both groups.

CONCLUSIONS

Our results suggest that cerebral SVD observed on MRI of patients with AD is associated with delusions and depression.

Enlarged thalamic volumes and increased fractional anisotropy in the thalamic radiations in veterans with suicide behaviors

Post-mortem studies have suggested a link between the thalamus, psychiatric disorders, and suicide. We evaluated the thalamus and anterior thalamic radiations (ATR) in a group of Veterans with and without a history of suicidal behavior (SB) to determine if thalamic abnormalities were associated with an increased risk of SB. Forty Veterans with mild traumatic brain injury (TBI) and no SB (TBI-SB), 19 Veterans with mild TBI and a history of SB (TB + SB), and 15 healthy controls (HC) underwent magnetic resonance imaging scanning including a structural and diffusion tensor imaging scan. SBs were evaluated utilizing the Columbia Suicide Rating Scale and impulsivity was measured using the Barratt Impulsiveness Scale (BIS). Differences in thalamic volumes and ATR fractional anisotropy (FA) were examined between (1) TBI + SB versus HC and (2) TBI + SB versus combined HC and TBI-SB and (3) between TBI + SB and TBI-SB. Left and right thalamic volumes were significantly increased in those with TBI + SB compared to the HC, TBI-SB, and the combined group. Veterans with TBI + SB had increased FA bilaterally compared to the HC, HC and TBI-SB group, and the TBI-SB only group. Significant positive associations were found for bilateral ATR and BIS in the TBI + SB group. Our findings of thalamic enlargement and increased FA in individuals with TBI + SB suggest that this region may be a biomarker for suicide risk. Our findings are consistent with previous evidence indicating that suicide may be associated with behavioral disinhibition and frontal-thalamic-limbic dysfunction and suggest a neurobiologic mechanism that may increase vulnerability to suicide.

Reduced posterior corpus callosum area in suicidal and non-suicidal patients with bipolar disorder

BACKGROUND

Impulsivity is a characteristic of bipolar disorder (BD) that can contribute to the risk for suicidal behavior. Evidence suggests that gray and white matter abnormalities are linked with impulsivity, but little is known about the association between corpus callosum (CC) and impulsivity in BD. We examined the CC area and impulsivity in euthymic bipolar I patients, with and without lifetime history of suicide attempts, and in healthy controls.

METHODS

Nineteen bipolar patients with a suicide attempt history (BP-S), 21 bipolar patients without suicide attempt history (BP-NS), and 22 healthy controls (HC) underwent clinical assessment by the Structured Clinical Interview with the DSM-IV axis I (SCID-I), the Barratt Impulsiveness Scale (BIS-11), and MRI scan.

RESULTS

No differences were observed for any CC subregion between BP-S and BP-NS groups. There was a significant reduction in the genu (p=0.04) and isthmus areas (p=0.01), in bipolar patients compared with HC. In the BP-S group, the BIS-11 total (p=0.01), attention (p=0.001) and non-planning (p=0.02) impulsivity scores were significantly higher than in the BP-NS and HC groups.

LIMITATIONS

These results cannot establish causality because of the cross-sectional nature of the study.

CONCLUSION

This report potentially provides evidence that a reduction in the CC area is present even in non-symptomatic bipolar patients, which may be evidence of a biological trait marker for BD. Furthermore, the study demonstrated that BP-S group had higher impulsivity even during euthymia, which points to a sustained association between lifetime history of suicide attempts and impulsivity in BD.

White matter hyperintensities and self-reported depression in a sample of patients with chronic headache

White matter hyperintensities (WMH) have been associated with mood disorders in psychiatric patients. In the present study, we aimed to assess whether WMHs are associated with depressive symptoms and different sensitivity of the behavioral inhibition (BIS), and activation (BAS) systems in patients with chronic headache. Participants were 85 adult outpatients (16 men and 69 women) with a diagnosis of chronic headache. All of the patients underwent brain magnetic resonance imaging (MRI) and were administered the BIS/BAS scales and the Center for Epidemiologic Studies Depression Scale. Above 40 % of patients had periventricular WMHs (PWMHs) and almost 98 % had deep WMHs (DWMHs). Patients with PWMHs reported fewer depressive symptoms than patients without PWMHs. Patients with more severe DWMHs (compared with patients with mild or without DWMH lesions) were older and reported lower scores on the drive dimension of the BIS/BAS scales. In multivariate analyses, patients with PWMHs were 1.06 times more likely to report fewer depressive symptoms than patients without PWMHs. WMH lesions in patients with chronic headache were associated with less depression severity.

Relationship between suicidality and impulsivity in bipolar I disorder: a diffusion tensor imaging study

BACKGROUND

Impulsivity is characteristic of individuals with bipolar disorder and may be a contributing factor to the high rate of suicide in patients with this disorder. Although white matter abnormalities have been implicated in the pathophysiology of bipolar disorder, their relationship to impulsivity and suicidality in this disorder has not been well-investigated.

METHODS

Diffusion tensor imaging scans were acquired in 14 bipolar disorder patients with a prior suicide attempt, 15 bipolar disorder patients with no prior suicide attempt, and 15 healthy volunteers. Bipolar disorder patients received clinical assessments including measures of impulsivity, depression, mania, and anxiety. Images were processed using the Tract-Based Spatial Statistics method in the FSL software package.

RESULTS

Bipolar disorder patients with a prior suicide attempt had lower fractional anisotropy (FA) within the left orbital frontal white matter (p < 0.05, corrected) and higher overall impulsivity compared to patients without a previous suicide attempt. Among patients with a prior suicide attempt, FA in the orbital frontal white matter region correlated inversely with motor impulsivity.

CONCLUSIONS

Abnormal orbital frontal white matter may play a role in impulsive and suicidal behavior among patients with bipolar disorder.

Affective temperaments: from neurobiological roots to clinical application

The Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A) has grown to be a clinically important outcome measure in the diagnosis and the clinical course of mood disorders. However, temperaments, which represent the biologically stable core of personality, are not just antecedents of major affective disorders, but also serve as a reservoir of genetically advantageous traits for the survival of different cultures. The rapidly growing body of research in psychiatric and non-psychiatric fields even raises the question of temperament as a common root in psychiatric and somatic disorders, providing a new meaning for the construct of psychosomatic disorders. In this review we aim to summarize current knowledge on both the neurobiological background and clinical importance of affective temperaments including implications for future research. Orv. Hetil., 2011, 152, 1879–1886.