Subcortical brain alterations in major depressive disorder: findings from the ENIGMA Major Depressive Disorder working group

Role of frontal white matter and corpus callosum on social function in schizophrenia

Patients with schizophrenia show severe impairment in social function and have difficulty in their daily social life. Although a recent large-scale multicenter study revealed alterations in white matter microstructures, the association between these anatomical changes and social dysfunction in schizophrenia remains unknown. Therefore, we investigated the association between the white matter integrity of regions of interest and social function in schizophrenia. A total of 149 patients with schizophrenia and 602 healthy comparison subjects (HCS) underwent DTI and completed the Picture Arrangement subtest of the Wechsler Adult Intelligence Scale-Third Edition and the Finance subscale of the University of California, San Diego, Performance-Based Skills Assessment Brief, as social indices of interest. The fractional anisotropy (FA) in the anterior corona radiata and corpus callosum was significantly lower in patients than in HCS, and the radial diffusivity (RD) in the anterior corona radiata and corpus callosum was significantly higher in patients. The Picture Arrangement and Finance scores were both significantly impaired in patients. The effect of the FA of the right anterior corona radiata on the Finance score and the Picture Arrangement score, of the RD of the right anterior corona radiata on the Picture Arrangement score, and of the RD of the corpus callosum on the Picture Arrangement score were significant. In conclusion, our results confirmed the association between structural connectivity in the right frontal white matter and corpus callosum and social function in schizophrenia. These findings may provide a foundation for developing an intervention for functional recovery in schizophrenia.

Genetic architecture of hippocampal subfields on standard resolution MRI: How the parts relate to the whole

The human hippocampus can be subdivided into subfields with unique functional properties and differential vulnerability to disease or neuropsychiatric conditions. Identifying genes that confer susceptibility to such processes is an important goal in developing treatments. Recent advances in automatic subfield segmentation from magnetic resonance images make it possible to use these measures as phenotypes in large-scale genome-wide association studies. Such analyses are likely to rely largely on standard resolution (~1 mm isotropic) T₁ -weighted images acquired on 3.0T scanners. Determining whether the genetic architecture of subfields can be detected from such images is therefore an important step. We used Freesurfer v6.0 to segment hippocampal subfields in two large twin studies, the Vietnam Era Twin Study of Aging and the Human Connectome Project. We estimated heritability of subfields and the genetic overlap with total hippocampal volume. Heritability was similar across samples, but little genetic variance remained after accounting for genetic influences on total hippocampal volume. Importantly, we examined genetic relationships between subfields to determine whether subfields can be grouped based on a smaller number of underlying, genetically independent factors. We identified three genetic factors in both samples, but the high degree of cross loadings precluded formation of genetically distinct groupings of subfields. These results confirm the reliability of Freesurfer v6.0 generated subfields across samples for phenotypic analyses. However, the current results suggest that it will be difficult for large-scale genetic analyses to identify subfield-specific genes that are distinct from both total hippocampal volume and other subfields using segmentations generated from standard resolution T₁ -weighted images.

Variations in Hippocampal White Matter Diffusivity Differentiate Response to Electroconvulsive Therapy in Major Depression

BACKGROUND

Electroconvulsive therapy (ECT) is an effective treatment for severe depression and is shown to increase hippocampal volume and modulate hippocampal functional connectivity. Whether variations in hippocampal structural connectivity occur with ECT and relate to clinical response is unknown.

METHODS

Patients with major depression (n = 36, 20 women, age 41.49 ± 13.57 years) underwent diffusion magnetic resonance imaging at baseline and after ECT. Control subjects (n = 32, 17 women, age 39.34 ± 12.27 years) underwent scanning twice. Functionally defined seeds in the left and right anterior hippocampus and probabilistic tractography were used to extract tract volume and diffusion metrics (fractional anisotropy and axial, radial, and mean diffusivity). Statistical analyses determined effects of ECT and time-by-response group interactions (>50% change in symptoms before and after ECT defined response). Differences between baseline measures across diagnostic groups and in association with treatment outcome were also examined.

RESULTS

Significant effects of ECT (all p < .01) and time-by-response group interactions (all p < .04) were observed for axial, radial, and mean diffusivity for right, but not left, hippocampal pathways. Follow-up analyses showed that ECT-related changes occurred in responders only (all p < .01) as well as in relation to change in mood examined continuously (all p < .004). Baseline measures did not relate to symptom change or differ between patients and control subjects. All measures remained stable across time in control subjects. No significant effects were observed for fractional anisotropy and volume.

CONCLUSIONS

Structural connectivity of hippocampal neural circuits changed with ECT and distinguished treatment responders. The findings suggested neurotrophic, glial, or inflammatory response mechanisms affecting axonal integrity.

Antidepressant Effects of Rhodomyrtone in Mice with Chronic Unpredictable Mild Stress-Induced Depression

BACKGROUND

Rhodomyrtone is one of the main active compounds derived from Rhodomyrtus tomentosa, which belongs to the Myrtaceae family. In the current study, we investigated the properties of rhodomyrtone as a potential drug candidate for the treatment of stress-caused depression.

METHODS

We assessed the function of rhodomyrtone in chronic unpredictable mild stress, a well-validated depression model in mice. Depression-like behavior tests, including a sucrose performance test, social interaction test, and forced swimming test, were used to validate the antidepressant effects of rhodomyrtone. The Morris water maze was used to evaluate the mice's learning and memory ability. Spine density, glycogen synthase kinase-3β, brain-derived neurotrophic factor, postsynaptic density protein 95, and apoptosis-associated protein were detected to reveal the underlying mechanism.

RESULTS

Rhodomyrtone was found to prevent source consumption decrease, decreased social behaviors, and increase immobility in the forced swimming test, suggesting a protective effect of rhodomyrtone against depression-like behaviors. Additionally, rhodomyrtone prevented the impairment of spatial memory in mice exposed to chronic unpredictable mild stress. Rhodomyrtone administration also reversed dendritic spine density defects in chronic unpredictable mild stress. Furthermore, rhodomyrtone inhibited the increase of glycogen synthase kinase-3β activity and reversed the decrease of brain-derived neurotrophic factor and postsynaptic density protein 95 in chronic unpredictable mild stress mice. Elevated expression of apoptosis-associated protein Bax and cleaved-caspase 3 was also reversed by rhodomyrtone treatment.

CONCLUSIONS

These results suggested that the antidepressant effect of rhodomyrtone involves the regulation of neurogenesis, neuronal survival, and synaptic plasticity in the hippocampus.

Prediction Models of Functional Outcomes for Individuals in the Clinical High-Risk State for Psychosis or With Recent-Onset Depression: A Multimodal, Multisite Machine Learning Analysis

IMPORTANCE

Social and occupational impairments contribute to the burden of psychosis and depression. There is a need for risk stratification tools to inform personalized functional-disability preventive strategies for individuals in at-risk and early phases of these illnesses.

OBJECTIVE

To determine whether predictors associated with social and role functioning can be identified in patients in clinical high-risk (CHR) states for psychosis or with recent-onset depression (ROD) using clinical, imaging-based, and combined machine learning; assess the geographic, transdiagnostic, and prognostic generalizability of machine learning and compare it with human prognostication; and explore sequential prognosis encompassing clinical and combined machine learning.

DESIGN, SETTING, AND PARTICIPANTS

This multisite naturalistic study followed up patients in CHR states, with ROD, and with recent-onset psychosis, and healthy control participants for 18 months in 7 academic early-recognition services in 5 European countries. Participants were recruited between February 2014 and May 2016, and data were analyzed from April 2017 to January 2018.

AIN OUTCOMES AND MEASURES

Performance and generalizability of prognostic models.

RESULTS

A total of 116 individuals in CHR states (mean [SD] age, 24.0 [5.1] years; 58 [50.0%] female) and 120 patients with ROD (mean [SD] age, 26.1 [6.1] years; 65 [54.2%] female) were followed up for a mean (SD) of 329 (142) days. Machine learning predicted the 1-year social-functioning outcomes with a balanced accuracy of 76.9% of patients in CHR states and 66.2% of patients with ROD using clinical baseline data. Balanced accuracy in models using structural neuroimaging was 76.2% in patients in CHR states and 65.0% in patients with ROD, and in combined models, it was 82.7% for CHR states and 70.3% for ROD. Lower functioning before study entry was a transdiagnostic predictor. Medial prefrontal and temporo-parieto-occipital gray matter volume (GMV) reductions and cerebellar and dorsolateral prefrontal GMV increments had predictive value in the CHR group; reduced mediotemporal and increased prefrontal-perisylvian GMV had predictive value in patients with ROD. Poor prognoses were associated with increased risk of psychotic, depressive, and anxiety disorders at follow-up in patients in the CHR state but not ones with ROD. Machine learning outperformed expert prognostication. Adding neuroimaging machine learning to clinical machine learning provided a 1.9-fold increase of prognostic certainty in uncertain cases of patients in CHR states, and a 10.5-fold increase of prognostic certainty for patients with ROD.

CONCLUSIONS AND RELEVANCE

Precision medicine tools could augment effective therapeutic strategies aiming at the prevention of social functioning impairments in patients with CHR states or with ROD.

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.

Volume of the Human Hippocampus and Clinical Response Following Electroconvulsive Therapy

BACKGROUND

Hippocampal enlargements are commonly reported after electroconvulsive therapy (ECT). To clarify mechanisms, we examined if ECT-induced hippocampal volume change relates to dose (number of ECT sessions and electrode placement) and acts as a biomarker of clinical outcome.

METHODS

Longitudinal neuroimaging and clinical data from 10 independent sites participating in the Global ECT-Magnetic Resonance Imaging Research Collaboration (GEMRIC) were obtained for mega-analysis. Hippocampal volumes were extracted from structural magnetic resonance images, acquired before and after patients (n = 281) experiencing a major depressive episode completed an ECT treatment series using right unilateral and bilateral stimulation. Untreated nondepressed control subjects (n = 95) were scanned twice.

RESULTS

The linear component of hippocampal volume change was 0.28% (SE 0.08) per ECT session (p < .001). Volume change varied by electrode placement in the left hippocampus (bilateral, 3.3 ± 2.2%, d = 1.5; right unilateral, 1.6 ± 2.1%, d = 0.8; p < .0001) but not the right hippocampus (bilateral, 3.0 ± 1.7%, d = 1.8; right unilateral, 2.7 ± 2.0%, d = 1.4; p = .36). Volume change for electrode placement per ECT session varied similarly by hemisphere. Individuals with greater treatment-related volume increases had poorer outcomes (Montgomery-Åsberg Depression Rating Scale change -1.0 [SE 0.35], per 1% volume increase, p = .005), although the effects were not significant after controlling for ECT number (slope -0.69 [SE 0.38], p = .069).

CONCLUSIONS

The number of ECT sessions and electrode placement impacts the extent and laterality of hippocampal enlargement, but volume change is not positively associated with clinical outcome. The results suggest that the high efficacy of ECT is not explained by hippocampal enlargement, which alone might not serve as a viable biomarker for treatment outcome.

GSK3β: a plausible mechanism of cognitive and hippocampal changes induced by erythropoietin treatment in mood disorders?

Mood disorders are associated with significant psychosocial and occupational disability. It is estimated that major depressive disorder (MDD) will become the second leading cause of disability worldwide by 2020. Existing pharmacological and psychological treatments are limited for targeting cognitive dysfunctions in mood disorders. However, growing evidence from human and animal studies has shown that treatment with erythropoietin (EPO) can improve cognitive function. A recent study involving EPO-treated patients with mood disorders showed that the neural basis for their cognitive improvements appeared to involve an increase in hippocampal volume. Molecular mechanisms underlying hippocampal changes have been proposed, including the activation of anti-apoptotic, antioxidant, pro-survival and anti-inflammatory signalling pathways. The aim of this review is to describe the potential importance of glycogen synthase kinase 3-beta (GSK3β) as a multi-potent molecular mechanism of EPO-induced hippocampal volume change in mood disorder patients. We first examine published associations between EPO administration, mood disorders, cognition and hippocampal volume. We then highlight evidence suggesting that GSK3β influences hippocampal volume in MDD patients, and how this could assist with targeting more precise treatments particularly for cognitive deficits in patients with mood disorders. We conclude by suggesting how this developing area of research can be further advanced, such as using pharmacogenetic studies of EPO treatment in patients with mood disorders.

Effects of cumulative illness severity on hippocampal gray matter volume in major depression: a voxel-based morphometry study

BACKGROUND

Patients with major depression show reduced hippocampal volume compared to healthy controls. However, the contribution of patients' cumulative illness severity to hippocampal volume has rarely been investigated. It was the aim of our study to find a composite score of cumulative illness severity that is associated with hippocampal volume in depression.

METHODS

We estimated hippocampal gray matter volume using 3-tesla brain magnetic resonance imaging in 213 inpatients with acute major depression according to DSM-IV criteria (employing the SCID interview) and 213 healthy controls. Patients' cumulative illness severity was ascertained by six clinical variables via structured clinical interviews. A principal component analysis was conducted to identify components reflecting cumulative illness severity. Regression analyses and a voxel-based morphometry approach were used to investigate the influence of patients' individual component scores on hippocampal volume.

RESULTS

Principal component analysis yielded two main components of cumulative illness severity: Hospitalization and Duration of Illness. While the component Hospitalization incorporated information from the intensity of inpatient treatment, the component Duration of Illness was based on the duration and frequency of illness episodes. We could demonstrate a significant inverse association of patients' Hospitalization component scores with bilateral hippocampal gray matter volume. This relationship was not found for Duration of Illness component scores.

CONCLUSIONS

Variables associated with patients' history of psychiatric hospitalization seem to be accurate predictors of hippocampal volume in major depression and reliable estimators of patients' cumulative illness severity. Future studies should pay attention to these measures when investigating hippocampal volume changes in major depression.

Pretreatment and early-treatment cortical thickness is associated with SSRI treatment response in major depressive disorder

To date, there are no biomarkers for major depressive disorder (MDD) treatment response in clinical use. Such biomarkers could allow for individualized treatment selection, reducing time spent on ineffective treatments and the burden of MDD. In search of such a biomarker, multisite pretreatment and early-treatment (1 week into treatment) structural magnetic resonance (MR) images were acquired from 184 patients with MDD randomized to an 8-week trial of the selective serotonin reuptake inhibitor (SSRI) sertraline or placebo. This study represents a large, multisite, placebo-controlled effort to examine the association between pretreatment differences or early-treatment changes in cortical thickness and treatment-specific outcomes. For standardization, a novel, robust site harmonization procedure was applied to structural measures in a priori regions (rostral and caudal anterior cingulate, lateral orbitofrontal, rostral middle frontal, and hippocampus), chosen based on previously published reports. Pretreatment cortical thickness or volume did not significantly associate with SSRI response. Thickening of the rostral anterior cingulate cortex in the first week of treatment was associated with better 8-week responses to SSRI (p = 0.010). These findings indicate that frontal lobe structural alterations in the first week of treatment may be associated with long-term treatment efficacy. While these associational findings may help to elucidate the specific neural targets of SSRIs, the predictive accuracy of pretreatment or early-treatment structural alterations in classifying treatment remitters from nonremitters was limited to 63.9%. Therefore, in this large sample of adults with MDD, structural MR imaging measures were not found to be clinically translatable biomarkers of treatment response to SSRI or placebo.

Unravelling the GSK3β-related genotypic interaction network influencing hippocampal volume in recurrent major depressive disorder

OBJECTIVE

Glycogen synthase kinase 3β (GSK3β) has been implicated in mood disorders. We previously reported associations between a GSK3β polymorphism and hippocampal volume in major depressive disorder (MDD). We then reported similar associations for a subset of GSK3β-regulated genes. We now investigate an algorithm-derived comprehensive list of genes encoding proteins that directly interact with GSK3β to identify a genotypic network influencing hippocampal volume in MDD.

PARTICIPANTS AND METHODS

We used discovery (N=141) and replication (N=77) recurrent MDD samples. Our gene list was generated from the NetworKIN database. Hippocampal measures were derived using an optimized Freesurfer protocol. We identified interacting single nucleotide polymorphisms using the machine learning algorithm Random Forest and verified interactions using likelihood ratio tests between nested linear regression models.

RESULTS

The discovery sample showed multiple two-single nucleotide polymorphism interactions with hippocampal volume. The replication sample showed a replicable interaction (likelihood ratio test: P=0.0088, replication sample; P=0.017, discovery sample; Stouffer's combined P=0.0007) between genes associated previously with endoplasmic reticulum stress, calcium regulation and histone modifications.

CONCLUSION

Our results provide genetic evidence supporting associations between hippocampal volume and MDD, which may reflect underlying cellular stress responses. Our study provides evidence of biological mechanisms that should be further explored in the search for disease-modifying therapeutic targets for depression.

The brain's hemodynamic response function rapidly changes under acute psychosocial stress in association with genetic and endocrine stress response markers

Ample evidence links dysregulation of the stress response to the risk for psychiatric disorders. However, we lack an integrated understanding of mechanisms that are adaptive during the acute stress response but potentially pathogenic when dysregulated. One mechanistic link emerging from rodent studies is the interaction between stress effectors and neurovascular coupling, a process that adjusts cerebral blood flow according to local metabolic demands. Here, using task-related fMRI, we show that acute psychosocial stress rapidly impacts the peak latency of the hemodynamic response function (HRF-PL) in temporal, insular, and prefrontal regions in two independent cohorts of healthy humans. These latency effects occurred in the absence of amplitude effects and were moderated by regulatory genetic variants of KCNJ2, a known mediator of the effect of stress on vascular responsivity. Further, hippocampal HRF-PL correlated with both cortisol response and genetic variants that influence the transcriptional response to stress hormones and are associated with risk for major depression. We conclude that acute stress modulates hemodynamic response properties as part of the physiological stress response and suggest that HRF indices could serve as endophenotype of stress-related disorders.

Cognitive impairment and medial temporal lobe structure in young adults with a depressive episode

BACKGROUND

Cognitive deficits are common in patients with a depressive episode although the predictors for their development and severity remain elusive. We investigated whether subjective and objective cognitive impairment in young depressed adults would be associated with cortical thinning in medial temporal subregions.

METHODS

High-resolution magnetic resonance imaging, cortical unfolding data analysis, and comprehensive assessments of subjective and objective cognitive abilities were performed on 27 young patients with a depressive episode (mean age: 29.0 ± 5.8 years) and 23 older participants without a history of a depressive disorder but amnestic mild cognitive impairment (68.5 ± 6.6 years) or normal cognition (65.2 ± 8.7 years).

RESULTS

Thickness reductions in parahippocampal, perirhinal and fusiform cortices were associated with subjective memory deficits only among young patients with a depressive episode and a measurable cognitive impairment.

LIMITATIONS

Long-term longitudinal data would be desirable to determine the trajectories of cognitive impairment associated with depression in patients with or without cortical structure changes.

CONCLUSIONS

The presence of clinically significant cognitive deficits in young people with a depressive episode may identify a patient population with extrahippocampal cortical thinning.

Electroconvulsive therapy increases brain volume in major depression: a systematic review and meta-analysis

OBJECTIVE

The main purpose of this review was to synthesise evidence on ECT's effects on brain's structure.

METHOD

A systematic literature review of longitudinal studies of depressed patients treated with ECT using magnetic resonance imaging (MRI) and meta-analysis of ECT's effect on hippocampal volume.

RESULTS

Thirty-two studies with 467 patients and 285 controls were included. The MRI studies did not find any evidence of ECT-related brain damage. All but one of the newer MRI volumetric studies found ECT-induced volume increases in certain brain areas, most consistently in hippocampus. Meta-analysis of effect of ECT on hippocampal volume yielded pooled effect size: g = 0.39 (95% CI = 0.18-0.61) for the right hippocampus and g = 0.31 (95% CI = 0.09-0.53) for the left. The DTI studies point to an ECT-induced increase in the integrity of white matter pathways in the frontal and temporal lobes. The results of correlations between volume increases and treatment efficacy were inconsistent.

CONCLUSION

The MRI studies do not support the hypothesis that ECT causes brain damage; on the contrary, the treatment induces volume increases in fronto-limbic areas. Further studies should explore the relationship between these increases and treatment effect and cognitive side effects.

Emerging depression in adolescence coincides with accelerated frontal cortical thinning

BACKGROUND

Adolescence is a transition period characterized by heightened emotional reactivity, which for some sets the stage for emerging depressive symptoms. Prior studies suggest that adolescent depression is associated with deviant cortical and subcortical brain structure. Longitudinal studies are, however, currently scarce, but critical to detect which adolescents are at risk for developing depressive symptoms.

METHODS

In this longitudinal study, a community sample of 205 participants underwent magnetic resonance imaging (MRI) in three biennial waves (522 scans) spanning 5 years across ages 8-25 years. Depressive symptomatology was assessed using self-report at the third time point. Mixed models were used to examine the relations between structural brain development, specifically regional change in cortical thickness, surface area and subcortical volumes (hippocampus and amygdala), and depressive symptoms.

RESULTS

Accelerated frontal lobe cortical thinning was observed in adolescents who developed depressive symptoms at the third time point. This effect remained after controlling for parent-reported affective problems at the first time point. Moreover, the effect was driven by specific lateral orbitofrontal and precentral regions. In addition, differential developmental trajectories of parietal cortical thickness and surface area in several regions were found for participants reporting higher depressive symptomatology, but these results did not survive correction for multiple comparisons. Volumes or developmental volume changes in hippocampus or amygdala were not related to depressive symptoms.

CONCLUSIONS

This study showed that emerging depression is associated with cortical thinning in frontal regions within individuals. These findings move beyond detecting cross-sectional correlations and set the stage for early detection, which may inform future intervention.

Elevated hippocampal choline level is associated with altered functional connectivity in females with major depressive disorder: A pilot study

Metabolic and functional alterations in hippocampus have been associated with the pathophysiology of major depressive disorder (MDD). However, how the hippocampal biochemical disruptions lead to dysfunction of limbic-cortical circuit remains unclear. The present pilot study combined magnetic resonance spectroscopy (MRS) and resting-state functional magnetic resonance imaging (rs-fMRI) to investigate the hippocampal metabolic alteration and its relationship with the intrinsic functional connectivity (FC) changes in MDD. Both MRS and fMRI data were obtained from twelve women with MDD and twelve age-matched, healthy women. Bilateral hippocampi were chosen as regions of interest, in which metabolite concentrations of total choline (tCho), N-acetylaspartate and creatine were quantified. Bilateral hippocampal FC to the whole brain and its correlations with hippocampal metabolite concentrations were conducted. Females with MDD showed significantly elevated left hippocampal tCho level, and decreased anti-correlations between the left hippocampus and bilateral superior frontal gyrus (SFG), left inferior frontal gyrus, and right superior temporal gyrus. More importantly, the left hippocampal tCho level was associated with FC to the right SFG and right fusiform gyrus in healthy women, whereas it was significantly associated with FC to the right lingual gyrus in women with MDD. Our findings suggested that regional metabolic alterations in the left hippocampus might be related to the network-level dysfunction.

Longitudinal brain volume changes in major depressive disorder

Patients with major depressive disorder (MDD) exhibit gray matter volume (GMV) reductions in limbic regions. Clinical variables-such as the number of depressive episodes-seem to affect volume alterations. It is unclear whether the observed cross-sectional GMV abnormalities in MDD change over time, and whether there is a longitudinal relationship between GMV changes and the course of disorder. We investigated T1 structural MRI images of 54 healthy control (HC) and 37 MDD patients in a 3-Tesla-MRI with a follow-up interval of 3 years. The Cat12 toolbox was used to analyze longitudinal data (p < 0.05, FWE-corrected, whole-brain analysis; flexible factorial design). Interaction effects indicated increasing GMV in MDD in the bilateral amygdala, and decreasing GMV in the right thalamus between T1 and T2. Further analyses comparing patients with a mild course of disorder (MCD; 0-1 depressive episode during the follow-up) to patients with a severe course of disorder (SCD; > 1 depressive episode during the follow-up) revealed increasing amygdalar volume in MCD. Our study confirms structural alterations in limbic regions in MDD patients and an association between these impairments and the course of disorder. Thus, we assume that the reported volumetric alterations in the left amygdala (i.e. volumetric normalization) are reversible and apparently driven by the clinical phenotype. Hence, these results support the assumption that the severity and progression of disease influences amygdalar GMV changes in MDD or vice versa.

Machine learning in major depression: From classification to treatment outcome prediction

AIMS

Major depression disorder (MDD) is the single greatest cause of disability and morbidity, and affects about 10% of the population worldwide. Currently, there are no clinically useful diagnostic biomarkers that are able to confirm a diagnosis of MDD from bipolar disorder (BD) in the early depressive episode. Therefore, exploring translational biomarkers of mood disorders based on machine learning is in pressing need, though it is challenging, but with great potential to improve our understanding of these disorders.

DISCUSSIONS

In this study, we review popular machine-learning methods used for brain imaging classification and predictions, and provide an overview of studies, specifically for MDD, that have used magnetic resonance imaging data to either (a) classify MDDs from controls or other mood disorders or (b) investigate treatment outcome predictors for individual patients. Finally, challenges, future directions, and potential limitations related to MDD biomarker identification are also discussed, with a goal of offering a comprehensive overview that may help readers to better understand the applications of neuroimaging data mining in depression.

CONCLUSIONS

We hope such efforts may highlight the need for an urgently needed paradigm shift in treatment, to guide personalized optimal clinical care.

Ten-Hour Exposure to Low-Dose Ketamine Enhances Corticostriatal Cross-Frequency Coupling and Hippocampal Broad-Band Gamma Oscillations

Introduction: Treatment-resistant depression, post-traumatic stress disorder, chronic pain, and L-DOPA-induced dyskinesia in Parkinson’s disease are characterized by hypersynchronous neural oscillations. Sub-anesthetic ketamine is effective at treating these conditions, and this may relate to ketamine’s capacity to reorganize oscillatory activity throughout the brain. For example, a single ketamine injection increases gamma (∼40 Hz) and high-frequency oscillations (HFOs, 120–160 Hz) in the cortex, hippocampus, and striatum. While the effects of single injections have been investigated, clinical ketamine treatments can involve 5-h up to 3-day sub-anesthetic infusions. Little is known about the effects of such prolonged exposure on neural synchrony. We hypothesized that hours-long exposure entrains circuits that generate HFOs so that HFOs become sustained after ketamine’s direct effects on receptors subside.

Methods: Local-field recordings were acquired from motor cortex (M1), striatum, and hippocampus of behaving rats (n = 8), and neural responses were measured while rats received 5 ketamine injections (20 mg/kg, i.p., every 2 h, 10-h exposure). In a second experiment, the same animals received injections of D1-receptor antagonist (SCH-23390, 1 mg/kg, i.p.) prior to ketamine injection to determine if D1 receptors were involved in producing HFOs.

Results: Although HFOs remained stable throughout extended ketamine exposure, broad-band high-frequency activity (40–140 Hz) in the hippocampus and delta-HFO cross-frequency coupling (CFC) in dorsal striatum increased with the duration of exposure. Furthermore, while ketamine-triggered HFOs were not affected by D1 receptor blockade, ketamine-associated gamma in motor cortex was suppressed, suggesting involvement of D1 receptors in ketamine-mediated gamma activity in motor cortex.

Conclusion: Prolonged ketamine exposure does not enhance HFOs in corticostriatal circuits, but, instead, enhances coordination between low and high frequencies in the striatum and reduces synchrony in the hippocampus. Increased striatal CFC may facilitate spike-timing dependent plasticity, resulting in lasting changes in motor activity. In contrast, the observed wide-band high-frequency “noise” in the hippocampus suggests that ketamine disrupts action-potential timing and reorganizes connectivity in this region. Differential restructuring of corticostriatal and limbic circuits may contribute to ketamine’s clinical benefits.

JNK Regulation of Depression and Anxiety

Depression and anxiety are the most common mood disorders affecting 300 million sufferers worldwide. Maladaptive changes in the neuroendocrine stress response is cited as the most common underlying cause, though how the circuits underlying this response are controlled at the molecular level, remains largely unknown. Approximately 40% of patients do not respond to current treatments, indicating that untapped mechanisms exist. Here we review recent evidence implicating JNK in the control of anxiety and depressive-like behavior with a particular focus on its action in immature granule cells of the hippocampal neurogenic niche and the potential for therapeutic targeting for affective disorders.

Neurotrophic factors and neuroplasticity pathways in the pathophysiology and treatment of depression

Depression is a major health problem with a high prevalence and a heavy socioeconomic burden in western societies. It is associated with atrophy and impaired functioning of cortico-limbic regions involved in mood and emotion regulation. It has been suggested that alterations in neurotrophins underlie impaired neuroplasticity, which may be causally related to the development and course of depression. Accordingly, mounting evidence suggests that antidepressant treatment may exert its beneficial effects by enhancing trophic signaling on neuronal and synaptic plasticity. However, current antidepressants still show a delayed onset of action, as well as lack of efficacy. Hence, a deeper understanding of the molecular and cellular mechanisms involved in the pathophysiology of depression, as well as in the action of antidepressants, might provide further insight to drive the development of novel fast-acting and more effective therapies. Here, we summarize the current literature on the involvement of neurotrophic factors in the pathophysiology and treatment of depression. Further, we advocate that future development of antidepressants should be based on the neurotrophin theory.

Smaller hippocampal volumes predict lower antidepressant response/remission rates in depressed patients: A meta-analysis

OBJECTIVES

Whether hippocampal volume predicts response and/or remission after antidepressant treatment of major depressive episodes (MDE) in major depressive disorder (MDD) remains unclear. We meta-analysed prospective studies comparing baseline hippocampal volume in patients with or without response/remission after antidepressant treatment.

METHODS

Pubmed, Embase and Google Scholar were searched for studies of patients with current MDE in MDD, with hippocampal volume assessments at baseline, initiation of antidepressant drug treatment, and prospective assessment of response/remission after treatment.

RESULTS

Six studies (374 patients), of which two were positive and four negative, were meta-analysed. Compared to responders/remitters, patients who failed to achieve response/remission had smaller total hippocampus volumes at baseline (mean volume difference = 260 mm³, 95% CI [93; 427], P = 0.002). These results remained significant in patients under 60 years of age (P = 0.02), in those over 60 years old (P = 0.04), and for right (P = 0.006) and left (P = 0.02) hippocampi. The probability of non-response/non-remission was 68.6% for patients with a total hippocampal volume at least 10% lower than the average, and 47.1% for patients with a total hippocampal volume 10% higher than the average.

CONCLUSIONS

In depressed patients treated with antidepressant drugs, smaller hippocampal volumes predict lower response/remission rates.

[Physical activity as therapeutic intervention for depression]

AIM

This article gives a conspectus of the present state of research on the efficiency of exercise as a treatment for patients suffering from depression.

METHODS

A systematic review of articles published between December 1980 and March 2016 was carried out. The review focused on studies that examined the effects of exercise compared to control conditions in the treatment of depression. Extracted and analyzed information from the articles included details about participants, characteristics of exercise and control conditions, assessments, study design and outcomes.

RESULTS

A total of 34 of the 48 studies included in the literature search reported a significant reduction of depressive symptoms due to exercise interventions. There was a trend to reduced depressive symptoms following the exercise interventions in five studies. In nine studies no positive impact of exercise on depression and affective well-being could be detected.

DISCUSSION

This review article shows that physical activity decreases depressive symptoms and increases affective well-being in patients with depressive diseases; therefore, exercise should be recommended as a component of depression treatment within the framework of a multi-dimensional approach.

Anxiety, depression, impulsivity, and brain structure in children and adolescents

The unique neuroanatomical underpinnings of internalizing symptoms and impulsivity during childhood are not well understood. In this study, we examined associations of brain structure with anxiety, depression, and impulsivity in children and adolescents. Participants were 7- to 21-year-olds (N = 328) from the Pediatric Imaging, Neurocognition, and Genetics (PING) study who completed high-resolution, 3-Tesla, T1-weighted MRI and self-report measures of anxiety, depression, and/or impulsivity. Cortical thickness and surface area were examined across cortical regions-of-interest (ROIs), and exploratory whole-brain analyses were also conducted. Gray matter volume (GMV) was examined in subcortical ROIs. When considered separately, higher depressive symptoms and impulsivity were each significantly associated with reduced cortical thickness in ventromedial PFC/medial OFC, but when considered simultaneously, only depressive symptoms remained significant. Higher impulsivity, but not depressive symptoms, was associated with reduced cortical thickness in the frontal pole, rostral middle frontal gyrus, and pars orbitalis. No differences were found for regional surface area. Higher depressive symptoms, but not impulsivity, were significantly associated with smaller hippocampal GMV and larger pallidal GMV. There were no significant associations between anxiety symptoms and brain structure. Depressive symptoms and impulsivity may be linked with cortical thinning in overlapping and distinct regions during childhood and adolescence.

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Internalizing problems and impulsivity may have shared and distinct neuroanatomical substrates in childhood.

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Higher depressive symptoms were uniquely associated with reduced cortical thickness in vmPFC/medial OFC.

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Higher impulsivity was uniquely associated with reduced cortical thickness in lateral PFC regions.

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Higher depressive symptoms were associated with smaller hippocampal volume and larger pallidal volume.

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These shared and distinct neuroanatomical correlates may inform the design of prevention and intervention strategies.

Common and distinct abnormal frontal-limbic system structural and functional patterns in patients with major depression and bipolar disorder

Major depressive disorder (MDD) and bipolar disorder (BD) are common severe affective diseases. Although previous neuroimaging studies have investigated brain abnormalities in MDD or BD, the structural and functional differences between these two disorders remain unclear. In this study, we adopted a multimodal approach, combining voxel-based morphometry (VBM) and functional connectivity (FC), to study the common and distinct structural and functional alterations in unmedicated MDD and BD patients. The VBM analysis revealed that both the MDD and BD patients showed decreased gray matter volume (GMV) in the left anterior cingulate cortex (ACC_L) and right hippocampus (HIP_R) compared with the healthy controls, and the MDD patients showed decreased GMV in the left superior frontal gyrus (SFG_L) and ACC_L compared with the BD patients. Furthermore, we took these clusters as seed regions to analyze the abnormal resting-state functional connectivity (RSFC) in the patients. We found that both the MDD and BD groups had decreased RSFC between the ACC_L and the left orbitofrontal cortex (OFC_L) and that the MDD group had decreased RSFC between the SFG_L and the HIP_L, compared with the healthy controls. Our results revealed that the MDD and BD patients were more similar than different in GMV and RSFC. These findings indicate that investigating the frontal-limbic system could be useful for understanding the underlying mechanisms of these two disorders.

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Both MDD and BD patients had reduced GMV in the ACC_L and HIP_R compared with HC.

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MDD patients had decreased GMV in the ACC_L and SFG_L compared with BD patients.

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Both BD and MDD patients had decreased ACC-OFC RSFC compared with HC.

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The MDD and BD patients were more similar than different in GMV and RSFC.

A morphometric signature of depressive symptoms in unmedicated patients with mood disorders

OBJECTIVE

A growing literature indicates that unipolar depression and bipolar depression are associated with alterations in grey matter volume. However, it is unclear to what degree these patterns of morphometric change reflect symptom dimensions. Here, we aimed to predict depressive symptoms and hypomanic symptoms based on patterns of grey matter volume using machine learning.

METHOD

We used machine learning methods combined with voxel-based morphometry to predict depressive and self-reported hypomanic symptoms from grey matter volume in a sample of 47 individuals with unmedicated unipolar and bipolar depression.

RESULTS

We were able to predict depressive severity from grey matter volume in the anteroventral bilateral insula in both unipolar depression and bipolar depression. Self-reported hypomanic symptoms did not predict grey matter loss with a significant degree of accuracy.

DISCUSSION

The results of this study suggest that patterns of grey matter volume alteration in the insula are associated with depressive symptom severity across unipolar and bipolar depression. Studies using other modalities and exploring other brain regions with a larger sample are warranted to identify other systems that may be associated with depressive and hypomanic symptoms across affective disorders.

Smaller hippocampal volume in current but not in past depression in comparison to healthy controls: Minor evidence from an older adults sample

BACKGROUND

Structural neuroimaging studies revealed a consistent pattern of volumetric reductions in both hippocampus (HC) and anterior cingulate cortex (ACC) of individuals with major depressive episode(s) (MDE). This study investigated HC and ACC volume differences in currently depressed individuals (n = 150), individuals with a past lifetime MDE history (n = 79) and healthy controls (n = 287).

METHODS

Non-demented individuals were recruited from a cohort of community-dwelling older adults (ESPRIT study). T1-weighted magnetic resonance images and FreeSurfer Software (automated method) were used. Concerning HC, a manual method of measurement dividing HC into head, body, and tail was also used. General Linear Model was applied adjusting for covariates.

RESULTS

Current depression was associated with lower left posterior HC volume, using manual measurement, in comparison to healthy status. However, when we slightly changed sub-group inclusion criteria, results did not survive to correction for multiple comparisons.

CONCLUSIONS

The finding of lower left posterior HC volume in currently depressed individuals but not in those with a past MDE compared to healthy controls could be related to brain neuroplasticity. Additionally, our results may suggest manual measures to be more sensitive than automated methods.

Negative fateful life events in midlife and advanced predicted brain aging

Negative fateful life events (FLEs) such as interpersonal conflict, death in the family, financial hardship, and serious medical emergencies can act as allostatic stressors that accelerate biological aging. However, the relationship between FLEs and neuroanatomical aging is not well understood. We examined 359 men (mean age 62 years) participating in the Vietnam Era twin study of aging (VETSA) to determine whether negative midlife FLEs are associated with advanced brain aging after controlling for physical, psychological, and lifestyle factors. At two different time points, participants were assessed for negative FLEs, health and well-being, general cognitive ability, socioeconomic status, depression, and ethnicity. Participants underwent a magnetic resonance imaging examination, and T1-weighted images were processed with FreeSurfer. Subsequent neuroanatomical measurements were entered into the Brain-Age Regression Analysis and Computation Utility software (BARACUS) to predict brain age. Having more midlife FLEs, particularly relating to interpersonal relationships, was associated with advanced predicted brain aging (i.e., higher predicted brain age relative to chronological age). This association remained after controlling for the significant covariates of alcohol consumption, cardiovascular risk, adult socioeconomic status, and ethnicity.

Central irisin administration affords antidepressant-like effect and modulates neuroplasticity-related genes in the hippocampus and prefrontal cortex of mice

Evidence has indicated that the practice of physical exercise has antidepressant effects that might be associated with irisin release and BDNF signaling. In this study we investigated the effects of the central administration of irisin or BDNF in predictive tests of antidepressant properties paralleled with the gene expression of peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α), fibronectin type III domain-containing protein 5 (FNDC5) and brain-derived neurotrophic factor (BDNF) in the hippocampus and prefrontal cortex of mice. Irisin (0.5-1 ng/mouse, i.c.v.) reduced the immobility time in the tail suspension test (TST) and forced swim test (FST), without altering locomotion in the open field test (OFT). Irisin reduced the immobility time in the TST up to 6 h after its administration. Irisin administration (6 h) increased PGC-1α mRNA in the hippocampus and prefrontal cortex and reduced (1 h) PGC-1α mRNA in the prefrontal cortex. FNDC5 and BDNF mRNA expression was decreased (1 h) in both structures and remained reduced up to 6 h in the prefrontal cortex. Moreover, BDNF administered at 0.25 μg/mouse, i.c.v. (1 and 6 h before the test) reduced the immobility time in the TST. BDNF administration reduced PGC-1α mRNA in the hippocampus (6 h) and prefrontal cortex (1 and 6 h). It also increased FNDC5 mRNA expression in the hippocampus (1 and 6 h), but reduced the expression of this gene and also BDNF mRNA in the prefrontal cortex (1 and 6 h). None of the treatments altered BDNF protein levels in both structures. In conclusion, irisin presents a behavioral antidepressant profile similar to BDNF, an effect associated with the modulation of gene expression of PGC-1α, FNDC5 and BDNF, reinforcing the pivotal role of these genes in mood regulation.

Neuroimaging biomarkers as predictors of treatment outcome in Major Depressive Disorder

BACKGROUND

Current practice for selecting pharmacological and non-pharmacological antidepressant treatments has yielded low response and remission rates in Major Depressive Disorder (MDD). Neuroimaging biomarkers of brain structure and function may be useful in guiding treatment selection by predicting response vs. non-response outcomes.

METHODS

In this review, we summarize data from studies examining predictors of treatment response using structural and functional neuroimaging modalities, as they pertain to pharmacotherapy, psychotherapy, and stimulation treatment strategies. A literature search was conducted in OVID Medline, EMBASE, and PsycINFO databases with coverage from January 1990 to January 2017.

RESULTS

Several imaging biomarkers of therapeutic response in MDD emerged: frontolimbic regions, including the prefrontal cortex, anterior cingulate cortex, hippocampus, amygdala, and insula were regions of interest. Since these sub-regions are implicated in the etiology of MDD, their association with response outcomes may be the result of treatments having a normalizing effect on structural or activation abnormalities.

LIMITATIONS

The direction of findings is inconsistent in studies examining these biomarkers, and variation across 'biotypes' within MDD may account for this. Limitations in sample size and differences in methodology likely also contribute.

CONCLUSIONS

The identification of accurate, reliable neuroimaging biomarkers of treatment response holds promise toward improving treatment outcomes and reducing burden of illness for patients with MDD. However, before these biomarkers can be translated into clinical practice, they will need to be replicated and validated in large, independent samples, and integrated with data from other biological systems.

Association of Brain Cortical Changes With Relapse in Patients With Major Depressive Disorder

IMPORTANCE

More than half of all patients with major depressive disorder (MDD) experience a relapse within 2 years after recovery. It is unclear how relapse affects brain morphologic features during the course of MDD.

OBJECTIVE

To use structural magnetic resonance imaging to identify morphologic brain changes associated with relapse in MDD.

DESIGN, SETTING, AND PARTICIPANTS

In this longitudinal case-control study, patients with acute MDD at baseline and healthy controls were recruited from the University of Münster Department of Psychiatry from March 21, 2010, to November 14, 2014, and were reassessed from November 11, 2012, to October 28, 2016. Depending on patients' course of illness during follow-up, they were subdivided into groups of patients with and without relapse. Whole-brain gray matter volume and cortical thickness of the anterior cingulate cortex, orbitofrontal cortex, middle frontal gyrus, and insula were assessed via 3-T magnetic resonance imaging at baseline and 2 years later.

MAIN OUTCOMES AND MEASURES

Gray matter was analyzed via group (no relapse, relapse, and healthy controls) by time (baseline and follow-up) analysis of covariance, controlling for age and total intracranial volume. Confounding factors of medication and depression severity were assessed.

RESULTS

This study included 37 patients with MDD and a relapse (19 women and 18 men; mean [SD] age, 37.0 [12.7] years), 23 patients with MDD and without relapse (13 women and 10 men; mean [SD] age, 32.5 [10.5] years), and 54 age- and sex-matched healthy controls (24 women and 30 men; mean [SD] age, 37.5 [8.7] years). A significant group-by-time interaction controlling for age and total intracranial volume revealed that patients with relapse showed a significant decline of insular volume (difference, -0.032; 95% CI, -0.063 to -0.002; P = .04) and dorsolateral prefrontal volume (difference, -0.079; 95% CI, -0.113 to -0.045; P < .001) from baseline to follow-up. In patients without relapse, gray matter volume in these regions did not change significantly (insula: difference, 0.027; 95% CI, -0.012 to 0.066; P = .17; and dorsolateral prefrontal volume: difference, 0.023; 95% CI, -0.020 to 0.066; P = .30). Volume changes were not correlated with psychiatric medication or with severity of depression at follow-up. Additional analysis of cortical thickness showed an increase in the anterior cingulate cortex (difference, 0.073 mm; 95% CI, 0.023-0.123 mm; P = .005) and orbitofrontal cortex (difference, 0.089 mm; 95% CI, 0.032-0.147 mm; P = .003) from baseline to follow-up in patients without relapse.

CONCLUSION AND RELEVANCE

A distinct association of relapse in MDD with brain morphologic features was revealed using a longitudinal design. Relapse is associated with brain structures that are crucial for regulation of emotions and thus needs to be prevented. This study might be a step to guide future prognosis and maintenance treatment in patients with recurrent MDD.

Widespread white matter microstructural differences in schizophrenia across 4322 individuals: results from the ENIGMA Schizophrenia DTI Working Group

The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies. Significant reductions in fractional anisotropy (FA) in schizophrenia patients were widespread, and detected in 20 of 25 regions of interest within a WM skeleton representing all major WM fasciculi. Effect sizes varied by region, peaking at (d=0.42) for the entire WM skeleton, driven more by peripheral areas as opposed to the core WM where regions of interest were defined. The anterior corona radiata (d=0.40) and corpus callosum (d=0.39), specifically its body (d=0.39) and genu (d=0.37), showed greatest effects. Significant decreases, to lesser degrees, were observed in almost all regions analyzed. Larger effect sizes were observed for FA than diffusivity measures; significantly higher mean and radial diffusivity was observed for schizophrenia patients compared with controls. No significant effects of age at onset of schizophrenia or medication dosage were detected. As the largest coordinated analysis of WM differences in a psychiatric disorder to date, the present study provides a robust profile of widespread WM abnormalities in schizophrenia patients worldwide. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.

Evidence for association between familial bipolar risk and ventral striatal volume

BACKGROUND

Recent genome-wide association studies (GWAS) of striatal volumes and bipolar disorder (BD) indicate these traits are heritable and share common genetic architecture, however little independent work has been conducted to help establish this relationship.

METHODS

Subcortical volumes (mm3) of young, healthy offspring of BD (N= 32) and major depressive disorder (MDD) patients (N= 158) were compared to larger healthy control sample (NRANGE= 925-1052) adjusting for potential confounds, using data from the latest release (S1200) of the Human Connectome Project. Based on recent GWAS findings, it was hypothesised that the accumbens and caudate would be smaller in offspring of BD, but not MDD patients.

RESULTS

After multiple comparison correction, there was a regional and BD specific relationship in the direction expected (Accumbens: F2,1067= 6.244, PFDR-CORRECTED= 0.014).

DISCUSSION

In line with recent GWAS, there was evidence supporting the hypothesis that reduced striatal volume may be part of the genetic risk for BD, but not MDD.

LIMITATIONS

It cannot be concluded whether this association was specific to BD or consistent with a broader psychosis phenotype, due to a small sample size for offspring of schizophrenia patients. Furthermore, one cannot rule out potential shared environmental influences of parental BD.

CONCLUSIONS

The common genetic architecture of BD may confer susceptibility via inherited genetic factors that affect striatal volume. Future work should establish how this relationship relates to specific BD symptomology. This work may also help to dissect clinical heterogeneity and improve diagnosis nosology.

Separating Symptomatic Alzheimer's Disease from Depression based on Structural MRI

Older patients with depression or Alzheimer’s disease (AD) at the stage of early dementia or mild cognitive impairment may present with objective cognitive impairment, although the pathology and thus therapy and prognosis differ substantially. In this study, we assessed the potential of an automated algorithm to categorize a test set of 65 T1-weighted structural magnetic resonance images (MRI). A convenience sample of elderly individuals fulfilling clinical criteria of either AD (n = 28) or moderate and severe depression (n = 37) was recruited from different settings to assess the potential of the pattern recognition method to assist in the differential diagnosis of AD versus depression. We found that our algorithm learned discriminative patterns in the subject’s grey matter distribution reflected by an area under the receiver operator characteristics curve of up to 0.83 (confidence interval ranged from 0.67 to 0.92) and a balanced accuracy of 0.79 for the separation of depression from AD, evaluated by leave-one-out cross validation. The algorithm also identified consistent structural differences in a clinically more relevant scenario where the data used during training were independent from the data used for evaluation and, critically, which included five possible diagnoses (specifically AD, frontotemporal dementia, Lewy body dementia, depression, and healthy aging). While the output was insufficiently accurate to use it directly as a means for classification when multiple classes are possible, the continuous output computed by the machine learning algorithm differed between the two groups that were investigated. The automated analysis thus could complement, but not replace clinical assessments.

Predicting individual responses to the electroconvulsive therapy with hippocampal subfield volumes in major depression disorder

Electroconvulsive therapy (ECT) is one of the most effective treatments for major depression disorder (MDD). ECT can induce neurogenesis and synaptogenesis in hippocampus, which contains distinct subfields, e.g., the cornu ammonis (CA) subfields, a granule cell layer (GCL), a molecular layer (ML), and the subiculum. It is unclear which subfields are affected by ECT and whether we predict the future treatment response to ECT by using volumetric information of hippocampal subfields at baseline? In this study, 24 patients with severe MDD received the ECT and their structural brain images were acquired with magnetic resonance imaging before and after ECT. A state-of-the-art hippocampal segmentation algorithm from Freesurfer 6.0 was used. We found that ECT induced volume increases in CA subfields, GCL, ML and subiculum. We applied a machine learning algorithm to the hippocampal subfield volumes at baseline and were able to predict the change in depressive symptoms (r = 0.81; within remitters, r = 0.93). Receiver operating characteristic analysis also showed robust prediction of remission with an area under the curve of 0.90. Our findings provide evidence for particular hippocampal subfields having specific roles in the response to ECT. We also provide an analytic approach for generating predictions about clinical outcomes for ECT in MDD.

Longitudinal development of hippocampal subregions from childhood to adulthood

Detailed descriptions of the development of the hippocampus promise to shed light on the neural foundation of development of memory and other cognitive functions, as well as the emergence of major mental disorders. Hippocampus is a heterogeneous structure with a well characterized internal complexity, but development of its distinct subregions in humans has remained poorly described. We analyzed magnetic resonance imaging (MRI) data from a large longitudinal sample (270 participants, 678 scans) using an automated segmentation tool and mixed models to delineate the development of hippocampal subregion volumes from childhood to adulthood. We also examined sex differences in subregion volumes and their development, and associations between hippocampal subregions and general cognitive ability. Nonlinear developmental trajectories with early volume increases were observed for subiculum, cornu ammonis (CA) 1, molecular layer (ML) and fimbria. In contrast, parasubiculum, presubiculum, CA2/3, CA4 and the granule cell layer of the dentate gyrus (GC-DG) showed linear volume decreases. No sex differences were found in hippocampal subregion development. Finally, general cognitive ability was positively associated with CA2/3 and CA4 volumes, as well as with ML development. In conclusion, hippocampal subregions appear to develop in diversified ways across adolescence, and specific subregions may link to general cognitive level.

Epigenetic Changes of FKBP5 as a Link Connecting Genetic and Environmental Risk Factors with Structural and Functional Brain Changes in Major Depression

The gene for the glucocorticoid receptor regulator FK506 binding protein 5 (FKBP5) plays a role for risk, response to treatment, and changes in brain areas in major depressive disorder (MDD). Chronic stress is associated with lower methylation of FKBP5. Our aim was to investigate whether methylation of FKBP5 reflected exposure to childhood adversity in MDD and controls and whether it was associated with structure and function of emotional processing regions. FKBP5 intron 7 GR response element region methylation and rs1360780 allelic status were assessed from whole blood in 56 MDD adults and 50 controls. Using magnetic resonance imaging, we assessed gray matter concentration of selected areas and their function during valence recognition of emotional images. Childhood adversity was investigated using the Childhood Trauma Questionnaire. In MDD patients carrying the high-risk T allele of rs1360780, lower methylation of FKBP5 was predicted by childhood adversity (F=4.95, p=0.04). In all participants, lower FKBP5 intron methylation levels were associated with reduced gray matter concentration in the inferior frontal orbital gyrus bilaterally (Wald chi-square=11.93, p_FDR<0.01) and, in MDD, with its bilaterally higher activation during valence recognition (Wald chi-square=5.58, p=0.02). Activation of this region, regardless of side, was found to be lower in MDD compared to controls (Wald chi-square=3.88, p=0.049) and to be inversely correlated with depression severity (Wald chi-square=4.65, p=0.03). Our findings support the hypothesis that, in genetically predisposed individuals carrying a high-risk variant of the gene, childhood maltreatment might induce demethylation of FKBP5. This is in turn associated with structural and functional changes in the inferior frontal orbital gyrus, a relevant area for the clinical symptoms of MDD.

Nineteen and Up study (19Up): understanding pathways to mental health disorders in young Australian twins

PURPOSE

The Nineteen and Up study (19Up) assessed a range of mental health and behavioural problems and associated risk factors in a genetically informative Australian cohort of young adult twins and their non-twin siblings. As such, 19Up enables detailed investigation of genetic and environmental pathways to mental illness and substance misuse within the Brisbane Longitudinal Twin Sample (BLTS).

PARTICIPANTS

Twins and their non-twin siblings from Queensland, Australia; mostly from European ancestry. Data were collected between 2009 and 2016 on 2773 participants (age range 18-38, 57.8% female, 372 complete monozygotic pairs, 493 dizygotic pairs, 640 non-twin siblings, 403 singleton twins).

FINDINGS TO DATE

A structured clinical assessment (Composite International Diagnostic Interview) was used to collect lifetime prevalence of diagnostic statistical manual (4th edition) (DSM-IV) diagnoses of major depressive disorder, (hypo)mania, social anxiety, cannabis use disorder, alcohol use disorder, panic disorder and psychotic symptoms. Here, we further describe the comorbidities and ages of onset for these mental disorders. Notably, two-thirds of the sample reported one or more lifetime mental disorder.In addition, the 19Up study assessed general health, drug use, work activity, education level, personality, migraine/headaches, suicidal thoughts, attention deficit hyperactivity disorder (ADHD) symptomatology, sleep-wake patterns, romantic preferences, friendships, familial environment, stress, anorexia and bulimia as well as baldness, acne, asthma, endometriosis, joint flexibility and internet use.The overlap with previous waves of the BLTS means that 84% of the 19Up participants are genotyped, 36% imaged using multimodal MRI and most have been assessed for psychological symptoms at up to four time points. Furthermore, IQ is available for 57%, parental report of ADHD symptomatology for 100% and electroencephalography for 30%.

FUTURE PLANS

The 19Up study complements a phenotypically rich, longitudinal collection of environmental and psychological risk factors. Future publications will explore hypotheses related to disease onset and development across the waves of the cohort. A follow-up study at 25+years is ongoing.

Brain structure alterations in depression: Psychoradiological evidence

Depression is the leading cause of disability around the world, but little is known about its pathology. Currently, the diagnosis of depression is made based on clinical manifestations, with little objective evidence. Magnetic resonance imaging (MRI) has been used to investigate the pathological changes in brain anatomy associated with this disorder. MRI can identify structural alterations in depressive patients in vivo, which could make considerable contributions to clinical diagnosis and treatment. Numerous studies that focused on gray and white matter have found significant brain region alterations in major depressive disorder patients, such as in the frontal lobe, hippocampus, temporal lobe, thalamus, striatum, and amygdala. The results are inconsistent and controversial because of the different demographic and clinical characteristics. However, some regions overlapped; thus, we think that there may be a "hub" in MDD and that an impairment in these regions contributes to disease severity. Brain connections contain both structural connections and functional connections, which reflect disease from a different view and support that MDD may be caused by the interaction of multiple brain regions. According to previous reports, significant circuits include the frontal-subcortical circuit, the suicide circuit, and the reward circuit. As has been recognized, the pathophysiology of major depressive disorder is complex and changeable. The current review focuses on the significant alterations in the gray and white matter of patients with the depressive disorder to generate a better understanding of the circuits. Moreover, identifying the nuances of depressive disorder and finding a biomarker will make a significant contribution to the guidance of clinical diagnosis and treatment.

The Myth of Optimality in Clinical Neuroscience

Clear evidence supports a dimensional view of psychiatric illness. Within this framework the expression of disorder-relevant phenotypes is often interpreted as a breakdown or departure from normal brain function. Conversely, health is reified, conceptualized as possessing a single ideal state. We challenge this concept here, arguing that there is no universally optimal profile of brain functioning. The evolutionary forces that shape our species select for a staggering diversity of human behaviors. To support our position we highlight pervasive population-level variability within large-scale functional networks and discrete circuits. We propose that, instead of examining behaviors in isolation, psychiatric illnesses can be best understood through the study of domains of functioning and associated multivariate patterns of variation across distributed brain systems.

Post-genomic behavioral genetics: From revolution to routine

What was once expensive and revolutionary-full-genome sequence-is now affordable and routine. Costs will continue to drop, opening up new frontiers in behavioral genetics. This shift in costs from the genome to the phenome is most notable in large clinical studies of behavior and associated diseases in cohorts that exceed hundreds of thousands of subjects. Examples include the Women's Health Initiative (www.whi.org), the Million Veterans Program (www.

RESEARCH

va.gov/MVP), the 100 000 Genomes Project (genomicsengland.co.uk) and commercial efforts such as those by deCode (www.decode.com) and 23andme (www.23andme.com). The same transition is happening in experimental neuro- and behavioral genetics, and sample sizes of many hundreds of cases are becoming routine (www.genenetwork.org, www.mousephenotyping.org). There are two major consequences of this new affordability of massive omics datasets: (1) it is now far more practical to explore genetic modulation of behavioral differences and the key role of gene-by-environment interactions. Researchers are already doing the hard part-the quantitative analysis of behavior. Adding the omics component can provide powerful links to molecules, cells, circuits and even better treatment. (2) There is an acute need to highlight and train behavioral scientists in how best to exploit new omics approaches. This review addresses this second issue and highlights several new trends and opportunities that will be of interest to experts in animal and human behaviors.

Hippocampal Subfields Volume Reduction in High Schoolers with Previous Verbal Abuse Experiences

Objective

Reduced hippocampal volume and alterations in white matter tracts have been frequently reported in adults having the history of emotional maltreatment. We investigated whether these structural change occur in adolescents with previous verbal abuse (VA) experiences.

Methods

Hippocampal subfield volume and white matter structural connectivity measures were assessed in 31 first year male high school students with various degrees of exposure to parental and peer VA.

Results

The high VA group showed significant volume reduction in the left cornu ammonis (CA) 1 and left subiculum compared to the low VA group (p＜0.05). Volumes of left hippocampal subfields CA1 and subiculum were negatively correlated with previous VA experiences (p＜0.05). Increased mean diffusivity (MD) of the splenium of the corpus callosum was related to high VA score across all subjects (p＜0.05). There was an inverse relationship between volume of the CA1 and subiculum and MD of the splenium (p＜0.05).

Conclusion

Exposure to parental and peer VA may affect development of the left hippocampal subfields and the splenium of corpus callosum. These structural alterations can be discernible during adolescence.

Cerebral blood flow velocity positively correlates with brain volumes in long-term remitted depression

BACKGROUND

Mechanisms involved in brain changes observed in major depression have been poorly investigated in clinical populations. Changes in cerebral blood flow (CBF) have been found in depressed patients and constitute a potential mechanism by which brain volume varies in depression. We have tested the association of cerebral blood flow velocity (CBFV) as assessed with Transcranial Doppler (TCD) and cerebral blood flow (CBF) as assessed with Arterial Spin Labeling Magnetic Resonance Imaging (ASL-MRI) with Total Brain Volume (TBV) and the volume of seven subcortical regions, in currently depressed and long-term remitted patients. In addition, we have evaluated other potential confounders for the association depression/brain volume, including dimensional symptoms of depression, cardiovascular risk factors (CVRF) and antidepressants.

METHODS

Seventy-five individuals were recruited, divided in 3 equal groups (currently depressed, remitted individuals and healthy controls) and were submitted to clinical assessment, MRI and Transcranial Doppler.

RESULTS

CBFV was positively correlated with TBV, Hippocampus and Thalamus volume, but only in remitted patients, who tend to have larger brains compared to both currently depressed and controls. CVRF were negatively associated with brain volumes in the 3 groups and antidepressant use was associated with larger Thalamus. We found no association between brain volumes and CBF as assessed with ASL-MRI, anhedonia, anxiety or psychomotor retardation.

DISCUSSION

Greater CBFV may be a physiological mechanism by which brain is enlarged in remitted patients. Future studies should consider CBFV, CVRF and antidepressants as possible confounders for the association depression/brain volumes, especially in remitted patients.

Evidence for neuroplastic compensation in the cerebral cortex of persons with depressive illness

We yoked anatomical brain magnetic resonance imaging to a randomized, double-blind, placebo-controlled trial (RCT) of antidepressant medication for 10-week's duration in patients with dysthymia. The RCT study design mitigated ascertainment bias by randomizing patients to receive either duloxetine or placebo, and it supported true causal inferences about treatment effects on the brain by controlling treatment assignment experimentally. We acquired 121 anatomical scans: at baseline and end point in 41 patients and once in 39 healthy controls. At baseline, patients had diffusely thicker cortices than did healthy participants, and patients who had thicker cortices had proportionately less severe symptoms. During the trial, symptoms improved significantly more in medication-compared with placebo-treated patients; concurrently, thicknesses in medication-treated patients declined toward values in healthy controls, but they increased slightly, away from control values, in placebo-treated patients. Changes in symptom severity during the trial mediated the association of treatment assignment with the change in thickness, suggesting that the beneficial effects of medication on symptom severity were at least partially responsible for normalizing cortical thickness. Together our findings suggest that baseline cortical hypertrophy in medication-free patients likely represented a compensatory, neuroplastic response that attenuated symptom severity. Medication then reduced symptoms and lessened the need for compensation, thereby normalizing thickness. This is to the best of our knowledge the first study to report within an RCT a differential change in cortical morphology during medication treatment for depressive illness and the first to provide within an RCT in vivo evidence for the presence of neuroanatomical plasticity in humans.

Insular subdivisions functional connectivity dysfunction within major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is a mental disorder characterized by cognitive and affective deficits. Previous studies suggested that insula is a crucial node of the salience network for initiating network switching, and dysfunctional connection to this region may be related to the mechanism of MDD. In this study, we systematically investigated and quantified the altered functional connectivity (FC) of the specific insular subdivisions and its relationship to psychopathology of MDD.

METHODS

Resting-state FC of insular subdivisions, including bilateral ventral/dorsal anterior insula and posterior insula, were estimated in 19 MDD patients and 19 healthy controls. Abnormal FC was quantified between groups. Additionally, we investigated the relationships between insular connectivity and depressive symptom severity.

RESULTS

MDD patients demonstrated aberrant FC for insular subdivisions to superior temporal sulcus, inferior prefrontal gyrus, amygdala and posterior parietal cortex. Moreover, depression symptoms (Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale scorers) were associated with the FC values of insular subdivisions.

LIMITATIONS

First, the sample size of our current study is relatively small, which may affect the statistic power. Second, using standardized insular subdivision seeds for FC analyses may neglect subtle natural differences in size and location of functional area across individuals and may thus affect connectivity maps.

CONCLUSIONS

Abnormal FC of insular subdivisions to default network and central executive network may represent impaired intrinsic networks switching which may affect the underlying emotional and sensory disturbances in MDD. And our findings can help to understand the pathophysiology and underlying neural mechanisms of MDD.

Smaller Hippocampal Volume in Posttraumatic Stress Disorder: A Multisite ENIGMA-PGC Study: Subcortical Volumetry Results From Posttraumatic Stress Disorder Consortia

BACKGROUND

Many studies report smaller hippocampal and amygdala volumes in posttraumatic stress disorder (PTSD), but findings have not always been consistent. Here, we present the results of a large-scale neuroimaging consortium study on PTSD conducted by the Psychiatric Genomics Consortium (PGC)-Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) PTSD Working Group.

METHODS

We analyzed neuroimaging and clinical data from 1868 subjects (794 PTSD patients) contributed by 16 cohorts, representing the largest neuroimaging study of PTSD to date. We assessed the volumes of eight subcortical structures (nucleus accumbens, amygdala, caudate, hippocampus, pallidum, putamen, thalamus, and lateral ventricle). We used a standardized image-analysis and quality-control pipeline established by the ENIGMA consortium.

RESULTS

In a meta-analysis of all samples, we found significantly smaller hippocampi in subjects with current PTSD compared with trauma-exposed control subjects (Cohen's d = -0.17, p = .00054), and smaller amygdalae (d = -0.11, p = .025), although the amygdala finding did not survive a significance level that was Bonferroni corrected for multiple subcortical region comparisons (p < .0063).

CONCLUSIONS

Our study is not subject to the biases of meta-analyses of published data, and it represents an important milestone in an ongoing collaborative effort to examine the neurobiological underpinnings of PTSD and the brain's response to trauma.

Subcortical volumetric differences between clinical stages of young people with affective and psychotic disorders

The aim of this study was to investigate differences in subcortical and hippocampal volumes between healthy controls, young people at an early stage of affective and psychotic disorders and those in more advanced stages, to identify markers associated with functional outcomes and illness severity. Young people presenting to youth mental health services with admixtures of depressive, manic and psychotic symptoms (n = 141), and healthy counterparts (n = 49), aged 18-25 were recruited. Participants underwent magnetic resonance imaging, clinical assessments and were rated as to their current clinical stage. Eighty-four patients were classified at the attenuated syndrome stage (Stage 1b) and 57 were classified as having discrete and persistent disorders (Stage 2+). Automated segmentation was performed using NeuroQuant® to determine volumes of subcortical and hippocampus structures which were compared between groups and correlated with clinical and functional outcomes. Compared to healthy controls, Stage 2+ patients showed significantly reduced right amygdala volumes. Whereas Stage 1b patients showed significantly reduced left caudate volumes compared to healthy controls. Smaller left caudate volume correlated with greater psychological distress and impaired functioning. This study shows a clinical application for an automated program to identify and track subcortical changes evident in young people with emerging psychopathology.