Overactivation of the middle cingulate cortex and the caudate nucleus as neural correlates of the familial liability to major depressiive disorder

Introduction

Unaffected healthy 1st degree relatives of patients with major depressive disorder (MDD) are 3.6 times more liable to develop the disease themselves than the standard population without the history of the disorder. Neural correlates of this liability are of particular interest since the phenomenon does not always have behavioral manifestations and early detected can enhance quicker and better MDD prevention.

Objective

The objective of our study was to establish neuronal correlates of susceptibility MDD in unaffected healthy 1st degree relatives of patients with MDD. Inhibition of emotional information was examined in the present study.

Aims

The aim of the study was to better understand the development of MDD and the role of altered inhibition of emotional processing in it. That, in consequence, may contribute to establishing new methods of prevention and quicker detection of MDD liability.

Methods

Twenty-one unaffected healthy 1st degree relatives of patients with MDD and twenty-five matched healthy controls underwent a functional magnetic resonance imaging procedure with a task involving inhibition of emotional processing of positive, negative and neutral emotional information. 2 × 3 ANOVA was performed to establish if the two groups differed significantly in the inhibition of one of the three types of emotions.

Results

The unaffected healthy 1st degree relatives displayed an increased neural activation during the inhibition of negative emotional information in the bilateral middle cingulate cortex (MCC) and the left caudate nucleus (p< 0.05, family wise error).

Conclusions

The overactivation of the MCC and caudate nucleus can be a marker of MDD liability

Cortical abnormalities in adults and adolescents with major depression based on brain scans from 20 cohorts worldwide in the ENIGMA Major Depressive Disorder Working Group

The neuro-anatomical substrates of major depressive disorder (MDD) are still not well understood, despite many neuroimaging studies over the past few decades. Here we present the largest ever worldwide study by the ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) Major Depressive Disorder Working Group on cortical structural alterations in MDD. Structural T1-weighted brain magnetic resonance imaging (MRI) scans from 2148 MDD patients and 7957 healthy controls were analysed with harmonized protocols at 20 sites around the world. To detect consistent effects of MDD and its modulators on cortical thickness and surface area estimates derived from MRI, statistical effects from sites were meta-analysed separately for adults and adolescents. Adults with MDD had thinner cortical gray matter than controls in the orbitofrontal cortex (OFC), anterior and posterior cingulate, insula and temporal lobes (Cohen's d effect sizes: -0.10 to -0.14). These effects were most pronounced in first episode and adult-onset patients (>21 years). Compared to matched controls, adolescents with MDD had lower total surface area (but no differences in cortical thickness) and regional reductions in frontal regions (medial OFC and superior frontal gyrus) and primary and higher-order visual, somatosensory and motor areas (d: -0.26 to -0.57). The strongest effects were found in recurrent adolescent patients. This highly powered global effort to identify consistent brain abnormalities showed widespread cortical alterations in MDD patients as compared to controls and suggests that MDD may impact brain structure in a highly dynamic way, with different patterns of alterations at different stages of life.

Association of Stress Hormone System, Epigenetics and Imaging

Introduction

Major depressive disorder (MDD) is a common psychiatric condition, affecting up to 350 million people worldwide. Its pathogenesis seems to involve dysregulation of the hypothalamic-pituitary (HPA) axis and inflammation as key elements of the condition. Stressful life events and in particular early life adversity seem to play an important role as risk factors for MDD. Epigenetic, which has been found to impact in the transcription of genes, seem to be associated with brain structure and function. Aim of the research was to provide an overview about neuroimaging (epi)-genetics in MDD.

Methods

Functional MRI, epigenetic and genetic information was obtained in a cohort of patients with MDD and healthy controls. Associations between, early life adversity, methylation of FKBP5 and SLC6A4, genetic variants and brain function and connectivity have been analysed.

Results

Higher methylation of SLC6A4 gene was associated with higher BOLD response during emotion processing and lower BOLD response during higher order cognitive processes. Healthy participants with higher SLC6A4 methylation involved prefrontal cortical regions to a greater extent than the participants with lower SLC6A4 methylation, when trying to switch attention away from negative emotional stimuli (Frodl et al., 2015). Moreover, FKBP5 methylation was association with HPA axis functioning and amygdala brain function in patients with MDD. FKBP5 methylation also was related to grey matter volume.

Conclusions

Our study provides further support to the hypothesis that DNA methylation plays a role. Particular peripheral DNA methylation states of MDD candidate genes are associated with brain function during emotion processing in patients with MDD.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

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

The pattern of structural brain alterations associated with major depressive disorder (MDD) remains unresolved. This is in part due to small sample sizes of neuroimaging studies resulting in limited statistical power, disease heterogeneity and the complex interactions between clinical characteristics and brain morphology. To address this, we meta-analyzed three-dimensional brain magnetic resonance imaging data from 1728 MDD patients and 7199 controls from 15 research samples worldwide, to identify subcortical brain volumes that robustly discriminate MDD patients from healthy controls. Relative to controls, patients had significantly lower hippocampal volumes (Cohen's d=-0.14, % difference=-1.24). This effect was driven by patients with recurrent MDD (Cohen's d=-0.17, % difference=-1.44), and we detected no differences between first episode patients and controls. Age of onset ⩽21 was associated with a smaller hippocampus (Cohen's d=-0.20, % difference=-1.85) and a trend toward smaller amygdala (Cohen's d=-0.11, % difference=-1.23) and larger lateral ventricles (Cohen's d=0.12, % difference=5.11). Symptom severity at study inclusion was not associated with any regional brain volumes. Sample characteristics such as mean age, proportion of antidepressant users and proportion of remitted patients, and methodological characteristics did not significantly moderate alterations in brain volumes in MDD. Samples with a higher proportion of antipsychotic medication users showed larger caudate volumes in MDD patients compared with controls. This currently largest worldwide effort to identify subcortical brain alterations showed robust smaller hippocampal volumes in MDD patients, moderated by age of onset and first episode versus recurrent episode status.

Reduced fractional anisotropy in the uncinate fasciculus in patients with major depression carrying the met-allele of the Val66Met brain-derived neurotrophic factor genotype

Experimental studies support a neurotrophic hypothesis of major depressive disorder (MDD). The aim of this study was to determine the effect of Val66Met brain-derived neurotrophic factor (BDNF) polymorphism on the white matter fiber tracts connecting hippocampus and amygdala with the prefrontal lobe in a sample of patients with MDD and healthy controls. Thirty-seven patients with MDD and 42 healthy volunteers were recruited. Diffusion tensor imaging (DTI) data with 61 diffusion directions were obtained with MRI 3 Tesla scanner. Deterministic tractography was applied with ExploreDTI and Val66Met BDNF SNP (rs6265) was genotyped. Fiber tracts connecting the hippocampus and amygdala with the prefrontal lobe, namely uncinate fasciculus (UF), fornix, and cingulum were analyzed. A significant interaction was found in the UF between BDNF alleles and diagnosis. Patients carrying the BDNF met-allele had smaller fractional anisotropy (FA) in the UF compared to those patients homozygous for val-allele and compared to healthy subjects carrying the met-allele. A significant three-way interaction was detected between region of the cingulum (dorsal, rostral, and parahippocampal regions), brain hemisphere and BDNF genotype. Larger FA was detectable in the left rostral cingulum for met-allele carriers when compared to val/val alelle carriers. We provide evidence for the importance of the neurotrophic involvement in limbic and prefrontal connections. The met-allele of the BDNF polymorphism seems to render subjects more vulnerable for dysfunctions associated with the UF, a tract known to be related to negative emotional-cognitive processing bias, declarative memory problems, and autonoetic self awareness.

Reduced expression of glucocorticoid-inducible genes GILZ and SGK-1: high IL-6 levels are associated with reduced hippocampal volumes in major depressive disorder

Neuroplasticity may have a core role in the pathophysiology of major depressive disorder (MDD), a concept supported by experimental studies that found that excessive cortisol secretion and/or excessive production of inflammatory cytokines impairs neuronal plasticity and neurogenesis in the hippocampus. The objective of this study was to examine how changes in the glucocorticoid and inflammatory systems may affect hippocampal volumes in MDD. A multimodal approach with structural neuroimaging of hippocampus and amygdala, measurement of peripheral inflammatory proteins interleukin (IL)-6 and C-reactive protein (CRP), glucocorticoid receptor (GR) mRNA expression, and expression of glucocorticoid-inducible genes (glucocorticoid-inducible genes Leucin Zipper (GILZ) and glucocorticoid-inducible kinase-1 (SGK-1)) was used in 40 patients with MDD and 43 healthy controls (HC). Patients with MDD showed smaller hippocampal volumes and increased inflammatory proteins IL-6 and CRP compared with HC. Childhood maltreatment was associated with increased CRP. Patients with MDD, who had less expression of the glucocorticoid-inducible genes GILZ or SGK-1 had smaller hippocampal volumes. Regression analysis showed a strong positive effect of GILZ and SGK-1 mRNA expression, and further inverse effects of IL-6 concentration, on hippocampal volumes. These findings suggest that childhood maltreatment, peripheral inflammatory and glucocorticoid markers and hippocampal volume are interrelated factors in the pathophysiology of MDD. Glucocorticoid-inducible genes GILZ and SGK-1 might be promising candidate markers for hippocampal volume changes relevant for diseases like MDD. Further studies need to explore the possible clinical usefulness of such a blood biomarker, for example, for diagnosis or prediction of therapy response.

Criteria for compulsory admission in some European countries

Compulsory admission to mental health facilities is a controversial topic, as it impinges on personal liberty and the right to choose, and it carries the risk of abuse for political, social and other reasons (Gostin, 2000). However, involuntary admission can prevent harm to self and others, and assist people in attaining their right to health, which, due to their mental disorder, they are unable to manage voluntarily. Since the 1950s and 1960s, the delivery of mental health has shifted from a paternalistic emphasis on the need to treat those who are not able to look after themselves, to the rights of patients who have a mental illness. The Principles for the Protection of Persons with Mental Illness ('the MI Principles') adopted by the United Nations in 1991 play an important role in raising awareness about the human rights of people with mental health problems. They provide guidance on areas such as the procedures for involuntary admission to mental health facilities and standards of care (Knapp et al, 2007). Legal frameworks for involuntary placement of those who are mentally ill have been reformed in many European countries. Most regulate compulsory admission and treatment by special mental health laws. Only Greece, Spain, Italy and those member states of the European Union (EU) that joined in 2004 and 2007 have no separate laws (Dressing & Salize, 2004).

Criteria for compulsory admission in some European countries

Compulsory admission to mental health facilities is a controversial topic, as it impinges on personal liberty and the right to choose, and it carries the risk of abuse for political, social and other reasons (Gostin, 2000). However, involuntary admission can prevent harm to self and others, and assist people in attaining their right to health, which, due to their mental disorder, they are unable to manage voluntarily. Since the 1950s and 1960s, the delivery of mental health has shifted from a paternalistic emphasis on the need to treat those who are not able to look after themselves, to the rights of patients who have a mental illness. The Principles for the Protection of Persons with Mental Illness (‘the MI Principles’) adopted by the United Nations in 1991 play an important role in raising awareness about the human rights of people with mental health problems. They provide guidance on areas such as the procedures for involuntary admission to mental health facilities and standards of care (Knapp et al, 2007). Legal frameworks for involuntary placement of those who are mentally ill have been reformed in many European countries. Most regulate compulsory admission and treatment by special mental health laws. Only Greece, Spain, Italy and those member states of the European Union (EU) that joined in 2004 and 2007 have no separate laws (Dressing & Salize, 2004).