An epigenetic mechanism links socioeconomic status to changes in depression-related brain function in high-risk adolescents

Developing a translational research framework for MDD: combining biomolecular mechanisms with a spiraling risk factor model

Objective

The global incidence and burden of Major Depressive Disorder (MDD) are increasing annually, with current antidepressant treatments proving ineffective for 30-40% of patients. Biomolecular mechanisms within the microbiota-gut-brain axis (MGBA) may significantly contribute to MDD, potentially paving the way for novel treatment approaches. However, integrating the MGBA with the psychological and environmental aspects of MDD remains challenging. This manuscript aims to: 1) investigate the underlying biomolecular mechanisms of MDD using a modeling approach, and 2) integrate this knowledge into a comprehensive 'spiraling risk factor model' to develop a biopsychosocial translational research framework for the prevention and treatment of MDD.

Methods

For the first aim, a systematic review (PROSPERO registration) was conducted using PubMed, Embase, and Scopus to query literature published between 2016-2020, with select additional sources. A narrative review was performed for the second aim.

Results

In addition to genetics and neurobiology, research consistently indicates that hyperactivation of the HPA axis and a pro-inflammatory state are interrelated components of the MGBA and likely underlying mechanisms of MDD. Dysregulation of the MGBA, along with imbalances in mental and physical conditions, lifestyle factors, and pre-existing treatments, can trigger a downward spiral of stress and anxiety, potentially leading to MDD.

Conclusions

MDD is not solely a brain disorder but a heterogeneous condition involving biomolecular, psychological, and environmental risk factors. Future interdisciplinary research can utilize the integrated biopsychosocial insights from this manuscript to develop more effective lifestyle-focused multimodal treatment interventions, enhance diagnosis, and stimulate early-stage prevention of MDD.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42020215412.

Socioeconomic status, individual behaviors and risk of anxiety disorders: A Mendelian randomization study

BACKGROUND

The association between socioeconomic status and individual behaviors (SES/IB) and anxiety disorders has garnered increasing attention, yet the impact of SES/IB on anxiety disorders remains unclear. Therefore, we employed a Mendelian randomization (MR) design to evaluate the causal relationship between SES/IB and anxiety disorders.

METHODS

We conducted a two-sample MR study to assess the causal effects of SES and IB (smoking behaviors, drinking behaviors, sleeping behaviors, habitual physical activity, leisure sedentary behaviors, and reproductive behaviors) on anxiety disorders. A series of filtering steps were taken to select eligible genetic instruments robustly associated with each of the traits. The inverse variance weighted was used for preliminary analysis, and multiple methods were used for sensitivity testing.

RESULTS

After Bonferroni correction and rigorous quality control, we found that educational attainment (odds ratio [OR]:0.75; 95 % confidence interval [CI]:0.69-0.81; P = 9.21E-12), alcohol consumption per week (OR: 1.62; 95 % CI: 1.33-1.97; P = 1.80E-06), insomnia (OR: 1.68; 95 % CI: 1.43-1.97; P = 1.45E-10),age at first birth (OR: 0.59; 95 % CI: 0.50-0.68; P = 1.31E-11),and number of sexual partners (OR: 2.19; 95 % CI: 1.71-2.80; P = 6.64E-10) were causally associated with anxiety disorders.

LIMITATIONS

The subjects included in this study were all of European descent, and whether this finding can be generalized to other populations needs to be further demonstrated.

CONCLUSIONS

The MR Study provides strong evidence that some factors influence anxiety disorders.

Epigenetic Insights into Substance Use Disorder and Associated Psychiatric Conditions

Background

Substance use disorder (SUD) is closely associated with epigenetic modifications that significantly impact mental health outcomes. Alcohol and drug misuse induce widespread changes in the epigenome and transcriptome of the central nervous system, disrupting critical processes such as reward signaling and emotional regulation. These alterations in epigenetic regulation and gene expression often persist even after substance cessation, potentially contributing to the onset or worsening of psychiatric conditions, including schizophrenia, depression, stress, and anxiety.

Summary

This review delves into key epigenetic mechanisms underlying SUD and its comorbid psychiatric disorders, with a focus on DNA methylation, histone modifications, and noncoding RNA regulation. Additionally, it examines the influence of environmental and biological factors on the epigenome and evaluates emerging epigenetic-based therapeutic strategies aimed at treating SUD and related psychiatric conditions.

Key Messages

Gaining a deeper understanding of the epigenetic mechanisms driving SUD and its associated psychiatric disorders is crucial for the development of effective therapeutic interventions. This review highlights the potential of epigenetic-based pharmacological strategies to mitigate the societal and personal burdens linked to SUD and its mental health complications.

Early-life adversity severity, timing, and context type are associated with SLC6A4 methylation in emerging adults: Results from a prospective cohort study

BACKGROUND

Epigenetic modifications, including DNA methylation (DNAm), can play a role in the biological embedding of early-life adversity (ELA) through serotonergic mechanisms. The current study examines methylation of the CpG island in the promoter region of the stress-responsive serotonin transporter gene (SLC6A4) and is the first to jointly assess how it is influenced by ELA severity, timing, and type-specifically, deprivation and threat.

METHODS

We use data from 627 Youth Emotion Project study participants, recruited from two US high schools. Using adjusted linear regressions, we analyze DNA collected in early adulthood from 410 participants and ELA based on interviewer-rated responses from concurrent Childhood Trauma Interviews, adjusting for survey-measured covariates.

RESULTS

ELA robustly predicted mean CpG island SLC6A4 DNAm percent across 71 CpG sites. Each additional major-severity ELA event was associated with a 0.121-percentage-point increase (p<0.001), equating to a 0.177 standard deviation (sd) higher DNAm level (95 % CI: 0.080, 0.274) with each 1-sd higher adversity score. When modeled separately, both childhood and adolescent ELA predicted SLC6A4 DNAm. When modeled jointly, adolescent ELA was most strongly predictive, and child adversity remained significantly associated with DNAm through indirect associations via adolescent adversity. Additionally, the ELA-SLC6A4 DNAm association may vary by adversity type. Across separate models for childhood and adolescent exposures, deprivation coefficients are positive and statistically significant. Meanwhile, threat coefficients are positive and not significantly significant but do not statistically differ from deprivation coefficients. In models including all ELA dimensions, one major adolescent deprivation event is associated with a 0.222-percentage-point increased SLC6A4 DNAm (p<0.05), or a 1-sd higher deprivation score with a 0.157-sd increased DNAm.

CONCLUSION

Results further implicate epigenetic modification on serotonergic neurotransmission via DNAm in the downstream sequelae of ELA-particularly adolescent deprivation-and support preventive interventions in adolescence to mitigate biological embedding.

Genetic-epigenetic-neuropeptide associations in mood and anxiety disorders: Toward personalized medicine

Mood and anxiety disorders are complex psychiatric conditions shaped by the multifactorial interplay of genetic, epigenetic, and neuropeptide factors. This review aims to elucidate the intricate interactions among these factors and their potential in advancing personalized medicine. We examine the genetic underpinnings, emphasizing key heritability studies and specific gene associations. The role of epigenetics is discussed, focusing on how environmental factors can modify gene expression and contribute to these disorders. Neuropeptides, including substance P, CRF, AVP, NPY, galanin, and kisspeptin, are evaluated for their involvement in mood regulation and their potential as therapeutic targets. Additionally, we address the emerging role of the gut microbiome in modulating neuropeptide activity and its connection to mood disorders. This review integrates findings from genetic, epigenetic, and neuropeptide research, offering a comprehensive overview of their collective impact on mood and anxiety disorders. By highlighting novel insights and potential clinical applications, we underscore the importance of a multi-omics approach in developing personalized treatment strategies. Future research directions are proposed to address existing knowledge gaps and translate these findings into clinical practice. Our review provides a fresh perspective on the pathophysiology of mood and anxiety disorders, paving the way for more effective and individualized therapies.

The Interaction Effect of Adverse Childhood Experiences and Socioeconomic Circumstances in Adolescent Depressive Symptomatology

PURPOSE

Limited research has examined the combined effects of psychosocial and material adversities experienced in childhood during adolescence, a sensitive period of rapid social, emotional, and cognitive development. We investigated the interaction effect of adverse childhood experiences (ACEs) and socioeconomic circumstances (SECs) during childhood on emerging self-reported depressive symptomatology among 13-year-old Portuguese adolescents.

METHODS

We utilized data from 4,280 participants in the Generation XXI birth cohort, collected during the baseline (2005-2006), third (2016-2017), and fourth waves (2018-2020). Adjusted odds ratios and 95% confidence intervals (CIs) were obtained from binary logistic regression analyses to estimate the likelihood of depressive symptoms based on exposure to ACEs and adverse family SECs. The interaction effect of ACEs and SECs was evaluated in terms of departure from additive and multiplicative models.

RESULTS

Adolescents who reported experiences of abuse, school-related problems, and household dysfunction, as well as those from less advantaged family SECs at age 10, were more likely to report moderate to severe depressive symptoms at age 13, compared to their more affluent counterparts. We observed a significant additive interaction between low household income and abuse in the development of moderate to severe depressive symptoms [relative excess risk due to interaction, 0.69, 95% CI: 0.11, 1.26]. This interaction remained statistically significant on a multiplicative scale [OR = 1.61, 95% CI: 0.99, 2.69].

DISCUSSION

ACEs and low family SECs during the first decade of life are associated with an elevated risk of moderate to severe depressive symptoms in adolescence.

Neighborhood-level deprivation and survival in lung cancer

BACKGROUND

Despite recent advances in lung cancer therapeutics and improving overall survival, disparities persist among socially disadvantaged populations. This study aims to determine the effects of neighborhood deprivation indices (NDI) on lung cancer mortality. This is a multicenter retrospective cohort study assessing the relationship between NDI and overall survival adjusted for age, disease stage, and DNA methylation among biopsy-proven lung cancer patients. State-specific NDI for each year of sample collection were computed at the U.S. census tract level and dichotomized into low- and high-deprivation.

RESULTS

A total of 173 non small lung cancer patients were included, with n = 85 (49%) and n = 88 (51%) in the low and high-deprivation groups, respectively. NDI was significantly higher among Black patients when compared with White patients (p = 0.003). There was a significant correlation between DNA methylation and stage for HOXA7, SOX17, ZFP42, HOXA9, CDO1 and TAC1. Only HOXA7 DNA methylation was positively correlated with NDI. The high-deprivation group had a statistically significant shorter survival than the low-deprivation group (p = 0.02). After adjusting for age, race, stage, and DNA methylation status, belonging to the high-deprivation group was associated with higher mortality with a hazard ratio of 1.81 (95%CI: 1.03-3.19).

CONCLUSIONS

Increased neighborhood-level deprivation may be associated with liquid biopsy DNA methylation, shorter survival, and increased mortality. Changes in health care policies that consider neighborhood-level indices of socioeconomic deprivation may enable a more equitable increase in lung cancer survival.

Epigenetic mechanisms linking early-life adversities and mental health

Early-life adversities, whether prenatal or postnatal exposure, have been linked to adverse mental health outcomes later in life increasing the risk of several psychiatric disorders. Research on its neurobiological consequences demonstrated an association between exposure to adversities and persistent alterations in the structure, function, and connectivity of the brain. Consistent evidence supports the idea that regulation of gene expression through epigenetic mechanisms are involved in embedding the impact of early-life experiences in the genome and mediate between social environments and later behavioral phenotypes. In addition, studies from rodent models and humans suggest that these experiences and the acquired risk factors can be transmitted through epigenetic mechanisms to offspring and the following generations potentially contributing to a cycle of disease or disease risk. However, one of the important aspects of epigenetic mechanisms, unlike genetic sequences that are fixed and unchangeable, is that although the epigenetic markings are long-lasting, they are nevertheless potentially reversible. In this review, we summarize our current understanding of the epigenetic mechanisms involved in the mental health consequences derived from early-life exposure to malnutrition, maltreatment and poverty, adversities with huge and pervasive impact on mental health. We also discuss the evidence about transgenerational epigenetic inheritance in mammals and experimental data suggesting that suitable social and pharmacological interventions could reverse adverse epigenetic modifications induced by early-life negative social experiences. In this regard, these studies must be accompanied by efforts to determine the causes that promote these adversities and that result in health inequity in the population.

Environmental enrichment attenuates depressive-like behavior in maternal rats by inhibiting neuroinflammation and apoptosis and promoting neuroplasticity

Gestational stress can exacerbate postpartum depression (PPD), for which treatment options remain limited. Environmental enrichment (EE) may be a therapeutic intervention for neuropsychiatric disorders, including depression, but the specific mechanisms by which EE might impact PPD remain unknown. Here we examined the behavioral, molecular, and cellular impact of EE in a stable PPD model in rats developed through maternal separation (MS). Maternal rats subjected to MS developed depression-like behavior and cognitive dysfunction together with evidence of significant neuroinflammation including microglia activation, neuronal apoptosis, and impaired synaptic plasticity. Expanding the duration of EE to throughout pregnancy and lactation, we observed an EE-associated reversal of MS-induced depressive phenotypes, inhibition of neuroinflammation and neuronal apoptosis, and improvement in synaptic plasticity in maternal rats. Thus, EE effectively alleviates neuroinflammation, neuronal apoptosis, damage to synaptic plasticity, and consequent depression-like behavior in mother rats experiencing MS-induced PPD, paving the way for new preventive and therapeutic strategies for PPD.

Epigenetic and Coping Mechanisms of Stress in Affective Disorders: A Scoping Review

This review aims to explore the intricate relationship among epigenetic mechanisms, stress, and affective disorders, focusing on how early life experiences and coping mechanisms contribute to susceptibility to mood disorders. Epigenetic factors play a crucial role in regulating gene expression without altering the DNA (deoxyribonucleic acid) sequence, and recent research has revealed associations between epigenetic changes and maladaptive responses to stress or psychiatric disorders. A scoping review of 33 studies employing the PRISMA-S (Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Statement) guidelines investigates the role of stress-induced epigenetic mechanisms and coping strategies in affective disorder occurrence, development, and progression. The analysis encompasses various stress factors, including childhood trauma, work-related stress, and dietary deficiencies, alongside epigenetic changes, such as DNA methylation and altered gene expression. Findings indicate that specific stress-related genes frequently exhibit epigenetic changes associated with affective disorders. Moreover, the review examines coping mechanisms in patients with bipolar disorder and major depressive disorder, revealing mixed associations between coping strategies and symptom severity. While active coping is correlated with better outcomes, emotion-focused coping may exacerbate depressive or manic episodes. Overall, this review underscores the complex interplay among genetic predisposition, environmental stressors, coping mechanisms, and affective disorders. Understanding these interactions is essential for developing targeted interventions and personalized treatment strategies for individuals with mood disorders. However, further research is needed to elucidate specific genomic loci involved in affective disorders and the clinical implications of coping strategies in therapeutic settings.

The race-based stress reduction intervention (RiSE) study on African American women in NYC and Chicago: Design and methods for complex genomic analysis

RiSE study aims to evaluate a race-based stress-reduction intervention as an effective strategy to improve coping and decrease stress-related symptoms, inflammatory burden, and modify DNA methylation of stress response-related genes in older AA women. This article will describe genomic analytic methods to be utilized in this longitudinal, randomized clinical trial of older adult AA women in Chicago and NYC that examines the effect of the RiSE intervention on DNAm pre- and post-intervention, and its overall influence on inflammatory burden. Salivary DNAm will be measured at baseline and 6 months following the intervention, using the Oragene-DNA kit. Measures of perceived stress, depressive symptoms, fatigue, sleep, inflammatory burden, and coping strategies will be assessed at 4 time points including at baseline, 4 weeks, 8 weeks, and 6 months. Genomic data analysis will include the use of pre-processed and quality-controlled methylation data expressed as beta (β) values. Association analyses will be performed to detect differentially methylated sites on the targeted candidate genes between the intervention and non-intervention groups using the Δβ (changes in methylation) with adjustment for age, health behaviors, early life adversity, hybridization batch, and top principal components of the probes as covariates. To account for multiple testing, we will use FDR adjustment with a corrected p-value of <0.05 regarded as statistically significant. To assess the relationship between inflammatory burden and Δβ among the study samples, we will repeat association analyses with the inclusion of individual inflammation protein measures. ANCOVA will be used because it is more statistically powerful to detect differences.

Gene-environment interaction: why genetic enhancement might never be distributed fairly

Ethical debates around genetic enhancement tend to include an argument that the technology will eventually be fairly accessible once available. That we can fairly distribute genetic enhancement has become a moral defence of genetic enhancement. Two distribution solutions are argued for, the first being equal distribution. Equality of access is generally believed to be the fairest and most just method of distribution. Second, equitable distribution: providing genetic enhancements to reduce social inequalities. In this paper, I make two claims. I first argue that the very assumption that genetic enhancements can be distributed fairly is problematic when considering our understanding of gene-environment interactions, for example, epigenetics. I then argue that arguments that genetic enhancements are permissible because the intended benefits can be distributed fairly as intended are misinformed. My first claim rests on the assertion that genetic enhancements do not enhance traits in a vacuum; genes are dependent on conducive environments for expression. If society cannot guarantee fair environments, then any benefit conferred from being genetically enhanced will be undermined. Thus, any argument that the distribution of genetic enhancements will be fair and that the technology is therefore morally permissible, is mistaken.

A systematic review of neuroimaging epigenetic research: calling for an increased focus on development

Epigenetic mechanisms, such as DNA methylation (DNAm), have gained increasing attention as potential biomarkers and mechanisms underlying risk for neurodevelopmental, psychiatric and other brain-based disorders. Yet, surprisingly little is known about the extent to which DNAm is linked to individual differences in the brain itself, and how these associations may unfold across development - a time of life when many of these disorders emerge. Here, we systematically review evidence from the nascent field of Neuroimaging Epigenetics, combining structural or functional neuroimaging measures with DNAm, and the extent to which the developmental period (birth to adolescence) is represented in these studies. We identified 111 articles published between 2011-2021, out of which only a minority (21%) included samples under 18 years of age. Most studies were cross-sectional (85%), employed a candidate-gene approach (67%), and examined DNAm-brain associations in the context of health and behavioral outcomes (75%). Nearly half incorporated genetic data, and a fourth investigated environmental influences. Overall, studies support a link between peripheral DNAm and brain imaging measures, but there is little consistency in specific findings and it remains unclear whether DNAm markers present a cause, correlate or consequence of brain alterations. Overall, there is large heterogeneity in sample characteristics, peripheral tissue and brain outcome examined as well as the methods used. Sample sizes were generally low to moderate (median nall = 98, ndevelopmental = 80), and attempts at replication or meta-analysis were rare. Based on the strengths and weaknesses of existing studies, we propose three recommendations on how advance the field of Neuroimaging Epigenetics. We advocate for: (1) a greater focus on developmentally oriented research (i.e. pre-birth to adolescence); (2) the analysis of large, prospective, pediatric cohorts with repeated measures of DNAm and imaging to assess directionality; and (3) collaborative, interdisciplinary science to identify robust signals, triangulate findings and enhance translational potential.

Nutritional Status and Poverty Condition Are Associated with Depression in Preschoolers

Consensus has been reached that symptoms of depression can begin as early as preschool. Nevertheless, only few studies have associated environmental (malnutrition) and social factors (poverty condition, access to health systems, etc.) to the onset of depression in preschoolers. The aim of this study was to explore possible associations between malnutrition (underweight, overweight/obesity), poverty status (home quality, overcrowding), access to healthcare systems and the presence of depressive symptoms in the preschoolers of a semi-rural community. In total, 695 children between 3 and 6 years from the municipality of Chiconcuac, Mexico were evaluated for symptoms of depression with the Preschool Depression Scale for Teachers (ESDM 3-6). Additionally, they were assessed for nutritional status and divided into three groups (low weight, normal weight, overweight/obesity), and their parents were asked to fill out a social demographic questionnaire. Malnutrition status OR = 2.702, 95% CI [1.771-4.145]; UW OR = 4.768, 95% CI [2.570-8.795] and OW/OB OR = 1.959, 95% CI [1.175-3.324]; poverty condition per se OR = 1.779, 95% CI [0.9911-2.630]; housing quality OR = 2.020, 95% CI [0.9606-2.659] and overcrowding = 1.619, 95% CI [0.8989-4.433] were associated to a greater risk for children to show depressive symptoms (DS). Access to healthcare was negatively related with the risk of presenting DS (OR = 0.660, 95% CI [0.3130 to 1.360]). Social and environmental factors such as malnutrition, home quality and overcrowding may increase the risk of presenting DS as soon as in preschool.

An epigenome-wide analysis of socioeconomic position and tumor DNA methylation in breast cancer patients

BACKGROUND

Disadvantaged socioeconomic position (SEP), including lower educational attainment and household income, may influence cancer risk and outcomes. We hypothesized that DNA methylation could function as an intermediary epigenetic mechanism that internalizes and reflects the biological impact of SEP.

METHODS

Based on tumor DNA methylation data from the Illumina 450 K array from 694 breast cancer patients in the Women's Circle of Health Study, we conducted an epigenome-wide analysis in relation to educational attainment and household income. Functional impact of the identified CpG sites was explored in silico using data from publicly available databases.

RESULTS

We identified 25 CpG sites associated with household income at an array-wide significance level, but none with educational attainment. Two of the top CpG sites, cg00452016 and cg01667837, were in promoter regions of NNT and GPR37, respectively, with multiple epigenetic regulatory features identified in each region. NNT is involved in β-adrenergic stress signaling and inflammatory responses, whereas GPR37 is involved in neurological and immune responses. For both loci, gene expression was inversely correlated to the levels of DNA methylation. The associations were consistent between Black and White women and did not differ by tumor estrogen receptor (ER) status.

CONCLUSIONS

In a large breast cancer patient population, we discovered evidence of the significant biological impact of household income on the tumor DNA methylome, including genes in the β-adrenergic stress and immune response pathways. Our findings support biological effects of socioeconomic status on tumor tissues, which might be relevant to cancer development and progression.

Effects of stress and mindfulness on epigenetics

Epigenetics are heritable changes in the rate of gene expression without any modification of the DNA sequence and occur in response to environmental changes. Tangible changes to the external surroundings may be practical causes for epigenetic modifications, playing a potential evolutionary role. While fight, flight, or freeze responses once served a concrete role in survival, modern humans may not face similar existential threats that warrant psychological stress. Yet, chronic mental stress is predominant in modern life. This chapter elucidates the deleterious epigenetic changes that occur due to chronic stress. In an exploration of mindfulness-based interventions (MBIs) as a potential antidote to such stress-induced epigenetic modifications, several pathways of action are uncovered. The epigenetic changes that occur because of mindfulness practice are demonstrated across the hypothalamic-pituitary-adrenal axis, serotonergic transmission, genomic health and aging, and neurological biomarkers.

Biomarkers in Child and Adolescent Depression

Despite the significant prevalence of Major Depressive Disorder in the pediatric population, the pathophysiology of this condition remains unclear, and the treatment outcomes poor. Investigating tools that might aid in diagnosing and treating early-onset depression seems essential in improving the prognosis of the future disease course. Recent studies have focused on searching for biomarkers that constitute biochemical indicators of MDD susceptibility, diagnosis, or treatment outcome. In comparison to increasing evidence of possible biomarkers in adult depression, the studies investigating this subject in the youth population are lacking. This narrative review aims to summarize research on molecular and biochemical biomarkers in child and adolescent depression in order to advocate future directions in the research on this subject. More studies on depression involving the youth population seem vital to comprehend the natural course of the disease and identify features that may underlie commonly observed differences in treatment outcomes between adults and children.

Serum extracellular vesicle microRNA dysregulation and childhood trauma in adolescents with major depressive disorder

Major depressive disorder (MDD) seriously endangers adolescent mental and physical health. Extracellular vesicles (EVs) are mediators of cellular communication and are involved in many physiological brain processes. Although EV miRNAshave been implicated in adults with major psychiatric disorders, investigation into their effects in adolescent MDDremains scarce. In discovery set, we conducted a genome-wide miRNA sequencing of serum EVs from 9 untreated adolescents with MDD and 8 matched healthy controls (HCs), identifying 32 differentially expressed miRNAs (18 upregulated and 14 downregulated). In the validation set, 8 differentially expressed and highly enriched miRNAs were verified in independent samples using RT-PCR, with 4 (miR-450a-2-3p, miR-3691-5p, miR-556-3p, and miR-2115-3p) of the 8 miRNAs found to be significantly elevated in 34 untreated adolescents with MDD compared with 38 HCs and consistent with the sequencing results. After the Bonferroni correction, we found that three miRNAs (miR-450a-2-3p, miR-556-3p, and miR-2115-3p) were still significantly different. Among them, miR-450a-2-3p showed the most markeddifferential expression and was able to diagnose disease with 67.6% sensitivity and 84.2% specificity. Furthermore, miR-450a-2-3p partially mediated the associations between total childhood trauma, emotional abuse, and physical neglect and adolescent MDD. We also found that the combination of miR-450a-2-3p and emotional abuse could effectively diagnose MDD in adolescents with 82.4% sensitivity and 81.6% specificity. Our data demonstrate the association of serum EV miRNA dysregulation with MDD pathophysiology and, furthermore, show that miRNAs may mediate the relationship between early stress and MDD susceptibility. We also provide a valid integrated model for the diagnosis of adolescent MDD.

The neuroanatomy of social trust predicts depression vulnerability

Trust attitude is a social personality trait linked with the estimation of others’ trustworthiness. Trusting others, however, can have substantial negative effects on mental health, such as the development of depression. Despite significant progress in understanding the neurobiology of trust, whether the neuroanatomy of trust is linked with depression vulnerability remains unknown. To investigate a link between the neuroanatomy of trust and depression vulnerability, we assessed trust and depressive symptoms and employed neuroimaging to acquire brain structure data of healthy participants. A high depressive symptom score was used as an indicator of depression vulnerability. The neuroanatomical results observed with the healthy sample were validated in a sample of clinically diagnosed depressive patients. We found significantly higher depressive symptoms among low trusters than among high trusters. Neuroanatomically, low trusters and depressive patients showed similar volume reduction in brain regions implicated in social cognition, including the dorsolateral prefrontal cortex (DLPFC), dorsomedial PFC, posterior cingulate, precuneus, and angular gyrus. Furthermore, the reduced volume of the DLPFC and precuneus mediated the relationship between trust and depressive symptoms. These findings contribute to understanding social- and neural-markers of depression vulnerability and may inform the development of social interventions to prevent pathological depression.

An avoidable crisis

In Scotland drug policy and consequently the progress of evidence-based treatment options has been struggling for many years. Political inaction is brought about by a complex chain of legal and operational obstructions with local authorities deferring to national Government which in turn is paralysed by international convention. Scotland represents a case study demonstrating the adverse consequences of management by non medical requirements rather than implementation of a clinically proven progressive policy. The difficulty of translating theory and evidence into practice is acknowledged but suggestions are made for pragmatic and humanitarian initiatives.

DNA methylation-based predictors of health: applications and statistical considerations

DNA methylation data have become a valuable source of information for biomarker development, because, unlike static genetic risk estimates, DNA methylation varies dynamically in relation to diverse exogenous and endogenous factors, including environmental risk factors and complex disease pathology. Reliable methods for genome-wide measurement at scale have led to the proliferation of epigenome-wide association studies and subsequently to the development of DNA methylation-based predictors across a wide range of health-related applications, from the identification of risk factors or exposures, such as age and smoking, to early detection of disease or progression in cancer, cardiovascular and neurological disease. This Review evaluates the progress of existing DNA methylation-based predictors, including the contribution of machine learning techniques, and assesses the uptake of key statistical best practices needed to ensure their reliable performance, such as data-driven feature selection, elimination of data leakage in performance estimates and use of generalizable, adequately powered training samples.

Why Deaths of Despair Are Increasing in the US and Not Other Industrial Nations-Insights From Neuroscience and Anthropology

The US National Academy of Sciences reports rising mortality for US adults, most steeply for White adults with a secondary education or less. The rise is largely attributable to deaths of despair (suicide and poisoning by alcohol and drugs) with strong contributions from the cardiovascular effects of rising obesity. Although the report does acknowledge a crisis, it proposes mild measures to manage it, such as strengthening programs to support recovery, prevent relapse, increase resilience, and perform more research toward clinically useful definitions of despair. The US National Academy of Sciences report notes that mortality is decreasing in a control group of 16 wealthy nations (including countries in Western Europe, Canada, Australia, and Japan), but it does not ask what protects those nations from despair. It has been observed that human beings are constrained by evolutionary strategy (ie, huge brain, prolonged physical and emotional dependence, education beyond adolescence for professional skills, and extended adult learning) to require communal support at all stages of the life cycle. Without support, difficulties accumulate until there seems to be no way forward. The 16 wealthy nations provide communal assistance at every stage, thus facilitating diverse paths forward and protecting individuals and families from despair. The US could solve its health crisis by adopting the best practices of the 16-nation control group.

Shedding light on biological sex differences and microbiota-gut-brain axis: a comprehensive review of its roles in neuropsychiatric disorders

Women and men are suggested to have differences in vulnerability to neuropsychiatric disorders, including major depressive disorder (MDD), generalized anxiety disorder (GAD), schizophrenia, eating disorders, including anorexia nervosa, and bulimia nervosa, neurodevelopmental disorders, such as autism spectrum disorder (ASD), and neurodegenerative disorders including Alzheimer's disease, Parkinson's disease. Genetic factors and sex hormones are apparently the main mediators of these differences. Recent evidence uncovers that reciprocal interactions between sex-related features (e.g., sex hormones and sex differences in the brain) and gut microbiota could play a role in the development of neuropsychiatric disorders via influencing the gut-brain axis. It is increasingly evident that sex-microbiota-brain interactions take part in the occurrence of neurologic and psychiatric disorders. Accordingly, integrating the existing evidence might help to enlighten the fundamental roles of these interactions in the pathogenesis of neuropsychiatric disorders. In addition, an increased understanding of the biological sex differences on the microbiota-brain may lead to advances in the treatment of neuropsychiatric disorders and increase the potential for precision medicine. This review discusses the effects of sex differences on the brain and gut microbiota and the putative underlying mechanisms of action. Additionally, we discuss the consequences of interactions between sex differences and gut microbiota on the emergence of particular neuropsychiatric disorders.

Disease characteristics and mortality among Asian women with breast cancer

BACKGROUND

Asian women with breast cancer are often studied in aggregate, belying significant intragroup diversity. The authors sought to examine differences in breast cancer characteristics and outcomes among Asian women.

METHODS

Asian, non-Hispanic Black, Hispanic, and non-Hispanic White women aged 18 years and older who were diagnosed with breast cancer from 1990 to 2016 were identified in the Surveillance, Epidemiology, and End Results 18 database. Asian patients were subclassified as Chinese, Japanese, Korean, Filipino, Vietnamese, South Asian (Asian Indian or Pakistani), Southeast Asian (SEA, i.e., Cambodian, Laotian, Hmong, or Thai), or other Asian. Unadjusted overall survival (OS) and cancer-specific survival (CSS) were estimated using the Kaplan-Meier method. Cox proportional hazards models were used to estimate adjusted OS and CSS.

RESULTS

In total, 910,415 women were included (Asian, n = 63,405; Black, n = 92,226; Hispanic, n = 84,451; White, n = 670,333). Asian women had higher rates of human epidermal growth factor receptor 2 (HER2)-positive disease compared with White women (18.7% vs 13.8%) and had the highest 10-year unadjusted OS and CSS among all racial/ethnic groups (all P < .001). SEA women had the highest rates of stage IV disease at presentation, whereas Japanese women had the lowest rates (5.9% vs 2.7%; P < .001). Japanese women had the highest 10-year unadjusted CSS (89.4%; 95% confidence interval, 88.7%-90.1%) of any distinct Asian group, whereas SEA women had the worst unadjusted CSS (78%; 95% confidence interval, 74.1%-81.3%; P < .001). After adjustment, SEA women had the worst OS of any Asian group and were the only Asian group without improved OS compared with White women (reference category; P = .08).

CONCLUSIONS

Breast cancer characteristics and outcomes vary significantly among Asian women. Future research should consider disaggregation by country or region of origin to identify subgroups that are at risk for worse outcomes than aggregated data may suggest.

LAY SUMMARY

Asian women with breast cancer are frequently studied as a single entity. However, Asian ethnic groups differ greatly by country of origin, genetic ancestry, disease frequency, socioeconomic status, patterns of immigration, as well as dietary and cultural practices. Women of different Asian ethnicities vary significantly with regard to cancer characteristics, such as mortality and tumor subtype. Future research should disaggregate these populations to better understand, treat, and counsel Asian patients with breast cancer.

Lower Socioeconomic Position Is Associated with Greater Activity in and Integration within an Allostatic-Interoceptive Brain Network in Response to Affective Stimuli

Socioeconomic inequities shape physical health and emotional well-being. As such, recent work has examined the neural mechanisms through which socioeconomic position (SEP) may influence health. However, there remain critical gaps in knowledge regarding the relationships between SEP and brain function. These gaps include a lack of research on: (1) the association between SEP and brain functioning in later life, (2) relationships between SEP and functioning of the whole brain beyond specific regions of interest, and (3) how neural responses to positive affective stimuli differ by SEP. The current study addressed these gaps by examining the association between SEP (i.e., education, income) and neural responses to affective stimuli among 122 mid- to late-life adults. During MRI scanning, participants viewed 30 positive, 30 negative, and 30 neutral images; activation and network connectivity analyses explored associations between SEP and neural responses to these affective stimuli. Analyses revealed that those with lower SEP showed greater neural activity to both positive and negative images in regions within the allostatic-interoceptive network, a system of regions implicated in representing and regulating physiological states of the body and the external environment. There were no positive associations between SEP and neural responses to negative or positive images. In addition, graph-theory network analyses showed that individuals with lower SEP demonstrated greater global efficiency within the allostatic-interoceptive network and executive control network, across all task conditions. The findings suggest that lower SEP is associated with enhanced neural sensitivity to affective cues that may be metabolically costly to maintain over time and suggest a mechanism by which SEP might get "under the skull" to influence mental and physical well-being.

Neighborhood characteristics and breast tumor methylation: using epigenomics to explore cancer outcome disparities

BACKGROUND

Social exposures may drive epigenetic alterations that affect racial disparities in breast cancer outcomes. This study examined the association between neighborhood-level factors and DNA methylation in non-Hispanic Black and White women diagnosed with breast cancer.

METHODS

Genome-wide DNA methylation was measured using the EPIC array in the tumor tissue of 96 women. Linear regression models were used to examine the association between nine neighborhood-level factors and methylation, regressing β values for each cytosine-phosphate guanine dinucleotide (CpG) site on neighborhood-level factors while adjusting for covariates. Neighborhood data were obtained from the Opportunity Atlas. We used a false discovery rate (FDR) threshold < 0.05, and for CpGs below this threshold, we examined interactions with race. We employed multivariable Cox proportional-hazards models to estimate whether aberrant methylation was associated with all-cause mortality.

RESULTS

26 of the CpG sites were associated with job density or college education (FDR < 0.05). Further exploration of these 26 CpG sites revealed no interactions by race, but a single probe in TMEM204 was associated with all-cause mortality.

CONCLUSION

We identified novel associations between neighborhood-level factors and the breast tumor DNA methylome. Our data are the first to show that dysregulation in neighborhood associated CpG sites may be associated with all-cause mortality. Neighborhood-level factors may contribute to differential tumor methylation in genes related to tumor progression and metastasis. This contributes to the increasing body of evidence that area-level factors (such as neighborhood characteristics) may play an important role in cancer disparities through modulation of the breast tumor epigenome.

An Epigenetic Perspective on Lifestyle Medicine for Depression: Implications for Primary Care Practice

Depression is the most common presenting mental health disorder in primary care. It is also a major contributor to somatic complaints, worsening of chronic medical conditions, poor quality of life, and suicide. Current pharmacologic and psychotherapeutic approaches avert less than half of depression's cumulative burden on society. However, there is a growing body of research describing both how maladaptive lifestyle choices contribute to the development and worsening of depression and how lifestyle-oriented medical interventions can reduce the incidence and severity of depression. This research, largely derived from an emerging field called epigenetics, elucidates the interactions between our lifestyle choices and those epigenetic factors which mediate our tendencies toward either health, or the onset, if not worsening of disease. The present review highlights how lifestyle choices involving diet, physical activity, sleep, social relationships, and stress influence epigenetic processes positively or negatively, and thereby play a significant role in determining whether one does or does not suffer from depression. The authors propose that medical training programs consider and adopt lifestyle medicine oriented instructional initiatives that will enable tomorrow's primary care providers to more effectively identify and therapeutically intervene in the maladaptive choices contributing to their patients' depression.

Multidimensional Analysis of Major Depression: Association Between BDNF Methylation, Psychosocial and Cognitive Domains

Major Depression is a complex disorder with a growing incidence worldwide and multiple variables have been associated with its etiology. Nonetheless, its diagnosis is continually changing and the need to understand it from a multidimensional perspective is clear. The purpose of this study was to identify risk factors for depression in a case-control study with 100 depressive inpatients and 87 healthy controls. A multivariate logistic regression analysis was performed including psychosocial factors, cognitive maladaptive schema domains, and specific epigenetic marks (BDNF methylation levels at five CpG sites in promoter IV). A family history of depression, the cognitive schemas of impaired autonomy/performance, impaired limits, other-directedness, and the methylation level of a specific CpG site were identified as predictors. Interestingly, we found a mediating effect of those cognitive schemas in the relationship between childhood maltreatment and depression. Also, we found that depressive patients exhibited hypomethylation in a CpG site of BDNF promoter IV, which adds to the current discussion about the role of methylation in depression. We highlight that determining the methylation of a specific region of a single gene offers the possibility of accessing a highly informative an easily measurable variable, which represents benefits for diagnosis. Following complete replication and validation on larger samples, models like ours could be applicable as additional diagnostic tools in the clinical context.

Biological, Psychological, and Social Determinants of Depression: A Review of Recent Literature

Depression is one of the leading causes of disability, and, if left unmanaged, it can increase the risk for suicide. The evidence base on the determinants of depression is fragmented, which makes the interpretation of the results across studies difficult. The objective of this study is to conduct a thorough synthesis of the literature assessing the biological, psychological, and social determinants of depression in order to piece together the puzzle of the key factors that are related to this condition. Titles and abstracts published between 2017 and 2020 were identified in PubMed, as well as Medline, Scopus, and PsycInfo. Key words relating to biological, social, and psychological determinants as well as depression were applied to the databases, and the screening and data charting of the documents took place. We included 470 documents in this literature review. The findings showed that there are a plethora of risk and protective factors (relating to biological, psychological, and social determinants) that are related to depression; these determinants are interlinked and influence depression outcomes through a web of causation. In this paper, we describe and present the vast, fragmented, and complex literature related to this topic. This review may be used to guide practice, public health efforts, policy, and research related to mental health and, specifically, depression.

Education, household income, and depressive symptoms in middle-aged and older Japanese adults

Background

Income inequality has dramatically increased worldwide, and there is a need to re-evaluate the association between socio-economic status (SES) and depression. Relative contributions of household income and education to depression, as well as their interactions, have not been fully evaluated. This study aimed to examine the association between SES and depressive symptoms in Japanese adults, focusing on interactions between education and household income levels.

Methods

This cross-sectional study used data from baseline surveys of two cohort studies. Participants were 38,499 community-dwelling people aged 40–74 years who participated in baseline surveys of the Murakami cohort study (2011–2012) and Uonuma cohort study (2012–2015) conducted in Niigata Prefecture, Japan. Information regarding marital status, education level, household income, occupation, activities of daily living (ADL), and history of cancer, myocardial infarction, stroke, and diabetes was obtained using a self-administered questionnaire. Depressive symptoms were examined using the Center for Epidemiologic Studies Depression Scale (CES-D). Logistic regression analysis was used to obtain odds ratios (ORs). Covariates included age, sex, marital status, education, household income, occupation, ADL, and disease history.

Results

Individuals with higher education levels had lower ORs (adjusted P for trend = 0.0007) for depressive symptoms, independently of household income level. The OR of the university-or-higher group was significantly lower than that of the junior high school group (adjusted OR = 0.79). Individuals with lower household income levels had higher ORs (adjusted P for trend< 0.0001) for depressive symptoms, independently of education level. The type of occupation was not associated with depressive symptoms. In subgroup analyses according to household income level, individuals with higher education levels had significantly lower ORs in the lowest- and lower-income groups (adjusted P for trend = 0.0275 and 0.0123, respectively), but not in higher- and highest-income groups (0.5214 and 0.0915, respectively).

Conclusions

Both education and household income levels are independently associated with the prevalence of depressive symptoms, with household income levels showing a more robust association with depressive symptoms than education levels. This suggests that a high household income level may offset the risk of depressive symptoms from having a low education level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12168-8.

Food and nutritional insecurity is associated with depressive symptoms mediated by NR3C1 gene promoter 1F methylation

The aim of this study was to investigate socioeconomic stressors predictive of depressive symptoms and possible epigenetic changes in the glucocorticoid receptor - NR3C1-1F - an encoding gene involved in depressive symptoms. A total of 321 adult volunteers from southeastern Brazil were recruited to evaluate depressive symptoms, socio-demographic and economic factors, including food and nutritional security (FNS) or insecurity (FNiS) status, and NR3C1-1F region methylation by pyrosequencing. Depressive symptom determinants were investigated using a Poisson regression model with robust variance. Mann-Whitney tests and structural mediation equation models were used to evaluate the relationship between NR3C1 DNA methylation, FNiS, and depressive symptoms. Multivariate Poisson regression with robust variance adjusted for sex and FNiS and NR3C1-1F region methylation predicted risk factors for depressive symptoms. Mediation analysis revealed that NR3C1-1F region methylation mediated the relationship between FNiS exposure and depressive symptoms as an outcome, and depressive volunteers and FNiS individuals exhibited a significant increase in NR3C1 methylation when compared to healthy individuals and FNS volunteers, respectively. Therefore, we suggest that stress caused by FNiS may lead to depressive symptoms and that NR3C1-1F DNA methylation can act as a mediator of both FNiS and depressive symptoms.

Socioeconomic status and the developing brain - A systematic review of neuroimaging findings in youth

A growing literature has shown associations between socioeconomic disadvantage and neural properties (such as brain structure and function). In this review, we aimed to synthesize findings on the neural correlates of socioeconomic status (SES) in youth samples across neuroimaging modalities. We also aimed to disentangle the effects of different SES measures (e.g., parent income and education) in our synthesis. We found relatively consistent patterns of positive associations between SES and both volume and cortical surface area of frontal regions, and amygdala, hippocampal, and striatal volume (with most consistent results for composite SES indices). Despite limited longitudinal work, results suggest that SES is associated with developmental trajectories of gray matter structure. Higher SES was also found to be associated with increased fractional anisotropy of some white matter tracts, although there were more null than positive findings. Finally, methodological heterogeneity in brain function and connectivity studies prevented us from making strong inferences. Based on our findings, we make recommendations for future research, discuss the role of mitigating factors, and implications for policy.

Highlighting Immune System and Stress in Major Depressive Disorder, Parkinson's, and Alzheimer's Diseases, with a Connection with Serotonin

There is recognition that both stress and immune responses are important factors in a variety of neurological disorders. Moreover, there is an important role of several neurotransmitters that connect these factors to several neurological diseases, with a special focus in this paper on serotonin. Accordingly, it is known that imbalances in stressors can promote a variety of neuropsychiatric or neurodegenerative pathologies. Here, we discuss some facts that link major depressive disorder, Alzheimer’s, and Parkinson’s to the stress and immune responses, as well as the connection between these responses and serotonergic signaling. These are important topics of investigation which may lead to new or better treatments, improving the life quality of patients that suffer from these conditions.

Glucocorticoid Signaling and Epigenetic Alterations in Stress-Related Disorders

Stress is defined as a state of threatened or perceived as threatened homeostasis. The well-tuned coordination of the stress response system is necessary for an organism to respond to external or internal stressors and re-establish homeostasis. Glucocorticoid hormones are the main effectors of stress response and aberrant glucocorticoid signaling has been associated with an increased risk for psychiatric and mood disorders, including schizophrenia, post-traumatic stress disorder and depression. Emerging evidence suggests that life-stress experiences can alter the epigenetic landscape and impact the function of genes involved in the regulation of stress response. More importantly, epigenetic changes induced by stressors persist over time, leading to increased susceptibility for a number of stress-related disorders. In this review, we discuss the role of glucocorticoids in the regulation of stress response, the mechanism through which stressful experiences can become biologically embedded through epigenetic alterations, and we underline potential associations between epigenetic changes and the development of stress-related disorders.

Neuroimaging and DNA Methylation: An Innovative Approach to Study the Effects of Early Life Stress on Developmental Plasticity

DNA methylation plays a key role in neural cell fate and provides a molecular link between early life stress and later-life behavioral phenotypes. Here, studies that combine neuroimaging methods and DNA methylation analysis in pediatric population with a history of adverse experiences were systematically reviewed focusing on: targeted genes and neural correlates; statistical models used to examine the link between DNA methylation and neuroimaging data also considering early life stress and behavioral outcomes. We identified 8 studies that report associations between DNA methylation and brain structure/functions in infants, school age children and adolescents faced with early life stress condition (e.g., preterm birth, childhood maltreatment, low socioeconomic status, and less-than optimal caregiving). Results showed that several genes were investigated (e.g., OXTR, SLC6A4, FKBP5, and BDNF) and different neuroimaging techniques were performed (MRI and f-NIRS). Statistical model used ranged from correlational to more complex moderated mediation models. Most of the studies (n = 5) considered DNA methylation and neural correlates as mediators in the relationship between early life stress and behavioral phenotypes. Understanding what role DNA methylation and neural correlates play in interaction with early life stress and behavioral outcomes is crucial to promote theory-driven studies as the future direction of this research fields.

Associations between childhood family emotional health, fronto-limbic grey matter volume, and saliva 5mC in young adulthood

Background

Poor family emotional health (FEH) during childhood is prevalent and impactful, and likely confers similar neurodevelopmental risks as other adverse social environments. Pointed FEH study efforts are underdeveloped, and the mechanisms by which poor FEH are biologically embedded are unclear. The current exploratory study examined whether variability in 5-methyl-cytosine (5mC) and fronto-limbic grey matter volume may represent pathways through which FEH may become biologically embedded.

Results

In 98 university students aged 18–22 years, retrospective self-reported childhood FEH was associated with right hemisphere hippocampus (b = 10.4, p = 0.005), left hemisphere amygdala (b = 5.3, p = 0.009), and right hemisphere amygdala (b = 5.8, p = 0.016) volumes. After pre-processing and filtering to 5mC probes correlated between saliva and brain, analyses showed that childhood FEH was associated with 49 5mC principal components (module eigengenes; MEs) (p_range = 3 × 10^–6 to 0.047). Saliva-derived 5mC MEs partially mediated the association between FEH and right hippocampal volume (Burlywood ME indirect effect b = − 111, p = 0.014), and fully mediated the FEH and right amygdala volume relationship (Pink4 ME indirect effect b = − 48, p = 0.026). Modules were enriched with probes falling in genes with immune, central nervous system (CNS), cellular development/differentiation, and metabolic functions.

Conclusions

Findings extend work highlighting neurodevelopmental variability associated with adverse social environment exposure during childhood by specifically implicating poor FEH, while informing a mechanism of biological embedding. FEH-associated epigenetic signatures could function as proxies of altered fronto-limbic grey matter volume associated with poor childhood FEH and inform further investigation into primarily affected tissues such as endocrine, immune, and CNS cell types.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01056-y.

Genetically predicted education attainment in relation to somatic and mental health

A deeper understanding of the causal links from education level to health outcomes may shed a light for disease prevention. In the present Mendelian randomization study, we found that genetically higher education level was associated with lower risk of major mental disorders and most somatic diseases, independent of intelligence. Higher education level adjusted for intelligence was associated with lower risk of suicide attempts, insomnia, major depressive disorder, heart failure, stroke, coronary artery disease, lung cancer, breast cancer, type 2 diabetes and rheumatoid arthritis but with higher risk of obsessive-compulsive disorder, anorexia nervosa, anxiety, bipolar disorder and prostate cancer. Higher education level was associated with reduced obesity and smoking, which mediated quite an extent of the associations between education level and health outcomes. These findings emphasize the importance of education to reduce the burden of common diseases.

Childhood adversity and common mental disorders in young employees in Sweden: is the association affected by early adulthood occupational class?

BACKGROUND

Childhood adversities are associated with an elevated risk for common mental disorders (CMDs). Whether the strength of the association also holds for young employees is unclear. Given the increase in CMD rates in young adults over the past decade, identification of risk factors has important implications for future public health interventions. The current study aimed to investigate the effects of childhood adversities on CMDs. Additionally, the role of occupational class (non-manual/manual workers) in the relationship was examined.

METHODS

This population-based longitudinal cohort study included 544,003 employees, 19-29 years, residing in Sweden in 2009. Adversities included parental death, parental mental and somatic disorders, parental separation or single-parent household, household public assistance and residential instability. Estimates of risk of CMDs, measured as prescription of antidepressants and/or psychiatric care with a clinical diagnosis of CMDs, between 2010 and 2016 were calculated as relative risks (RR) with 95% confidence intervals (CI), using a modified Poisson regression analysis. Occupational class (non-manual/manual workers) was explored as a potential moderator.

RESULTS

In both manual and non-manual workers, childhood adversities were associated with an elevated risk of subsequent CMDs. The risk was moderated by occupational class, i.e., especially pronounced risk was found in manual workers who had experienced cumulative adversity (adjusted RR 1.76, 95% CI 1.70-1.83) when compared to non-manual workers with no adversity. Among the adversities examined, having had a parent treated for a mental disorder, having grown up in a household living on public assistance or having experienced residential instability were the strongest predictors of CMDs.

CONCLUSION

Our findings suggest that, among young employees, manual workers with a history of multiple childhood adversities are especially vulnerable to subsequent CMDs.

Developmental cannabidiol exposure increases anxiety and modifies genome-wide brain DNA methylation in adult female mice

BACKGROUND

Use of cannabidiol (CBD), the primary non-psychoactive compound found in cannabis, has recently risen dramatically, while relatively little is known about the underlying molecular mechanisms of its effects. Previous work indicates that direct CBD exposure strongly impacts the brain, with anxiolytic, antidepressant, antipsychotic, and other effects being observed in animal and human studies. The epigenome, particularly DNA methylation, is responsive to environmental input and can direct persistent patterns of gene regulation impacting phenotype. Epigenetic perturbation is particularly impactful during embryogenesis, when exogenous exposures can disrupt critical resetting of epigenetic marks and impart phenotypic effects lasting into adulthood. The impact of prenatal CBD exposure has not been evaluated; however, studies using the psychomimetic cannabinoid Δ9-tetrahydrocannabinol (THC) have identified detrimental effects on psychological outcomes in developmentally exposed adult offspring. We hypothesized that developmental CBD exposure would have similar negative effects on behavior mediated in part by the epigenome. Nulliparous female wild-type Agouti viable yellow (Avy) mice were exposed to 20 mg/kg CBD or vehicle daily from two weeks prior to mating through gestation and lactation. Coat color shifts, a readout of DNA methylation at the Agouti locus in this strain, were measured in F1 Avy/a offspring. Young adult F1 a/a offspring were then subjected to tests of working spatial memory and anxiety/compulsive behavior. Reduced-representation bisulfite sequencing was performed on both F0 and F1 cerebral cortex and F1 hippocampus to identify genome-wide changes in DNA methylation for direct and developmental exposure, respectively.

RESULTS

F1 offspring exposed to CBD during development exhibited increased anxiety and improved memory behavior in a sex-specific manner. Further, while no significant coat color shift was observed in Avy/a offspring, thousands of differentially methylated loci (DMLs) were identified in both brain regions with functional enrichment for neurogenesis, substance use phenotypes, and other psychologically relevant terms.

CONCLUSIONS

These findings demonstrate for the first time that despite positive effects of direct exposure, developmental CBD is associated with mixed behavioral outcomes and perturbation of the brain epigenome.

The Identifying Depression Early in Adolescence Risk Stratified Cohort (IDEA-RiSCo): Rationale, Methods, and Baseline Characteristics

Background: The characterization of adolescents at high risk for developing depression has traditionally relied on the presence or absence of single risk factors. More recently, the use of composite risk scores combining information from multiple variables has gained attention in prognostic research in the field of mental health. We previously developed a sociodemographic composite score to estimate the individual level probability of depression occurrence in adolescence, the Identifying Depression Early in Adolescence Risk Score (IDEA-RS). Objectives: In this report, we present the rationale, methods, and baseline characteristics of the Identifying Depression Early in Adolescence Risk Stratified Cohort (IDEA-RiSCo), a study designed for in-depth examination of multiple neurobiological, psychological, and environmental measures associated with the risk of developing and with the presence of depression in adolescence, with a focus on immune/inflammatory and neuroimaging markers. Methods: Using the IDEA-RS as a tool for risk stratification, we recruited a new sample of adolescents enriched for low (LR) and high (HR) depression risk, as well as a group of adolescents with a currently untreated major depressive episode (MDD). Methods for phenotypic, peripheral biological samples, and neuroimaging assessments are described, as well as baseline clinical characteristics of the IDEA-RiSCo sample. Results: A total of 7,720 adolescents aged 14-16 years were screened in public state schools in Porto Alegre, Brazil. We were able to identify individuals at low and high risk for developing depression in adolescence: in each group, 50 participants (25 boys, 25 girls) were included and successfully completed the detailed phenotypic assessment with ascertainment of risk/MDD status, blood and saliva collections, and magnetic resonance imaging (MRI) scans. Across a variety of measures of psychopathology and exposure to negative events, there was a clear pattern in which either the MDD group or both the HR and the MDD groups exhibited worse indicators in comparison to the LR group. Conclusion: The use of an empirically-derived composite score to stratify risk for developing depression represents a promising strategy to establish a risk-enriched cohort that will contribute to the understanding of the neurobiological correlates of risk and onset of depression in adolescence.

Prenatal exposure to polycyclic aromatic hydrocarbons modifies the effects of early life stress on attention and Thought Problems in late childhood

BACKGROUND

Risk for childhood psychopathology is complex and multifactorial, implicating direct and interacting effects of familial and environmental factors. The role of environmental neurotoxicants in psychiatric risk is of growing concern, including polycyclic aromatic hydrocarbons (PAH), common in air pollution. Prenatal PAH exposure is linked to adverse physical, behavioral, and cognitive outcomes as well as increasing psychiatric risk. It is unclear whether environmental exposures, like PAH, magnify the effects of exposure to early life stress (ELS), a critical risk factor for psychopathology. The current work aimed to test potential interactions between prenatal PAH exposure and psychosocial/socioeconomic stress on psychiatric symptoms in school-age children.

METHODS

Data were from the Columbia Center for Children's Environmental Health Mothers and Newborns longitudinal birth cohort study. Prenatal PAH exposure was ascertained though air monitoring during pregnancy and maternal PAH-DNA adducts at delivery. Mothers reported on ELS (child age 5) and on child psychiatric symptoms across childhood (child age 5, 7, 9, and 11) using the Child Behavior Checklist (CBCL).

RESULTS

Significant prenatal airborne PAH × ELS interactions (FDR-corrected) predicted CBCL Attention (β = 0.22, t(307) = 3.47, p < .001, p_fdr  = .003) and Thought Problems T-scores (β = 0.21, t(307) = 3.29, p = .001, p_fdr  = .004) at age 11 (n = 319). Relative to those with lower exposure, children with higher prenatal PAH exposure exhibited stronger positive associations between ELS and CBCL Attention and Thought Problem T-scores. This interaction was also significant examining convergent ADHD measures (Conners, DuPaul) and examining maternal PAH-DNA adducts (β = 0.29, t(261) = 2.48, p = .01; n = 273). A three-way interaction with assessment wave indicated that the PAH × ELS interaction on Attention Problems was stronger later in development (β = 0.03, t(1,601) = 2.19, p = .03; n = 477).

CONCLUSIONS

Prenatal exposure to PAH, a common neurotoxicant in air pollution, may magnify or sustain the effects of early life psychosocial/socioeconomic stress on psychiatric outcomes later in child development. This work highlights the critical role of air pollution exposure on child mental health.

Subacute cannabidiol alters genome-wide DNA methylation in adult mouse hippocampus

Use of cannabidiol (CBD), the most abundant non-psychoactive compound found in cannabis (Cannabis sativa), has recently increased as a result of widespread availability of CBD-containing products. CBD is FDA-approved for the treatment of epilepsy and exhibits anxiolytic, antipsychotic, prosocial, and other behavioral effects in animal studies and clinical trials, however, the underlying mechanisms governing these phenotypes are still being elucidated. The epigenome, particularly DNA methylation, is responsive to environmental input and can govern persistent patterns of gene regulation affecting phenotype across the life course. In order to understand the epigenomic activity of cannabidiol exposure in the adult brain, 12-week-old male wild-type a/a Agouti viable yellow (A^vy ) mice were exposed to either 20 mg/kg CBD or vehicle daily by oral administration for 14 days. Hippocampal tissue was collected and reduced-representation bisulfite sequencing (RRBS) was performed. Analyses revealed 3,323 differentially methylated loci (DMLs) in CBD-exposed animals with a small skew toward global hypomethylation. Genes for cell adhesion and migration, dendritic spine development, and excitatory postsynaptic potential were found to be enriched in a gene ontology term analysis of DML-containing genes, and disease ontology enrichment revealed an overrepresentation of DMLs in gene sets associated with autism spectrum disorder, schizophrenia, and other phenotypes. These results suggest that the epigenome may be a key substrate for CBD's behavioral effects and provides a wealth of gene regulatory information for further study.

Macrosomia and psychiatric risk in adolescence

The prenatal environment can exert important effects on mental health. While much research has linked low birth weight to psychopathology, the intrauterine environment associated with high birth weight (macrosomia; > 4000 g) is also sub-optimal and may increase risk. Given the increasing prevalence of macrosomic births, understanding the mental health outcomes of infants born macrosomic can help refine theories of etiology, predict disorder, and target preventive interventions. Using data from the 2014 Ontario Child Health Study (OCHS), we examined the risk for psychiatric disorders in adolescents born macrosomic. Youth (N = 2151) aged 12-17 years completed the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID). Rates of common mental disorders assessed by the MINI-KID were compared between those born at normal birth weight (NBW; 2500-4000 g, n = 1817) and adolescents born macrosomic (> 4000 g, n = 334). These associations were then adjusted for participant age, sex, socioeconomic status (SES) of the family, parental mental health, and gestational diabetes mellitus. After adjustment for covariates, adolescents born macrosomic had higher odds of conduct disorder (CD; OR = 3.19, 95% CI: 1.37-7.43), oppositional defiant disorder (ODD; OR = 1.79, 95% CI: 1.11-2.91), and ADHD (OR = 1.77, 95% CI: 1.21-2.80). Moderation analyses revealed that males born macrosomic were more likely to have psychiatric problems than their female peers. Socioeconomic disadvantage also amplified the risk posed by macrosomia for ODD, ADHD, major depressive disorder, and generalized anxiety disorder. In this study, macrosomia was associated with an increased risk of clinically significant externalizing problems in adolescence, most notably among boys and those facing socioeconomic disadvantage.

Scars of childhood socioeconomic stress: A systematic review

Childhood socioeconomic position (SEP) is associated with the development of adult psychological outcomes, with DNA methylation (DNAm) as a mechanism to potentially explain these changes. We present the first systematic review synthesising the literature investigating childhood SEP and DNAm. Thirty-two publications were included. Seventeen studies focused on candidate genes, typically focusing on genes implicated with the stress response and/or development of psychiatric conditions. These studies typically investigated different regions of the genes, which revealed inconsistent results. Six studies calculated epigenetic age, with a small number revealing an elevated significant association with childhood SEP. Epigenome-wide studies revealed altered patterns of DNAm which varied between the nine studies. This research area is emerging and demonstrated great variance in findings with no clear patterns identified across studies. Multiple methodological shortcomings are identified, including at the phenotypic level where construct validity of childhood SEP is highly inconsistent, with studies using a wide range of measures. Larger cohorts will be required with international collaborations to strengthen this research area.

Clinical correlates of socioeconomic status in adolescent bipolar disorder

BACKGROUND

Lower socioeconomic status (SES) is associated with symptomatic severity, comorbidity, and functional impairment in adults with bipolar disorder (BD). Little is known about clinical correlates of SES in adolescents with BD.

METHODS

Participants included 195 adolescents, 13-20 years old, with BD type I, II or not otherwise specified (NOS). Diagnoses were determined by standardized semi-structured interviews. Based on the Hollingshead scale, participants were divided into "low" (SES 1-3) and the "high" (SES 4-5) SES groups. Demographic and clinical correlates of SES were evaluated in univariate analyses; significant variables were evaluated in a logistic regression model.

RESULTS

Compared to participants in the high SES group (n = 150), participants in the low SES group (n = 45) were significantly younger, less likely to be of Caucasian race and living with natural parents. In the logistic regression model, controlling for age and race, the low SES group had higher risk of police contact or arrest (OR = 2.41, 95% CI:1.14-5.11, p = 0.022), less treatment with stimulants(OR = 0.20 95% CI: 0.06-0.67, p = 0.009), and more post-traumatic stress disorder (PTSD) (OR = 4.08, 95% CI:1.33-12.46, p = 0.014) compared to the high SES group. In sensitivity analyses that further controlled for intact family, the finding of higher rates of police contact or arrest was no longer significant.

LIMITATIONS

Cross-sectional design; higher-skewed SES sample.

CONCLUSIONS

Lower SES in adolescent BD is associated with higher legal risk, increased PTSD, and under-treatment of attention-deficit/hyperactivity disorder (ADHD). Future studies are needed to evaluate the inter-relationships of these correlates, using prospective designs that can evaluate the direction of these associations. Further studies incorporating neurobiological markers are also needed to explore mechanisms underlying SES-related differences in BD.

Promoter Activity-Based Case-Control Association Study on SLC6A4 Highlighting Hypermethylation and Altered Amygdala Volume in Male Patients With Schizophrenia

Associations between altered DNA methylation of the serotonin transporter (5-HTT)-encoding gene SLC6A4 and early life adversity, mood and anxiety disorders, and amygdala reactivity have been reported. However, few studies have examined epigenetic alterations of SLC6A4 in schizophrenia (SZ). We examined CpG sites of SLC6A4, whose DNA methylation levels have been reported to be altered in bipolar disorder, using 3 independent cohorts of patients with SZ and age-matched controls. We found significant hypermethylation of a CpG site in SLC6A4 in male patients with SZ in all 3 cohorts. We showed that chronic administration of risperidone did not affect the DNA methylation status at this CpG site using common marmosets, and that in vitro DNA methylation at this CpG site diminished the promoter activity of SLC6A4. We then genotyped the 5-HTT-linked polymorphic region (5-HTTLPR) and investigated the relationship among 5-HTTLPR, DNA methylation, and amygdala volume using brain imaging data. We found that patients harboring low-activity 5-HTTLPR alleles showed hypermethylation and they showed a negative correlation between DNA methylation levels and left amygdala volumes. These results suggest that hypermethylation of the CpG site in SLC6A4 is involved in the pathophysiology of SZ, especially in male patients harboring low-activity 5-HTTLPR alleles.

DNA methylation and brain structure and function across the life course: A systematic review

MRI has enhanced our capacity to understand variations in brain structure and function conferred by the genome. We identified 60 studies that report associations between DNA methylation (DNAm) and human brain structure/function. Forty-three studies measured candidate loci DNAm; seventeen measured epigenome-wide DNAm. MRI features included region-of-interest and whole-brain structural, diffusion and functional imaging features. The studies report DNAm-MRI associations for: neurodevelopment and neurodevelopmental disorders; major depression and suicidality; alcohol use disorder; schizophrenia and psychosis; ageing, stroke, ataxia and neurodegeneration; post-traumatic stress disorder; and socio-emotional processing. Consistency between MRI features and differential DNAm is modest. Sources of bias: variable inclusion of comparator groups; different surrogate tissues used; variation in DNAm measurement methods; lack of control for genotype and cell-type composition; and variations in image processing. Knowledge of MRI features associated with differential DNAm may improve understanding of the role of DNAm in brain health and disease, but caution is required because conventions for linking DNAm and MRI data are not established, and clinical and methodological heterogeneity in existing literature is substantial.

Peripheral serotonin transporter DNA methylation is linked to increased salience network connectivity in females with anorexia nervosa

BACKGROUND

Epigenetic variation in the serotonin transporter gene (SLC6A4) has been shown to modulate the functioning of brain circuitry associated with the salience network and may heighten the risk for mental illness. This study is, to our knowledge, the first to test this epigenome–brain–behaviour pathway in patients with anorexia nervosa.

METHODS

We obtained resting-state functional connectivity (rsFC) data and blood samples from 55 acutely underweight female patients with anorexia nervosa and 55 age-matched female healthy controls. We decomposed imaging data using independent component analysis. We used bisulfite pyrosequencing to analyze blood DNA methylation within the promoter region of SLC6A4. We then explored salience network rsFC patterns in the group × methylation interaction.

RESULTS

We identified a positive relationship between SLC6A4 methylation levels and rsFC between the dorsolateral prefrontal cortex and the salience network in patients with anorexia nervosa compared to healthy controls. Increased rsFC in the salience network mediated the link between SLC6A4 methylation and eating disorder symptoms in patients with anorexia nervosa. We confirmed findings of rsFC alterations for CpG-specific methylation at a locus with evidence of methylation correspondence between brain and blood tissue.

LIMITATIONS

This study was cross-sectional in nature, the sample size was modest for the method and methylation levels were measured peripherally, so findings cannot be fully generalized to brain tissue.

CONCLUSION

This study sheds light on the neurobiological process of how epigenetic variation in the SLC6A4 gene may relate to rsFC in the salience network that is linked to psychopathology in anorexia nervosa.