The serotonin transporter promoter variant (5-HTTLPR), stress, and depression meta-analysis revisited: evidence of genetic moderation

The serotonin gene 5-HTTLPR and brain food-reward responses during sadness: a mood-induction neuroimaging study

BACKGROUND

High-calorie foods become particularly rewarding and difficult to resist under affective stressful circumstances. Individuals carrying the short allele variant of the serotonin transporter gene (s-allele 5-HTTLPR) often exhibit enhanced emotional and neuroendocrine stress responsiveness, which increases their risk to gain weight or to develop obesity.

OBJECTIVE

To explore whether homozygous S-allele 5-HTTLPR carriers are more sensitive to the rewarding effects of high- compared to low-calorie foods during sad mood.

METHODS

From a large (n = 827) DNA 5-HTTLPR database, a selected subgroup of homozygous S-allele and L-allele carriers were monitored for affective-motivational (mood, wanting-liking) and neural (fMRI) food-reward responsiveness during a food exposure task, before and after sad mood induction. Brain responsiveness was measured for high versus low calorie food pictures in a set of appetitive- and cognitive control ROIs, respectively.

RESULTS

Mood induction significantly increased sad mood in the majority of participants. Analyses revealed a genotype x mood induction interaction in cognitive control but not in affective ROIs. LL- compared to SS-carriers exhibited greater contrast value in the inferior frontal sulcus, dorsolateral PFC and superior parietal lob when viewing high- compared to low-calorie food pictures, which only in LL-genotypes significantly declined after sad mood induction.

CONCLUSION

LL- compared to SS-genotypes may have stronger high-calorie food responses in cognitive control brain areas in the absence of stress indicating better capacity to resist the rewarding effects of palatable foods.

Harmonizing the inner orchestra: the impact of urbanization and evolution of stress, inflammation, diet, and lifestyles in depression

PURPOSE OF REVIEW

This review explores the intersection of urbanization, stress, inflammation, diet, lifestyle changes, and digital evolution as key factors influencing depression, emphasizing the necessity for integrative and evolutionary perspectives in mental health and intervention.

RECENT FINDINGS

Epidemiological studies reveal a dramatic increase in common mental disorders, particularly depression, alongside parallel increases in suicide, unemployment, and divorce rates. Evolutionary perspectives suggest that mechanisms once advantageous for survival, such as stress responses and inflammatory processes, may contribute to mental health challenges in modern urban environments. Moreover, the mental health crisis among generation Z underscores the impact of digital evolution, where the shift from play-based to phone-based childhood contributes significantly to rising depression rates. Recent research highlights the significant role of omega-3 fatty acids, circadian rhythm regulation, mindfulness, and anti-inflammatory lifestyle interventions in mitigating depressive symptoms.

SUMMARY

The interplay between our evolutionary heritage and rapid societal changes has created a "symphony" of factors contributing to depression. Understanding these evolutionary mismatches in stress responses, inflammatory processes, dietary shifts, circadian disruptions, and digitalization provides new insights into the etiology of depression. This holistic approach, conceptualized as "harmonizing the inner orchestra," offers promising avenues for prevention and treatment strategies that address the multifaceted nature of depression in our modern world.

NRXN3-NLGN1 complex influences the development of depression induced by maternal separation in rats

Early-life stress (ELS) increases the risk of major depressive disorder in children and adolescents. However, the molecular and cellular mechanisms of major depressive disorder (MDD) induced by ELS are poorly understood. Here, we establish a stress model in rats in which maternal separation stress (MS) during the postnatal period increases susceptibility to restraint stress (RS) later in life. In terms of mechanism, MS causes long-lasting synaptic plasticity alterations in rats, which is accompanied by reduced branch and spine lengths in the hippocampus. We identified the role of the cell adhesion factor neurexin 3 (NRXN3) and its ligand neuroligin 1 (NLGN1) as mediators of these effects. NRXN3 and NLGN1 downregulation in the hippocampus occurred prior to the observed synaptic changes and depression-related behaviors. In conclusion, NRXN3 is involved in the development of depression induced by maternal separation, and the specific mechanism involves the NRXN3-NLGN1 complex, which can mediate synaptic plasticity and increase susceptibility todepression.

Serotonin dysfunction in ADHD

It is well accepted that attention deficit hyperactivity disorder (ADHD) is in part driven by dysfunction in the monoaminergic neurotransmitter system, but both the extent of dysfunction and possible therapeutic avenues presented by serotonergic neurotransmission is frequently overlooked. As such, we present key evidence for dysfunction in serotonergic transmission, as seen from biochemical, genetic and pharmacological perspectives. An overall deficit in serotonin availability is a common theme throughout the literature, thus this review aims to explore possible dysfunctions in the serotonin synthesis pathway which result in this reduced bioavailability, and investigate whether such dysfunctions could be loci of change in ADHD. We have identified several steps in transmission, namely the conversion of tryptophan to 5-hydroxytryptophan and its use of cofactor tetrahydrobiopterin, which could present promising avenues for development of novel clinical interventions for ADHD.

The minor allele of the serotonin transporter gene variant rs4251417 is associated with increased resilience in soldiers experiencing acute stress during survival training: preliminary findings

BACKGROUND

Variation in cognitive, emotional and physical performance in response to stress is attributable to environmental and genetic factors. Ability to adapt to stress is resilience.

OBJECTIVES

This study investigated genetic factors associated with resilience in soldiers exposed to severe stress due to intense physical and mental demands at Survive, Evade, Resist and Escape school, a unique environment to study acute stress and resiliency in real-world circumstances.

DESIGN

A preliminary correlational study was conducted to identify genetic markers for resilience to stress.

METHODS

Mood state, resiliency and dissociative state of 73 soldiers were assessed using: Connor-Davidson Resilience Scale (CD-RISC); Profile of Mood States (POMS); and Clinician-Administered Dissociative States Scale (CADSS). Change scores for resilience-related stress markers were computed; 116 single nucleotide polymorphisms (SNPs) associated with stress, depression, anxiety, sleep, or psychiatric disorders were assessed.

RESULTS

A significant association between change in CD-RISC score and SNP rs4251417, present in an intron of SLC6A4, the serotonin transporter gene, was observed.

CONCLUSIONS

Individuals with the minor allele of SNP rs4251417 had a greater positive change in CD-RISC, indicating increased self-assessed resilience. This study suggests the minor allele of SNP rs4251417 of SLC6A4 is associated with resilience when individuals are exposed to high stress.

A Machine Learning Model for Predicting Depression in Moroccan Rheumatoid Arthritis Patients

Background and objective Rheumatoid arthritis (RA) is a chronic inflammatory condition that significantly impacts the quality of life. Depression in RA exacerbates pain and reduces the likelihood of remission. Predicting depression in RA is often neglected due to time and resource constraints. Hence, this study aimed to develop a machine learning (ML) model for predicting depression in RA patients. Methodology We included 112 RA patients from CHU Hassan II, Fez, Morocco. Depression was assessed using the Hospital Anxiety and Depression Scale (HADS) scale, and clinical data were extracted from medical records. Twelve features were used to develop five ML models: support vector machine (SVM), random forest (RF), decision tree (DT), logistic regression (LR), and gradient boosting classifier (GBC). Data preprocessing involved managing missing values, normalizing data, and encoding variables. Model performance was evaluated using accuracy, precision, recall, F1 score, and area under the curve (AUC). Results The ML-based feature selection method showed the optimal performance. The LR model performed best in predicting depression, with 76.5% accuracy, 72.2% precision, 81.2% recall, an F1 score of 0.765, and an area under the receiver operating characteristic curve (ROC AUC) of 0.767. Conclusions Our study highlights the significance of ML models in predicting depression in RA patients. The selected features and the LR model showed promising performance. Further research is required to validate these results and develop more advanced models. Utilizing such tools could significantly impact the management of RA patients by identifying those at risk of depression and providing appropriate psychological support.

More and Less Fear in Serotonin Transporter Knockout Mice

Recent theories suggest that reduced serotonin transporter (5-HTT) function, which increases serotonin (5-HT) levels at the synapse, enhances neural plasticity and affects sensitivity to environmental cues. This may promote learning about emotionally relevant events. However, the boundaries that define such emotional learning remain to be established. This was investigated using 5-HTT knockout (5-HTTKO) mice which provide a model of long-term elevated 5-HT transmission and are associated with increased anxiety. Compared to wild-type controls, 5-HTTKO mice were faster to discriminate between an auditory cue that predicted footshock (CS+) and a cue predicting no footshock (CS-). Notably, this enhanced discrimination performance was driven not by faster learning that the CS+ predicted footshock, but rather by faster learning that the CS- cue signals the absence of footshock and thus provides temporary relief from fear/anxiety. Similarly, 5-HTTKO mice were also faster to reduce their fear of the CS+ cue during subsequent extinction. These findings are consistent with facilitated inhibitory learning that predicts the absence of potential threats in 5-HTTKO mice. However, 5-HTTKO mice also exhibited increased generalisation of fear learning about ambiguous aversive cues in a novel context, different from the training context. Thus, 5-HTTKO mice can exhibit both more and less fear compared to wild-type controls. Taken together, our results support the idea that loss of 5-HTT function, and corresponding increases in synaptic 5-HT availability, may facilitate learning by priming of aversive memories. This both facilitates inhibitory learning for fear memories but also enhances generalisation of fear.

Polygene by environment interactions predicting depressive outcomes

Depression is a major public health problem with a continued need to uncover its etiology. Current models of depression contend that gene-by-environment (G × E) interactions influence depression risk, and further, that depression is polygenic. Thus, recent models have emphasized two polygenic approaches: a hypothesis-driven multilocus genetic profile score (MGPS; "MGPS × E") and a polygenic risk score (PRS; "PRS × E") derived from genome-wide association studies (GWAS). This review for the first time synthesizes current knowledge on polygene by environment "P × E" interaction research predicting primarily depression-related outcomes, and in brief, neurobiological outcomes. The "environment" of focus in this project is stressful life events. It further discusses findings in the context of differential susceptibility and diathesis-stress theories-two major theories guiding G × E work. This synthesis indicates that, within the MGPS literature, polygenic scores based on the serotonin system, the HPA axis, or across multiple systems, interact with environmental stress exposure to predict outcomes at multiple levels of analyses and most consistently align with differential susceptibility theory. Depressive outcomes are the most studied, but neuroendocrine, and neuroimaging findings are observed as well. By contrast, vast methodological differences between GWAS-based PRS studies contribute to mixed findings that yield inconclusive results.

Neural Circuit Mechanisms of Sinisan formula for the Treatment of adolescent Depression: prefrontal cortex to dorsal raphe nucleus

ETHNOPHARMACOLOGICAL RELEVANCE

Sinisan formula (SNSF), documented in the classic books Shanghan Lun, is known for its ability to regulate liver-qi and treat depression. However, its underlying mechanism, particularly its effects on dynamic real-time neuron activity and circuits remains to be fully elucidated.

AIM OF THE STUDY

This study aimed to investigate the antidepressant effect of SNSF and its central nervous system mechanism on depression-like behaviors, focusing on the prefrontal cortex (PFC) to dorsal raphe nucleus (DRN) neural circuit in a stress-induced adolescent animal model.

MATERIALS AND METHODS

SNSF comprised four herbs, the root of Bupleurum chinense DC., the root of Paeonia lactiflora Pall., the fruit of Citrus aurantium L., the rhizome of Glycyrrhiza uralensis Fisch., in equal propotions. The adolescent depression animal model was induced by maternal separation (MS) and chronic restraint stress (CRS). In-vivo multichannel physiological electrodes were implanted into the PFC on PND 28 and animals were recorded 5 times during PND 35-46. From PND 47, the behavioral tests were performed to evaluate the antidepressant efficacy of SNSF. Subsequently, brain tissue was collected for Western blot and immunofluorescence staining analysis. Retro virus was injected into the DRN to explore sources of projections received by serotonergic (5-HTergic) neurons. And the PFC-to-DRN circuit was activated or inhibited through chemogenetic techniques to investigate the effects of SNSF on depression-like behaviors.

RESULTS

Administration of SNSF for 18 days effectively alleviated depression-like behaviors in MS&CRS adolescent mice. The PFC emerged as the primary glutamatergic projection source of the DRN5-HT neurons. Following SNSF administration for 13/15/18 days, there was an increase in the firing rate of excitatory neurons and excitatory/inhibitory (E/I) ratio in the PFC. MS&CRS stress let to a reduction in the density of 5-HT+ and CaMKII + neurons in the DRN, accompanied by an increase in the density of GAD + neurons in the DRN, while SNSF administration reversed the alterations. Chemogenetic activation of the PFC-to-DRN circuit rescued the depression-like behaviors induced by MS&CRS, whereas suppression of this circuit attenuated the antidepressant effect of SNSF.

CONCLUSIONS

SNSF significantly mitigated depression-like behaviors in MS&CRS mice. SNSF exerts its antidepressant effects by increasing the E/I ratio in the PFC and enhancing glutamatergic projections from the PFC to the DRN.

The role of serotonin in depression-A historical roundup and future directions

Depression is one of the most common psychiatric disorders worldwide, affecting approximately 280 million people, with probably much higher unrecorded cases. Depression is associated with symptoms such as anhedonia, feelings of hopelessness, sleep disturbances, and even suicidal thoughts. Tragically, more than 700 000 people commit suicide each year. Although depression has been studied for many decades, the exact mechanisms that lead to depression are still unknown, and available treatments only help a fraction of patients. In the late 1960s, the serotonin hypothesis was published, suggesting that serotonin is the key player in depressive disorders. However, this hypothesis is being increasingly doubted as there is evidence for the influence of other neurotransmitters, such as noradrenaline, glutamate, and dopamine, as well as larger systemic causes such as altered activity in the limbic network or inflammatory processes. In this narrative review, we aim to contribute to the ongoing debate on the involvement of serotonin in depression. We will review the evolution of antidepressant treatments, systemic research on depression over the years, and future research applications that will help to bridge the gap between systemic research and neurotransmitter dynamics using biosensors. These new tools in combination with systemic applications, will in the future provide a deeper understanding of the serotonergic dynamics in depression.

Recent Progress in Biosensors for Depression Monitoring-Advancing Personalized Treatment

Depression is currently a major contributor to unnatural deaths and the healthcare burden globally, and a patient's battle with depression is often a long one. Because the causes, symptoms, and effects of medications are complex and highly individualized, early identification and personalized treatment of depression are key to improving treatment outcomes. The development of wearable electronics, machine learning, and other technologies in recent years has provided more possibilities for the realization of this goal. Conducting regular monitoring through biosensing technology allows for a more comprehensive and objective analysis than previous self-evaluations. This includes identifying depressive episodes, distinguishing somatization symptoms, analyzing etiology, and evaluating the effectiveness of treatment programs. This review summarizes recent research on biosensing technologies for depression. Special attention is given to technologies that can be portable or wearable, with the potential to enable patient use outside of the hospital, for long periods.

Combined effects of physical activity and life events on depression and PTSD in Chinese students aged 16-24 years

Background

Life events are important risk factors for depression and post-traumatic stress disorder (PTSD). Physical activity is a beneficial behavior to physiological and psychological health. While it has not been reported at present the combined effect of physical activity and life events on individual depression and PTSD, and whether it can alleviate the psychological risks induced by life events.

Objective

To comprehensively investigate the current status of life events experiences in Chinese students aged 16-24 years and analyze the combined effects of physical activity and life events on their depression and PTSD.

Methods

An online cross-sectional survey was conducted on physical activity levels, life events experiences, depression and PTSD of 1,552 Chinese students aged 16-24 using short version of International Physical Activity Questionnaire (IPAQ-S), adolescent self-rating life events checklist (ASLEC), PTSD Check List-Civilian Version (PCL-C) and Patient Health Questionnaire Depression Scale. Then, logistic regression equation and stratified analysis were used to explore the combined effects of physical activity and life events on depression and PTSD.

Results

Regression analysis showed that, except for female, <8 h of sleep, smoking, single parent/reorganized families and poor family economic status, experiencing medium-intensity and high-intensity life events were both risk factors for depression. Compared with those who experienced low-intensity life events, those who experienced medium- and high-intensity life events had a 27 and 131% increased risk of depression, respectively. In contrast, medium- and high-level physical activity could reduce the risk of depression by 49 and 53%, respectively. Similar results were obtained with PTSD as a dependent variable. Combined correlation analysis showed that, compared with those with high-level physical activity and low-intensity life events, those with low-level physical activity and high-intensity life events had a 209 and 121% increased risk of depression and PTSD, respectively. Stratified analysis showed that the threshold for life events induced depression and PTSD rose with the increase in the level of physical activity.

Conclusion

Lack of physical activity and experience of high-intensity life events are independent risk factors for depression and PTSD, and strengthening physical activity can compensate for the harm of depression and PTSD caused by life events to some extent.

Duloxetine improves chronic orofacial pain and comorbid depressive symptoms in association with reduction of serotonin transporter protein through upregulation of ubiquitinated serotonin transporter protein

ABSTRACT

Chronic orofacial pain (COP) is relieved by duloxetine (DLX) and frequently causes depressive symptoms. The aim of this study was to confirm effects of DLX on pain and depressive symptoms, and to associate with their effectiveness in platelet serotonin transporter (SERT) expression, which is a target molecule of DLX and plasma serotonin concentration in COP patients with depressive symptoms. We assessed for the severity of pain and depressive symptoms using the Visual Analog Scale (VAS) and 17-item Hamilton Depression Rating Scale (HDRS), respectively. Chronic orofacial pain patients were classified into 2 groups based on their HDRS before DLX-treatment: COP patients with (COP-D) and without (COP-ND) depressive symptoms. We found that the VAS and HDRS scores of both groups were significantly decreased after DLX treatment compared with those before DLX treatment. Upregulation of total SERT and downregulation of ubiquitinated SERT were observed before DLX treatment in both groups compared with healthy controls. After DLX treatment, there were no differences in total SERT of both groups and in ubiquitinated SERT of COP-D patients compared with healthy controls; whereas, ubiquitinated SERT of COP-ND patients remained downregulated. There were positive correlations between changes of serotonin concentrations and of VAS or HDRS scores in only COP-D patients. Our findings indicate that DLX improves not only pain but also comorbid depressive symptoms of COP-D patients. Duloxetine also reduces platelet SERT through upregulation of ubiquitinated SERT. As the result, decrease of plasma serotonin concentrations may be related to the efficacy of DLX in relieving pain and depression in COP patients.

Inclusion of the severe and enduring anorexia nervosa phenotype in genetics research: a scoping review

BACKGROUND

Anorexia nervosa has one of the highest mortality rates of all mental illnesses. For those who survive, less than 70% fully recover, with many going on to develop a more severe and enduring phenotype. Research now suggests that genetics plays a role in the development and persistence of anorexia nervosa. Inclusion of participants with more severe and enduring illness in genetics studies of anorexia nervosa is critical.

OBJECTIVE

The primary goal of this review was to assess the inclusion of participants meeting the criteria for the severe enduring anorexia nervosa phenotype in genetics research by (1) identifying the most widely used defining criteria for severe enduring anorexia nervosa and (2) performing a review of the genetics literature to assess the inclusion of participants meeting the identified criteria.

METHODS

Searches of the genetics literature from 2012 to 2023 were performed in the PubMed, PsycINFO, and Web of Science databases. Publications were selected per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). The criteria used to define the severe and enduring anorexia nervosa phenotype were derived by how often they were used in the literature since 2017. The publications identified through the literature search were then assessed for inclusion of participants meeting these criteria.

RESULTS

most prevalent criteria used to define severe enduring anorexia nervosa in the literature were an illness duration of ≥ 7 years, lack of positive response to at least two previous evidence-based treatments, a body mass index meeting the Diagnostic and Statistical Manual of Mental Disorders-5 for extreme anorexia nervosa, and an assessment of psychological and/or behavioral severity indicating a significant impact on quality of life. There was a lack of consistent identification and inclusion of those meeting the criteria for severe enduring anorexia nervosa in the genetics literature.

DISCUSSION

This lack of consistent identification and inclusion of patients with severe enduring anorexia nervosa in genetics research has the potential to hamper the isolation of risk loci and the development of new, more effective treatment options for patients with anorexia nervosa.

Polygenic risk for depression predicting temperament trajectories over 15 years - A general population study

BACKGROUND

A great number of case-control and population-based studies have shown that depression patients differ from healthy controls in their temperament traits. We investigated whether polygenic risk for depression predicts trajectories of temperament traits from early adulthood to middle age.

METHODS

Participants came from the population-based Young Finns Study (n = 2212). The calculation for Polygenic risk for depression (PRS) was based on the most recent genome-wide association study. Temperament traits of Harm Avoidance, Novelty Seeking, Reward Dependence, and Persistence were assessed with the Temperament and Character Inventory in 1997, 2001, 2007, and 2012 (participants being 24-50-year-olds). As covariates, we used depressive symptoms as assessed by a modified version of the Beck Depression Inventory, psychosocial family environment from parent-filled questionnaires, and socioeconomic factors from adulthood.

RESULTS

High PRS predicted higher Persistence from early adulthood to middle age (p = 0.003) when controlling for depressive symptoms, psychosocial family environment, and socioeconomic factors. PRS did not predict trajectories of Novelty Seeking (p = 0.063-0.416 in different models) or Reward Dependence (p = 0.531-0.736). The results remained unaffected when participants with diagnosed affective disorders were excluded. Additionally, we found an interaction between PRS and depressive symptoms when predicting the Harm Avoidance subscale Anticipatory Worry, indicating that the association of Anticipatory Worry with depressive symptoms is stronger in individuals with higher (vs. lower) PRS.

LIMITATIONS

There was some attrition due to the long follow-up.

CONCLUSIONS

High polygenic risk for major depression may predict differences in temperament trajectories among those who have not developed any severe affective disorders.

Digging into the intrinsic capacity concept: Can it be applied to Alzheimer's disease?

Historically, aging research has largely centered on disease pathology rather than promoting healthy aging. The World Health Organization's (WHO) policy framework (2015-2030) underscores the significance of fostering the contributions of older individuals to their families, communities, and economies. The WHO has introduced the concept of intrinsic capacity (IC) as a key metric for healthy aging, encompassing five primary domains: locomotion, vitality, sensory, cognitive, and psychological. Past AD research, constrained by methodological limitations, has focused on single outcome measures, sidelining the complexity of the disease. Our current scientific milieu, however, is primed to adopt the IC concept. This is due to three critical considerations: (I) the decline in IC is linked to neurocognitive disorders, including AD, (II) cognition, a key component of IC, is deeply affected in AD, and (III) the cognitive decline associated with AD involves multiple factors and pathophysiological pathways. Our study explores the application of the IC concept to AD patients, offering a comprehensive model that could revolutionize the disease's diagnosis and prognosis. There is a dearth of information on the biological characteristics of IC, which are a result of complex interactions within biological systems. Employing a systems biology approach, integrating omics technologies, could aid in unraveling these interactions and understanding IC from a holistic viewpoint. This comprehensive analysis of IC could be leveraged in clinical settings, equipping healthcare providers to assess AD patients' health status more effectively and devise personalized therapeutic interventions in accordance with the precision medicine paradigm. We aimed to determine whether the IC concept could be extended from older individuals to patients with AD, thereby presenting a model that could significantly enhance the diagnosis and prognosis of this disease.

Enhanced polygenic risk score incorporating gene-environment interaction suggests the association of major depressive disorder with cardiac and lung function

BACKGROUND

Depression has been linked to an increased risk of cardiovascular and respiratory diseases; however, its impact on cardiac and lung function remains unclear, especially when accounting for potential gene-environment interactions.

METHODS

We developed a novel polygenic and gene-environment interaction risk score (PGIRS) integrating the major genetic effect and gene-environment interaction effect of depression-associated loci. The single nucleotide polymorphisms (SNPs) demonstrating major genetic effect or environmental interaction effect were obtained from genome-wide SNP association and SNP-environment interaction analyses of depression. We then calculated the depression PGIRS for non-depressed individuals, using smoking and alcohol consumption as environmental factors. Using linear regression analysis, we assessed the associations of PGIRS and conventional polygenic risk score (PRS) with lung function (N = 42 886) and cardiac function (N = 1791) in the subjects with or without exposing to smoking and alcohol drinking.

RESULTS

We detected significant associations of depression PGIRS with cardiac and lung function, contrary to conventional depression PRS. Among smokers, forced vital capacity exhibited a negative association with PGIRS (β = -0.037, FDR = 1.00 × 10-8), contrasting with no significant association with PRS (β = -0.002, FDR = 0.943). In drinkers, we observed a positive association between cardiac index with PGIRS (β = 0.088, FDR = 0.010), whereas no such association was found with PRS (β = 0.040, FDR = 0.265). Notably, in individuals who both smoked and drank, forced expiratory volume in 1-second demonstrated a negative association with PGIRS (β = -0.042, FDR = 6.30 × 10-9), but not with PRS (β = -0.003, FDR = 0.857).

CONCLUSIONS

Our findings underscore the profound impact of depression on cardiac and lung function, highlighting the enhanced efficacy of considering gene-environment interactions in PRS-based studies.

Organic cation transporters in psychiatric and substance use disorders

Psychiatric and substance use disorders inflict major public health burdens worldwide. Their widespread burden is compounded by a dearth of effective treatments, underscoring a dire need to uncover novel therapeutic targets. In this review, we summarize the literature implicating organic cation transporters (OCTs), including three subtypes of OCTs (OCT1, OCT2, and OCT3) and the plasma membrane monoamine transporter (PMAT), in the neurobiology of psychiatric and substance use disorders with an emphasis on mood and anxiety disorders, alcohol use disorder, and psychostimulant use disorder. OCTs transport monoamines with a low affinity but high capacity, situating them to play a central role in regulating monoamine homeostasis. Preclinical evidence discussed here suggests that OCTs may serve as promising targets for treatment of psychiatric and substance use disorders and encourage future research into their therapeutic potential.

Precision Medicine in Depression: The Role of Proteomics and Metabolomics in Personalized Treatment Approaches

Depression, or major depressive disorder (MDD), is a widespread mental health condition marked by enduring feelings of sorrow and loss of interest. Treatment of depression frequently combines psychotherapy, medication, and lifestyle modifications. However, the occurrence of treatment resistance in certain individuals makes it difficult for physicians to effectively manage this disorder, calling for the implementation of alternative therapeutic strategies. Recently, precision medicine has gained increased attention in the field of mental health, paving the way for more personalized and effective therapeutic interventions in depression. Also known as personalized medicine, this approach relies on genetic composition, molecular profiles, and environmental variables to customize therapies to individual patients. In particular, precision medicine has offered novel viewpoints on depression through two specific domains: proteomics and metabolomics. On one hand, proteomics is the thorough study of proteins in a biological system, while metabolomics focuses on analyzing the complete set of metabolites in a living being. In the past few years, progress in research has led to the identification of numerous depression-related biomarkers using proteomics and metabolomics techniques, allowing for early identification, precise diagnosis, and improved clinical outcome. However, despite significant progress in these techniques, further efforts are required for advancing precision medicine in the diagnosis and treatment of depression. The overarching goal of this chapter is to provide the current state of knowledge regarding the use of proteomics and metabolomics in identifying biomarkers related to depression. It also highlights the potential of proteomics and metabolomics in elucidating the intricate processes underlying depression, opening the door for tailored therapies that could eventually enhance clinical outcome in depressed patients. This chapter finally discusses the main challenges in the use of proteomics and metabolomics and discusses potential future research directions.

Biomarker adoption in developmental science: A data-driven modelling of trends from 90 biomarkers across 20 years

Developmental scientists have adopted numerous biomarkers in their research to better understand the biological underpinnings of development, environmental exposures, and variation in long-term health. Yet, adoption patterns merit investigation given the substantial resources used to collect, analyse, and train to use biomarkers in research with infants and children. We document trends in use of 90 biomarkers between 2000 and 2020 from approximately 430,000 publications indexed by the Web of Science. We provide a tool for researchers to examine each of these biomarkers individually using a data-driven approach to estimate the biomarker growth trajectory based on yearly publication number, publication growth rate, number of author affiliations, National Institutes of Health dedicated funding resources, journal impact factor, and years since the first publication. Results indicate that most biomarkers fit a "learning curve" trajectory (i.e., experience rapid growth followed by a plateau), though a small subset decline in use over time.

Investigating the Role of BDNF in Insomnia: Current Insights

Insomnia is a common disorder defined as frequent and persistent difficulty initiating, maintaining, or going back to sleep. A hallmark symptom of this condition is a sense of nonrestorative sleep. It is frequently associated with other psychiatric disorders, such as depression, as well as somatic ones, including immunomediated diseases. BDNF is a neurotrophin primarily responsible for synaptic plasticity and proper functioning of neurons. Due to its role in the central nervous system, it might be connected to insomnia of multiple levels, from predisposing traits (neuroticism, genetic/epigenetic factors, etc.) through its influence on different modes of neurotransmission (histaminergic and GABAergic in particular), maintenance of circadian rhythm, and sleep architecture, and changes occurring in the course of mood disturbances, substance abuse, or dementia. Extensive and interdisciplinary evaluation of the role of BDNF could aid in charting new areas for research and further elucidate the molecular background of sleep disorder. In this review, we summarize knowledge on the role of BDNF in insomnia with a focus on currently relevant studies and discuss their implications for future projects.

Potential genetic and epigenetic mechanisms in insomnia: A systematic review

Insomnia is a stress-related sleep disorder conceptualised within a diathesis-stress framework, which it is thought to result from predisposing factors interacting with precipitating stressful events that trigger the development of insomnia. Among predisposing factors genetics and epigenetics may play a role. A systematic review of the current evidence for the genetic and epigenetic basis of insomnia was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) system. A total of 24 studies were collected for twins and family heritability, 55 for genome-wide association studies, 26 about candidate genes for insomnia, and eight for epigenetics. Data showed that insomnia is a complex polygenic stress-related disorder, and it is likely to be caused by a synergy of genetic and environmental factors, with stress-related sleep reactivity being the important trait. Even if few studies have been conducted to date on insomnia, epigenetics may be the framework to understand long-lasting consequences of the interaction between genetic and environmental factors and effects of stress on the brain in insomnia. Interestingly, polygenic risk for insomnia has been causally linked to different mental and medical disorders. Probably, by treating insomnia it would be possible to intervene on the effect of stress on the brain and prevent some medical and mental conditions.

Evaluating the interaction between 3'aQTL and alcohol consumption/smoking on anxiety and depression: 3'aQTL-by-environment interaction study in UK Biobank cohort

BACKGROUND

Smoking and alcohol consumption were associated with the development of depression and anxiety. 3'UTR APA quantitative trait loci (3'aQTLs) have been associated with multiple health states and conditions. Our aim is to evaluate the interactive effects of 3'aQTLs-alcohol consumption/tobacco smoking on the risk of anxiety and depression.

METHODS

The 3'aQTL data of 13 brain regions were extracted from the large-scale 3'aQTL atlas. The phenotype data (frequency of cigarette smoking and alcohol drinking, anxiety score, self-reported anxiety, depression score and self-reported depression) of 90,399-103,011 adults aged 40-69 years living in the UK and contributing to the UK Biobank during 2006-2010, were obtained from the UK Biobank cohort. The frequency of cigarette smoking and alcohol drinking of each subject were defined by the amount of smoking and alcohol drinking of self-reported, respectively. The continuous alcohol consumption/smoking terms were further categorized in tertiles. 3'aQTL-by-environmental interaction analysis was then performed to evaluate the associations of gene-smoking/alcohol consumption interactions with anxiety and depression using generalized linear model (GLM) of PLINK 2.0 with an additive mode of inheritance. Furthermore, GLM was also used to explore the relationship between alcohol consumption/smoking with hazard of anxiety/depression stratified by allele for the significant genotyped SNPs that modified the alcohol consumption/smoking-anxiety/depression association.

RESULTS

The interaction analysis identified several candidate 3'aQTLs-alcohol consumption interactions, such as rs7602638 located in PPP3R1 (β = 0.08, P = 6.50 × 10-6) for anxiety score; rs10925518 located in RYR2 (OR = 0.95, P = 3.06 × 10-5) for self-reported depression. Interestingly, we also observed that the interactions between TMOD1 (β = 0.18, P = 3.30 × 10-8 for anxiety score; β = 0.17, P = 1.42 × 10-6 for depression score), ZNF407 (β = 0.17, P = 2.11 × 10-6 for anxiety score; β = 0.15, P = 4.26 × 10-5 for depression score) and alcohol consumption was not only associated with anxiety, but related to depression. Besides, we found that relationship between alcohol consumption and hazard of anxiety/depression was significantly different for different SNPs genotypes, such as rs34505550 in TMOD1 (AA: OR = 1.03, P = 1.79 × 10-6; AG: OR = 1.00, P = 0.94; GG: OR = 1.00, P = 0.21) for self-reported anxiety.

LIMITATIONS

The identified 3'aQTLs-alcohol consumption/smoking interactions were associated with depression and anxiety, and its potential biological mechanisms need to be further revealed.

CONCLUSIONS

Our study identified important interactions between candidate 3'aQTL and alcohol consumption/smoking on depression and anxiety, and found that the 3'aQTL may modify the associations between consumption/smoking with depression and anxiety. These findings may help to further explore the pathogenesis of depression and anxiety.

The neurobiology of openness as a personality trait

Openness is a multifaceted behavioral disposition that encompasses personal, interpersonal, and cultural dimensions. It has been suggested that the interindividual variability in openness as a personality trait is influenced by various environmental and genetic factors, as well as differences in brain functional and structural connectivity patterns along with their various associated cognitive processes. Alterations in degree of openness have been linked to several aspects of health and disease, being impacted by both physical and mental health, substance use, and neurologic conditions. This review aims to explore the current state of knowledge describing the neurobiological basis of openness and how individual differences in openness can manifest in brain health and disease.

Associations of the serotonin transporter gene polymorphism, 5-HTTLPR, and adverse life events with late life depression in the elderly Lithuanian population

Late-life depression (LLD) is a multifactorial disorder, with susceptibility and vulnerability potentially influenced by gene-environment interaction. The aim of this study was to investigate whether the 5-HTTLPR polymorphism is associated with LLD. The sample of 353 participants aged 65 years and over was randomly selected from the list of Kaunas city inhabitants by Residents' Register Service of Lithuania. Depressive symptoms were ascertained using the EURO-D scale. The List of Threatening Events Questionnaire was used to identify stressful life events that happened over the last 6 months and during lifetime. A 5-HTTLPR and lifetime stressful events interaction was indicated by higher odds of depression in those with s/s genotype who experienced high stress compared to l/l carriers with low or medium stress, while 5-HTTLPR and current stressful events interaction analysis revealed that carriers of either one or two copies of the s allele had increased odds of depressive symptoms associated with stress compared to participants with the l/l genotype not exposed to stressful situations. Although no significant direct association was found between the 5-HTTLPR short allele and depression, our findings demonstrated that lifetime or current stressful life events and their modification by 5-HTTLPR genotype are risk factors for late-life depression.

The serotonin theory of depression: a systematic umbrella review of the evidence

The serotonin hypothesis of depression is still influential. We aimed to synthesise and evaluate evidence on whether depression is associated with lowered serotonin concentration or activity in a systematic umbrella review of the principal relevant areas of research. PubMed, EMBASE and PsycINFO were searched using terms appropriate to each area of research, from their inception until December 2020. Systematic reviews, meta-analyses and large data-set analyses in the following areas were identified: serotonin and serotonin metabolite, 5-HIAA, concentrations in body fluids; serotonin 5-HT1A receptor binding; serotonin transporter (SERT) levels measured by imaging or at post-mortem; tryptophan depletion studies; SERT gene associations and SERT gene-environment interactions. Studies of depression associated with physical conditions and specific subtypes of depression (e.g. bipolar depression) were excluded. Two independent reviewers extracted the data and assessed the quality of included studies using the AMSTAR-2, an adapted AMSTAR-2, or the STREGA for a large genetic study. The certainty of study results was assessed using a modified version of the GRADE. We did not synthesise results of individual meta-analyses because they included overlapping studies. The review was registered with PROSPERO (CRD42020207203). 17 studies were included: 12 systematic reviews and meta-analyses, 1 collaborative meta-analysis, 1 meta-analysis of large cohort studies, 1 systematic review and narrative synthesis, 1 genetic association study and 1 umbrella review. Quality of reviews was variable with some genetic studies of high quality. Two meta-analyses of overlapping studies examining the serotonin metabolite, 5-HIAA, showed no association with depression (largest n = 1002). One meta-analysis of cohort studies of plasma serotonin showed no relationship with depression, and evidence that lowered serotonin concentration was associated with antidepressant use (n = 1869). Two meta-analyses of overlapping studies examining the 5-HT1A receptor (largest n = 561), and three meta-analyses of overlapping studies examining SERT binding (largest n = 1845) showed weak and inconsistent evidence of reduced binding in some areas, which would be consistent with increased synaptic availability of serotonin in people with depression, if this was the original, causal abnormaly. However, effects of prior antidepressant use were not reliably excluded. One meta-analysis of tryptophan depletion studies found no effect in most healthy volunteers (n = 566), but weak evidence of an effect in those with a family history of depression (n = 75). Another systematic review (n = 342) and a sample of ten subsequent studies (n = 407) found no effect in volunteers. No systematic review of tryptophan depletion studies has been performed since 2007. The two largest and highest quality studies of the SERT gene, one genetic association study (n = 115,257) and one collaborative meta-analysis (n = 43,165), revealed no evidence of an association with depression, or of an interaction between genotype, stress and depression. The main areas of serotonin research provide no consistent evidence of there being an association between serotonin and depression, and no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations. Some evidence was consistent with the possibility that long-term antidepressant use reduces serotonin concentration.

In vivo serotonin transporter and 1A receptor binding potential and ecological momentary assessment (EMA) of stress in major depression and suicidal behavior

We examined relationships between the serotonin system and stress in major depression and suicidal behavior. Twenty-five medication-free depressed participants (13 suicide attempters) underwent same-day [11C]DASB and [11C]CUMI-101 positron emission tomography (PET) imaging. Binding potential (BPND) to the serotonin transporter (5-HTT) and serotonin 1A (5-HT1A) receptor, respectively, was quantified using the NRU 5-HT atlas, reflecting distinct spatial distributions of multiple serotonin targets. Ecological momentary assessment (EMA) measured current stress over one week proximal to imaging. EMA stress did not differ between attempters and non-attempters. In all depressed participants, 5-HTT and 5-HT1A BPND were unrelated to EMA stress. There were region-specific effects of 5-HTT (p=0.002) and 5-HT1A BPND (p=0.03) in attempters vs. nonattempters. In attempters, region-specific associations between 5-HTT (p=0.03) and 5-HT1A (p=0.005) BPND and EMA stress emerged. While no post-hoc 5-HTT BPND correlations were significant, 5-HT1A BPND correlated positively with EMA stress in attempters in 9/10 regions (p-values<0.007), including the entire cortex except the largely occipital region 5. Brodmann-based regional analyses found diminished effects for 5-HTT and subcortically localized positive corrrelations between 5-HT1A and EMA stress, in attempters only. Given comparable depression severity and childhood and current stress between attempters and nonattempters, lower 5-HTT binding in attempters vs. nonattempters may suggest a biological risk marker. Localized lower 5-HTT and widespread higher 5-HT1A binding with stress among attempters specifically may suggest that a serotonergic phenotype might be a key determinant of risk or resiliency for suicidal behavior.

Associations of SLC6A4 methylation with salivary cortisol, salivary alpha-amylase, and subjective stress in everyday life

Dysregulations of the hypothalamic-pituitary-adrenal (HPA) and sympatho-adrenal medullary (SAM) axis are associated with mental and somatic illness. However, there is lack of knowledge regarding the molecular mechanisms underlying these effects. Epigenetic states in the serotonin transporter gene (SLC6A4) were shown to be associated with stress in various forms. We hypothesized that levels of DNA methylation (DNAm) of SLC6A4 would be associated with altered SAM- and HPA regulation in daily life. N = 74 healthy persons participated in the study. An ecological momentary assessment (EMA) approach was used to assess indicators of stress in daily life. Each day included six concurrent assessments of saliva, to quantify cortisol (sCort; HPA axis) and alpha-amylase (sAA; SAM axis), and to assess self-reports on subjective stress. To assess SLC6A4 DNAm, peripheral blood was drawn and analyzed via bisulfite pyrosequencing. All data were assessed in two waves three months apart, each including two days of EMA and the assessment of SLC6A4 DNAm. Data were analyzed using multilevel models. On the between-person level, higher average levels of SLC6A4 DNAm were associated with higher average levels of sAA, but not with average levels of sCort. On the within-person level, higher levels of SLC6A4 DNAm were associated with lower levels of sAA and sCort. There were no associations of subjective stress with SLC6A4 DNAm. The results help to clarify the association between environmental stress and stress axes regulation, pointing towards an important role of differential within- and between-person effects of SLC6A4 DNAm, which might shape this association.

Endocannabinergic modulation of central serotonergic activity in healthy human volunteers

BACKGROUND

The serotonergic and the endocannabinoid system are involved in the etiology of depression. Depressive patients exhibit low serotonergic activity and decreased level of the endocannabinoids anandamide (AEA) and 2-arachidonylglycerol (2AG). Since the cannabinoid (CB) 1 receptor is activated by endogenous ligands such as AEA and 2AG, whose concentration are controlled by the fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase, respectively, we investigated the effects on serotonergic utilization. In this study, we investigated the impact of the rs1049353 single-nucleotide polymorphism (SNP) of the cannabinoid receptor 1 (CNR1) gene, which codes the endocannabinoid CB1 receptor, and the rs324420 SNP of the FAAH gene on the serotonergic and endocannabinoid system in 59 healthy volunteers.

METHODS

Serotonergic activity was measured by loudness dependence of auditory-evoked potentials (LDAEP). Plasma concentrations of AEA, 2AG and its inactive isomer 1AG were determined by mass spectrometry. Genotyping of two SNPs (rs1049353, rs344420) was conducted by polymerase chain reaction (PCR) and differential enzymatic analysis with the PCR restriction fragment length polymorphism method.

RESULTS

Genotype distributions by serotonergic activity or endocannabinoid concentration showed no differences. However, after detailed consideration of the CNR1-A-allele-carriers, a reduced AEA (A-allele-carrier M = 0.66, SD = 0.24; GG genotype M = 0.72, SD = 0.24) and 2AG (A-allele-carriers M = 0.70, SD = 0.33; GG genotype M = 1.03, SD = 0.83) plasma concentration and an association between the serotonergic activity and the concentrations of AEA and 2AG has been observed.

CONCLUSIONS

Our results suggest that carriers of the CNR1-A allele may be more susceptible to developing depression.

Neurobiology of depression in Parkinson's disease: Insights into epidemiology, molecular mechanisms and treatment strategies

Parkinson's disease (PD) is characterized mainly by motor dysfunctions due to the progressive loss of dopaminergic neurons. However, PD patients experience a multitude of debilitating non-motor symptoms, including depression, which may have deleteriously detrimental effects on life. Depression is multifactorial and exhibits a bimodal progression in PD, but its underlying molecular mechanisms are poorly understood. Studies demonstrating the pathophysiology of depression in PD and the specific treatment strategies for depression-like symptoms in PD patients are largely lacking, often underrated, under-recognized and, consequently, inadequately/under-treated. Nevertheless, reports suggest that the incidence of depression is approximately 20-30% of PD patients and may precede the onset of motor symptoms. Diagnosing depression in PD becomes difficult due to the clinical overlap in symptomatology between the two diseases, and the nigrostriatal dysfunction alone is insufficient to explain depressive symptoms in PD. Therefore, the current study provides an overview of the molecular mechanisms underlying the development of depression in PD and new insights into developing current antidepressant strategies to treat depression in PD. This review will identify and understand the molecular pathological mechanisms of depression in PD that will fundamentally help tailoring therapeutic interventions for depressive symptoms in PD.

The interactive association of adverse childhood experiences and polygenic susceptibility with depressive symptoms and chronic inflammation in older adults: a prospective cohort study

BACKGROUND

Adverse childhood experiences (ACEs) and genetic liability are important risk factors for depression and inflammation. However, little is known about the gene-environment (G × E) mechanisms underlying their aetiology. For the first time, we tested the independent and interactive associations of ACEs and polygenic scores of major depressive disorder (MDD-PGS) and C-reactive protein (CRP-PGS) with longitudinal trajectories of depression and chronic inflammation in older adults.

METHODS

Data were drawn from the English longitudinal study of ageing (N~3400). Retrospective information on ACEs was collected in wave3 (2006/07). We calculated a cumulative risk score of ACEs and also assessed distinct dimensions separately. Depressive symptoms were ascertained on eight occasions, from wave1 (2002/03) to wave8 (2016/17). CRP was measured in wave2 (2004/05), wave4 (2008/09), and wave6 (2012/13). The associations of the risk factors with group-based depressive-symptom trajectories and repeated exposure to high CRP (i.e. ⩾3 mg/L) were tested using multinomial and ordinal logistic regression.

RESULTS

All types of ACEs were independently associated with high depressive-symptom trajectories (OR 1.44, 95% CI 1.30-1.60) and inflammation (OR 1.08, 95% CI 1.07-1.09). The risk of high depressive-symptom trajectories (OR 1.47, 95% CI 1.28-1.70) and inflammation (OR 1.03, 95% CI 1.01-1.04) was also higher for participants with higher MDD-PGS. G×E analyses revealed that the associations between ACEs and depressive symptoms were larger among participants with higher MDD-PGS (OR 1.13, 95% CI 1.04-1.23). ACEs were also more strongly related to inflammation in participants with higher CRP-PGS (OR 1.02, 95% CI 1.01-1.03).

CONCLUSIONS

ACEs and polygenic susceptibility were independently and interactively associated with elevated depressive symptoms and chronic inflammation, highlighting the clinical importance of assessing both ACEs and genetic risk factors to design more targeted interventions.

RNA epitranscriptomics dysregulation: A major determinant for significantly increased risk of ASD pathogenesis

Autism spectrum disorders (ASDs) are perhaps the most severe, intractable and challenging child psychiatric disorders. They are complex, pervasive and highly heterogeneous and depend on multifactorial neurodevelopmental conditions. Although the pathogenesis of autism remains unclear, it revolves around altered neurodevelopmental patterns and their implications for brain function, although these cannot be specifically linked to symptoms. While these affect neuronal migration and connectivity, little is known about the processes that lead to the disruption of specific laminar excitatory and inhibitory cortical circuits, a key feature of ASD. It is evident that ASD has multiple underlying causes and this multigenic condition has been considered to also dependent on epigenetic effects, although the exact nature of the factors that could be involved remains unclear. However, besides the possibility for differential epigenetic markings directly affecting the relative expression levels of individual genes or groups of genes, there are at least three mRNA epitranscriptomic mechanisms, which function cooperatively and could, in association with both genotypes and environmental conditions, alter spatiotemporal proteins expression patterns during brain development, at both quantitative and qualitative levels, in a tissue-specific, and context-dependent manner. As we have already postulated, sudden changes in environmental conditions, such as those conferred by maternal inflammation/immune activation, influence RNA epitranscriptomic mechanisms, with the combination of these processes altering fetal brain development. Herein, we explore the postulate whereby, in ASD pathogenesis, RNA epitranscriptomics might take precedence over epigenetic modifications. RNA epitranscriptomics affects real-time differential expression of receptor and channel proteins isoforms, playing a prominent role in central nervous system (CNS) development and functions, but also RNAi which, in turn, impact the spatiotemporal expression of receptors, channels and regulatory proteins irrespective of isoforms. Slight dysregulations in few early components of brain development, could, depending upon their extent, snowball into a huge variety of pathological cerebral alterations a few years after birth. This may very well explain the enormous genetic, neuropathological and symptomatic heterogeneities that are systematically associated with ASD and psychiatric disorders at large.

Addressing Emotional Dysregulation and Potential Pharmacogenetic Implication of 5-HTTLPR Genotype in Attention Deficit Hyperactivity Disorder

Background

This review unpacks the emotional presentation of externalizing behaviors in attention deficit hyperactivity disorder (ADHD), by diving into the psychophysiology, neurophysiology, and neurogenetics in relation to executive function. The correlations among these three variables are identified, showing that standard assessments for ADHD leave out the emotional dysregulation element. This may lead to suboptimal management outcomes during the developmental progression into adolescence and adulthood.

Summary

The emotional impulsivity manifestation in adolescence and adulthood related to the under-managed emotional dysregulation in childhood is found to be associated with subtle confounding impact of 5-HTTLPR (serotonin-transporter-linked promoter region) genotype. The genotype of interest affects the neurochemistry, neurophysiology, and psychophysiology of the cognition for executive function. The established practice of using methylphenidate in treating ADHD surprisingly has a neurogenetic effect in targeting the genotype of interest. Methylphenidate provides neuroprotective effects throughout the neurodevelopment timeline from childhood to adulthood.

Key Messages

The emotional dysregulation element in ADHD which is often overlooked should be addressed to improve the prognostic outcomes in adolescence and adulthood.

Genome-wide by Environment Interaction Study of Stressful Life Events and Hospital-Treated Depression in the iPSYCH2012 Sample

Background

Researchers have long investigated a hypothesized interaction between genetic risk and stressful life events in the etiology of depression, but studies on the topic have yielded inconsistent results.

Methods

We conducted a genome-wide by environment interaction study (GWEIS) in 18,532 patients with depression from hospital-based settings and 20,184 population controls. All individuals were drawn from the iPSYCH2012 case-cohort study, a nationally representative sample identified from Danish national registers. Information on stressful life events including family disruption, serious medical illness, death of a first-degree relative, parental disability, and child maltreatment was identified from the registers and operationalized as a time-varying count variable. Hazard ratios for main and interaction effects were estimated using Cox regressions weighted to accommodate the case-cohort design. Our replication sample included 22,880 depression cases and 50,378 controls from the UK Biobank.

Results

The GWEIS in the iPSYCH2012 sample yielded three novel, genome-wide-significant (p < 5 × 10-8) loci located in the ABCC1 gene (rs56076205, p = 3.7 × 10-10), the AKAP6 gene (rs3784187, p = 1.2 × 10-8), and near the MFSD1 gene (rs340315, p = 4.5 × 10-8). No hits replicated in the UK Biobank (rs56076205: p = .87; rs3784187: p = .93; rs340315: p = .71).

Conclusions

In this large, population-based GWEIS, we did not find any replicable hits for interaction. Future gene-by-stress research in depression should focus on establishing even larger collaborative GWEISs to attain sufficient power.

Additive serotonergic genetic sensitivity and cortisol reactivity to lab-based social evaluative stress: Influence of severity across two samples

Prior work demonstrates that an additive serotonergic multilocus genetic profile score (MGPS) predicts amplified risk for depression following significant life stress, and that it interacts with elevations in the cortisol awakening response to predict depression. The serotonin system and HPA-axis have bidirectional influence, but whether this MGPS predicts acute cortisol reactivity, which might then serve as a mechanism for depression, is unknown. Our prior work suggests that depression risk factors predict blunted cortisol reactivity to explicit negative evaluative lab-based stress. Thus, we hypothesized that a 4-variant serotonergic MGPS (three SNPs from the original 5-variant version plus 5HTTLPR) would predict blunted cortisol reactivity to explicit negative evaluative stress versus a control. In Sample 1, growth curve modeling showed that the MGPS predicted heightened cortisol reactivity (p = 0.0001) in an explicitly negative evaluative Trier Social Stress Test variant (TSST) versus a control condition among non-depressed emerging adults (N = 152; 57% female). In Sample 2, 125 males completed the Socially Evaluative Cold Pressor Test (SECPT), an ambiguously negative evaluative manipulation; findings displayed a similar pattern but did not reach statistical significance (ps.075-.091). A participant-level meta-analysis of the two samples demonstrated a significant effect of negative evaluation severity, such that the MGPS effect size on reactivity increased linearly from control to SECPT to an explicitly negative evaluative TSST. Findings indicate that this MGPS contributes to sensitivity to social threat and that cortisol dysregulation in the context of social stress may be one mechanism by which this MGPS contributes to depression.

The Architecture of Happiness

Happiness is an increasingly prominent topic of interest across academia. However, relatively little attention has been paid to how it is created, especially not in a multidimensional sense. By ‘created’ we do not mean its influencing factors, for which there is extensive research, but how it actually forms in the person. The work that has been done in this arena tends to focus on physiological dynamics, which are certainly part of the puzzle. But they are not the whole picture, with psychological, phenomenological, and socio cultural processes also playing their part. As a result, this paper offers a multidimensional overview of scholarship on the ‘architecture’ of happiness, providing a stimulus for further work into this important topic.

Is subthreshold depression in adolescence clinically relevant?

BACKGROUND

Subthreshold depression is highly prevalent in adolescence, but compared to major depressive disorder, the clinical impact is under-researched. The aim of this review was to compare subthreshold depression and major depressive disorder in adolescents by reviewing available literature on epidemiology, risk factors, illness trajectories, brain anatomy and function, genetics, and treatment response.

METHODS

We conducted a scoping review of papers on subthreshold depression and major depressive disorder in adolescence published in English. Studies in adults were included when research in adolescence was not available.

RESULTS

We found that individuals with subthreshold depression were similar to individuals with major depressive disorder in several regards, including female/male ratio, onset, functional impairment, comorbidity, health care utilization, suicidal ideation, genetic predisposition, brain alterations, and treatment response. Further, subthreshold depression was about two times more common than major depressive disorder.

LIMITATIONS

The definition of subthreshold depression is highly variable across studies. Adolescent-specific data are limited in the areas of neurobiology and treatment.

CONCLUSIONS

The findings of the current review support the idea that subthreshold depression is of clinical importance and provide evidence for a spectrum, versus categorical model, for depressive symptomatology. Given the frequency of subthreshold depression escalating to major depressive disorder, a greater recognition and awareness of the significance of subthreshold depression in research, clinical practice and policy-making may facilitate the development and application of early prevention and intervention.

Time moderates the interplay between 5-HTTLPR and stress on depression risk: gene x environment interaction as a dynamic process

The serotonin-transporter-linked promoter region (5-HTTLPR) has been widely investigated as contributing to depression vulnerability. Nevertheless, empirical research provides wide contrasting findings regarding its involvement in the etiopathogenesis of the disorder. Our hypothesis was that such discrepancy can be explained considering time as moderating factor. We explored this hypothesis, exploiting a meta analytic approach. We searched PubMed, PsychoINFO, Scopus and EMBASE databases and 1096 studies were identified and screened, resulting in 22 studies to be included in the meta-analyses. The effect of the 5-HTTLPR x stress interaction on depression risk was found to be moderated by the following temporal factors: the duration of stress (i.e. chronic vs. acute) and the time interval between end of stress and assessment of depression (i.e. within 1 year vs. more than 1 year). When stratifying for the duration of stress, the effect of the 5-HTTLPR x stress interaction emerged only in the case of chronic stress, with a significant subgroup difference (p = 0.004). The stratification according to time interval revealed a significant interaction only for intervals within 1 year, though no difference between subgroups was found. The critical role of time interval clearly emerged when considering only chronic stress: a significant effect of the 5-HTTLPR and stress interaction was confirmed exclusively within 1 year and a significant subgroup difference was found (p = 0.01). These results show that the 5-HTTLPR x stress interaction is a dynamic process, producing different effects at different time points, and indirectly confirm that s-allele carriers are both at higher risk and more capable to recover from depression. Overall, these findings expand the current view of the interplay between 5-HTTLPR and stress adding the temporal dimension, that results in a three-way interaction: gene x environment x time.

Mental Health and Social Support Are Key Predictors of Resilience in German Women with Endometriosis during the COVID-19 Pandemic

Background: Endometriosis is a multifaceted chronic pain disorder that can have an impact on both physical and mental health. Women suffering from chronic pain may be more susceptible to various health disorders, especially during adversity, such as the COVID-19 pandemic. Previous research has identified resilience as a mediator between internal or external stressors and well-being. Methods: An online survey was conducted during the first wave of the COVID-19 pandemic in Germany through patient support groups of women with endometriosis. The Brief Resilience Score (BRS) was employed to evaluate resilience, while the PHQ-4 questionnaire was used to assess self-reported mental health. Univariate and multivariate logistic regression analyses were applied to determine resilience’s independent risk and protective parameters. Results: High educational level was found to be an independent supportive moderator of high resilience in women with a resilience score greater than the study population’s median (BRS > 2.66; OR 2.715; 95% CI 1.472−5.007; p = 0.001) but not in women in the highest resilience score quartile (BRS > 3.33). A decrease in perceived social support was detected to be the most powerful independent risk factor for low resilience: OR 0.541, 95% CI 0.307−0.952, p = 0.033 for predicting BRS > 2.66, and OR 0.397, 95% CI 0.189−0.832, p = 0.014 for predicting scores > 3.33 on the BRS scale. A high burden of mental health symptoms, as measured by the PHQ-4 scale, was negatively associated with resilience. Conclusions: Satisfying social support and good mental health were shown to be key resources for resilience. The results of this study may assist in the identification of women at risk for low resilience and the development of resilience-building strategies in patients with endometriosis.

Early Life Adversity and Neuropsychiatric Disease: Differential Outcomes and Translational Relevance of Rodent Models

It is now well-established that early life adversity (ELA) predisposes individuals to develop several neuropsychiatric conditions, including anxiety disorders, and major depressive disorder. However, ELA is a very broad term, encompassing multiple types of negative childhood experiences, including physical, sexual and emotional abuse, physical and emotional neglect, as well as trauma associated with chronic illness, family separation, natural disasters, accidents, and witnessing a violent crime. Emerging literature suggests that in humans, different types of adverse experiences are more or less likely to produce susceptibilities to certain conditions that involve affective dysfunction. To investigate the driving mechanisms underlying the connection between experience and subsequent disease, neuroscientists have developed several rodent models of ELA, including pain exposure, maternal deprivation, and limited resources. These studies have also shown that different types of ELA paradigms produce different but somewhat overlapping behavioral phenotypes. In this review, we first investigate the types of ELA that may be driving different neuropsychiatric outcomes and brain changes in humans. We next evaluate whether rodent models of ELA can provide translationally relevant information regarding links between specific types of experience and changes in neural circuits underlying dysfunction.

Investigation of the Serotonergic Activity and the Serotonin Content in Serum and Platelet, and the Possible Role of the Serotonin Transporter in Patients with Depression

According to the monoamine hypothesis, the development of depression is associated with dysfunctions of the serotonergic system. Alterations in the serotonin transporter gene (5-HTTLPR), the serotonergic activity in the brain, and the content of serotonin (5-HT) have been related to depression and were examined separately by previous studies. This study investigates these parameters in 89 depressed patients and 89 healthy participants. We investigated the serotonergic activity measured by the loudness dependence of auditory evoked potentials (LDAEP). In addition to the examination of the serotonin content (serum and platelet), enzyme-linked immunosorbent assays (ELISA) were used and 5-HTTLPR genotypes were analyzed. We observed a lower serotonin content in patients compared to healthy participants. Further, we noticed a correlation between anxiety and depression-associated symptoms with serotonergic activity. Patients treated with SSRI/SNRI showed decreased contents of serum serotonin compared to patients without any psychotropic medication or other psychotropic medications. Since the serotonergic activity, peripheral serotonin content, and 5-HTTLPR were unrelated, the results suggest independent alterations of central and peripheral serotonergic systems in depression. In line with this finding, serotonergic activity was related to anxiety and depression symptoms. Furthermore, the applied medication seems to influence serum serotonin content in patients with depression.

Under the skin: does psychiatric outcome of bullying victimization in school persist over time? A prospective intervention study

BACKGROUND

Research has shown a direct path between peer victimization and poor mental health outcomes. However, the impact of bullying prevention on mental health is a largely unexplored field. Therefore, our study examined the longitudinal association between bullying development and trajectories of psychiatric symptoms (emotional problems, total difficulties, nonsuicidal self-injury, and suicidality) and health-related quality of life (HRQL) during the implementation of school-based bullying prevention.

METHODS

Data of 4,873 pupils (grades 5-13) were collected in 23 schools implementing the Olweus Bullying Prevention Program (OBPP). Self-report questionnaires were administered at three annual assessment waves and individual codes enabled the association of repeated assessments to the same pupil. Latent growth curve models (LGCMs) were used to examine the relation among bullying status and mental health outcome with mixed-effects linear regressions estimating the association of changes in bullying with changes in continuous scores and mixed-effects logistic regressions for categorical variables.

RESULTS

Latent growth curve models revealed an improvement of mental health and HRQL through the termination of bullying for every outcome variable of interest (all p < .001). Correspondingly, we found an explicit increase in psychopathology as well as decrease in HRQL within one year as a result of developing victimization (all p < .001). Interestingly, the growth of psychopathology associated with the onset of bullying was significantly steeper than its decline associated with the termination of bullying. The postulated cumulative effect of ongoing bullying for a further year could only be shown for HRQL (p = .025) and total difficulties (p = .034), but not for specific mental health problems (all p > .117).

CONCLUSIONS

Latent growth curve models clearly showed that the adverse psychosocial consequences of bullying arise quickly but seem to reduce much slower and partly persist over time. Future long-term studies are necessary to clarify if mental health problems will return to baseline after several years or if residual symptoms will remain.

Associations Between Personality Traits, Perceived Stress and Depressive Symptoms in Gynecological Cancer Patients Characterized by the Short and Long Allele Variant of the 5-HTTLPR Genotype: Preliminary Results

Objective

The study explored associations between personality traits, perceived stress and symptoms of depression in oncological patients characterized by the two variants of the serotonin transporter (5-HTTLPR) polymorphisms.

Method

The sample was composed of 41 gynecological cancer patients who completed self-reported questionnaires including the NEO Five-Factor Inventory, the dimension of depression-dejection (D/D) of the Profile of Moods State and the Perceived Stress Scale (PSS). The polymerase chain reaction was also employed to identify genotypes in the serotonin (5HTT) polymorphism.

Results

The one-way ANOVA test, across the 5-HTTLPR genotype groups, showed significant effects of the short variants on neuroticism (p=0.009) and of the long variant on agreeableness (p=0.022), as well as a tendency to a statistical significance of the l/l variant on consciousness (p=0.074). Bivariate correlations showed positive correlations of neuroticism with both psychopathological symptoms (D/D r=0.522; PSS r=0.586) in the combined group S, negative association of agreeableness with depression (D/D r=-0.613) and of consciousness with depression (D/D r=-0.750) and perceived stress (PSS r=-0.702) in the group of the long variant of 5-HT-TLPR genotype.

Conclusions

Personalized medicine should consider the interaction between genotype and phenotype in reducing levels of clinical psychological distress, highlighting how psychotherapeutic processes should improve patients' quality of life.

Relationship between a Self-Reported History of Depression and Persistent Elevation in C-Reactive Protein after Myocardial Infarction

Background: Elevated levels of C-reactive protein (CRP) are associated with both an increased risk of cardiovascular disease (CVD) and depression. We aimed to test the hypothesis that a self-report history of depression is associated with a smaller decrease in CRP levels from hospital admission to 3-month follow-up in patients with acute myocardial infarction (MI). Methods: We assessed 183 patients (median age 59 years; 84% men) with verified MI for a self-report history of lifetime depression and plasma CRP levels within 48 h of an acute coronary intervention and again for CRP levels at three months. CRP values were categorized according to their potential to predict CVD risk at hospital admission (acute inflammatory response: 0 to <5 mg/L, 5 to <10 mg/L, 10 to <20 mg/L, and ≥20 mg/L) and at 3 months (low-grade inflammation: 0 to <1 mg/L, 1 to <3 mg/L, and ≥3 mg/L). Additionally, in a subsample of 84 patients showing admission CRP levels below 20 mg/L, changes in continuous CRP values over time were also analyzed. Results: After adjustment for a range of potentially important covariates, depression history showed a significant association with a smaller decrease in both CRP risk categories (r = 0.261, p < 0.001) and log CRP levels (r = 0.340, p = 0.005) over time. Conclusions: Self-reported history of depression may be associated with persistently elevated systemic inflammation three months after MI. This finding warrants studies to test whether lowering of inflammation in patients with an acute MI and a history of depression may improve prognosis.

Neurobiology of early life adversity: A systematic review of meta-analyses towards an integrative account of its neurobiological trajectories to mental disorders

Adverse childhood experiences (ACEs) may leave long-lasting neurobiological scars, increasing the risk of developing mental disorders in later life. However, no review has comprehensively integrated existing evidence across the fields: hypothalamic-pituitary-adrenal axis, immune/inflammatory system, neuroimaging, and genetics/epigenetics. We thus systematically reviewed previous meta-analyses towards an integrative account of ACE-related neurobiological alterations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, a total of 27 meta-analyses until October 2021 were identified. This review found that individuals with ACEs possess blunted cortisol response to psychosocial stressors, low-grade inflammation evinced by increased C-reactive protein levels, exaggerated amygdalar response to emotionally negative information, and diminished hippocampal gray matter volume. Importantly, these alterations were consistently observed in those with and without psychiatric diagnosis. These findings were integrated and discussed in a schematic model of ACE-related neurobiological alterations. Future longitudinal research based on multidisciplinary approach is imperative for ACE-related mental disorders' prevention and treatment.

Going beyond risk factor: Childhood maltreatment and associated modifiable targets to improve life-long outcomes in mood disorders

Childhood maltreatment increases risk for mood disorders and is associated with earlier onset-and more pernicious disease course following onset-of mood disorders. While the majority of studies to date have been cross-sectional, longitudinal studies are emerging and support the devastating role(s) childhood maltreatment has on development of, and illness course in, mood disorders. This manuscript extends prior reviews to emphasize more recent work, highlighting longitudinal data, and discusses treatment studies that provide clues to mechanisms that mediate disease risk, course, relapse, and treatment response. Evidence suggesting systemic inflammation, alterations in hypothalamic-pituitary-adrenal (HPA) axis function and corticotropin-releasing factor (CRF) neural systems, genetic and other familial factors as mechanisms that mediate risk and onset of, and illness course in, mood disorders following childhood maltreatment is discussed. Risky behaviors following maltreatment, e.g., substance use and unhealthy lifestyles, may further exacerbate alterations in the HPA axis, CRF neural systems, and systematic inflammation to contribute to a more pernicious disease course. More research on sex differences and the impact of maltreatment in vulnerable populations is needed. Future research needs to be aimed at leveraging knowledge on modifiable targets, going beyond childhood maltreatment as a risk factor, to inform prevention and treatment strategies and foster trauma-informed care.

Childhood adversity and approach/avoidance-related behaviour in boys

Childhood adversity has been suggested to affect the vulnerability for developmental psychopathology, including both externalizing and internalizing symptoms. This study examines spontaneous attention biases for negative and positive emotional facial expressions as potential intermediate phenotypes. In detail, typically developing boys (6-13 years) underwent an eye-tracking paradigm displaying happy, angry, sad and fearful faces. An approach bias towards positive emotional facial expressions with increasing childhood adversity levels was found. In addition, an attention bias away from negative facial expressions was observed with increasing childhood adversity levels, especially for sad facial expressions. The results might be interpreted in terms of emotional regulation strategies in boys at risk for reactive aggression and depressive behaviour.

The Influence of 5-HTTLPR, BDNF Rs6265 and COMT Rs4680 Polymorphisms on Impulsivity in Bipolar Disorder: The Role of Gender

Impulsivity has been proposed as an endophenotype for bipolar disorder (BD); moreover, impulsivity levels have been shown to carry prognostic significance and to be quality-of-life predictors. To date, reports about the genetic determinants of impulsivity in mood disorders are limited, with no studies on BD individuals. Individuals with BD and healthy controls (HC) were recruited in the context of an observational, multisite study (GECOBIP). Subjects were genotyped for three candidate single-nucleotide polymorphisms (SNPs) (5-HTTLPR, COMT rs4680, BDNF rs6265); impulsivity was measured through the Italian version of the Barratt Impulsiveness Scale (BIS-11). A mixed-effects regression model was built, with BIS scores as dependent variables, genotypes of the three polymorphisms as fixed effects, and centers of enrollment as random effect. Compared to HC, scores for all BIS factors were higher among subjects with euthymic BD (adjusted β for Total BIS score: 5.35, p < 0.001). No significant interaction effect was evident between disease status (HC vs. BD) and SNP status for any polymorphism. Considering the whole sample, BDNF Met/Met homozygosis was associated with lower BIS scores across all three factors (adjusted β for Total BIS score: −10.2, p < 0.001). A significant 5-HTTLPR x gender interaction was found for the SS genotype, associated with higher BIS scores in females only (adjusted β for Total BIS score: 12.0, p = 0.001). Finally, COMT polymorphism status was not significantly associated with BIS scores. In conclusion, BD diagnosis did not influence the effect on impulsivity scores for any of the three SNPs considered. Only one SNP—the BDNF rs6265 Met/Met homozygosis—was independently associated with lower impulsivity scores. The 5-HTTLPR SS genotype was associated with higher impulsivity scores in females only. Further studies adopting genome-wide screening in larger samples are needed to define the genetic basis of impulsivity in BD.

From society to cells and back again: new opportunities for discovery at the biosocial interface

A new generation of community- and population-based research is combining measures of social context, experience, and behavior with direct measures of physiology, gene sequence and function, and health. Studies drawing on models and methods from the social and biological sciences have the potential to illuminate the multilevel mechanisms through which experience becomes biology, and to move past decontextualized and reductionistic approaches to human development, behavior, and health. In this perspective we highlight challenges and opportunities at the biosocial interface, and briefly discuss COVID-19 as a case study demonstrating the importance of linking across levels of analysis.