Impact of variation in the BDNF gene on social stress sensitivity and the buffering impact of positive emotions: replication and extension of a gene-environment interaction

Psychosocial functioning in individuals with advanced oesophago-gastric cancer: a mixed methods systematic review

BACKGROUND

Oesophago-gastric cancer is an aggressive disease with a high rate of recurrence and mortality across the disease trajectory. Reduced psychosocial functioning has been evidenced amongst those with advanced disease, however little is known about the contributing factors. Determining these factors is an important clinical consideration to inform assessment and intervention. This review aimed to synthesise the available evidence on the psychosocial functioning of individuals with advanced oesophago-gastric cancer and their carers.

METHODS

A JBI mixed-methods systematic review. Four bibliographic databases, MEDLINE, Embase, PsycINFO, and CINAHL, were searched. Quantitative and qualitative studies were screened for inclusion and critically appraised for methodological quality. Both types of data were extracted using JBI tools for mixed-methods systematic reviews. A convergent segregated approach to synthesis and integration was used. The findings of the synthesis have been configured according to JBI methodology.

RESULTS

A total of 12 studies were included in this review, including 6 quantitative studies and 6 qualitative studies. The quantitative results provide preliminary indication of several physical, biological, psychological and macro-level contextual factors associated with psychosocial functioning in this clinical population. The qualitative findings shed light on a range of physical, psychosocial, and existential challenges faced by advanced oesophago-gastric cancer patients. These multiple and often persistent challenges appear to cause considerable distress; however, patients describe the importance of maintaining a sense of normality and control over their illness and its effects. Patients value continuity and structure, however many report shortcomings when accessing care. No findings reporting the experiences from the perspective of carers were found, therefore all findings represent the perspective of the patient.

CONCLUSIONS

Further high-quality research is needed to understand how best to support and manage the palliative care needs of individuals living with advanced oesophago-gastric cancer. Implications for practice are discussed, suggesting that psychosocial interventions, complex symptom management and continuity of care could improve the psychosocial functioning of individuals in this setting.

PRE-REGISTRATION

The systematic review was pre-registered at the International Prospective Register of Systematic Reviews (PROSPERO; CRD42020181273) and the protocol can be viewed on the OSF ( http://osf.io/exuzf ).

Genetic associations with resilience to potentially traumatic events and vantage sensitivity to social support

INTRODUCTION

Stress responses and mental health outcomes greatly vary when individuals are exposed to potentially traumatic events (PTEs). The Differential Susceptibility Model (DSM) (Pluess, 2015) suggests individual differences in stress responses are influenced by gene-environment interactions, with genes conferring reactivity. While individuals can be resilient (or vulnerable) to PTEs, they can also have vantage sensitivity (or resistance) to social support. This study examined whether selected genotypes moderated the effect of PTEs and social support on mental health.

METHODS

This cross-sectional candidate gene study included 450 college students (M age = 20.4, 79.3 % women) who provided buccal cells for genotyping and completed measures of psychosocial variables. DNA was genotyped for 12 genetic variants.

RESULTS

Hierarchical regression revealed that the Mental Health Inventory (MHI) was associated with the Trauma History Questionnaire (THQ), rs1800795 in IL-6, and THQ × rs1800795 [R² = 0.10, F(3, 418) = 15.68, p < .01]. The MHI was associated with the Social Support Survey (SSS), rs4680 in COMT, and SSS × rs4680 [R² = 0.24, F(3, 429) = 44.19, p < .01]. Only THQ and SSS survived multiple testing corrections.

DISCUSSION

Findings partially support the DSM that the G/G genotype of rs1800795 in IL-6 is associated with resilience to PTEs, and the Met/Met genotype of rs4680 in COMT is associated with vantage sensitivity to social support. Limitations include cross-sectional design, limited PTE measurement, small convenience sample, and noncorrection for multiple significance test. Clinicians need to view resilience holistically and understand resilience is associated with psychosocial and genetic factors.

Interaction between the BDNF rs11030101 genotype and job stress on cognitive empathy

BACKGROUND

Empathy refers to an individual's ability to experience the emotional and cognitive processes of another person during social interactions. Although many studies have examined the effects of genetic variation on emotional empathy, little is currently known about whether genetic factors may influence cognitive empathy. This study investigated the relationship between BDNF rs11030101 genotype, job stress, and empathy, especially cognitive empathy, in a Chinese Han population.

METHODS

A cross-sectional design was used and 340 participants were recruited from a university in Beijing. Interpersonal Reactivity Index (IRI) was used to measure empathy. Job stress was measured using House and Rizzo's Job Stress Scale. The BDNF rs11030101 was genotyped in all participants.

RESULTS

Gender and age were associated with various IRI subscales (p < 0.001). After controlling for gender, age and education level, BDNF rs11030101 genotype had no main effect on all empathy subscales (p > 0.05). Job stress was negatively associated with Perspective Taking (p = 0.006) and positively associated with Personal Distress (p < 0.001). In addition, the BDNF rs11030101 genotype modulated the relationship between job stress and Fantasy (p = 0.013), indicating that T allele carriers had higher Fantasy scores at higher job stress and lower Fantasy scores at lower job stress than AA homozygotes. This interaction was only present in women.

LIMITATIONS

The sample size and single-nucleotide polymorphism are limited, and the cross-sectional design should be improved.

CONCLUSIONS

Female university faculty with the BDNF rs11030101 T allele may utilize higher emotional job demands, thereby fostering their cognitive empathy.

Genetic Variants Associated With Resilience in Human and Animal Studies

Resilience is broadly defined as the ability to maintain or regain functioning in the face of adversity and is influenced by both environmental and genetic factors. The identification of specific genetic factors and their biological pathways underpinning resilient functioning can help in the identification of common key factors, but heterogeneities in the operationalisation of resilience have hampered advances. We conducted a systematic review of genetic variants associated with resilience to enable the identification of general resilience mechanisms. We adopted broad inclusion criteria for the definition of resilience to capture both human and animal model studies, which use a wide range of resilience definitions and measure very different outcomes. Analyzing 158 studies, we found 71 candidate genes associated with resilience. OPRM1 (Opioid receptor mu 1), NPY (neuropeptide Y), CACNA1C (calcium voltage-gated channel subunit alpha1 C), DCC (deleted in colorectal carcinoma), and FKBP5 (FKBP prolyl isomerase 5) had both animal and human variants associated with resilience, supporting the idea of shared biological pathways. Further, for OPRM1, OXTR (oxytocin receptor), CRHR1 (corticotropin-releasing hormone receptor 1), COMT (catechol-O-methyltransferase), BDNF (brain-derived neurotrophic factor), APOE (apolipoprotein E), and SLC6A4 (solute carrier family 6 member 4), the same allele was associated with resilience across divergent resilience definitions, which suggests these genes may therefore provide a starting point for further research examining commonality in resilience pathways.

CyberGenomics: Application of Behavioral Genetics in Cybersecurity

Cybersecurity (CS) is a contemporary field for research and applied study of a range of aspects from across multiple disciplines. A cybersecurity expert has an in-depth knowledge of technology but is often also recognized for the ability to view technology in a non-standard way. This paper explores how CS specialists are both a combination of professional computing-based skills and genetically encoded traits. Almost every human behavioral trait is a result of many genome variants in action altogether with environmental factors. The review focuses on contextualizing the behavior genetics aspects in the application of cybersecurity. It reconsiders methods that help to identify aspects of human behavior from the genetic information. And stress is an illustrative factor to start the discussion within the community on what methodology should be used in an ethical way to approach those questions. CS positions are considered stressful due to the complexity of the domain and the social impact it can have in cases of failure. An individual risk profile could be created combining known genome variants linked to a trait of particular behavior using a special biostatistical approach such as a polygenic score. These revised advancements bring challenging possibilities in the applications of human behavior genetics and CS.

Measuring resilience in children: a review of recent literature and recommendations for future research

PURPOSE OF REVIEW

Understanding variability in developmental outcomes following exposure to early life adversity (ELA) has been an area of increasing interest in psychiatry, as resilient outcomes are just as prevalent as negative ones. However, resilient individuals are understudied in most cohorts and even when studied, resilience is typically defined as an absence of psychopathology. This review examines current approaches to resilience and proposes more comprehensive and objective ways of defining resilience.

RECENT FINDINGS

Of the 36 studies reviewed, the most commonly used measure was the Strengths and Difficulties Questionnaire (n = 6), followed by the Child Behavior Checklist (n = 5), the Resilience Scale for Chinese Adolescents (n = 5), the Rosenberg Self-Esteem Scale (n = 4), and the Child and Youth Resilience Scale (n = 3).

SUMMARY

This review reveals that studies tend to rely on self-report methods to capture resilience which poses some challenges. We propose a complementary measure of child resilience that relies on more proactive behavioral and observational indicators; some of our preliminary findings are presented. Additionally, concerns about the way ELA is characterized as well as the influence of genetics on resilient outcomes prompts further considerations about how to proceed with resiliency research.

Polymorphisms of brain-derived neurotrophic factor genes are associated with anxiety and body mass index in fibromyalgia syndrome patients

Objective

Fibromyalgia syndrome has been associated with familial clusters although the specific genetic predisposition is not clear. Accordingly, studies concerning genetic factors associated with this disease are important. Brain-derived neurotrophic factor (BDNF) has been shown to play a role in patients with fibromyalgia syndrome, particularly in mediating manifestations of pain and mood-related symptoms. Research on genetic factors, including genetic variations or single nucleotide polymorphisms, especially related to BDNF in fibromyalgia is very limited. Therefore, this study was aiming at determining the association of polymorphisms of BDNF, particularly rs2049046 (A>T) and rs7124442 (A>G), with body mass index (BMI) and mood-related symptoms in FMS.

Results

In fibromyalgia syndrome cases, BDNF polymorphisms were associated with body mass index and anxiety score, specifically rs7124442 (A>G) (Fisher’s exact test χ²; p < 0.05; odds ratio (OR): 1.02) and rs2049046 (A>T) (Fisher’s exact test χ²; p < 0.05; OR: 0.55), respectively. Additionally, patients with fibromyalgia syndrome who have AA (95% CI (8.71, 11.63)) and AT (95% CI (9.32, 11.74)) alleles of rs2049046 showed higher score of anxiety compared to patients with TT (95% CI (3.98, 8.20) allele (ANOVA test; p < 0.01). These results suggest that BDNF polymorphisms (rs7124442 and rs2049046) are associated with body mass index and anxiety symptoms in patients with fibromyalgia syndrome.

Polymorphisms in the BDNF and BDNFOS genes are associated with hypothalamus-pituitary axis regulation in major depression

Major depression is a stress-related disorder with robust clinical and preclinical data implicating that both, dysregulation of the hypothalamus-pituitary-adrenocortical (HPA) axis and of the neurotrophin system of the brain are involved in the pathophysiology. Genetic variations within the brain-derived neurotrophic factor (BDNF) gene region, a major representative of the brain neurotrophins, are suggested to influence response to antidepressant treatment. Specifically, we recently identified two BDNF single nucleotide polymorphisms (SNP), rs2049046 and rs11030094, as associated with antidepressant treatment response in a large pharmacogenetic study of hospitalized patients. We now analyzed these two SNPs in a sub-sample for their association with HPA axis dysregulation using the combined dexamethasone suppression/corticotropin releasing hormone challenge (dex/CRH) test at hospital admission (N = 266) and at discharge (N = 190). Rs11030094, located 3' outside the coding region of BDNF, is also located in an intron of BDNFOS coding for a functional antagonist of BDNF. We further included the non-synonymous Val66Met (rs6265) polymorphism in our analysis, for which - albeit being extensively studied - conflicting results in respect to its role in antidepressant treatment response have been reported. Similar to the previous analysis, rs2049046 and rs11030094 showed a significant effect on antidepressant response. In a gene-dose dependent manner, we found significant lower cortisol responses to the dex/CRH test at discharge in carriers of the respective SNP alleles ('T' of rs2049046 and 'G' of rs11030094) that were associated with antidepressant response (beneficial alleles). These genetic effects on HPA axis regulation were independent of age, sex, medication and depressive symptomatology. Although not reaching statistical significance, the same direction of effect was observed for cortisol at admission, as well as the ACTH response at admission and discharge. An interaction analysis of both SNPs revealed highest cortisol levels in subjects that were non-carriers of both beneficial alleles. The Val66Met (rs6265) was neither associated with antidepressant response nor with HPA axis regulation. Our findings provide further evidence for an interaction of the HPA axis and the neurotrophin system in major depression. This study stresses the importance investigating BDNF variants beyond the extensively studied Val66Met polymorphism. In-depth analyses of both pathophysiologically relevant systems may point to possible new targets for pharmaceutical intervention and precision medicine of major depression in the future.

Social support and unsupportive interactions in relation to depressive symptoms: Implication of gender and the BDNF polymorphism

Reduced levels of brain derived neurotrophic factor (BDNF), through its role in neurogenesis and neuroplasticity, may be involved in the evolution and maintenance of depression. Depression has also been tied to fewer social relationships, which can vary by gender. Thus, we assessed whether the functional single nucleotide polymorphism (SNP) on the BDNF gene, Val66Met, moderated the relationship between depressive symptoms and perceived social support and unsupportive relationships, and whether these associations differed by gender. Among 945 students, (n = 667 females; n= 278 males), depressive scores were inversely related to social support, and positively related with unsupportive relations. Females reported greater social support and depressive scores compared to males. A3-way interaction was found between unsupportive relations, the Val66Met SNP, and gender, such that irrespective of genotype, females displayed astrong relationship between unsupport and depressive scores. Male Met carriers displayed this relationship, but this was less apparent among males with the Val/Val genotype. The Val66Met SNP did not moderate the link between support and depressive scores. This BDNF SNP may serve to moderate the links between psychosocial factors and depressive symptoms, but such links are nuanced, being gender-dependent and varying with the nature of the social interactions experienced.

A Systematic Review of Genetic Influence on Psychological Resilience

When exposed to adversity, some individuals are at an increased risk of posttraumatic stress disorder, experiencing persistent biopsychosocial disturbances, whereas others adapt well, described as resilience. Resilience is a complex biopsychosocial phenomenon conceptualized as adaptation to adversity influenced by an individual’s genetic variants, epistasis, epigenetics, and gene-by-environment interactions. Studies on psychological resilience have focused on behavioral and psychosocial variables with far less examination of the genetic contributions. The purpose of this review is to identify specific genetic variants contributing to the biological capacity for psychological resilience. PubMed and PsycINFO were searched using the following key words: psychological resilience AND genotype(s). Additional articles were identified from the Human Genome Epidemiology Navigator using the term resilience, psychological. Ten studies met the criteria. Six genes were empirically associated with psychological resilience: serotonin-transporter-linked polymorphic region ( 5-HTTLPR), dopamine receptor D4, brain-derived neurotrophic factor ( BDNF), corticotropin-releasing hormone receptor 1, oxytocin receptor and regulator of G-protein signaling 2 . The findings of this systematic review suggest that the L/L or L’/L’ genotype of 5-HTTLPR and rs25531 in children/adolescents and the S/S or S’/S’ genotype in adults are most frequently related to resilience. Additionally, the Val/Val genotype of rs6265 in BDNF in Caucasians was also associated with resilience. There are numerous factors contributing to the complexity of determining the genetic influence on resilience including analysis of rs25531, assumptions of the mode of inheritance, operationalization of resilience, demographic and population characteristics, sample size, and other types of genetic influence including epistasis and epigenetics. While current evidence is supportive, further investigation of the genetic influence on resilience is required.

Exploring the emotional dynamics of subclinically depressed individuals with and without anhedonia: An experience sampling study

BACKGROUND

Anhedonia has been linked to worse prognosis of depression. The present study aimed to construct personalized models to elucidate the emotional dynamics of subclinically depressed individuals with versus without symptoms of anhedonia.

METHODS

Matched subclinically depressed individuals with and without symptoms of anhedonia (N = 40) of the HowNutsAreTheDutch sample completed three experience sampling methodology assessments per day for 30 days. For each individual, the impact of physical activity, stress experience, and high/low arousal PA/NA on each other was estimated through automated impulse response function analysis (IRF). These individual IRF associations were combined to compare anhedonic versus non-anhedonic individuals.

RESULTS

Physical activity had low impact on affect in both groups. In non-anhedonic individuals, stress experience increased NA and decreased PA and physical activity more strongly. In anhedonic individuals, PA high arousal showed a diminished favorable impact on affect (increasing NA/stress experience, decreasing PA/physical activity). Finally, large heterogeneity in the personalized models of emotional dynamics were found.

LIMITATIONS

Stress experience was measured indirectly by assessing level of distress; the timeframe in between measurements was relatively long with 6h; and only information on one of the two hallmarks of anhedonia, loss of interest, was gathered.

CONCLUSIONS

Our results suggest different pathways of emotional dynamics underlie depressive symptomatology. Subclinically depressed individuals with anhedonic complaints are more strongly characterized by diminished favorable impact of PA high arousal and heightened NA reactivity, whereas subclinically depressed individuals without these anhedonic complaints seem more characterized by heightened stress reactivity. The automatically generated personalized models may offer patient-specific insights in emotional dynamics, which may show clinical relevance.

Prefrontal cortex modulates the correlations between brain-derived neurotrophic factor level, serotonin, and the autonomic nervous system

Top-down regulation in the human brain and anatomical connections between the prefrontal cortex (PFC) and specific catecholamine-related regions have been well-studied. However, the way in which the PFC modulates downstream neuro-networks in terms of serotonin and the autonomic nervous system (ANS) by variation in the level of brain-derived neurotrophic factor (BDNF) is still unclear. We recruited sixty-seven healthy subjects. Serotonin transporter (SERT) availability was examined by SPECT with [¹²³I]ADAM analysis; heart rate variability (HRV) testing was performed, and the BDNF level was measured. The Wisconsin card-sorting test (WCST), which assesses PFC activation, was also conducted. The interactions of BDNF level and SERT availability were significant in relation to the HRV indexes of low frequency, high frequency, total power, and mean heart rate range. Moderate to significant positive correlations between SERT availability and the above-mentioned HRV indexes existed only in subjects with a low BDNF level. Furthermore, in the low BDNF level group, only those with high WCST perseveration errors or low category completions exhibited significant positive correlations between SERT availability and HRV indexes. A lower BDNF level and poorer PFC function might modulate the synergistic effects of serotonergic and ANS systems in order to maintain brain physiological and psychological homeostasis.

Genetic polymorphisms associated with smoking behaviour predict the risk of surgery in patients with Crohn's disease

BACKGROUND

Smoking is a strong environmental factor leading to adverse outcomes in Crohn's disease, but a more benign course in ulcerative colitis. Several single nucleotide polymorphisms (SNPs) are associated with smoking quantity and behaviour.

AIM

To assess whether smoking-associated SNPs interact with smoking to influence the clinical course of inflammatory bowel diseases.

METHODS

Genetic and prospectively obtained clinical data from 1434 Swiss inflammatory bowel disease cohort patients (821 Crohn's disease and 613 ulcerative colitis) were analysed. Six SNPs associated with smoking quantity and behaviour (rs588765, rs1051730, rs1329650, rs4105144, rs6474412 and rs3733829) were combined to form a risk score (range: 0-12) by adding the number of risk alleles. We calculated multivariate models for smoking, risk of surgery, fistula, Crohn's disease location and ulcerative colitis disease extent.

RESULTS

In Crohn's disease patients who smoke, the number of surgeries was associated with the genetic risk score. This translates to a predicted 3.5-fold (95% confidence interval: 2.4- to 5.7-fold, P<.0001) higher number of surgical procedures in smokers with 12 risk alleles than individuals with the lowest risk. Patients with a risk score >7 had a significantly shorter time to first intestinal surgery. The genetic risk score did not predict surgery in ulcerative colitis or occurrence of fistulae in Crohn's disease. SNP rs6265 was associated with ileal disease in Crohn's disease (P<.05) and proctitis in ulcerative colitis (P<.05).

CONCLUSIONS

SNPs associated with smoking quantity is associated with an increased risk for surgery in Crohn's disease patients who smoke. Our data provide an example of genetics interacting with the environment to influence the disease course of inflammatory bowel disease.

Gene-environment interaction and psychiatric disorders: Review and future directions

Empirical studies suggest that psychiatric disorders result from a complex interplay between genetic and environmental factors. Most evidence for such gene-environment interaction (GxE) is based on single candidate gene studies conducted from a Diathesis-Stress perspective. Recognizing the short-comings of candidate gene studies, GxE research has begun to focus on genome-wide and polygenic approaches as well as drawing on different theoretical concepts underlying GxE, such as Differential Susceptibility. After reviewing evidence from candidate GxE studies and presenting alternative theoretical frameworks underpinning GxE research, more recent approaches and findings from whole genome approaches are presented. Finally, we suggest how future GxE studies may unpick the complex interplay between genes and environments in psychiatric disorders.

BDNF Val66Met polymorphism tunes frontolimbic circuitry during affective contextual learning

Adaptive learning impairments are common in cognitive and behavioral disorders, but the neurogenetic mechanisms supporting human affective learning are poorly understood. We designed a higher-order contextual learning task in which healthy participants genotyped for the Val⁶⁶Met polymorphism of the brain derived neurotropic factor gene (BDNF) were required to choose the member of a picture pair most congruent with the emotion in a previously-viewed facial expression video in order to produce an advantageous monetary outcome. Functional magnetic resonance imaging (fMRI) identified frontolimbic blood oxygenation level dependent (BOLD) reactivity that was associated with BDNF Val⁶⁶Met genotype during all three phases of the learning task: aversive and reward-predictive learning, contextually-challenging decision-making, and choice-related monetary loss-avoidance and gain outcomes. Relative to Val homozygotes, Met carriers showed attenuated ventromedial prefrontal response to predictive affective cues, dorsolateral prefrontal signaling that depended on decision difficulty, and enhanced ventromedial prefrontal reactivity that was specific to loss-avoidance. These findings indicate that the BDNF Val⁶⁶Met polymorphism is associated with functional tuning of behaviorally-relevant frontolimbic circuitry, particularly involving the ventromedial prefrontal cortex, during higher-order learning.

Daily fluctuation of emotions and memories thereof: Design and methods of an experience sampling study of major depression, social phobia, and controls

Symptom fluctuations and the dynamic contexts provoking these are poorly understood. This deficit is compounded by people's limited ability to accurately report about such dimensions in retrospect. Utilizing the advantages of experience sampling methodology (ESM), this study rigorously describes and tests proximal environmental, neurobiological and psychological factors associated with symptoms and mood states. Participants were assigned to three diagnostic groups: Major Depressive Disorder (MDD; n = 118), Social Phobia (SP; n = 47), or a Control Group without SP or MDD (CG; n = 119). Laboratory assessments included cognitive abilities, memory, constructs, and brain derived neurotrophic factor (BDNF). ESM lasted seven days, with six assessments per day covering symptoms, affect, daily events, social interactions, post-event processing, well-being, etc. Morning cortisol and actigraphy were also assessed during ESM. Thereafter, participants provided subjective retrospective recall estimates of the emotions they reported during ESM. The multi-level data of >10,000 observations will allow for thorough examination of fluctuations of psychopathology and well-being in two highly prevalent disorders. Using two clinical groups and a non-affected control group, the clinical specificity versus generalizability of processes can be directly tested, thus providing stimulating information about the overlap and differences between anxiety and affective disorders. This research informs about the development, fluctuation, and maintaining factors of emotions and symptoms and examines the accuracy with which participants recall these dimensions.

Modification of the association between early adversity and obsessive-compulsive disorder by polymorphisms in the MAOA, MAOB and COMT genes

The monoamine oxidases (MAOA/B) and catechol-O-methyltransferase (COMT) enzymes break down regulatory components within serotonin and dopamine pathways, and polymorphisms within these genes are candidates for OCD susceptibility. Childhood trauma has been linked OCD psychopathology, but little attention has been paid to the interactions between genes and environment in OCD aetiology. This pilot study investigated gene-by-environment interactions between childhood trauma and polymorphisms in the MAOA, MAOB and COMT genes in OCD. Ten polymorphisms (MAOA: 3 variants, MAOB: 4 variants, COMT: 3 variants) were genotyped in a cohort of OCD patients and controls. Early-life trauma was assessed using the Childhood Trauma Questionnaire (CTQ). Gene-by-gene (GxG) and gene-by-environment interactions (GxE) of the variants and childhood trauma were assessed using logistic regression models. Significant GxG interactions were found between rs362204 (COMT) and two independent polymorphisms in the MAOB gene (rs1799836 and rs6651806). Haplotype associations for OCD susceptibility were found for MAOB. Investigation of GxE interactions indicated that the sexual abuse sub-category was significantly associated with all three genes in haplotype x environment interaction analyses. Preliminary findings indicate that polymorphisms within the MAOB and COMT genes interact resulting in risk for OCD. Childhood trauma interacts with haplotypes in COMT, MAOA and MAOB, increasing risk for OCD.

Decreased Plasma BDNF Levels of Patients with Somatization Disorder

OBJECTIVE

Brain-derived neurotrophic factor (BDNF), one of the most abundant and important neurotrophins, is known to be involved in the development, survival, maintenance, and plasticity of neurons in the nervous system. Some studies have suggested that BDNF may play a role in the pathophysiology of several psychiatric illnesses such as depression and schizophrenia. Similarly, it is likely that the alteration of BDNF may be associated with the neuro-modulation that contributes to the development of somatization disorder.

METHODS

The purpose of this study was to determine whether there is an abnormality of plasma BDNF levels in patients with somatization disorder, and to analyze the nature of the alteration after pharmacotherapy using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The plasma BDNF levels of the patients with a somatization disorder were significantly lower compared with those of the control volunteers (83.61±89.97 pg/mL vs. 771.36±562.14 pg/mL); moreover, the plasma BDNF levels of those patients who received an antidepressant were significantly increased after the treatment (118.13±91.45 pg/mL vs. 72.92±88.21 pg/mL).

CONCLUSION

These results suggest that BDNF may play a role in the pathophysiology of somatization disorder.

The Interaction between Childhood Bullying and the FKBP5 Gene on Psychotic-Like Experiences and Stress Reactivity in Real Life

AIM

The present study employed Experience Sampling Methodology to examine whether the interaction between childhood bullying and FKBP5 variability (i) is associated with the expression of psychotic-like experiences, paranoia, and negative affect, and (ii) moderates psychotic-like, paranoid, and affective reactivity to different forms of momentary stress (situational and social) in daily life.

METHODS

A total of 206 nonclinical young adults were interviewed for bullying with the Childhood Experience of Care and Abuse and were prompted randomly eight times daily for one week to complete assessments of their current experiences, affect, and stress appraisals. Participants were genotyped for three FKBP5 single nucleotide polymorphisms (SNPs) (rs3800373, rs9296158, and rs1360780) that have been linked to hypothalamus-pituitary-adrenal axis reactivity. Multilevel analyses were conducted to examine the effect of the interaction between childhood bullying and the FKBP5 haplotype derived from these three SNPs.

RESULTS

The interaction between bullying and the FKBP5 haplotype was associated with positive, but not negative, psychotic-like experiences, paranoia, and negative affect. The bullying x FKBP5 interaction also moderated the association of a social stress appraisal (specifically, being alone because people do not want to be with you) with psychotic-like experiences and negative affect in daily life. Simple slopes analyses indicated that, in all cases, the associations were significantly increased by exposure to bullying in participants with the risk haplotype, but not for those with the non-risk haplotype.

DISCUSSION

The present study provides the first evidence of the interplay between childhood bullying and FKBP5 variability in the real-world expression of psychosis proneness and social stress reactivity. The findings underscore the importance of investigating how gene-environment interactions are involved in mechanistic pathways to the extended psychosis phenotype and lend further support to the increasing relevance given to socially defeating appraisals in the experience of reality distortion.

Genetic polymorphisms and the adequacy of brain stimulation: state of the art

INTRODUCTION

Heterogeneity of therapeutic response to brain stimulation techniques has inspired scientists to uncover the secrets to success or failure of these projects. Genetic polymorphisms are one of the major causes of this heterogeneity.

AREAS COVERED

More than twenty genetic variants within more than ten genes (e.g. BDNF, COMT, DRD2, TRPV1, 5-HT1A, 5-HHT, P2RX7, VEGF, TPH1, TPH2, ACE, APOE, GNB3, NET, NMDA receptors, and RGS4) have been investigated, among which the BDNF gene and its polymorphism, Val66Met, is the best documented variant. We review the genotypic combinations, which are reported to interact with the work of brain stimulation, of which the DRD2 C957T polymorphism is the most prominent type. Finally, implications of transcranial magnetic stimulation in deciphering the interaction between genetic background (e.g. SCN1A and 5-HTT) and drugs (e.g. carbamazepine and citalopram) at the cortical excitability level is explained. Expert commentary: Studies are ongoing to find missing factors responsible for heterogeneity of response to brain stimulation techniques. Further knowledge about genetic factors affecting the therapeutic response to brain stimulation techniques might provide helpful guidelines for choosing ideal candidates for treatment.

Genetic epidemiology of migraine and depression

Background

Migraine and major depressive disorder (commonly referred to as depression) are both common disorders with a significant impact on society. Studies in both clinical and community-based settings have demonstrated a strong relationship between migraine and depression. In addition to complicating the diagnosis, depression that is comorbid with migraine may lower treatment adherence, increase risk of medication overuse and is associated with migraine chronification, thus leading to higher direct and indirect costs and poorer health-related outcomes with increased disability.

Aim

The aim of this review is to summarise the current knowledge on the genetic epidemiology of migraine and depression and the possible biological mechanisms underlying their comorbidity.

Methods

We present a narrative review reporting on the current literature.

Results and conclusions

Epidemiological findings indicate that there is a bidirectional relationship between migraine and depression, with one disorder increasing the risk for the other and vice versa, suggesting shared biological mechanisms. Twin and family studies indicate that this bidirectional relationship can be explained, at least partly, by shared underlying genetically determined disease mechanisms. Although no genes have been robustly associated with the aetiology of both migraine and depression, genes from serotonergic, dopaminergic and GABAergic systems together with variants in the MTHFR and BDNF genes remain strong candidates.

BDNF Val66Met genotype and neuroticism predict life stress: A longitudinal study from childhood to adulthood

The brain-derived neurotrophic factor gene (BDNF) Val66Met polymorphism and life stress have been associated with negative emotionality (e.g., neuroticism), but relevant evidence is far from unequivocal. Possible confounding factors include the type and timing of stressful events measured, such as childhood adversity vs. recent stressful events, and variable gene × environment interactions. The aim of this study was to longitudinally assess the BDNF Val66Met polymorphism and environment interaction effect on neuroticism in a population representative sample, depending upon the type of stress, gender and family relations. In the original older cohort of the Estonian Children Personality Behavior and Health Study (ECPBHS, n=593), neuroticism was measured at age 15 (parental assessment), 18 and 25 (self-assessments). Childhood stress was reported at age 15, quality of family relations was measured at age 18, and recent stressful life events at age 25. The BDNF Val66Met polymorphism interacted with recent stressful life events, but not with childhood adversities, to impact neuroticism. Interestingly, in female participants, neuroticism at age 18 predicted future stressful life events dependent upon genotype: individuals with Val/Val genotype and high neuroticism experienced higher, but Met-allele carriers with high neuroticism lower stress exposure at age 25. Similar tendencies were observed using parental assessments at age 15. The protective effect of Met-allele in the high stress exposure group could result from better early family environment. In conclusion, we herewith provide further evidence for a role of BDNF gene variance contributing to plasticity in response to environmental demands.

Differential Vulnerability to Early-Life Parental Death: The Moderating Effects of Family Suicide History on Risks for Major Depression and Substance Abuse in Later Life

Only a portion of those individuals exposed to parental death in early life (PDE) develop behavioral health disorders. We utilized demographic pedigree data from the Utah Population Database to test for differential vulnerability to PDE by creating a risk score of familial susceptibility to suicide (FS) at the population level. Using logistic panel regression models, we tested for multiplicative interactions between PDE and FS on the risks of major depressive disorder (MDD) and substance abuse (SA), measured using Medicare claims, after age 65. The final sample included 155,983 individuals (born 1886-1944), yielding 1,431,060 person-years at risk (1992-2009). Net of several potential confounders, including probability of survival to age 65, we found an FS × PDE interaction for females, in which PDE and FS as main effects had no impact but jointly increased MDD risk. No statistically significant main or interactive effects were found for SA among females or for either phenotype among males. Our findings are consistent with a differential vulnerability model for MDD in females, in which early-life stress increases the risk for poor behavioral health only among the vulnerable. Furthermore, we demonstrate how demographic and pedigree data might serve as tools for investigating differential vulnerability hypotheses.

Differential Susceptibility of the Developing Brain to Contextual Adversity and Stress

A swiftly growing volume of literature, comprising both human and animal studies and employing both observational and experimental designs, has documented striking individual differences in neurobiological sensitivities to environmental circumstances within subgroups of study samples. This differential susceptibility to social and physical environments operates bidirectionally, in both adverse and beneficial contexts, and results in a minority subpopulation with remarkably poor or unusually positive trajectories of health and development, contingent upon the character of environmental conditions. Differences in contextual susceptibility appear to emerge in early development, as the interactive and adaptive product of genetic and environmental attributes. This paper surveys what is currently known of the mechanisms or mediators of differential susceptibility, at the levels of temperament and behavior, physiological systems, brain circuitry and neuronal function, and genetic and epigenetic variation. It concludes with the assertion that differential susceptibility is inherently grounded within processes of biological moderation, the complexities of which are at present only partially understood.

Population difference in the association of BDNF promoter methylation with mild cognitive impairment in the Xinjiang Uygur and Han populations

BACKGROUND

Mild cognitive impairment (MCI) is a clinical transitional stage between normal aging and Alzheimer disease, which leads to memory loss and a reduction in cognitive function. Brain derived neurotrophic factor (BDNF) plays an important role in neuronal development and plasticity. The aim of this study was to explore the association between BDNF promoter methylation and MCI in the Xinjiang Uygur and Han populations.

METHODS

A DNA methylation assay using bisulfite pyrosequencing technology was performed on 96 Uygur and 96 Han Chinese individuals from Xinjiang province, China.

RESULTS

We found a significantly higher BDNF methylation level in Han MCI cases than in Uygur MCI cases in males from Xinjiang province (p=0.022). In addition, the methylation level was significantly higher in Xinjiang Han healthy Chinese individuals (Northwestern China) than in Ningbo Han healthy Chinese individuals (Southeastern China) (Female and Male: p=1.17E-05; Female: p=0.020; Male: p=1.37E-04). But our results showed no significant association of BDNF methylation with MCI in either the Uygur or Han Chinese populations (p>0.05). Further gender-based subgroup analyses did not find any significant results (p>0.05).

CONCLUSION

Our results indicate that different levels of BDNF methylation may be present in different populations and environments. This study also provides further information regarding the relationship between BDNF methylation levels and MCI in Xinjiang Uygur and Han ethnic groups.

Development and the epigenome: the 'synapse' of gene-environment interplay

This paper argues that there is a revolution afoot in the developmental science of gene-environment interplay. We summarize, for an audience of developmental researchers and clinicians, how epigenetic processes - chromatin structural modifications that regulate gene expression without changing DNA sequences - may offer a strong, parsimonious account for the convergence of genetic and contextual variation in the genesis of adaptive and maladaptive development. Epigenetic processes may play a plausible explanatory role in understanding: divergent trajectories and sexual dimorphisms in brain development; statistical interactions between genes and environments; the biological embedding of early psychosocial adversities; the linkages of such adversities to disorders of mental health; the striking individual variation in the strength of those linkages; the molecular origins of critical and sensitive periods; and the transgenerational inheritance of risk and protection. Taken together, these arguments converge in a claim that epigenetic processes constitute a promising and illuminating point of connection - a 'synapse' - between genes and environments.

Unravelling psychosis: psychosocial epidemiology, mechanism, and meaning

This paper reviews a revolution in our understanding of psychosis over the last 20 years. To a major extent, this has resulted from a process of cross-fertilization between psychosocial epidemiology and cognitive behavior therapy for psychosis (CBT-p). This encouraged complementary strategies for the acquisition and analysis of data. These include the use of a range of dependent variables related to psychosis, and the exploitation of data from cross-sectional and longitudinal epidemiological surveys, virtual reality experiments, experience sampling methodology, and treatment trials. The key element is to investigate social and psychological measures in relation to each other. This research has confirmed the role of the external social world in the development and persistence of psychotic disorder. In addition, several psychological drivers of psychotic experiences have been identified. There is now persuasive evidence that the influence of social factors in psychosis is significantly mediated by non-psychotic symptoms, particularly mood symptoms and other attributes of affect such as insomnia. Psychotic symptoms are also driven by reasoning biases such as jumping to conclusions and belief inflexibility, though little is known about social influences on such biases. It is now clear that there are many routes to psychosis and that it takes many forms. Treatment of all kinds should take account of this: the dependence of CBT-p on a detailed initial formulation in terms of psychological processes and social influences is an example of the required flexibility. Individual mediators are now being targeted in specific forms of CBT-p, with good effect. This in turn corroborates the hypothesized role of non-psychotic symptoms in mediation, and attests to the power of the approaches described.

Daily life stress reactivity in remitted versus non-remitted depressed individuals

BACKGROUND

Little is known about how daily life mood reactivity to minor stressors (stress reactivity) might change following major depressive disorder (MDD) treatment. We investigate whether (i) mood states and appraisals of daily stressors change after treatment; (ii) stress reactivity to event, activity, or social stress differs; (iii) stress reactivity depends on severity of residual depressive symptoms; and (iv) stress reactivity in individuals with remitted or non-remitted depression differ from that of never-depressed individuals.

METHODS

Thirty depressed individuals participated in an experience sampling study before and after a treatment period of 18 months; 39 healthy individuals formed a comparison group. Reactivity of positive affect (PA) and negative affect (NA) to daily stressors were measured.

RESULTS

More residual symptoms were associated with larger NA responses to stress. Compared to healthy controls, participants with non-remitted MDD showed higher NA-reactivity to all stressors. In contrast, stress reactivity to event and activity stressors was normalized in remitted patients. However, they still showed heightened NA-reactivity to social stress.

CONCLUSIONS

Greater stress reactivity to event and activity stress appears to be state-dependent. The heightened social stress reactivity in remitted patients suggests that sensitivity to social stress may reflect an underlying vulnerability in MDD.

Overexpression of DeltaFosB in nucleus accumbens mimics the protective addiction phenotype, but not the protective depression phenotype of environmental enrichment

Environmental enrichment produces protective addiction and depression phenotypes in rats. ΔFosB is a transcription factor that regulates reward in the brain and is induced by psychological stress as well as drugs of abuse. However, the role played by ΔFosB in the protective phenotypes of environmental enrichment has not been well studied. Here, we demonstrate that ΔFosB is differentially regulated in rats reared in an isolated condition (IC) compared to those in an enriched condition (EC) in response to restraint stress or cocaine. Chronic stress or chronic cocaine treatment each elevates ΔFosB protein levels in the nucleus accumbens (NAc) of IC rats, but not of EC rats due to an already elevated basal accumulation of ΔFosB seen under EC conditions. Viral-mediated overexpression of ΔFosB in the NAc shell of pair-housed rats (i.e., independent of environmental enrichment/isolation) increases operant responding for sucrose when motivated by hunger, but decreases responding in satiated animals. Moreover, ΔFosB overexpression decreases cocaine self-administration, enhances extinction of cocaine seeking, and decreases cocaine-induced reinstatement of intravenous cocaine self-administration; all behavioral findings consistent with the enrichment phenotype. In contrast, however, ΔFosB overexpression did not alter responses of pair-housed rats in several tests of anxiety- and depression-related behavior. Thus, ΔFosB in the NAc the shell mimics the protective addiction phenotype, but not the protective depression phenotype of environmental enrichment.