The genetics of mood disorders

Ketogenic Diet and Inflammation: Implications for Mood and Anxiety Disorders

The ketogenic diet, known as a low-carbohydrate, high-protein, and high-fat diet, drastically restrains the major source of energy for the body, forcing it to burn all excess fat through a process called ketosis-the breaking down of fat into ketone bodies. First suggested as a medical treatment for children suffering from epilepsy, this diet has gained increased popularity as a rapid weight loss strategy. Over the past few years, there have been numerous studies suggesting that the ketogenic diet may provide therapeutic effects for several psychiatric conditions such as mood- and anxiety-related disorders. However, despite significant progress in research, the mechanisms underlying its therapeutic effects remain largely unexplored and are yet to be fully elucidated. This chapter provides an in-depth overview of preclinical and clinical evidence supporting the use of a ketogenic diet in the management of mood and anxiety disorders and discusses its relationship with inflammatory processes and potential mechanisms of actions for its therapeutic effects.

Rumination thinking in childhood and adolescence: a brief review of candidate genes

BACKGROUND

rumination has been reported as a cognitive vulnerability factor in adolescent and adult depression. The present brief review aimed at summarizing the results of the genetic studies that investigate the candidate genes for rumination in children and adolescents.

METHODS

bibliographic research was conducted on PubMed and Science Direct from their inception to February 2020. The search terms used were: 'rumination, ruminative thinking, repetitive thinking and 'gene, gen*'.

RESULTS

eight studies were identified. Results suggest that variations in the 5-HTTLPR and BDNF genes may contribute to the tendency to ruminate, modelling the relationship between life stress and rumination.

LIMITATIONS

the interpretation of these results is limited by the sample sizes of the selected studies, the study designs, and the heterogeneity of the instruments assessing rumination.

CONCLUSIONS

these findings partially support the notion that variation in in the 5-HTTLPR and BDNF genes is associated with biological sensitivity to rumination.

Measuring More Than Exposure: Does Stress Appraisal Matter for Black-White Differences in Anxiety and Depressive Symptoms Among Older Adults?

BACKGROUND AND OBJECTIVES

Prior research and theory suggest that exposure to objectively stressful events contributes to mental health disparities. Yet, blacks report higher cumulative stress exposure than whites but lower levels of common psychiatric disorders. In order to understand why blacks bear disproportionate stress exposure but similar or better mental health relative to whites, we need to consider race differences in not only stress exposure, but also stress appraisal-how upsetting stress exposures are perceived to be.

RESEARCH DESIGN AND METHODS

We examine whether race differences in the number of reported chronic stressors across 5 domains (health, financial, residential, relationship, and caregiving) and their appraised stressfulness explain black-white differences in anxiety and depressive symptoms. Data come from 6019 adults aged older than 52 from the 2006 Health and Retirement Study.

RESULTS

Older blacks in this sample experience greater exposure to chronic stressors but appraise stressors as less upsetting relative to whites. In fully adjusted models, stress exposure is related to higher levels of anxiety and depressive symptoms, and perceiving stress as upsetting is associated with higher symptomology for whites and blacks. We also find that blacks report greater anxiety symptoms but fewer depressive symptoms with more stress exposure relative to whites. Stress appraisal partially explains race differences in the association between stress exposure and anxiety symptoms and fully explains race differences in the association between exposure and depressive symptoms.

DISCUSSION AND IMPLICATIONS

The relationship between race, chronic stress exposure, and mental health is mediated by stress appraisal. Stress appraisal provides insight on important pathways contributing to black-white mental health disparities in older adulthood.

[Formula: see text] Addressing the neurodevelopmental needs of children and adolescents with congenital heart disease: A review of the existing intervention literature

Congenital heart disease (CHD) is among the most prevalent birth defects in the United States. Given that children with CHD are at risk for differences with development, learning, and psychosocial functioning, effective intervention becomes a central tenant of recommendations following neuropsychological consultation and evaluation. The primary focus of this review is to summarize available interventions for children and adolescents with CHD. The existing CHD literature has concentrated on early developmental services, psychopharmacological treatment, and need for academic supports. The literature is limited with regard to intervention studies that target cognitive deficits and psychosocial difficulties. To address this discrepancy, efficacious interventions that have been used to mitigate these concerns within other medical groups are also discussed in an effort to provide options for alternative recommendations and services. The current paper is intended to facilitate comprehensive care for cardiac patients by providing clinicians with a review of the available intervention literature, as well as potential interventions that may serve as supplemental strategies in the interim.

Emerging Genetic and Epigenetic Mechanisms Underlying Pubertal Maturation in Adolescence

The adolescent transition begins with the onset of puberty which, upstream in the brain, is initiated by the gonadotropin-releasing hormone (GnRH) pulse generator that activates the release of peripheral sex hormones. Substantial research in human and animal models has revealed a myriad of cellular networks and heritable genes that control the GnRH pulse generator allowing the individual to begin the process of reproductive competence and sexual maturation. Here, we review the latest knowledge in neuroendocrine pubertal research with emphasis on genetic and epigenetic mechanisms underlying the pubertal transition.

Adolescent and adult differences in major depression symptom profiles

BACKGROUND

Depression is the leading global cause of disability and often begins in adolescence. The genetic architecture and treatment response profiles for adults and adolescents differ even though identical criteria are used to diagnose depression across different age groups. There is no clear consensus on how these groups differ in their symptom profiles.

METHODS

Using data from a two-generation family study, we compared the presentation of DSM-IV depressive symptoms in adolescents and adults with MDD (Major Depressive Disorder). We also compared DSM-IV depressive symptom counts using latent class analysis.

RESULTS

Vegetative symptoms (appetite and weight change, loss of energy and insomnia) were more common in adolescent MDD than adult MDD. Anhedonia/loss of interest and concentration problems were more common in adults with MDD. When using latent class analysis to look at depressive symptoms, a vegetative symptom profile was also seen in adolescent depression only.

LIMITATIONS

Adults and adolescents were recruited in different ways. Adolescent cases were more likely to be first-onset while adult cases were recurrences. It was not possible to examine how recurrence affected adolescent depression symptom profiles.

CONCLUSION

Differences in how depression presents in adolescents and adults may be consistent with different pathophysiological mechanisms. For adolescents, we found that vegetative/physical disturbances were common (loss of energy, changes in weight, appetite and sleep changes). For adults, anhedonia/loss of interest and concentration difficulties were more common.

A role for genes in the 'caregiver stress process'?

The stress that accompanies caring for one's parent, and the contribution of that stress to adverse physical and mental-health outcomes, is extensively studied and widely acknowledged. Yet there has been almost no attempt to incorporate the well-documented role of genetic variation in psychological distress into research on caregiving. We use phenotypic data from a large, population-based sample linked to extensive genotype data to develop a polygenic risk score (PRS) for depression, and test for both direct and interactive effects of the PRS in a multilevel repeat-measures model of caregiver-related stress. We distinguish three groups: potential caregivers (those with a living parent who does not need care), noncaregivers (those who do not provide care to their parent that needs care), and caregivers. We also obtain separate estimates according to the gender of both the parent and child. We found that a parent's need for care, and the child's provision of care, are associated with depression in some but not all cases; in contrast the PRS was significantly associated with the risk for increased depressive symptoms (with P ≤ 0.01) in all cases. These findings support an additive genetic contribution to the diathesis-stress model of depression in the context of caregiving.

Inpatient Profile of Patients with Major Depression in Portuguese National Health System Hospitals, in 2008 and 2013: Variation in a Time of Economic Crisis

The economic crisis has placed Portugal in a situation of budgetary constraints with repercussions on mental health, since 2009. This study analyses the association between economic crisis and the inpatient profile of major depression in the working-age population in Portuguese National Health System hospitals. This was an observational, descriptive and cross-sectional study. An individual analysis of hospitalisation and an ecological analysis at district level, were performed before 2008 and during the crisis (2013). Data on the hospitalisation episodes, working-age population and psychiatric inpatient beds were analysed. An increase in hospitalisation rates for major depression were observed, and across country, high spatial variations were perceived: districts with lower rates of urbanisation and population density had higher hospitalisation rates for major depression. Hospitalisation rates were positively influenced by the available inpatient beds. The results for 2013 were more critical (higher hospitalisation rates, less beds). Further research is needed to understand all patterns, considering other individual and contextual information.

Causality and Pleiotropy in the Association Between Bullying Victimization in Adolescence and Depressive Episodes in Adulthood

Children and adolescents who are victims or perpetrators of bullying victimization are at elevated risk for maladjustment problems, concurrently and in the long run. Previous studies suggest that this correlation is partly explained by genetic influence. However, whether the genetic correlation is independent of a causal effect of victimization on maladjustment remains unclear. Using data from 2,510 females from the TwinsUK registry, we applied an innovative extension of the Cholesky decomposition to investigate to what extent the association between victimization in adolescence and self-reported depressive episodes in adulthood is caused by shared genetic effects (pleiotropy), and to what extent it is due to a phenotypic causal relationship. We find that around 60% of the association between victimization and self-reported depressive episodes is due to a causal effect of victimization on depressive episodes, and 40% is due to pleiotropic effects. These findings underline the importance of integrating genetic information into social science research and demonstrate a neat strategy to elucidate causal mechanisms in the absence of experimental designs.

Receptiveness to participation in genetic research: A pilot study comparing views of people with depression, diabetes, or no illness

BACKGROUND

Genetic research in human health relies on the participation of individuals with or at-risk for different types of diseases, including health conditions that may be stigmatized, such as mental illnesses. This preliminary study examines the differences in attitudes toward participation in genetic research among individuals with a psychiatric disorder, individuals with a physical disorder, and individuals with no known illness.

METHODS

Seventy-nine individuals with a history of diabetes or depression, or no known illness, underwent a simulated consent process for a hypothetical genetic research study. They were then surveyed about their willingness to participate in the hypothetical study and their attitudes about future and family participation in genetic research.

RESULTS

Participants with and without a history of depression ranked participating in genetic and medical research as very important and indicated that they were likely to participate in the hypothetical genetics study. Expressed willingness to participate was generally stable and consistent with future willingness. Individuals less strongly endorsed willingness to ask family members to participate in genetic research.

CONCLUSION

Individuals with and without a history of mental illness viewed genetic and medical research favorably and expressed willingness to participate in real-time and in the future. Informed consent processes ideally include an exploration of influences upon volunteers' enrollment decisions. Additional empirical study of influences upon genetic research participation is important to ensure that volunteers' rights are respected and that conditions that greatly affect the health of the public are not neglected scientifically.

The effect of COMT Val158Met and DRD2 C957T polymorphisms on executive function and the impact of early life stress

INTRODUCTION

Previous research has indicated that variation in genes encoding catechol-O-methyltransferase (COMT) and dopamine receptor D2 (DRD2) may influence cognitive function and that this may confer vulnerability to the development of mental health disorders such as schizophrenia. However, increasing evidence suggests environmental factors such as early life stress may interact with genetic variants in affecting these cognitive outcomes. This study investigated the effect of COMT Val158Met and DRD2 C957T polymorphisms on executive function and the impact of early life stress in healthy adults.

METHODS

One hundred and twenty-two healthy adult males (mean age 35.2 years, range 21-63) were enrolled in the study. Cognitive function was assessed using Cambridge Neuropsychological Test Automated Battery and early life stress was assessed using the Childhood Traumatic Events Scale (Pennebaker & Susman, 1988).

RESULTS

DRD2 C957T was significantly associated with executive function, with CC homozygotes having significantly reduced performance in spatial working memory and spatial planning. A significant genotype-trauma interaction was found in Rapid Visual Information Processing test, a measure of sustained attention, with CC carriers who had experienced early life stress exhibiting impaired performance compared to the CC carriers without early life stressful experiences. There were no significant findings for COMT Val158Met.

CONCLUSIONS

This study supports previous findings that DRD2 C957T significantly affects performance on executive function related tasks in healthy individuals and shows for the first time that some of these effects may be mediated through the impact of childhood traumatic events. Future work should aim to clarify further the effect of stress on neuronal systems that are known to be vulnerable in mental health disorders and more specifically what the impact of this might be on cognitive function.

Prenatal Depressive Symptoms and Toddler Behavior Problems: The Role of Maternal Sensitivity and Child Sex

Increasing evidence suggests that maternal depression during pregnancy is associated with child behavioral outcomes even after accounting for later maternal depression. The purpose of this study was to examine various mechanisms, including maternal sensitivity, neonatal problems, and concurrent maternal depression, that might explain the association between prenatal maternal depressive symptoms and toddler behavior problems. Young, low income, African American mothers (n = 196) were interviewed during pregnancy and at 24-months postpartum, medical records were collected at the birth, and mother-child interactions were video-recorded at 24 months. Path analyses revealed that the association between prenatal depression and toddler behavior problems was mediated by maternal sensitivity and maternal depressive symptoms at 24 months. No evidence was found for a mediating effect of neonatal problems. Path models examining sex differences suggested that different mediating factors may be important for boys and girls, with boys being particularly susceptible to the effects of maternal sensitivity.

Aetiological influences on stability and change in emotional and behavioural problems across development: a systematic review

Emotional and behavioural problems in childhood and adolescence can be chronic and are predictive of future psychiatric problems. Understanding what factors drive the development and maintenance of these problems is therefore crucial. Longitudinal behavioural genetic studies using twin, sibling or adoption data can be used to explore the developmental aetiology of stability and change in childhood and adolescent psychopathology. We present a systematic review of longitudinal, behavioural genetic analyses of emotional and behavioural problems between ages 0 to 18 years. We identified 58 studies, of which 19 examined emotional problems, 30 examined behavioural problems, and 9 examined both. In the majority of studies, stability in emotional and behavioural problems was primarily genetically influenced. Stable environmental factors were also widely found, although these typically played a smaller role. Both genetic and environmental factors were involved in change across development. We discuss the findings in the context of the wider developmental literature and make recommendations for future research.

Mice lacking circadian clock components display different mood-related behaviors and do not respond uniformly to chronic lithium treatment

Genomic studies suggest an association of circadian clock genes with bipolar disorder (BD) and lithium response in humans. Therefore, we tested mice mutant in various clock genes before and after lithium treatment in the forced swim test (FST), a rodent behavioral test used for evaluation of depressive-like states. We find that expression of circadian clock components, including Per2, Cry1 and Rev-erbα, is affected by lithium treatment, and thus, these clock components may contribute to the beneficial effects of lithium therapy. In particular, we observed that Cry1 is important at specific times of the day to transmit lithium-mediated effects. Interestingly, the pathways involving Per2 and Cry1, which regulate the behavior in the FST and the response to lithium, are distinct as evidenced by the phosphorylation of GSK3β after lithium treatment and the modulation of dopamine levels in the striatum. Furthermore, we observed the co-existence of depressive and mania-like symptoms in Cry1 knock-out mice, which resembles the so-called mixed state seen in BD patients. Taken together our results strengthen the concept that a defective circadian timing system may impact directly or indirectly on mood-related behaviors.

Emphasizing Malleability in the biology of depression: Durable effects on perceived agency and prognostic pessimism

Biological attributions for depression, which are currently ascendant, can lead to prognostic pessimism-the perception that symptoms are relatively immutable and unlikely to abate (Kvaale, Haslam, & Gottdiener, 2013; Lebowitz, Ahn, & Nolen-Hoeksema, 2013). Among symptomatic individuals, this may have important clinical ramifications, as reduced confidence in one's own ability to overcome depression carries the risk of becoming a self-fulfilling prophecy. Previous research (Lebowitz, Ahn, et al., 2013) has demonstrated that educational interventions teaching symptomatic individuals about how the effects of genetic and neurobiological factors involved in depression are malleable and can be modified by experiences and environmental factors can reduce prognostic pessimism. While previous research demonstrated such effects only in the immediate term, the present research extends these findings by testing whether such benefits persist six weeks after the intervention. Indeed, among individuals who initially considered biological factors to play a major role in influencing their levels of depression, exposure to malleability-focused psychoeducation reduced levels of depression-related prognostic pessimism and stronger belief in their ability to regulate their moods. Critically, this benefit persisted six weeks after the intervention. Clinical implications of the findings are discussed.

Circadian Clock Dysfunction and Psychiatric Disease: Could Fruit Flies have a Say?

There is evidence of a link between the circadian system and psychiatric diseases. Studies in humans and mammals suggest that environmental and/or genetic disruption of the circadian system leads to an increased liability to psychiatric disease. Disruption of clock genes and/or the clock network might be related to the etiology of these pathologies; also, some genes, known for their circadian clock functions, might be associated to mental illnesses through clock-independent pleiotropy. Here, we examine the features which we believe make Drosophila melanogaster a model apt to study the role of the circadian clock in psychiatric disease. Despite differences in the organization of the clock system, the molecular architecture of the Drosophila and mammalian circadian oscillators are comparable and many components are evolutionarily related. In addition, Drosophila has a rather complex nervous system, which shares much at the cell and neurobiological level with humans, i.e., a tripartite brain, the main neurotransmitter systems, and behavioral traits: circadian behavior, learning and memory, motivation, addiction, social behavior. There is evidence that the Drosophila brain shares some homologies with the vertebrate cerebellum, basal ganglia, and hypothalamus-pituitary-adrenal axis, the dysfunctions of which have been tied to mental illness. We discuss Drosophila in comparison to mammals with reference to the: organization of the brain and neurotransmitter systems; architecture of the circadian clock; clock-controlled behaviors. We sum up current knowledge on behavioral endophenotypes, which are amenable to modeling in flies, such as defects involving sleep, cognition, or social interactions, and discuss the relationship of the circadian system to these traits. Finally, we consider if Drosophila could be a valuable asset to understand the relationship between circadian clock malfunction and psychiatric disease.

Cytokine gene variations associated with subsyndromal depressive symptoms in patients with breast cancer

PURPOSE

This study explored the relationships between variations in cytokines genes and depressive symptoms in a sample of patients who were assessed prior to and for six months following breast cancer surgery. Phenotypic differences between Resilient (n = 155) and Subsyndromal (n = 180) depressive symptom classes, as well as variations in cytokine genes were evaluated.

METHOD

Patients were recruited prior to surgery and followed for six months. Growth mixture modeling was used to identify distinct latent classes based on Center for Epidemiological Studies Depression (CES-D) Scale scores. Eighty-two single nucleotide polymorphisms and 35 haplotypes among 15 candidate cytokine genes were evaluated.

RESULTS

Patients in the Subsyndromal class were significantly younger, more likely to be married or partnered, and reported a significantly lower functional status. Variation in three cytokine genes (i.e., interferon gamma receptor 1 (IFNGR1 rs9376268), interleukin 6 (IL6 rs2069840), tumor necrosis factor alpha (TNFA rs1799964)), as well as age and functional status predicted membership in the Subsyndromal versus the Resilient class.

CONCLUSIONS

A variation in TNFA that was associated with Subsyndromal depressive symptoms in a sample of patients and their family caregivers was confirmed in this sample. Variations in cytokine genes may place these patients at higher risk for the development of Subsyndromal levels of depressive symptoms.

Etiological heterogeneity of symptom dimensions of adolescent depression

The aim was to investigate the underlying factor structure of adolescent depression and etiological heterogeneity in the symptom dimensions of adolescent depression. The sample included 842 pairs of same-sex adolescent twins, among which 613 pairs were monozygotic twins and 229 pairs were dizygotic twins. The ages of the participants ranged from 11 to 17 years (M = 13.64, SD = 1.80). Adolescents' depressive symptoms were assessed using the self-reported Children's Depression Inventory. Exploratory and confirmatory factor analyses were used to explore the factor structure of youth depression and twin genetic analyses were employed to estimate genetic and environmental influences on the derived dimensions. Results showed that adolescent depression encompassed five correlated dimensions: dysphoria mood, somatic symptoms, study and externalizing problems, anhedonia symptoms, and cognitive symptoms. These five symptom dimensions had heterogeneous etiologies: Dysphoria mood, somatic symptoms, and cognitive symptoms were moderately heritable (heritability ranged from 33 to 40%), whereas study and externalizing problems, and anhedonia symptoms were mainly environmentally influenced with minimal genetic basis. Our findings supported the multidimensionality of adolescent depression and the etiological heterogeneity of these symptom dimensions.

Relationship between attributional style, perceived control, self-esteem, and depressive mood in a nonclinical sample: a structural equation-modelling approach

BACKGROUND

The aim of this study was to examine the intricate relationship between some personality traits (i.e., attributional style, perceived control over consequences, self-esteem), and depressive mood in a nonclinical sample (N= 334). Method. Structural equation modelling was used to estimate five competing models: two vulnerability models describing the effects of personality traits on depressive mood, one scar model describing the effects of depression on personality traits, a mixed model describing the effects of attributional style and perceived control over consequences on depressive mood, which in turn affects self-esteem, and a reciprocal model which is a non-recursive version of the mixed model that specifies bidirectional effects between depressive mood and self-esteem.

RESULTS

The best-fitting model was the mixed model. Moreover, we observed a significant negative effect of depression on self-esteem, but no effect in the opposite direction.

CONCLUSIONS

These findings provide supporting arguments against the continuum model of the relationship between self-esteem and depression, and lend substantial support to the scar model, which claims that depressive mood damages and erodes self-esteem. In addition, the 'depressogenic' nature of the pessimistic attributional style, and the 'antidepressant' nature of perceived control over consequences plead in favour of the vulnerability model.

The long arm of parental addictions: the association with adult children's depression in a population-based study

Parental addictions have been associated with adult children's depression in several clinical and population-based studies. However, these studies have not examined if gender differences exist nor have they controlled for a range of potential explanatory factors. Using a regionally representative sample of 6268 adults from the 2005 Canadian Community Health Survey (response rate=83%), we investigated the association between parental addictions and adulthood depression controlling for four clusters of variables: adverse childhood experiences, adult health behaviors, adult socioeconomic status and other stressors. After controlling for all factors, adults exposed to parental addiction had 69% higher odds of depression compared to their peers with non-addicted parents (OR=1.69; 95% CI, 1.25-2.28). The relationship between parental addictions and depression did not vary by gender. These findings underscore the intergenerational consequences of drug and alcohol addiction and reinforce the need to develop interventions that support healthy childhood development.

Genetic and Environmental Influences on Rumination, Distraction, and Depressed Mood in Adolescence

Rumination is an established cognitive vulnerability for depression. Despite substantial work on the environmental origins of rumination, the heritability of rumination has not been examined and it is not known whether rumination accounts for some of the genetic vulnerability associated with depression. 756 adolescent twins ages 12-14 years completed the Response Styles Questionnaire and multiple measures of depressive symptoms. Brooding correlated positively and distraction correlated negatively with concurrent depressive symptoms. Estimated heritabilites were 54% for depression, 21% for brooding, 37% for reflection, and 30% for distraction. Bivariate genetic analyses suggested that (1) individual differences in distraction share both genetic and environmental sources of variation with depression; and (2) although the heritable influences on brooding are small, these heritable influences account for the majority of the relationship between brooding and depression (h2 = .62).

Therapygenetics: Using genetic markers to predict response to psychological treatment for mood and anxiety disorders

Considerable variation is evident in response to psychological therapies for mood and anxiety disorders. Genetic factors alongside environmental variables and gene-environment interactions are implicated in the etiology of these disorders and it is plausible that these same factors may also be important in predicting individual differences in response to psychological treatment. In this article, we review the evidence that genetic variation influences psychological treatment outcomes with a primary focus on mood and anxiety disorders. Unlike most past work, which has considered prediction of response to pharmacotherapy, this article reviews recent work in the field of therapygenetics, namely the role of genes in predicting psychological treatment response. As this is a field in its infancy, methodological recommendations are made and opportunities for future research are identified.

Fixable or fate? Perceptions of the biology of depression

OBJECTIVE

Previous research has shown that biological (e.g., genetic, biochemical) accounts of depression--currently in ascendancy--are linked to the general public's pessimism about the syndrome's prognosis. This research examined for the first time whether people with depressive symptoms would associate biological accounts of depression with pessimism about their own prognoses and whether a psychoeducation intervention portraying the biology of depression as malleable could decrease prognostic pessimism among symptomatic individuals.

METHOD

In 3 studies, participants were recruited online and assessed for depression symptoms. Those with significant depressive symptomatology (a Beck Depression Inventory-II score of at least 16) rated their endorsement of biochemical and genetic causal attributions for their symptoms and indicated expected length of symptom duration. An audiovisual intervention emphasizing the malleability of gene effects and neurochemistry was developed, and its effects on symptomatic individuals' prognostic pessimism, feelings of agency, guilt, and general hopelessness were measured.

RESULTS

Biochemical and genetic causal attributions for depression were significantly associated with prognostic pessimism among symptomatic individuals. The malleability intervention significantly reduced prognostic pessimism, increased feelings of agency, and decreased general hopelessness.

CONCLUSIONS

Biochemical and genetic attributions for depression are related to prognostic pessimism among individuals with depressive symptoms, and not just among the general public. However, emphasizing the malleability of gene effects and brain chemistry in depression can foster more optimism about depression-related beliefs.

The implications of genomics on the nursing care of adults with neuropsychiatric conditions

PURPOSE

Neuropsychiatric disorders contribute substantially to disease burden and quality of life across the lifespan and the globe. The purpose of this article is to review the state of the science regarding genomic contributions to selected common neuropsychiatric conditions and to examine the consequent immediate and future implications for nursing practice and research.

ORGANIZING CONSTRUCT

Our work is guided by an ecological model that recognizes that common diseases are complex or multifactorial, meaning that multiple genomic and environmental factors contribute to their etiology.

METHODS

A review of the literature was conducted to determine the state of the science in relationship to the genomic contributions to selected neuropsychiatric disorders.

FINDINGS

Neuropsychiatric conditions are genomically heterogeneous, both within a single disorder and across groups of disorders. While recent genomic research yields clinically validated and useful information for a small subset of persons (e.g., predictive genetic testing for Huntington disease and early-onset Alzheimer disease), broad clinical application of genetic information is not yet available. In addition, the implications of genomics for the development and targeting of nonpharmacologic treatment strategies is largely unexplored.

CONCLUSIONS

Further research is needed to expand knowledge beyond genomic risk for the presence of disease to knowledge about the genomic risk for symptoms, symptom burden, and tailored symptom management interventions.

CLINICAL RELEVANCE

Knowledge about the genomic influences on neuropsychiatric conditions suggests important implications for practicing nurses in the identification of persons at risk, provision of follow-up support, and in the administration of medications.

5-HTTLPR and early childhood adversities moderate cognitive and emotional processing in adolescence

BACKGROUND

Polymorphisms in the promoter region of the serotonin transporter gene (5-HTTLPR) and exposure to early childhood adversities (CA) are independently associated with individual differences in cognitive and emotional processing. Whether these two factors interact to influence cognitive and emotional processing is not known.

METHODOLOGY AND PRINCIPAL FINDINGS

We used a sample of 238 adolescents from a community study characterised by the presence of the short allele of 5-HTTLPR (LL, LS, SS) and the presence or absence of exposure to CA before 6 years of age. We measured cognitive and emotional processing using a set of neuropsychological tasks selected predominantly from the CANTAB® battery. We found that adolescents homozygous for the short allele (SS) of 5-HTTLPR and exposed to CA were worse at classifying negative and neutral stimuli and made more errors in response to ambiguous negative feedback. In addition, cognitive and emotional processing deficits were associated with diagnoses of anxiety and/or depressions.

CONCLUSION AND SIGNIFICANCE

Cognitive and emotional processing deficits may act as a transdiagnostic intermediate marker for anxiety and depressive disorders in genetically susceptible individuals exposed to CA.

The association between parental history of diagnosed mood/anxiety disorders and psychiatric symptoms and disorders in young adult offspring

BACKGROUND

Parental history of mood or anxiety disorders is one of the strongest and most consistent risk factors for the development of these disorders in offspring. Gaps remain however in our knowledge of whether maternal or paternal disorders are more strongly associated with offspring disorders, and whether the association exists in non-clinical samples. This study uses a large population-based sample to test if maternal or paternal history of mood and/or anxiety disorders increases the risk of mood and/or anxiety disorders, or symptoms of specific anxiety disorders, in offspring.

METHODS

Data were drawn from the Nicotine Dependence in Teens Study, a prospective cohort investigation of 1293 grade 7 students. Data on mental health outcomes were collected in mailed self-report questionnaires when participants were aged 20.4 (0.7) years on average. Parental data were collected in mailed self-report questionnaires. This current analysis pertains to 564 participants with maternal and/or paternal data. The association between maternal and paternal history and each of diagnosed anxiety disorder, diagnosed mood disorder, and symptoms of specific anxiety disorders in offspring was studied in multivariate logistic regression.

RESULTS

A higher proportion of mothers than fathers had a diagnosed mood/anxiety disorder (23% versus 12%). Similarly, 14% of female offspring had a diagnosed mood/anxiety disorder, compared to 6% of male offspring. The adjusted odds ratio (95% confidence interval) for maternal history was 2.2 (1.1, 4.5) for diagnosed mood disorders, 4.0 (2.1, 7.8) for diagnosed anxiety disorders, and 2.2 (1.2, 4.0) for social phobia symptoms. Paternal history was not associated with any of the mental health outcomes in offspring.

CONCLUSION

Maternal, but not paternal mood/anxiety disorders were associated with diagnosed psychiatric disorders, as well as symptoms of specific anxiety disorders, in offspring. Efforts to detect mood and anxiety disorders in offspring with a maternal history should be encouraged.

Neuroticism mediates the effect of P2RX7 on outcomes of mood disorders

BACKGROUND

We previously reported an association between P2RX7 variant rs208294, diagnosis, and the longitudinal course of mood disorders. Here, we test whether the personality trait neuroticism mediates the effect of P2RX7 on the course of mood disorders.

METHODS

Patients with DSM-IV mood disorder (256 with major depressive disorder and 168 with bipolar disorder [BD]) were diagnosed with semistructured interviews, genotyped, and followed up for a median of 60 (range 6-83) months. The primary outcome was the prospectively assessed proportion of time spent in any DSM-IV mood episode (time ill). Three types of genetic effect were tested in structural equations models: Model 1: genes directly affect outcome independent of neuroticism, Model 2: neuroticism mediates the effect of genes on outcome, and Model 3: neuroticism and the genetic variant interact in their effect on outcome.

RESULTS

Neuroticism mediated the P2RX7 genetic effect on outcome. The T allele of rs208294 was associated with higher neuroticism, which in turn predicted a higher proportion of time spent in mood episodes (the bootstrap-based test of indirect effect, P = .02). There was no significant interaction between neuroticism and the genotype.

CONCLUSION

Neuroticism is likely to lie on the causal pathway between the rs208294 T variant and the adverse long-term course of major depressive and BDs.

Biomarkers: symptoms, survivorship, and quality of life

OBJECTIVES

To review the evidence on a number of biomarkers that show potential clinical utility in the prediction of and treatment responsiveness for the four most common symptoms associated with cancer and its treatment (ie, pain, fatigue, sleep disturbance, depression).

DATA SOURCES

Review and synthesis of review articles and data-based publications.

CONCLUSION

A growing body of evidence suggests that sensitive and specific biomarkers will be available to assist clinicians with the assessment and management of symptoms.

IMPLICATIONS FOR NURSING PRACTICE

Nurses will play a critical role in educating patients about their risk for specific symptoms based on an evaluation of specific biomarkers. Nurses will be involved in using biomarker data to titrate medications based on patient's responses to symptom management interventions.

Mood disorders and risk of lung cancer in the EAGLE case-control study and in the U.S. Veterans Affairs inpatient cohort

Background

Mood disorders may affect lung cancer risk. We evaluated this hypothesis in two large studies.

Methodology/Principal Findings

We examined 1,939 lung cancer cases and 2,102 controls from the Environment And Genetics in Lung cancer Etiology (EAGLE) case-control study conducted in Italy (2002–2005), and 82,945 inpatients with a lung cancer diagnosis and 3,586,299 person-years without a lung cancer diagnosis in the U.S. Veterans Affairs Inpatient Cohort (VA study), composed of veterans with a VA hospital admission (1969–1996). In EAGLE, we calculated odds ratios (ORs) and 95% confidence intervals (CI), with extensive adjustment for tobacco smoking and multiple lifestyle factors. In the VA study, we estimated lung cancer relative risks (RRs) and 95% CIs with time-dependent Poisson regression, adjusting for attained age, calendar year, hospital visits, time within the study, and related previous medical diagnoses. In EAGLE, we found decreased lung cancer risk in subjects with a personal history of mood disorders (OR: 0.59, 95% CI: 0.44–0.79, based on 121 lung cancer incident cases and 192 controls) and family history of mood disorders (OR: 0.62, 95% CI: 0.50–0.77, based on 223 lung cancer cases and 345 controls). The VA study analyses yielded similar results (RR: 0.74, 95% CI: 0.71–0.77, based on 2,304 incident lung cancer cases and 177,267 non-cancer person-years) in men with discharge diagnoses for mood disorders. History of mood disorders was associated with nicotine dependence, alcohol and substance use and psychometric scales of depressive and anxiety symptoms in controls for these studies.

Conclusions/Significance

The consistent finding of a relationship between mood disorders and lung cancer risk across two large studies calls for further research into the complex interplay of risk factors associated with these two widespread and debilitating diseases. Although we adjusted for smoking effects in EAGLE, residual confounding of the results by smoking cannot be ruled out.

The brain-derived neurotrophic-factor (BDNF) val66met polymorphism is associated with geriatric depression: a meta-analysis

Depression has been associated with reduced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. Genetic association studies of the BDNF Val66Met polymorphism (rs6265) in geriatric depression have produced inconsistent results. A meta-analysis of studies was conducted to compare the frequency of the BDNF Val66Met variant between cases with geriatric depression and age-matched controls. A total of five studies involving 523 cases with geriatric depression and 1,220 psychiatrically healthy controls was included. Met allele carriers had an increased risk for geriatric depression when compared to Val/Val homozygotes (P = 0.004, OR = 1.48, 95% CI = 1.13-1.93). Our findings suggest the BDNF Met allele may confer increased risk for depression as individual age.

Integrating etiological models of social anxiety and depression in youth: evidence for a cumulative interpersonal risk model

Models of social anxiety and depression in youth have been developed separately, and they contain similar etiological influences. Given the high comorbidity of social anxiety and depression, we examine whether the posited etiological constructs are a correlate of, or a risk factor for, social anxiety and/or depression at the symptom level and the diagnostic level. We find core risk factors of temperament, genetics, and parent psychopathology (i.e., depression and anxiety) are neither necessary nor sufficient for the development of social anxiety and/or depression. Instead, aspects of children's relationships with parents and/or peers either mediates (i.e., explains) or moderates (i.e., interacts with) these core risks being related to social anxiety and/or depression. We then examine various parent- and peer-related constructs contained in the separate models of social anxiety and depression (i.e., parent-child attachment, parenting, social skill deficits, peer acceptance and rejection, peer victimization, friendships, and loneliness). Throughout our review, we report evidence for a Cumulative Interpersonal Risk model that incorporates both core risk factors and specific interpersonal risk factors. Most studies fail to consider comorbidity, thus little is known about the specificity of these various constructs to depression and/or social anxiety. However, we identify shared, differential, and cumulative risks, correlates, consequences, and protective factors. We then put forth demonstrated pathways for the development of depression, social anxiety, and their comorbidity. Implications for understanding comorbidity are highlighted throughout, as are theoretical and research directions for developing and refining models of social anxiety, depression, and their comorbidity. Prevention and treatment implications are also noted.

Maternal depression, socioeconomic position, and temperament in early childhood: the EDEN Mother-Child Cohort

BACKGROUND

Children of mothers who experience depression in pregnancy may be at high risk of emotional disturbances; however heterogeneity in risk suggests that other factors could play a moderating role. We test the hypothesis that children growing up in families characterised by both maternal depression and socioeconomic disadvantage are especially likely to have temperamental difficulties.

METHODS

Data come from the mother-child EDEN cohort study based in France (n=1903 mother-child pairs followed from 24 weeks of pregnancy to 12 months of age). Maternal depressive symptoms were assessed using the CES-D questionnaire, family socioeconomic position by family income and child temperament by the EAS at age 12 months. Linear regression analyses were adjusted for demographic characteristics (child's age, sex, mother's age at birth, number of siblings, parental separation, nonmaternal care) as well as child's premature birth, birth weight, duration of breastfeeding, maternal anxiety during pregnancy and maternal postnatal depression.

RESULTS

Accounting for age and sex, family risk (i.e. combined maternal depression and family income) was associated with children' scores of emotionality (p<0.0001) and activity (p=0.02). In multivariate analyses, children growing up exposed to both maternal depression and low income had the highest emotionality scores (β=0.57, se=0.14, p=0.0001).

LIMITATIONS

Maternal depression symptoms are self-reported.

CONCLUSIONS

Addressing the mental health needs of socioeconomically disadvantaged families with young children may help reduce the burden of internalising problems in the next generation.

Offspring of parents with recurrent depression: which features of parent depression index risk for offspring psychopathology?

BACKGROUND

Parental depression is associated with an increased risk of psychiatric disorder in offspring, although outcomes vary. At present relatively little is known about how differences in episode timing, severity, and course of recurrent depression relate to risk in children. The aim of this study was to consider the offspring of parents with recurrent depression and examine whether a recent episode of parental depression indexes risk for offspring psychopathology over and above these other parental depression features.

METHODS

Three hundred and thirty seven recurrently depressed parents and their offspring (aged 9-17) were interviewed as part of an ongoing study, the 'Early Prediction of Adolescent Depression Study'. The Child and Adolescent Psychiatric Assessment was used to assess two child outcomes; presence of a DSM-IV psychiatric disorder and number of DSM-IV child-rated depression symptoms.

RESULTS

Children whose parents had experienced a recent episode of depression reported significantly more depression symptoms, and odds of child psychiatric disorder were doubled relative to children whose parents had not experienced a recent episode of depression. Past severity of parental depression was also significantly associated with child depression symptoms.

LIMITATIONS

Statistical analyses preclude causal conclusions pertaining to parental depression influences on offspring psychopathology; several features of parental depression were recalled retrospectively.

CONCLUSIONS

This study suggests that particular features of parental depression, specifically past depression severity and presence of a recent episode, may be important indicators of risk for child psychiatric disorder and depressive symptoms.

Maternal depression and child and adolescent depression symptoms: an exploratory test for moderation by CRHR1, FKBP5 and NR3C1 gene variants

This study investigated moderation of the association between recurrent maternal depression and offspring depression symptoms by a selection of biologically relevant gene variants. 271 children/adolescents (aged 9.00 to 16.00 years) whose mothers had experienced at least two episodes of DSM-IV major depression and 165 controls (aged 12.25 to 16.67 years) drawn from a population-based twin register were used. Seven single nucleotide polymorphisms (SNPs) from three genes were genotyped in children. The genes were the Corticotropin Receptor Type 1 gene (CRHR1), the gene coding for the FK506 binding protein 5 (FKBP5) and the Glucocorticoid receptor gene (NR3c1) along with a haplotype formed by the SNPs in CRHR1. A significant association was found between recurrent maternal depression and depression symptoms in offspring. None of the SNPs were associated with offspring depression symptoms and associations did not differ according to the presence of recurrent maternal depression. However, caution is required due to a relatively small sample size.

Common genetic influences on depression, alcohol, and substance use disorders in Mexican-American families

Multiple genetic and environmental factors influence the risk for both major depression and alcohol/substance use disorders. In addition, there is evidence that these illnesses share genetic factors. Although, the heritability of these illnesses is well established, relatively few studies have focused on ethnic minority populations. Here, we document the prevalence, heritability, and genetic correlations between major depression and alcohol and drug disorders in a large, community-ascertained sample of Mexican-American families. A total of 1,122 Mexican-American individuals from 71 extended pedigrees participated in the study. All subjects received in-person psychiatric interviews. Heritability, genetic, and environmental correlations were estimated using SOLAR. Thirty-five percent of the sample met criteria for DSM-IV lifetime major depression, 34% met lifetime criteria for alcohol use disorders, and 8% met criteria for lifetime drug use disorders. The heritability for major depression was estimated to be h(2) = 0.393 (P = 3.7 × 10(-6)). Heritability estimates were higher for recurrent depression (h(2) = 0.463, P = 4.0 × 10(-6)) and early onset depression (h(2) = 0.485, P = 8.5 × 10(-5)). While the genetic correlation between major depression and alcohol use disorders was significant (ρ(g) = 0.58, P = 7 × 10(-3)), the environmental correlation between these traits was not significant. Although, there is evidence for increased rates of depression and substance use in US-born individuals of Mexican ancestry, our findings indicate that genetic control over major depression and alcohol/substance use disorders in the Mexican-American population is similar to that reported in other populations.

Glucocorticoids and stress‐related depression: an evaluation of biological mechanisms and the potential for new therapeutics

Purpose

Principles of epigenesis that provide a foundation for research into chronic medical disorders are increasingly being applied in the context of mental health. The purpose of this paper is to consider recent research evidence for epigenetic influences in the pathogenesis of depression, and the putative links with stress biology during exposure to chronic stress, with the aim of placing this into a context of potential new therapeutics.

Design/methodology/approach

Substantive reviews published during the last ten years were identified in a search of the Pubmed database in September 2010 using the terms “epigenetics” or “epigenesis” with “mental health”, “mood disorder”, “depression”, stress', “chronic stress” or “environment”, supplemented by hand‐searching of citations in the reviews.

Findings

Epigenetic mechanisms are both heritable and acquired, and their impact on the underlying genome helps explain individual vulnerability and patterns of occurrence of depression.

Originality/value

The paper shows that this relatively new field of research is in its infancy, and the influence of adverse environments (i.e. stressors) on genetic/epigenetic predisposition has promise for the advent of novel therapeutics based on epigenetic manipulation.

Genetics of depression: an overview of the current science

Most psychiatric disorders, including major depressive disorder (MDD), are known to involve complex interactions between genetic and environmental influences that impact the development and severity of symptomatology. Health care practitioner competencies have been expanded to include application of genetic knowledge in mental health. Yet this information is difficult to decipher and apply. To assist with these challenges, this article synthesizes recent literature related to the genetics of MDD and illustrates the genetic pathways for major depression.

Cognition and depression: current status and future directions

Cognitive theories of depression posit that people's thoughts, inferences, attitudes, and interpretations, and the way in which they attend to and recall information, can increase their risk for depression. Three mechanisms have been implicated in the relation between biased cognitive processing and the dysregulation of emotion in depression: inhibitory processes and deficits in working memory, ruminative responses to negative mood states and negative life events, and the inability to use positive and rewarding stimuli to regulate negative mood. In this review, we present a contemporary characterization of depressive cognition and discuss how different cognitive processes are related not only to each other, but also to emotion dysregulation, the hallmark feature of depression. We conclude that depression is characterized by increased elaboration of negative information, by difficulties disengaging from negative material, and by deficits in cognitive control when processing negative information. We discuss treatment implications of these conclusions and argue that the study of cognitive aspects of depression must be broadened by investigating neural and genetic factors that are related to cognitive dysfunction in this disorder. Such integrative investigations should help us gain a more comprehensive understanding of how cognitive and biological factors interact to affect the onset, maintenance, and course of depression.