Assessing the effects of age, sex and shared environment on the genetic aetiology of depression in childhood and adolescence

Sexual dimorphism in neurobehavioural phenotype and gut microbial composition upon long-term exposure to structural analogues of bisphenol-A

Bisphenol S (BPS) and Bisphenol F (BPF), the analogues of the legacy endocrine disrupting chemical, Bisphenol A (BPA) are ubiquitous in the environment and present in various consumer goods, and potentially neurotoxic. Here, we studied sex-specific responses of bisphenols on behavioural phenotypes, including their association with pro-inflammatory biomarkers and altered neurotransmitters levels, and the key gut microbial abundances. Neurobehavioural changes, using standard test battery, biochemical and molecular estimations for inflammatory cytokines, neurotransmitters, and oxido-nitrosative stress markers, gene expression analysis using qRT-PCR, H&E based histological investigations, gut permeability assays and Oxford Nanopore-based 16S-rRNA metagenomics sequencing for the gut microbial abundance estimations were performed. Bisphenol(s) exposure induces anxiety and depression-like behaviours, particularly in the male mice, with heightened pro-inflammatory cytokines levels and systemic endotoxemia, altered monoamine neurotransmitters levels/turnovers and hippocampal neuronal degeneration and inflammatory responses in the brain. They also increased gut permeability and altered microbial diversity, particularly in males. Present study provides evidence for sex-specific discrepancies in neurobehavioural phenotypes and gut microbiota, which necessitate a nuanced understanding of sex-dependent responses to bisphenols. The study contributes to ongoing discussions on the multifaceted implications of bisphenols exposure and underscores the need for tailored regulatory measures to mitigate potential health risks associated with them.

Familial genetic and environmental transmission of depression: A multi-informant twin family study

The phenomenon of familial clustering in depression is well established, yet the mechanisms by which depression is transmitted within families remain poorly understood. In the current study, we investigate the familial genetic and environmental transmission of depression by incorporating data from both adolescent twins and their parents. A total of 987 twin families were recruited from the Beijing Twin Study. Depression assessments were conducted for both adolescents and their parents. Twins' depression was assessed through reports from both the twins themselves and their parents, while parental depression was assessed by parental self-report. We employed a nuclear twin family model to examine genetic and environmental influences on adolescent depression. Our results, based on both self- and parent-report, demonstrate significant additive and dominant genetic influences on depression. We also found mild yet significant sibling environmental influences, while familial environmental influences were absent. Notably, parent-reported depression showed higher heritability but lower unique environmental influences compared with self-reported depression. These results highlight the important role of genetic transmission and sibling environmental transmission in explaining depression. Our study delineates the underlying mechanism of familial transmission in depression and can inform early treatments to halt transmission during adolescence.

Progression of Comorbid Depression and Substance Use among Racially Diverse Adults

Comorbidity of depression and substance abuse is common and a major public health burden. Studies of this form of comorbidity in racial and ethnic minoritized (REM) populations are minimal and have mixed findings. The present study examined the effect of general risk factors (family bonding, supervision, involvement, peer delinquency), depression risk factors (caregiver depression), and substance use risk factors (adult family members, sibling, and peer substance use) in early adolescence (~ ages 13-14) on comorbid depression and substance use in later adolescence (~ ages 15-17) and adulthood (~ ages 29-31) and continuity in comorbidity from adolescence to adulthood. Longitudinal data on 1000 Black (n = 680) Hispanic (n = 170) and White (n = 150) individuals came from the Rochester Youth Development Study. Participants were interviewed 14 times over 17 years beginning in 1988. General risk factors predicted comorbidity across racial/ethnic groups. Substance specific risk predicted comorbidity among Black and Hispanic individuals whereas depression specific risk was predictive among White individuals. Adolescent comorbidity predicted comorbidity in adulthood across race. These findings highlight the importance of substance use intervention for racial and ethnic minoritized individuals and mental health risk factors in Whites. The continuity of comorbidity from adolescence to adulthood highlights the importance of targeting adolescents for intervention to prevent long-term manifestation of this form of comorbidity and its associated consequences.

Developing a simple risk metric for the effect of sport-related concussion and physical pain on mental health

Risk factors associated with depression in athletes include biological sex, physical pain, and history of sport-related concussion (SRC). Due to the well-documented benefits of sport and physical activity on mental health, athletes and non-athletes were recruited to assess any differences. Beyond this, athletes were also grouped by sport-type (contact/non-contact sports) due to the increased prevalence of pain and SRC in contact sports. To our knowledge, there has been no research on how these factors influence the likelihood of depression. In the current study, 144 participants completed a short survey on the above factors and the Center for Epidemiological Studies Depression Scale. Sixty-two of these reported a history of concussion. Logistic regression revealed all the above predictors to be significantly associated with the depression scale. Individuals that had previously sustained SRC, were experiencing greater physical pain and females were more likely to display poor mental health. However, we provide further evidence for the benefits of engaging in sport and physical activity as those that took part in sport were less likely to report depression. Therefore, this study provides a simple risk metric whereby sportspeople can make a better informed choice of their sporting participation, making their own cost/reward judgement.

Sex difference in the associations among risk factors with depression in a large Taiwanese population study

Background

Depression is a common psychiatric health issue affecting an estimated 5% of adults worldwide, and it can lead to disability and increased economic burden. Consequently, identifying the factors associated with depression as early as possible is a vital issue. The aim of this study was to explore these associations in a large cohort of 121,601 Taiwanese participants in the Taiwan Biobank, and also to identify sex differences in the associations.

Methods

The study cohort included 77,902 women and 43,699 men (mean age, 49.9 ± 11.0 years), who were further classified into those with depression (n = 4,362; 3.6%) and those without depression (n = 117,239; 96.4%).

Results

The results of multivariable analysis showed that female sex (vs. male sex; odds ratio = 2.578; 95% confidence interval = 2.319–2.866; p < 0.001) was significantly associated with depression. Older age, diabetes mellitus (DM), hypertension, low systolic blood pressure (SBP), smoking history, living alone, low glycated hemoglobin (HbA1c), high triglycerides, and low uric acid were significantly associated with depression in the men. In the women, older age, DM, hypertension, low SBP, smoking history, alcohol history, education level of middle and high school (vs. lower than elementary school), living alone, high body mass index (BMI), menopause, low HbA1c, high triglycerides, high total cholesterol, low estimated glomerular filtration rate (eGFR), and low uric acid were significantly associated with depression. Further, there were significant interactions between sex and DM (p = 0.047), smoking history (p < 0.001), alcohol use (p < 0.001), BMI (p = 0.022), triglyceride (p = 0.033), eGFR (p = 0.001), and uric acid (p = 0.004) on depression.

Conclusion

In conclusion, our results showed sex differences in depression, and the women were significantly associated with depression compared to men. Furthermore, we also found sex differences among the risk factors associated with depression.

Shared genetic influences between depression and conduct disorder in children and adolescents: A systematic review

INTRODUCTION

The co-occurrence between major depression disorder (MDD) and conduct disorder (CD) is common across development and represents a significant risk factor for future psychiatric problems and long-term impairment. Large-scale quantitative genetic studies suggest that the MDD-CD co-occurrence may be partly explained by shared genetic vulnerability factors, in line with transdiagnostic models of psychopathology, but no systematic synthesis of the literature is currently available.

METHODS

We therefore conducted a systematic review of the available genetic literature on the co-occurrence between MDD and CD in children and adolescents. We identified 10 eligible studies, including 5 cross-sectional bivariate/multivariate twin studies, 3 longitudinal bivariate/multivariate twin studies, and 2 latent profile/trajectory twin studies.

RESULTS

Most of the reviewed studies found a strong contribution of shared genetic factors on the covariation between depression and conduct problems, in line with the prominent effect of a common genetic liability across development.

LIMITATIONS

The scientific literature on this psychiatric comorbidity is still limited, as it solely consists of twin studies from high income countries.

CONCLUSION

Considering the joint burden of MDD and CD on youth, families and society worldwide, future studies are needed to better investigate the shared risk processes of these frequently co-occurring conditions, in order to inform new treatments through personalized medicine.

Gender differences in the association of polygenic risk and divergent depression trajectories from mid to late life: a national longitudinal study

Our research fills a critical gap in the depression literature by utilizing a life course perspective to examine gender-gene interactions in association with depression trajectories over time. Using data from the Health and Retirement Study, we estimated multi-level negative binomial and logistic mixed models to analyze gender-specific trajectories of depressive symptoms (CESD-8) and potential clinical depression risk from middle to late adulthood in relation to gender-by-polygenic-risk (PRS) interactions. We found increasingly greater female-male gaps in the CESD-8 scale and a higher probability of clinical depression risk with increasing polygenic risk scores. Furthermore, females' higher genetic vulnerabilities to depressive conditions than males vary from ages 51 to 90 years, with most salient larger differences at oldest old ages at 76-85 (e.g. 0.28 higher CESD-8 scale for females at ages 76-85 years than for similar-aged males; higher 3.44% probability of depression risk for females at ages 81-85 compared to similar-aged males) followed by old ages at 61-70  years (e.g. about 2.40% higher probability of depression risk for females at ages 61-70 years than for similar-aged males) in comparison to younger ages during middle adulthood. This study contributes to new knowledge of how gender-by-polygenic-risk interactions are associated with depression trajectories across the life course.

Polygenic risk for depression, anxiety and neuroticism are associated with the severity and rate of change in depressive symptoms across adolescence

BACKGROUND

Adolescence marks a period where depression will commonly onset. Twin studies show that genetic influences play a role in how depression develops and changes across adolescence. Recent genome-wide association studies highlight that common genetic variants - which can be combined into polygenic risk scores (PRS) - are also implicated in depression. However, the role of PRS in adolescent depression and changes in adolescent depression is not yet understood. We aimed to examine associations between PRS for five psychiatric traits and depressive symptoms measured across adolescence using cross-sectional and growth-curve models. The five PRS were as follows: depression (DEP), major depressive disorder (MDD), anxiety (ANX), neuroticism (NEU) and schizophrenia (SCZ).

METHODS

We used data from over 6,000 participants of the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine associations between the five PRS and self-reported depressive symptoms (Short Mood and Feelings Questionnaire) over 9 occasions from 10 to 24 years. The PRS were created from well-powered genome-wide association studies conducted in adult populations. We examined cross-sectional associations between the PRS at each age and then again with longitudinal trajectories of depressive symptoms in a repeated measures framework using multilevel growth-curve analysis to examine the severity and the rate of change.

RESULTS

There was strong evidence that higher PRS for DEP, MDD and NEU were associated with worse depressive symptoms throughout adolescence and into young adulthood in our cross-sectional analysis, with consistent associations observed across all nine occasions. Growth-curve analyses provided stronger associations (as measured by effect sizes) and additional insights, demonstrating that individuals with higher PRS for DEP, MDD and NEU had steeper trajectories of depressive symptoms across development, all with a greater increasing rate of change during adolescence. Evidence was less consistent for the ANX and SCZ PRS in the cross-sectional analysis, yet there was some evidence for an increasing rate of change in adolescence in the growth-curve analyses with the ANX PRS.

CONCLUSIONS

These results show that common genetic variants as indexed by varying psychiatric PRS show patterns of specificity that influence both the severity and rate of change in depressive symptoms throughout adolescence and then into young adulthood. Longitudinal data that make use of repeated measures designs have the potential to provide greater insights how genetic factors influence the onset and persistence of adolescent depression.

Genetic contributions to anxiety disorders: where we are and where we are heading

Anxiety disorders are among the most common psychiatric disorders worldwide. They often onset early in life, with symptoms and consequences that can persist for decades. This makes anxiety disorders some of the most debilitating and costly disorders of our time. Although much is known about the synaptic and circuit mechanisms of fear and anxiety, research on the underlying genetics has lagged behind that of other psychiatric disorders. However, alongside the formation of the Psychiatric Genomic Consortium Anxiety workgroup, progress is rapidly advancing, offering opportunities for future research.Here we review current knowledge about the genetics of anxiety across the lifespan from genetically informative designs (i.e. twin studies and molecular genetics). We include studies of specific anxiety disorders (e.g. panic disorder, generalised anxiety disorder) as well as those using dimensional measures of trait anxiety. We particularly address findings from large-scale genome-wide association studies and show how such discoveries may provide opportunities for translation into improved or new therapeutics for affected individuals. Finally, we describe how discoveries in anxiety genetics open the door to numerous new research possibilities, such as the investigation of specific gene-environment interactions and the disentangling of causal associations with related traits and disorders.We discuss how the field of anxiety genetics is expected to move forward. In addition to the obvious need for larger sample sizes in genome-wide studies, we highlight the need for studies among young people, focusing on specific underlying dimensional traits or components of anxiety.

Common Liabilities in Internalizing Symptoms and Cigarette Use in Adolescence

INTRODUCTION

Substance use and mood disorders account for about 10% of the global burden of disease and, among adolescents, are a significant source of disability. The present study examined whether additive genetic or shared environmental factors influenced the covariance of internalizing symptoms and cigarette use during adolescence when both of these problems begin to increase.

AIMS AND METHODS

We used data (n = 1230 pairs of twins) from the Virginia Twin Study of Adolescent Behavioral Development (mean age = 15.3) to decompose the variance of internalizing symptoms, cigarette initiation, and quantity of cigarettes smoked in a variance decomposition model that included a beta coefficient to allow for estimates of cigarette initiation to influence quantity of cigarettes smoked.

RESULTS

In biometric models we were able to equate all parameter estimates by sex. After identifying the best fitting model, parameter estimates were calculated and the significance of overlapping paths between internalizing symptoms and cigarette initiation were tested. After accounting for the genetic architecture of cigarette initiation and quantity smoked, the covariance between internalizing symptoms and cigarette use was accounted for by sex-specific shared and unique environmental factors.

CONCLUSIONS

Among adolescents, the overlap in risk factors between internalizing symptoms and cigarette use is because of non-genetic, environmental factors. Further exploration of the environmental sources of variance involved in the onset of adolescents internalizing symptoms and cigarette use is warranted.

IMPLICATIONS

We find that during adolescence common environmental factors influence the association between internalizing symptoms and cigarette use. Correlated vulnerabilities because of environmental sources between internalizing and cigarette use may be open to intervention and likely will influence the progression of internalizing and cigarette use.

Gender Differences in Depression: Evidence From Genetics

Compared with men, female accounts for a larger proportion of patients with depression. Behavioral genetics researches find gender differences in genetic underpinnings of depression. We found that gender differences exist in heritability and the gene associated with depression after reviewing relevant research. Both genes and gene-environment interactions contribute to the risk of depression in a gender-specific manner. We detailed the relationships between serotonin transporter gene-linked promoter region (5-HTTLPR) and depression. However, the results of these studies are very different. We explored the reasons for the contradictory conclusions and provided some suggestions for future research on the gender differences in genetic underpinnings of depression.

Sad Dads and Troubled Tots: Protective Factors Related to the Stability of Paternal Depression and Early Childhood Internalizing Problems

The present study tested the moderating role of interparental relationship quality and child inhibitory control on the stability of paternal depression over time and associations between paternal depression and child internalizing problems in early childhood. Participants were a subsample (n = 166) of families from the Early Steps Multisite study, a longitudinal study of low-income parents and children. Interparental relationship quality (age 2) attenuated the association between paternal depressive symptoms at age 2 and paternal depressive symptoms at age 3. Both interparental relationship quality (age 3) and child inhibitory control (age 3) attenuated the association between paternal depressive symptoms (age 3) and age 4 child internalizing problems. Results suggest that high interparental relationship quality may be a protective factor in terms of lessening the stability of paternal depressive symptoms over time, as well as the association between paternal depression and later child internalizing problems. Similarly, high levels of inhibitory control may buffer children from the negative effects of paternal depression on the development of internalizing problems.

Parental Presence Impacts a Neural Correlate of Anxiety (the Late Positive Potential) in 5-7 Year Old Children: Interactions with Parental Sensitivity to Child Anxiety

Anxiety disorders tend to onset early in development and often result in chronic impairment across the lifespan. Thus, there is substantial interest in identifying early neural markers of anxiety and leveraging these markers to better understand processes leading to anxiety. The late positive potential (i.e., LPP) indexes sustained attention to motivationally relevant stimuli; and the LPP to negative images is increased in individuals with anxiety. In the current study, we examined how parental presence impacts the LPP to threatening images in children (52.6% male) between 5 and 7 years-old (N = 78). Moreover, we explored interactions with parental sensitivity to child anxiety symptoms. Results suggest that when children are in the presence of their parent (compared to the presence of an experimenter), they displayed a larger LPP to threatening images. LPP activity was modulated by parental response to their child's anxiety symptoms, such that children with parents who were overly reactive to their children's anxiety symptoms had the greatest LPP response when viewing threatening stimuli in their parent's presence. Additionally, exploratory analyses indicated that children with clinical and subclinical anxiety were characterized by an increased LPP to negative images, but only when the LPP was measured with parents in the room. Findings are novel and extend previous work by suggesting that parents who react strongly when observing their children's anxiety symptoms in turn increase their child's engagement with threatening stimuli, thereby placing them at greater risk for anxiety.

Sex differences in the genetic architecture of depression

The prevalence and clinical characteristics of depressive disorders differ between women and men; however, the genetic contribution to sex differences in depressive disorders has not been elucidated. To evaluate sex-specific differences in the genetic architecture of depression, whole exome sequencing of samples from 1000 patients (70.7% female) with depressive disorder was conducted. Control data from healthy individuals with no psychiatric disorder (n = 72, 26.4% female) and East-Asian subpopulation 1000 Genome Project data (n = 207, 50.7% female) were included. The genetic variation between men and women was directly compared using both qualitative and quantitative research designs. Qualitative analysis identified five genetic markers potentially associated with increased risk of depressive disorder in females, including three variants (rs201432982 within PDE4A, and rs62640397 and rs79442975 within FDX1L) mapping to chromosome 19p13.2 and two novel variants (rs820182 and rs820148) within MYO15B at the chromosome 17p25.1 locus. Depressed patients homozygous for these variants showed more severe depressive symptoms and higher suicidality than those who were not homozygotes (i.e., heterozygotes and homozygotes for the non-associated allele). Quantitative analysis demonstrated that the genetic burden of protein-truncating and deleterious variants was higher in males than females, even after permutation testing. Our study provides novel genetic evidence that the higher prevalence of depressive disorders in women may be attributable to inherited variants.

Interpersonal childhood adversity and stress generation in adolescence: Moderation by HPA axis multilocus genetic variation

Research suggests that childhood adversity (CA) is associated with a wide range of repercussions, including an increased likelihood of interpersonal stress generation. This may be particularly true following interpersonal childhood adversity (ICA) and for youth with high hypothalamic-pituitary-adrenal (HPA) axis-related genetic risk. In the current study, we applied a multilocus genetic profile score (MGPS) approach to measuring HPA axis-related genetic variation and examined its interaction with ICA to predict interpersonal stress generation in a sample of adolescents aged 14–17 (N = 241, Caucasian subsample n = 192). MGPSs were computed using 10 single nucleotide polymorphisms from HPA axis-related genes (CRHR1, NRC31, NRC32, and FKBP5). ICA significantly predicted greater adolescent interpersonal dependent stress. Additionally, MGPS predicted a stronger association between ICA and interpersonal dependent (but not independent or noninterpersonal dependent) stress. No gene–environment interaction (G×E) effects were found for noninterpersonal CA and MGPS in predicting adolescent interpersonal dependent stress. Effects remained after controlling for current depressive symptoms and following stratification by race. Findings extend existing G×E research on stress generation to HPA axis-related genetic variation and demonstrate effects specific to the interpersonal domain.

Genetic and Environmental Risk Factors Associated With Trajectories of Depression Symptoms From Adolescence to Young Adulthood

Importance

Less favorable trajectories of depressive mood from adolescence to early adulthood are associated with current and later psychopathology, impaired educational attainment, and social dysfunction, yet the genetic and environmental risk factors associated with these trajectories are not fully established. Examining what risk factors are associated with different trajectories of depressive mood could help identify the nature of depression symptoms and improve preventive interventions for those at most risk.

Objective

To examine the differential associations of genetic and environmental risk factors with trajectories of depression symptoms among individuals observed from ages 10 to 24 years.

Design, Setting, and Participants

In a longitudinal cohort study established in 1990 and currently ongoing (the Avon Longitudinal Study of Parents and Children [ALSPAC]), growth mixture modeling was used to identify trajectories of depression symptoms in 9394 individuals in the United Kingdom. Associations of different risk factors with these trajectories were then examined. Analysis was conducted between August 2018 and January 2019.

Main Outcomes and Measures

Trajectories were composed from depression symptoms measured using the Short Mood and Feelings Questionnaire at 9 occasions from ages 10 to 24 years. Risk factors included sex, a polygenic risk score taken from a recent genome-wide association study of depression symptoms, maternal postnatal depression, partner cruelty to the offspring's mother when the child was aged 2 to 4 years, childhood anxiety at age 8 years, and being bullied at age 10 years.

Results

Data on all risk factors, confounders, and the outcome were available for 3525 individuals, including 1771 (50.2%) who were female. Trajectories were assessed between the mean (SD) age of 10.7 (0.3) years and mean (SD) age of 23.8 (0.5) years. Overall, 5 distinct trajectories of depression symptoms were identified: (1) stable low (2506 individuals [71.1%]), (2) adolescent limited (325 individuals [9.2%]), (3) childhood limited (203 individuals [5.8%]), (4) early-adult onset (393 individuals [11.1%]), and (5) childhood persistent (98 individuals [2.8%]). Of all the associations of risk factors with trajectories, sex (odds ratio [OR], 6.45; 95% CI, 2.89-14.38), the polygenic risk score for depression symptoms (OR, 1.47; 95% CI, 1.10-1.96), and childhood anxiety (OR, 1.30; 95% CI, 1.16-1.45) showed the strongest association with the childhood-persistent trajectory of depression symptoms compared with the stable-low trajectory. Maternal postnatal depression (OR, 2.39; 95% CI, 1.41-4.07) had the strongest association with the early-adult-onset trajectory, while partner cruelty to mother (OR, 2.30; 95% CI, 1.36-3.90) had the strongest association with the adolescent-limited trajectory. Bullying (OR, 8.08; 95% CI, 4.92-13.26) showed the strongest association with the childhood-limited trajectory.

Conclusions and Relevance

The least favorable trajectories of depression symptoms (childhood persistent and early-adult onset) were associated with both genetic and environmental risk factors, but the 2 trajectories of limited duration that had resolved by early adulthood (childhood limited and adolescent limited) were not associated with the polygenic risk score or maternal postnatal depression. Bullying was strongly associated with both the childhood-persistent and childhood-limited trajectories, suggesting that this risk factor may have a time-specific effect. These findings suggest that examining genetic and multiple time-specific environmental antecedents could help identify trajectories of varying onset and chronicity.

Daily intake of soft drinks is associated with symptoms of anxiety and depression in Chinese adolescents

OBJECTIVE

The association of soft drink consumption with mental problems in Asian adolescents has not been reported. The present study aimed to investigate the association of soft drink consumption and symptoms of anxiety and depression in adolescents in China.

DESIGN

A cross-sectional study to investigate the association of intake of soft drinks and sugars from soft drinks with symptoms of anxiety and depression measured by the two-item Generalized Anxiety Disorder (GAD-2) and the Patient Health Questionnaire (PHQ-2), respectively.

SETTING

A comprehensive university in Changsha, China.

PARTICIPANTS

Newly enrolled college students in 2017.

RESULT

In total, 8226 students completed the investigation and 8085 students with no systemic disorders were finally analysed. Students consuming soft drinks ≥7 times/week had significantly higher (mean difference; 95 % CI) GAD-2 (0·15; 0·07, 0·23) and PHQ-2 (0·27; 0·19, 0·35) scores compared with those barely consuming soft drinks, adjusted for demographic and behavioural factors. Those consuming >25 g sugar/d from soft drinks had significantly higher GAD-2 (0·11; 0·04, 0·18) and PHQ-2 (0·22; 0·15, 0·29) scores compared with non-consumers. The mediation effect of obesity in the associations was not clinically significant.

CONCLUSIONS

Adolescents consuming soft drinks ≥7 times/week, or >25 g sugar/d from soft drinks, had significantly higher levels of anxiety and depression. Dietary suggestion is needed to prevent anxiety and depression in adolescents.

Characterizing Developmental Trajectories and the Role of Neuropsychiatric Genetic Risk Variants in Early-Onset Depression

Importance

Depression often first manifests in adolescence. Thereafter, individual trajectories vary substantially, but it is not known what shapes depression trajectories in youth. Adult studies suggest that genetic risk for schizophrenia, a psychiatric disorder with a neurodevelopmental component, may contribute to an earlier onset of depression.

Objective

To test the hypothesis that there are distinct trajectories of depressive symptoms and that genetic liability for neurodevelopmental psychiatric disorders (eg, schizophrenia, attention deficit/hyperactivity disorder [ADHD]), as well as for major depressive disorder (MDD), contribute to early-onset depression.

Design, Setting, and Participants

The Avon Longitudinal Study of Parents and Children is an ongoing, prospective, longitudinal, population-based cohort that has been collecting data since September 6, 1990, including data on 7543 adolescents with depressive symptoms at multiple time points. The present study was conducted between November 10, 2017, and August 14, 2018.

Main Outcomes and Measures

Trajectories based on self-reported depressive symptoms dichotomized by the clinical cutpoint; MDD, schizophrenia, and ADHD polygenic risk score (PRS) were predictors.

Results

In 7543 adolescents with depression data on more than 1 assessment point between a mean (SD) age of 10.64 (0.25) years and 18.65 (0.49) years (3568 [47.3%] male; 3975 [52.7%] female), 3 trajectory classes were identified: persistently low (73.7%), later-adolescence onset (17.3%), and early-adolescence onset (9.0%). The later-adolescence-onset class was associated with MDD genetic risk only (MDD PRS: odds ratio [OR], 1.27; 95% CI, 1.09-1.48; P = .003). The early-adolescence-onset class was also associated with MDD genetic risk (MDD PRS: OR, 1.24; 95% CI, 1.06-1.46; P = .007) but additionally with genetic risk for neurodevelopmental disorders (schizophrenia PRS: OR, 1.22; 95% CI, 1.04-1.43; P = .01; ADHD PRS: OR, 1.32; 95% CI, 1.13-1.54; P < .001) and childhood ADHD (χ21 = 6.837; P = .009) and neurodevelopmental traits (pragmatic language difficulties: OR, 1.31; P = .004; social communication difficulties: OR, 0.68; P < .001).

Conclusions and Relevance

The findings of this study appear to demonstrate evidence of distinct depressive trajectories, primarily distinguished by age at onset. The more typical depression trajectory with onset of clinically significant symptoms at age 16 years was associated with MDD genetic risk. The less-common depression trajectory, with a very early onset, was particularly associated with ADHD and schizophrenia genetic risk and, phenotypically, with childhood ADHD and neurodevelopmental traits. Findings are consistent with emerging evidence for a neurodevelopmental component in some cases of depression and suggest that the presence of this component may be more likely when the onset of depression is very early.

Genetic and environmental influences on internalizing psychopathology across age and pubertal development

Symptoms of anxiety and depression are commonly comorbid and partially share a genetic etiology. Mean levels of anxiety and depression increase over the transition to adolescence, particularly in girls, suggesting a possible role of pubertal development in the activation of underlying genetic risks. The current study examined how genetic and environmental influences on anxiety and depression differed by chronological age and pubertal status. We analyzed composite scores from child self-reports and parent informant-reports of internalizing symptomology in a racially and socioeconomically diverse sample of 1,913 individual twins from 1,006 pairs (ages 8-20 years) from the Texas Twin Project. Biometric models tested age and pubertal status as moderators of genetic and environmental influences shared between and specific to anxiety and depression to determine whether etiology of internalizing symptomology differs across development as a function of age or puberty. Genetic influences did not increase as a function of age or puberty, but instead shared environmental effects decreased with age. In an exploratory model that considered the moderators simultaneously, developmental differences in etiology were reflected in genetic and environmental effects unique to depression. Results suggest that genetic variance in internalizing problems is relatively constant during adolescence, with environmental influences more varied across development. (PsycINFO Database Record

The presentation of depression symptoms in attention-deficit/hyperactivity disorder: comparing child and parent reports

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) frequently co-occurs with depression, and outcomes are poor when both are present. Little is known about whether depression symptoms present differently in ADHD compared to the general population, or how reliable young people with ADHD are at reporting these symptoms. This study aimed to describe depression symptoms in a clinical ADHD sample compared to a population sample, and compare self-reports of depression symptoms with parent-reports.

METHODS

Two hundred and forty-nine children with ADHD and their parents completed follow-up questionnaires around 5 years after taking part in a Cardiff University ADHD study. Child depression symptoms were measured using parent- and child-reported Mood and Feelings Questionnaires (MFQ) and compared to a population sample with MFQ data (n = 1460). Within both samples, child- and parent-reported depression symptoms were compared.

RESULTS

Although the profile of depression symptoms was similar between young people with ADHD and those in the general population, depression symptoms were much more common in the ADHD sample (parent-rated MFQ score = 24.52 vs. 9.39; child-rated = 21.02 vs. 11.86). The most common symptoms in both samples included irritability, restlessness and concentration difficulties, with core depression symptoms such as feeling miserable/unhappy also prominent. Within the ADHD sample, but not the population sample, children reported depression symptoms less frequently than their parents.

CONCLUSIONS

Young people with ADHD are at high risk of experiencing symptoms of depression but may under-report the severity of their symptoms. Obtaining parent reports of depression symptoms in this group may be important to avoid missing key indicators of risk.

Should we prescribe antidepressants to children?

In June last year, the committee on safety of medicines (CSM) advised against the use of paroxetine in depressed children and adolescents. This was subsequently followed by a similar warning regarding the use of other selective serotonin reuptake inhibitors (SSRIs), with the exception of fluoxetine (http://www.mhra.gov.uk/). The basis of this decision was a detailed review of both the published and the unpublished data. The latter were obtained from pharmaceutical companies who had not reported negative results from clinical trials to the medical community. The addition of the pharmaceutical industry data to published results exerted dramatic effects on the efficacy of available compounds. Thus with the exception of fluoxetine, the risks outweigh the benefits of the SSRIs in the treatment of childhood depression. In particular, there is evidence of a non-significant trend towards increased suicidality with most SSRIs compared with placebo. These findings have been supported by a further recent meta-analysis of the available published and unpublished data (Whittington et al, 2004). A review of the safety and efficacy of antidepressants in children and adolescents by Jureidini et al (2004) has also criticised the quality of reporting of the published trials. The review concluded that the benefits of SSRIs have been exaggerated, including those of fluoxetine, and the adverse effects have been downplayed. The authors suggest that psychological treatments are probably safer and more effective.

Predictors of Internalizing Behaviors in Ukrainian Children

OBJECTIVE

To (a) estimate the level of child internalizing problems in a sample of Ukrainian school-age children and (b) examine the relationships between child internalizing psychopathology and parenting practices, depression, alcohol use, and sociodemographics.

BACKGROUND

Most research on child internalizing behaviors has used samples from high-income countries, but there is a lack of information about children's behaviors and associated risk and protective factors from low- and middle-income countries such as Ukraine. An ecological-transactional model framework was used in this study to examine maternal and family-level factors associated with child internalizing behavior problems.

METHOD

Data were gathered from a community-based sample of Ukrainian mothers and children between 9 and 16 years of age (n = 251) using face-to-face interviews. Multiple linear regression analysis was used to examine the relationship among the independent variables (e.g., alcohol use, depression, and parenting behaviors) and children's internalizing behaviors.

RESULTS

Older children, especially boys, reported fewer internalizing problems. Increased internalizing symptomatology was associated with mothers' older age, higher level of depression, lower use of positive parenting, and poor child monitoring and supervision.

CONCLUSION

These results raise awareness about the importance of child familial backgrounds while trying to address child mental health problems in Ukraine.

IMPLICATIONS

Family practitioners may want to help mothers learn and apply positive parenting and effective supervision and monitoring skills to help reduce their children's depression and anxiety symptoms. Additionally, helping to decrease maternal depression may have a positive trickle-down effect on their children's internalizing behaviors.

Genetics of depressive symptoms in adolescence

BACKGROUND

Despite many attempts to understand the genetic architecture of depression, little progress has been made. The majority of these studies, however, have been carried out in adults and do not account for the potential influence of development.

METHODS

The Avon Longitudinal Study of Parents and Children (ALSPAC) is a longitudinal pregnancy cohort which recruited participants between April 1991 and December 1992. Analyses were replicated in two independent European cohorts. Genome-wide complex trait analysis (GCTA) software was used to investigate SNP-heritability (h2SNP) of depression across adolescence, the role of puberty was investigated by stratifying these estimates according to pubertal onset. Genome-wide association studies were performed to identify genetic variants associated with depression at different stages of development.

RESULTS

Heritability was estimated between the ages of 11 and 18 with sample sizes ranging from 3289 to 5480. Heritability was low with an apparent peak was found at age 13 (h2 = 0.17, p = 0.006). Confidence intervals around these estimates suggest an upper-bound to h2SNP of around 30%. A variant located on chromosome 7 was found to be associated with depressive symptoms at age 13 in ALSPAC (rs138191010: β = 0.142, p = 2.51 × 10-8), although this was not replicated.

CONCLUSIONS

Although power is a potential limitation, the observed patterns provide interesting hypotheses surrounding the heritability of depression at different developmental stages. We found substantially lower estimates for depressive symptoms at age 11 (0.07) compared to those previously estimated in adults (0.21). We also found a peak in heritability at age 13. These findings suggest environmental factors are likely to be more important in the aetiology of depressive symptoms in early adolescence than in adulthood.

Time-varying and time-invariant dimensions of depression in children and adolescents: Implications for cross-informant agreement

The longitudinal structure of depression in children and adolescents was examined by applying a Trait-State-Occasion structural equation model to 4 waves of self, teacher, peer, and parent reports in 2 age groups (9 to 13 and 13 to 16 years old). Analyses revealed that the depression latent variable consisted of 2 longitudinal factors: a time-invariant dimension that was completely stable over time and a time-varying dimension that was not perfectly stable over time. Different sources of information were differentially sensitive to these 2 dimensions. Among adolescents, self- and parent reports better reflected the time-invariant aspects. For children and adolescents, peer and teacher reports better reflected the time-varying aspects. Relatively high cross-informant agreement emerged for the time-invariant dimension in both children and adolescents. Cross-informant agreement for the time-varying dimension was high for adolescents but very low for children. Implications emerge for theoretical models of depression and for its measurement, especially when attempting to predict changes in depression in the context of longitudinal studies. (PsycINFO Database Record

Callous-unemotional behaviors in early childhood: Genetic and environmental contributions to stability and change

Callous-unemotional (CU) behaviors demonstrate meaningful individual differences in early childhood, even in nonclinical samples with low mean levels of CU, but the factors underlying this variation have not been examined. This study investigated genetic and environmental contributions to individual differences and to sources of continuity and change in CU in toddler twins (145 monozygotic, 169 dizygotic) assessed at ages 2 and 3 years. CU, as assessed by the Child Behavior Checklist 1.5-5 (Achenbach & Rescorla, 2000), was moderately stable across age (r = .45, p < .0001). Longitudinal biometric analyses revealed genetic and nonshared environmental influences on CU at both ages, with no significant contribution from shared environmental factors. Stability from age 2 to 3 was due to genetic factors, whereas change was due to both genetic and nonshared environmental influences. This genetic and nonshared environmental change was substantial, suggesting malleability of CU in early childhood. Over 50% of the genetic influences and 100% of the nonshared environmental influences on CU at age 3 were independent of those that operated at age 2. Implications of novel sources of variance across age are discussed.

Parental Depressive Symptoms and Youth Internalizing and Externalizing Problems: The Moderating Role of Interparental Conflict

The current investigation examined if interparental conflict (IPC), including psychological and physical violence, moderated the relationship between parental depressive symptoms and youth internalizing and externalizing problems, respectively, in a sample of youth with a parent with a history of Major Depressive Disorder (MDD). One hundred and eighty families with a parent with a history of MDD (M_age = 41.96; 88.9% mothers) and a youth in the target age range of 9-to-15 years (49.4% females; M_age = 11.46) participated. Findings indicated that IPC exacerbated the effect of parental depressive symptoms on internalizing, but not externalizing, problems for both males and females. Findings suggest that, in families with a parent who has a history of depression, parental depressive symptoms and IPC together have important implications for youth internalizing problems. Targeting improvement for both parent depressive symptoms and interparental conflict may directly lead to decreases in youth internalizing symptoms in the context of parental depression.

Developmental changes in genetic and environmental influences on Chinese child and adolescent anxiety and depression

BACKGROUND

Twin and family studies using Western samples have established that child and adolescent anxiety and depression are under substantial genetic, modest shared environmental, and substantial non-shared environmental influences. Generalizability of these findings to non-Western societies remains largely unknown, particularly regarding the changes of genetic and environmental influences with age. The current study examined changes in genetic and environmental influences on self-reported anxiety and depression from late childhood to mid-adolescence among a Chinese twin sample. Sex differences were also examined.

METHOD

Self-reported anxiety and depression were collected from 712 10- to 12-year-old Chinese twins (mean = 10.88 years, 49% males) and again 3 years later. Quantitative genetic modeling was used to examine developmental changes in genetic and environmental influences on anxiety and depression, and sex differences.

RESULTS

Heritability of anxiety and depression in late childhood (23 and 20%) decreased to negligible in mid-adolescence, while shared environmental influences increased (20 and 27% to 57 and 60%). Shared environmental factors explained most of the continuity of anxiety and depression (75 and 77%). Non-shared environmental factors were largely time-specific. No sex differences were observed.

CONCLUSIONS

Shared environmental influences might be more pronounced during the transition period of adolescence in non-Western societies such as China. Future research should examine similarities and differences in the genetic and environmental etiologies of child and adolescent internalizing and other psychopathology in development between Western and non-Western societies.

Environmental and genetic determinants of childhood depression: The roles of DAT1 and the antenatal environment

Research on adolescent and adult populations has linked depression to variation in several monoaminergic genes, but genetic association studies on depression in children are limited. Additionally, few studies have investigated whether stressors occurring very early in development moderate the influence of certain genes on depression. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) from monoaminergic genes interacted with measures of early life stress to influence depressive symptoms in children. Participants were members of the Auckland Birthweight Collaborative cohort. Small for gestational age (SGA) and maternal stress during pregnancy were measured at birth and used as indicators of early life stress. At age 11, depressive symptoms were measured using the Centre for Epidemiological Studies Depression Scale for Children (CES-DC) and DNA samples were collected for genotyping. A two-way ANOVA revealed that SGA and a SNP from the dopamine transporter gene DAT1 had an interactive effect on children's depressive symptoms. Specifically, symptoms were greater in children born SGA who are T homozygous for the rs1042098 SNP. These findings suggest that adverse intrauterine environments leading to low birth weight also seem to exacerbate the effects of certain DAT1 variants on depression.

Stability and Change in Genetic and Environmental Influences on Well-Being in Response to an Intervention

Genetic and environmental influences on complex traits can change in response to developmental and environmental contexts. Here we explore the impact of a positive activity intervention on the genetic and environmental influences on well-being and mental health in a sample of 750 adolescent twins. Twins completed a 10-week online well-being intervention, consisting of kindness and gratitude tasks and matched control activities. The results showed significant improvements both in well-being and in internalizing symptoms in response to the intervention activities. We used multivariate twin analyses of repeated measures, tracking stability and change in genetic and environmental influences, to assess the impact of this environmental intervention on these variance components. The heritability of well-being remained high both before and after the intervention, and the same genetic effects were important at each stage, even as well-being increased. The overall magnitude of environmental influences was also stable across the intervention; however, different non-shared environmental influences emerged during the intervention. Our study highlights the value of exploring the innovations in non-shared environmental influences that could provide clues to the mechanisms behind improvements in well-being. The findings also emphasize that even traits strongly influenced by genetics, like well-being, are subject to change in response to environmental interventions.

Genetic and Environmental Influences on Parent-Child Conflict and Child Depression Through Late Adolescence

Few studies have investigated potential gender differences in the genetic and environmental influences on the prospective associations between parent-child conflict and later depression, a notable gap given substantial gender differences in rates of depression and suggestive evidence of differences in the etiology of depression among females and males. To fill this gap, we evaluated whether the prospective relationship between parent-child conflict and major depressive disorder symptoms varied as a function of parent-child gender composition. A combined twin and adoption sample was used (53% female; 85% European ancestry), containing 1,627 adolescent sibling pairs (789 monozygotic twin pairs, 594 dizygotic/full-biological pairs, 244 genetically unrelated pairs) with assessments at two time points in adolescence (approximate ages 15 and 18). Prospective associations between parent-child conflict and subsequent adolescent depression were explained predominately through common genetic influences for mother-daughter and mother-son pairs but less so for father-daughter and father-son pairs. Results support the notion that processes of gene-environment correlation involved in the prospective associations between parent-child conflict, and later adolescent depression appear to be less relevant to father-child relationships in comparison to mother-child relationships. Notably, results did not show that parent-child conflict was more relevant to the etiology of major depressive disorder (MDD) for girls than boys; gender differences in depression do not appear to be due to differences in the associations between parent-child conflict and child depression.

Profiling depression in childhood and adolescence: the role of conduct problems

BACKGROUND

Depression is typically more common in females and rates rise around puberty. However, studies of children and adolescents suggest that depression accompanied by conduct problems may represent a different subtype not characterised by a female preponderance, with differing risk factors and genetic architecture compared to pure-depression. This study aimed to identify aetiologically distinct profiles of depressive symptoms, distinguished by the presence or absence of co-occurring conduct problems.

METHODS

Latent profile analysis was conducted on a school sample of 1648 children (11-12 years) and replicated in a sample of 2006 twins (8-17 years).

RESULTS

In both samples pure-depressive and conduct-depressive profiles were identified. The pure-depressive profile was associated with female gender, while the conduct-depressive profile was associated with lower cognitive ability but not with gender. Twin analyses indicated possible differences in genetic aetiology.

CONCLUSIONS

There was evidence for aetiologically heterogeneous depression symptom profiles based on the presence or absence of co-occurring conduct problems.

Understanding the genetic and environmental specificity and overlap between well-being and internalizing symptoms in adolescence

Moderate inverse correlations are typically found between well-being and mental illness. We aimed to investigate the role of genes and environments in explaining the relationships between two aspects of well-being and two measures of internalizing symptoms. Altogether, 4700 pairs of 16-year-old twins contributed data on subjective happiness and life satisfaction, as well as symptoms of depression and emotional problems. Well-being was moderately correlated with internalizing symptoms (range = -0.45, -0.58). Multivariate twin model-fitting indicated both genetic and environmental overlap. Life satisfaction and happiness demonstrated different patterns of overlap, with stronger genetic links between life satisfaction and depression. Non-shared environmental influences were largely specific to each trait. This study supports the theory of mental health and illness being partly (but not entirely) correlated dimensions. There are also significant genetic and environmental factors to identify for well-being that go beyond the absence of mental illness. It is therefore possible that different interventions are needed for treating mental illness and promoting mental health.

BDNF Val66Met polymorphism and stressful life events in melancholic childhood-onset depression

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) polymorphisms have been examined for their contribution toward depression with equivocal results. More homogeneous phenotypes might be used to improve our understanding of genetic liability to depression. The aim of our study was to (a) test for an association between the BDNF Val66Met polymorphism and childhood-onset melancholic depression and (b) to examine the interactive effects of stressful life events (SLE) and the Val66Met polymorphism on the risk of childhood-onset melancholic depression.

MATERIALS AND METHODS

A total of 583 depressed probands were involved in this study (162 of the melancholic subtype). Diagnoses were derived through the Interview Schedule for Children and Adolescents - Diagnostic Version and life event data were collected using an Intake General Information Sheet.

RESULTS

Overall, 27.8% of the participants fulfilled the criteria for melancholy. In the melancholic group, the proportion of females was higher (53.1%), although there were more males in the overall depressed sample. We detected no significant differences in genotype or allele frequency between the melancholic and the nonmelancholic depressed group. The BDNF Val66Met polymorphism and SLE interaction was not significantly associated with the melancholy outcome.

CONCLUSION

In our study, females were more prone to developing the early-onset melancholic phenotype. To our knowledge, this is the first study to investigate the differentiating effect of the genotype and the G×E interaction on the melancholic phenotype in a large sample of depressed young patients. We did not find an association between the melancholic subtype of major depression and the BDNF genotype and SLE interaction in this sample, which is representative of the Hungarian clinic-referred population of depressed youths.

Income, personality, and subjective financial well-being: the role of gender in their genetic and environmental relationships

Increasing levels of financial inequality prompt questions about the relationship between income and well-being. Using a twins sample from the Survey of Midlife Development in the U. S. and controlling for personality as core self-evaluations (CSE), we found that men, but not women, had higher subjective financial well-being (SFWB) when they had higher incomes. This relationship was due to ‘unshared environmental’ factors rather than genes, suggesting that the effect of income on SFWB is driven by unique experiences among men. Further, for women and men, we found that CSE influenced income and SFWB, and that both genetic and environmental factors explained this relationship. Given the relatively small and male-specific relationship between income and SFWB, and the determination of both income and SFWB by personality, we propose that policy makers focus on malleable factors beyond merely income in order to increase SFWB, including financial education and building self-regulatory capacity.

Analyzing pathways from childhood maltreatment to internalizing symptoms and disorders in children and adolescents (AMIS): a study protocol

BACKGROUND

Effective interventions for maltreated children are impeded by gaps in our knowledge of the etiopathogenic mechanisms leading from maltreatment to mental disorders. Although some studies have already identified individual risk factors, there is a lack of large-scale multilevel research on how psychosocial, neurobiological, and genetic factors act in concert to modulate risk of internalizing psychopathology in childhood following maltreatment. To help close this gap, we aim to delineate gender-specific pathways from maltreatment to psychological disorder/resilience. To this end, we examine the interplay of specific maltreatment characteristics and psychological, endocrine, metabolomic, and (epi-)genomic stress response patterns as well as cognitive-emotional/social processes as determinants of developmental outcome. Specifically, we will explore endocrine, metabolomic, and epigenetic mechanisms leading from maltreatment to a higher risk of depression and anxiety disorders.

METHODS/DESIGN

Four large samples amounting to a total of N = 920 children aged 4-16 years will be assessed: Two cohorts with prior internalizing psychopathology and controls will be checked for maltreatment and two cohorts with substantiated maltreatment will be checked for internalizing (and externalizing) psychopathology. We will apply a multi-source (interview, questionnaires, official records), multi-informant strategy (parents, children, teachers) to assess maltreatment characteristics (e.g., subtypes, developmental timing, chronicity) and psychopathological symptoms, supplemented with multiple measurements of risk and protective factors and cutting-edge laboratory analyses of endocrine, steroid metabolomic and epigenetic factors. As previous assessments in the two largest samples are already available, longitudinal data will be generated within the three year study period.

DISCUSSION

Our results will lay the empirical foundation for (a) detection of early biopsychosocial markers, (b) development of screening measures, and

Testing Models for the Contributions of Genes and Environment to Developmental Change in Adolescent Depression

We tested two models to identify the genetic and environmental processes underlying longitudinal changes in depression among adolescents. The first assumes that observed changes in covariance structure result from the unfolding of inherent, random individual differences in the overall levels and rates of change in depression over time (random growth curves). The second assumes that observed changes are due to time-specific random effects (innovations) accumulating over time (autoregressive effects). We found little evidence of age-specific genetic effects or persistent genetic innovations. Instead, genetic effects are consistent with a gradual unfolding in the liability to depression and rates of change with increasing age. Likewise, the environment also creates significant individual differences in overall levels of depression and rates of change. However, there are also time-specific environmental experiences that persist with fidelity. The implications of these differing genetic and environmental mechanisms in the etiology of depression are considered.

Sex Differences in Genetic and Environmental Influences on Adolescent Depressive Symptoms: A Meta-Analytic Review

Although sex difference in the mean level of depressive symptoms has been well established, the sex difference in genetic and environmental influences on adolescent depressive symptoms is unclear. The current study conducted a meta-analysis of twin studies on sex differences in self- and parent-reported adolescent depressive symptoms. For self-reports, genetic factors influenced adolescent depressive symptoms equally for boys and girls, accounting for 46% of variation, but shared environmental factors had stronger impacts on adolescent girls' versus boys' depressive symptoms (13% versus 1% of the variance). For parent-reports, genetic, shared, and nonshared environmental factors influenced adolescent depressive symptoms equally, with separate estimates of 34%, 35%, and 31%. The implications of sex difference in genetic and environmental etiologies of depressive symptoms are discussed.

Genetic susceptibility to family environment: BDNF Val66met and 5-HTTLPR influence depressive symptoms

Functional genetic polymorphisms associated with Brain-Derived Neurotrophic Factor (BDNF) and serotonin (5-HTTLPR) have demonstrated associations with depression in interaction with environmental stressors. In light of evidence for biological connections between BDNF and serotonin, it is prudent to consider genetic epistasis between variants in these genes in the development of depressive symptoms. The current study examined the effects of val66met, 5-HTTLPR, and family environment quality on youth depressive symptoms in adolescence and young adulthood in a longitudinal sample oversampled for maternal depression history. A differential susceptibility model was tested, comparing the effects of family environment on depression scores across different levels of a cumulative plasticity genotype, defined as presence of both, either, or neither plasticity alleles (defined here as val66met Met and 5-HTTLPR 'S'). Cumulative plasticity genotype interacted with family environment quality to predict depression among males and females at age 15. After age 15, however, the interaction of cumulative plasticity genotype and early family environment quality was only predictive of depression among females. Results supported a differential susceptibility model at age 15, such that plasticity allele presence was associated with more or less depressive symptoms depending on valence of the family environment, and a diathesis-stress model of gene-environment interaction after age 15. These findings, although preliminary because of the small sample size, support prior results indicating interactive effects of 5-HTTLPR, val66met, and environmental stress, and suggest that family environment may have a stronger influence on genetically susceptible women than men.

Transmission of parental neuroticism to offspring's depression: the mediating role of rumination

Rumination is a cognitive process that involves repetitively focusing on the causes, situational factors and consequences of one's negative emotion, and it is a potent risk factor for depression. Parental depression and neuroticism may exert an influence on offspring's development of rumination, which may increase offspring's risk for depression. The current study included 375 biological parent-offspring dyads. Parents were assessed for depressive symptoms and neuroticism; adult offspring were assessed for depressive symptoms and rumination. Structural equation modelling was used to examine the effects of parental depressive symptoms and parental neuroticism on adult offspring's depression, and to determine whether offspring's rumination mediated this relationship. Results provided evidence that offspring's rumination fully mediated the relationship between parental neuroticism and offspring's depressive symptoms. Parental depressive symptoms and neuroticism may contribute a genetic predisposition for depressive symptoms in offspring, but it also may promote an environment in which maladaptive cognitive processes, such as rumination, are learned. Given the role that rumination plays in mediating the association between neuroticism and depressive symptoms-targeting rumination in the treatment of high risk individuals would be important in reducing onset of depressive disorders.

Genetic and environmental contributions to social anxiety across different ages: a meta-analytic approach to twin data

Social anxiety disorder (SAD) and social anxiety symptoms (SAS) have been largely studied both epidemiologically and genetically, however, estimates of genetic and environmental influences for these phenotypes widely vary across reports. Based upon available literature, 13 cohorts (42,585 subjects) were included in 3 meta-analytic estimates of the standardized variance components of aetiological influences on SAD/SAS, on the effect of age and of phenotype (symptoms vs. diagnosis). The proportions of variance accounted for by genetic and environmental factors were calculated by averaging estimates among studies, and pondered by the number of individuals in each sample. Meta-analytic estimations showed that genetic and non-shared environmental factors explain most of individual differences for SAD/SAS. In adults, the genetic contribution was half than that in younger patients, with higher contribution of non-shared environmental influences. In contrast, the shared environmental factors seem to be less relevant.

Transitions in the transcriptome of the serotonergic and dopaminergic systems in the human brain during adolescence

Adolescence is a period of profound neurophysiological, behavioral, cognitive and psychological changes, but not much is known about the underlying molecular neural mechanisms. The aim of this study was to systematically analyze expression levels of the genes forming serotonergic and dopaminergic synapses during adolescence. We analyzed the mRNA expression profiles of genes that code for all components of serotonergic and dopaminergic synapses, in 16 brain areas from human and non-human primates from public domain databases, to detect genes whose expression changes during adolescence. Two serotonin receptors, HTR1E and HTR1B had expression levels that exhibit a sharp transition in the prefrontal cortex in adolescence, but we found no similar transition in the dopaminergic system. A similar but smoother rise in expression levels is observed in HTR4 and HTR5A, and in HTR1E and HTR1B in three other expression datasets published. An earlier rise is observed in HTR1A, and a smooth and significant rise with age is observed in the expression of HTR1E in microarray measurements in macaque monkeys. The expression of HTR1E and HTR1B is correlated across subjects within each age group, suggesting that they are controlled by common mechanisms. These results point to HTR1E and HTR1B as major candidate genes involved in adolescence maturation processes, and to their operation through common control mechanisms. The maturation profiles may also involve several other 5-HT receptors, including the genes HTR5A, HTR4 and HTR1A.

Parent-child hostility and child and adolescent depression symptoms: the direction of effects, role of genetic factors and gender

Identifying environmental risk factors in the pathway to depression is an important research goal. To extend prior research, designs that rule out alternative explanatory factors; genetic effects and reverse causation, and permit tests of both parent and child gender are required. The present study used two different samples to address these issues. A longitudinal community sample of 316 families (157 boys, 159 girls) aged 11-12 years (mean 11.7) at Time 1 and 12-13 years at Time 2 (mean 12.7) was used to test the direction of effects between parent hostility and child and adolescent depression symptoms. A genetically sensitive sample of 1,075 twin pairs; 653 dizygotic (135 male, 183 female, 335 opposite sex) and 422 monozygotic (180 male and 242 female) aged 12-20 years (mean 16.12) was used to test whether parent hostility had environmental effects. Analyses were conducted separately by parent and child gender. Using cross-lagged panel analyses, the association between mother-daughter hostility and depression symptoms was found to be longitudinal and bidirectional with reciprocal effects between mothers and daughters. Behavioural genetic analyses in the twin sample revealed a significant environmental link between mother hostility and symptoms of daughter depression independent of genetic factors. A significant pathway was found between daughter depressive symptoms and father hostility but not vice versa. This association was accounted for by genetic factors in behavioural genetic analyses. Findings provide evidence of an environmental risk pathway to depression symptoms and identify patterns of variation according to parent and child gender. Results are discussed in relation to underlying explanatory processes and clinical implications.

Negative emotionality mediates the association of 5-HTTLPR genotype and depression in children with and without ADHD

The 44-base-pair polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) has been implicated in the etiology of depression, but relatively little is known about potential mediators of this association. Although dimensions of temperament are likely to be proximal to the neurobiological and genetic factors underlying depression, studies have yet to formally evaluate temperament as a potential causal pathway. We examined individual differences in dimensions of temperament [negative emotionality (NE), prosociality (PRO), and daring (DA)] as potential mediators of 5-HTTLPR genotype and child depression. Using a multiple mediation framework, we tested the association of child 5-HTTLPR genotype and these dimensions of temperament with multi-informant ratings of child depression in a sample of 218 children with and without attention-deficit/hyperactivity disorder (ADHD). The long allele of 5-HTTLPR was associated with higher NE and lower PRO, but not DA. High NE mediated the association of 5-HTTLPR genotype and separate parent and teacher ratings of depression. ADHD status did not moderate the mediational role of NE for 5-HTTLPR and depression. Results suggest that NE may constitute a pathway between 5-HTTLPR and child depression. The role of genetic variation and temperament dimensions as intermediate traits in the development of depression is discussed.

Genetic and environmental etiologies of adolescent dysfunctional attitudes: a twin study

Despite the importance of dysfunctional attitudes in the development and maintenance of depression, little is known about the etiological origin of dysfunctional attitudes. The Dysfunctional Attitudes Scale for Children was administered to 674 adolescent twins derived from the Beijing Twin Study (BeTwiSt). Four hundred and thirty-nine monozygotic and 235 same-gender dizygotic twin pairs were included. Approximately 54% were females. The age range of the twins was 11-17 years. Model-fitting analyses were conducted. Biometric genetic model-fitting estimates indicated that additive genetic factors accounted for 31% (95% CI: 11%, 45%) of variance in adolescent dysfunctional attitude. The influence of shared environmental factors was small and negligible (9% [95% CI: 0%, 27%]). Non-shared environmental factors explained 60% (95% CI: 55%, 66%) of variance. Equating the estimate parameters across gender or age groups resulted in a non-significant difference of model fit, but there were trends suggesting higher heritability in females and older adolescents. Our results provide evidence for moderate heritability of dysfunctional attitudes in adolescents. Dysfunctional attitudes can be used as an endophenotype to identify risk genes for depression.

Genetic and environmental influences on depressive symptoms in Chinese adolescents

Adolescent depression is common and has become a major public health concern in China, yet little research has examined the etiology of depression in Chinese adolescents. In the present study, genetic and environmental influences on Chinese adolescent depressive symptoms were investigated in 1,181 twin pairs residing in Beijing, China (ages 11-19 years). Child- and parent-versions of the children's depression inventory were used to measure adolescents' depressive symptoms. For self-reports, genetic factors, shared environmental factors, and non-shared environmental factors accounted for 50, 5, and 45 % of the variation in depressive symptoms, respectively; for parent-reports, genetic factors, shared environmental factors, and non-shared environmental factors accounted for 51, 18, and 31 % of the variation, respectively. These estimates are generally consistent with previous findings in Western adolescents, supporting the cross-cultural generalizability of etiological model of adolescent depression. Neither qualitative nor quantitative sex differences were found in the etiological model. Future studies are needed to investigate how genes and environments work together (gene-environment interaction, gene-environment correlation) to influence depression in Chinese adolescents.

Father absence and depressive symptoms in adolescence: findings from a UK cohort

BACKGROUND

Previous studies suggest a link between parental separation or divorce and risk of depression in adolescence. There are, however, few studies that have prospectively examined the effects of timing of biological father absence on risk for depressive symptoms in adolescence while controlling for a range of confounding factors.

METHOD

We examine the association between father absence occurring in early (the first 5 years) and middle childhood (5-10 years) and adolescent depressive symptoms in a sample comprising 5631 children from the UK-based Avon Longitudinal Study of Parents and Children (ALSPAC). Self-reported depressive symptoms at 14 years were assessed using the Short Mood and Feelings Questionnaire (SMFQ). Father absence was assessed from maternal questionnaires completed at regular intervals from the birth of the study child up to 10 years.

RESULTS

There was evidence for an association between father absence in early childhood and increased odds of depressive symptoms at 14 years. This association was stronger in girls than in boys and remained after adjusting for a range of socio-economic, maternal and familial confounders assessed prior to the father's departure. Conversely, there was no evidence for an association between father absence in middle childhood and depressive symptoms at 14 years.

CONCLUSIONS

Father absence in early childhood increases risk for adolescent depressive symptoms, particularly in girls. Future research should be aimed at identifying possible biological and psychosocial mechanisms linking father absence to depressive symptomatology to enable the development of family-based early prevention and intervention programmes targeting young children at risk.