Effects of environmental stress and gender on associations among symptoms of depression and the serotonin transporter gene linked polymorphic region (5-HTTLPR)

Recent insights into depression from transcriptomic analysis

Purpose

Depression is a widespread mood disorder with a high rate of relapse and chronicity that can be affected by gender, and caused by traumatic or stressful events. Transcriptome analysis measures gene expression heterogeneity in cells, tissues, organs, and the whole body. The purpose of the study was to investigate both gender-specific and tissue-specific variations in gene expression regarding depression based on transcriptomic analysis using RNA-Seq data.

Methods

The depression datasets GSE190518 and GSE214921 were downloaded from the Gene Expression Omnibus database provided by the NCBI. The GSE190518 datasets include peripheral blood samples (4 patients, 4 healthy controls), and the GSE214921 datasets contain human postmortem orbitofrontal cortex bulk tissue (20 patients, 19 healthy controls). All datasets were analyzed separately with the DESeq2 package in R. Later, GO and KEGG enrichment analyses of differentially expressed genes were performed using the clusterProfiler package in R.

Results

Our results reveal that depression stimulates genes linked to the immune system, which is a common denominator in both brain tissue and blood samples. Overall, tissue-specific factors contribute to the association between depression and the immune system via distinct genes. Furthermore, gene ontology analyses revealed that HSPA6, HSPA7, HSPA1L, HSPA1A, and HSPA1B genes are co-represented in different pathways involved in molecular function, biological processes, and cellular components.

Conclusions

Comparative transcriptomic evidence supports the immune hypothesis of depression in different tissue samples. Gender-specific depression may be triggered by protein misfolding.

Sex differences in prevalence and clinical correlates of subclinical hypothyroidism in Chinese patients with first-episode untreated major depressive disorder

BACKGROUND

Previous studies showed sex differences in the prevalences of both major depressive disorder (MDD) and subclinical hypothyroidism (SCH). This study aimed to further compare the prevalence and correlates of moderate-to-severe SCH between male and female Chinese MDD patients.

METHODS

A total of 1706 first-episode drug naïve Chinese patients with MDD were recruited. Depressive symptoms were assessed by the 17-item Hamilton Depression Rating Scale, psychotic symptoms by the Positive and Negative Syndrome Scale and anxiety symptoms by the Hamilton Anxiety Rating Scale. Serum thyroid stimulating hormone (TSH), free triiodothyronine (fT3) and free thyroxine (fT4) concentrations were measured by chemiluminescence immunoassay. Moderate-to-severe SCH was defined as serum TSH > 8 mIU/L with normal fT4.

RESULTS

The prevalence of moderate-to-severe SCH was 10.4% in male patients and 15.1% in female patients (χ2 = 7.22, p < 0.01). In female patients, binary logistic regression showed that systolic blood pressure (SBP), suicide attempts and psychotic symptoms (all p < 0.001) were associated with moderate-to-severe SCH. In male patients, SBP and psychotic symptoms were associated with moderate-to-severe SCH (both p < 0.001), while suicide attempts and severe anxiety were not (p > 0.05).

CONCLUSIONS

Our findings reveal a higher prevalence rate of moderate-to-severe SCH in female untreated first-episode MDD patients compared with males. Moreover, there is a positive association between suicide attempts and moderate-to-severe SCH only in female MDD patients.

Environmental enrichment affects behavioral and pharmacological response to antidepressants in CF1 mice

It has been described that environmental enrichment (EE) exerts beneficial effects on cognitive and emotional performances, dendritic branching, synaptic density, neurogenesis and modulation of neurotrophic systems and neurotransmitters in rodents. However, the influence of EE on pharmacological and behavioral responses in animal models of psychiatric disorders has not been fully established. In this context, the aim of this study was to evaluate the influence of exposure to EE on mice behavior in the open field test (OFT) and forced swimming tests (FST), as well as the response to antidepressant drugs (fluoxetine 30 mg/kg and bupropion 30 mg/kg, p.o.). CF1 mice were exposed to an enriched housing condition at different developmental stages: from mating to postnatal day (PND) 55 (lifelong enrichment), from mating to PND21 (perinatal enrichment) and from PND21 to PND55 (post-weaning enrichment). At PND58 the male offspring were evaluated in the OFT and FST. BDNF gene expression in the hippocampus was determined through qPCR. Mice exposed to perinatal enrichment remained longer in the peripheral zone of the OFT and performed fewer grooming than mice housed under standard condition, and these effects were independent of drug treatment. Post-weaning and lifelong enrichment increased grooming behavior. Bupropion reduced grooming in all groups except in perinatal enriched. In turn, fluoxetine decreased grooming only in post-weaning enriched group. None of the enriched housing conditions altered the immobility time in the FST, which indicates that EE had no antidepressant-like effect. However, all enriched housing conditions abolished the anti-immobility effect of bupropion. None of the EE protocols affected BDNF hippocampal expression. The main conclusion is that mice behavior in the OFT is sensitive to alterations in the housing environment and depends on the developmental stage of exposure. Bupropion and fluoxetine yielded divergent responses depending on the housing condition, which suggests that EE modulates monoaminergic neurotransmission pathways.

A Combined Effect of Polygenic Scores and Environmental Factors on Individual Differences in Depression Level

The risk of depression could be evaluated through its multifactorial nature using the polygenic score (PGS) approach. Assuming a "clinical continuum" hypothesis of mental diseases, a preliminary assessment of individuals with elevated risk for developing depression in a non-clinical group is of high relevance. In turn, epidemiological studies suggest including social/lifestyle factors together with PGS to address the "missing heritability" problem. We designed regression models, which included PGS using 27 SNPs and social/lifestyle factors to explain individual differences in depression levels in high-education students from the Volga-Ural region (VUR) of Eurasia. Since issues related to population stratification in PGS scores may lead to imprecise variant effect estimates, we aimed to examine a sensitivity of PGS calculated on summary statistics of depression and neuroticism GWAS from Western Europeans to assess individual proneness to depression levels in the examined sample of Eastern Europeans. A depression score was assessed using the revised version of the Beck Depression Inventory (BDI) in 1065 young adults (age 18-25 years, 79% women, Eastern European ancestry). The models based on weighted PGS demonstrated higher sensitivity to evaluate depression level in the full dataset, explaining up to 2.4% of the variance (p = 3.42 × 10^-7); the addition of social parameters enhanced the strength of the model (adjusted r² = 15%, p < 2.2 × 10^-16). A higher effect was observed in models based on weighted PGS in the women group, explaining up to 3.9% (p = 6.03 × 10^-9) of variance in depression level assuming a combined SNPs effect and 17% (p < 2.2 × 10^-16)-with the addition of social factors in the model. We failed to estimate BDI-measured depression based on summary statistics from Western Europeans GWAS of clinical depression. Although regression models based on PGS from neuroticism (depression-related trait) GWAS in Europeans were associated with a depression level in our sample (adjusted r² = 0.43%, p = 0.019-for unweighted model), the effect was mainly attributed to the inclusion of social/lifestyle factors as predictors in these models (adjusted r² = 15%, p < 2.2 × 10^-16-for unweighted model). In conclusion, constructed PGS models contribute to a proportion of interindividual variability in BDI-measured depression in high-education students, especially women, from the VUR of Eurasia. External factors, including the specificity of rearing in childhood, used as predictors, improve the predictive ability of these models. Implementation of ethnicity-specific effect estimates in such modeling is important for individual risk assessment.

Novel GxE effects and resilience: A case:control longitudinal study of psychosocial stress with war-affected youth

Responses to early life adversity differ greatly across individuals. Elucidating which factors underlie this variation can help us better understand how to improve health trajectories. Here we used a case:control study of refugee and non-refugee youth, differentially exposed to war-related trauma, to investigate the effects of genetics and psychosocial environment on response to trauma. We investigated genetic variants in two genes (serotonin transporter, 5-HTT, and catechol-O-methyltransferase, COMT) that have been implicated in response to trauma. We collected buccal samples and survey data from 417 Syrian refugee and 306 Jordanian non-refugee youth who were enrolled in a randomized controlled trial to evaluate a mental health-focused intervention. Measures of lifetime trauma exposure, resilience, and six mental health and psychosocial stress outcomes were collected at three time points: baseline, ~13 weeks, and ~48 weeks. We used multilevel models to identify gene x environment (GxE) interactions and direct effects of the genetic variants in association with the six outcome measures over time. We did not identify any interactions with trauma exposure, but we did identify GxE interactions with both genes and resilience; 1) individuals with high expression (HE) variants of 5-HTTLPR and high levels of resilience had the lowest levels of perceived stress and 2) individuals homozygous for the Val variant of COMT with high levels of resilience showed stable levels of post-traumatic stress symptoms. We also identified a direct protective effect of 5-HTTLPR HE homozygotes on perceived insecurity. Our results point to novel interactions between the protective effects of genetic variants and resilience, lending support to ideas of differential susceptibility and altered stress reactivity in a cohort of war-affected adolescents.

The Role of Sex in Genetic Association Studies of Depression

Depression is the most common mental illness in the U.S. affecting nearly 40 million adults age 18 years and older. Depression has both genetic and environmental influences. In addition, women are more likely to be affected by depression than men. However, the relationship between genes and depression is complex and may be influenced by sex. Understanding the genetic basis of sex-specific differences for depression has the potential to lead to new biological understanding of the etiology of depression in females compared to males and to promote the development of novel and more effective pharmacotherapies. This review examines the role of sex in genetic associations with depression for both genome-wide association and candidate gene studies. While the genetic association signals of depression differ by sex, the role of sex in the heritability of depression is complex and warrants further investigation.

Depressive Symptoms are Associated with low Serotonin Levels in Plasma but are not 5-HTTLPR Genotype Dependent in Older Adults

Depressive symptoms are diagnosed by physicians using scales but their pathophysiology is unclear. Low serotonin (5-HT) levels play an important role in depression, and the 5-HT transporter (5-HTT) is an important regulator of plasma serotonin levels and reuptake. Additionally, the 5-HTT gene-linked polymorphic region (5-HTTLPR) is associated with depression. The aim was to clarify the roles of plasma serotonin levels in plasma and the 5HTTPLR polymorphism in depressive symptoms in older adults. A total of 84 older adult participants were evaluated. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale of 20 items (CESD-20). The plasma serotonin levels were determined by ELISA, and the 5-HTTLPR genotype was analyzed by PCR. Depressive symptoms were present in 39.3% (N = 33) of the participants. The median plasma serotonin level was 204.34 ng/mL (SD = 93.88). A significant correlation was found between the CESD-20 scale and plasma serotonin levels (r = -.256; p = .019). Low serotonin levels were associated with the presence of depressive symptoms (p = .001). The 5-HTTLPR analysis showed that of the 84 older adults, 35.7% had the SS genotype, 10.7% had the LL genotype, and 53.6% were heterozygous. The 5-HTTLPR polymorphism was not associated with depressive symptoms (p = .587) and plasma serotonin levels (p = 0.391). Depressive symptoms correlate with low serotonin levels in plasma, but not with the 5-HTTLPR polymorphism in older Mexican adults.

Association of 5-HTTLPR/rs25531 with depressive symptoms in patients with coronary heart disease: A prospective study

BACKGROUND

5-HTTLPR/rs25531 is suspected to be involved in the pathogenesis of both coronary heart disease (CHD)¹ and depression. We aimed to investigate the role of 5-HTTLPR/rs25531 in the development of depressive symptoms among CHD patients in a longitudinal design.

METHODS

N = 265 participants with CHD diagnosis were included while hospitalized in a department of cardiology and genotyped for the 5-HTTLPR/rs25531. Depressive symptoms were measured using the Patient Health Questionnaire (PHQ-9)⁷ at baseline and after 6 and 12 months. Binary logistic regression models were used to analyze the association of 5-HTTLPR/rs25531 with the prevalence of depressive symptoms at each time point as well as with the incidence and persistence of depressive symptoms at follow-up.

RESULTS

"L_AL_A" genotype was associated with a higher prevalence of depressive symptoms 12 months after study inclusion. "L_AL_A" genotype was associated with a higher incidence of depressive symptoms 6 and 12 months after study inclusion. There was no association of 5-HTTLPR/rs25531 with the persistence of depressive symptoms.

LIMITATIONS

Inclusion criteria did not demand a particular cardiac event at baseline, which aggravated the interpretation of the time-specific results. The majority of the participants was of male gender which could cause bias. The present study only vaguely differentiated between ethnical groups which might cause bias regarding nationality-dependent allele distributions.

CONCLUSION

The present study suggests a time-dependent association of the "L_AL_A" genotype with depressive symptoms in CHD patients. 5-HTTLPR/rs25531 might be an important marker to detect risk groups for later onset depressive symptoms among CHD patients.

AVPR1A main effect and OXTR-by-environment interplay in individual differences in depression level

Background

Multiple studies of depression indicated a significant role of gene-by-environment interactions; however, they are mainly limited to the examination of modulating effect of recent stressful life events. Other environmental factors occurring at different stages of ante- and postnatal development may affect the association between multiple genes and depression. The study aimed to analyze the main and haplotype-based effect of serotonergic system and HPA-axis gene polymorphisms on depression and to detect gene-by-environment interaction models explaining individual variance in depression in mentally healthy young adults from Russia.

Methods

Depression score was assessed using Beck Depression Inventory (BDI) in 623 healthy individuals (81% women; 17-25 years) of Caucasian origin (Russians, Tatars, Udmurts) from Russia. The main- and gene-based effects of 12 SNPs in SLC6A4 (5-HTTLPR, rs1042173), HTR2A (rs7322347), OXTR (rs7632287, rs2254298, rs13316193, rs53576, rs2228485, rs237911), AVPR1A (rs3803107, rs1042615), and AVPR1B (rs33911258) genes, and gene-by-environment interactions were tested with linear regression models (PLINK v.1.9) adjusted for multiple comparisons.

Results

We observed ethnicity-specific main effect of the AVPR1A rs3803107 (P = 0.003; P_FDR = 0.047) and gene-based effect of the OXTR gene (Р = 0.005; P_perm = 0.034) on BDI-measured depression, and modifying effect of paternal care on OXTR rs53576 (P = 0.004; P_FDR = 0.012) and birth order on OXTR rs237911 (P = 0.006; P_FDR = 0.018) association with depression level.

Limitations

A hypothesis driven candidate gene approach, which examined a limited number of genetic variants in a moderately large sample, was used.

Conclusions

Our preliminary findings indicate that familial environment may play a permissive role modulating the manifestation of OXTR-based depression variance in mentally healthy subjects.

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.

Serotonergic sensitivity alleles moderate relations between attachment security at age three and socioemotional competence at age five

Children with higher socioemotional competence are more likely to build constructive relationships with others and experience more positive adjustment outcomes in later periods. Securely attached children are likely to develop better socioemotional competence, but genetic moderation of associations between attachment and later socioemotional competence has received less attention. Using structural equation modeling, this study analyzed data collected from 1,337 children (51% male) born from 1998 to 2000 in the Fragile Families and Child Wellbeing study. The results demonstrated that relations between attachment security at age 3 years and their social competence at age 5 years differed by two serotonin transporter variants (5-HTTLPR, STin2). Effect sizes of these interactions were larger than effect sizes of main effects and the benefit of having sensitive alleles was consistently supported. This implies that having more secure attachment in the early developmental period is advantageous especially for children with minor alleles who have greater environmental sensitivity.

Length Polymorphisms in the Angiotensin I-Converting Enzyme Gene and the Serotonin-Transporter-Linked Polymorphic Region Constitute a Risk Haplotype for Depression in Patients with Coronary Artery Disease

Genetic variations affecting the course of depressive symptoms in patients with coronary artery disease (CAD) have not yet been well studied. Therefore, we set out to investigate whether distinct haplotypes of the two insertion/deletion polymorphisms in the serotonin-transporter-linked polymorphic region (5-HTTLPR) and the angiotensin I-converting enzyme (ACE) gene located on chromosome 17 can be identified as risk factors for trajectories of depression. Clinical and genotyping data were derived from 507 depressed CAD patients participating in the randomized, controlled, multicenter Stepwise Psychotherapy Intervention for Reducing Risk in Coronary Artery Disease (SPIRR-CAD) trial, of whom the majority had an acute cardiac event before study inclusion. Depression scores on the Hospital Anxiety and Depression Scale (HADS) were assessed at baseline and at five follow-up time points up to 2 years after study entrance. At baseline, depression scores did not significantly differ between patients carrying the risk haplotype ACE D/D, 5-HTTLPR I/I (n = 46) and the non-risk haplotypes (n = 461, 10.9 ± 2.7 versus 10.4 ± 2.5, p = 0.254). HADS-depression scores declined from study inclusion during the first year irrespective of the genotype. At each follow-up time point, HADS-depression scores were significantly higher in ACE D/D, 5-HTTLPR I/I carriers than in their counterparts. Two years after study inclusion, the mean HADS depression score remained 1.8 points higher in patients with the risk haplotype as compared to subjects not carrying this haplotype (9.9 ± 4.2 versus 8.1 ± 4.0, p = 0.009). In summary, the presence of the ACE D/D, 5-HTTLPR I/I haplotype may be a vulnerability factor for comorbid depressive symptoms in CAD patients.

Serotonergic influence on depressive symptoms and trait anxiety is mediated by negative life events and frontal activation in children and adolescents

Depression and anxiety are common in childhood and adolescence. Even though cardinal symptoms differ, there is a considerable overlap regarding the pathogenic influence of serotonergic innervation, negative life experience, disturbed emotion perception/affect regulation, and impaired neural functioning in the fronto-limbic circuit. In this study, we examined the effect of the 5-HTTLPR/rs25531 genotype on depressive symptoms and trait anxiety under the consideration of the amount of negative life events in healthy children and adolescents (N = 389). In a subsample of 49 subjects, we performed fMRI to add fronto-limbic brain activation as a second interacting factor. Across all subjects, negative life events moderated the influence of the 5-HTTLPR/rs25531 genotype on both depressive symptoms and trait anxiety. In the fMRI subsample, 5-HTTLPR/rs25531 S + S/L_G + S/L_A + L_GL_A + L_GL_G genotype-associated left middle frontal gyrus (MFG) activation mediated the influence of 5-HTTLPR/rs25531 genotype on depressive symptoms, however, only in combination with negative life events. Genetic influence on trait anxiety was predominantly mediated by negative life events; only L_AL_A genotype-specific activation in the right MFG worked as a mediator in combination with negative life events. The present findings hint towards distinct mechanisms mediating the influence of 5-HTTLPR/rs25531 genotype on depressive symptoms and anxiety, with negative life events playing a crucial role in both phenotypes. With regard to depressive symptoms, however, this influence was only visible in combination with MFG activation, whereas, in anxiety, it was independent of brain activation.

FMR1 Low Zone CGG Repeats: Phenotypic Associations in the Context of Parenting Stress

The FMR1 gene on the X chromosome has varying numbers of CGG repeats. The modal number is 30, and expansion to >200 results in fragile X syndrome, but the copy number extends down to 6. Past research suggests that individuals whose CGGs are in the "low zone" (LZ; defined here as ≤ 25 CGGs) may be more environmentally-reactive than those with normal range repeats (26-40 CGGs)-a gene x environment interaction. Using a population-based DNA biobank, in our primary analysis we compared 96 mothers with LZ CGG repeats on both alleles to 280 mothers who had CGG repeats in the normal range. Secondarily, we conducted parallel analyses on fathers. We investigated how parents in these two CGG repeat categories differentially responded to stress, defined as parenting a child with disabilities. Significant gene x environment interactions indicated that LZ mothers who had children with disabilities had greater limitations (in executive functioning, depression, anxiety, daily health symptoms, and balance) than LZ mothers whose children did not have disabilities. In contrast, mothers with normal-range CGG repeats did not differ based on stress exposure. For fathers, a similar pattern was evident for one phenotype only (hand tremors). Although on average LZ CGGs are not associated with compromised functioning, the average masks differential response to the environment.

Constitutive Serotonin Transporter Reduction Resembles Maternal Separation with Regard to Stress-Related Gene Expression

Interactive effects between allelic variants of the serotonin transporter (5-HTT) promoter-linked polymorphic region (5-HTTLPR) and stressors on depression symptoms have been documented, as well as questioned, by meta-analyses. Translational models of constitutive 5-htt reduction and experimentally controlled stressors often led to inconsistent behavioral and molecular findings and often did not include females. The present study sought to investigate the effect of 5-htt genotype, maternal separation, and sex on the expression of stress-related candidate genes in the rat hippocampus and frontal cortex. The mRNA expression levels of Avp, Pomc, Crh, Crhbp, Crhr1, Bdnf, Ntrk2, Maoa, Maob, and Comt were assessed in the hippocampus and frontal cortex of 5-htt ^± and 5-htt ^+/+ male and female adult rats exposed, or not, to daily maternal separation for 180 min during the first 2 postnatal weeks. Gene- and brain region-dependent, but sex-independent, interactions between 5-htt genotype and maternal separation were found. Gene expression levels were higher in 5-htt ^+/+ rats not exposed to maternal separation compared with the other experimental groups. Maternal separation and 5-htt ^+/- genotype did not yield additive effects on gene expression. Correlative relationships, mainly positive, were observed within, but not across, brain regions in all groups except in non-maternally separated 5-htt ^+/+ rats. Gene expression patterns in the hippocampus and frontal cortex of rats exposed to maternal separation resembled the ones observed in rats with reduced 5-htt expression regardless of sex. These results suggest that floor effects of 5-htt reduction and maternal separation might explain inconsistent findings in humans and rodents.

Interaction Effects between the Cumulative Genetic Score and Psychosocial Stressor on Self-Reported Drinking Urge and Implicit Attentional Bias for Alcohol: A Human Laboratory Study

Aims

The current candidate gene and environment interaction (cGxE) study examined whether the effects of an experimentally manipulated psychosocial stressor on self-reported drinking urge and implicit attentional bias for alcohol cues differ as a function of a cumulative genetic score of 5-HTTLPR, MAO-A, DRD4, DAT1 and DRD2 genotypes. The current study also examined whether salivary alpha-amylase level or self-reported anxiety state mediate these cGxE effects.

Short Summary

Individuals with high cumulative genetic risk score of the five monoamergic genotypes showed greater attentional bias toward alcohol cues when exposed to a psychosocial stressor than when not exposed.

Methods

Frequent binge-drinking Caucasian young adults (N = 105; mean age = 19; 61% male) completed both the control condition and stress condition (using the Trier Social Stress Test) in order.

Results

Regarding attentional bias, individuals with high and medium cumulative genetic risk scores showed greater attentional bias toward alcohol stimuli in the stress condition than in the control condition, whereas, those with low genetic risk scores showed greater attentional bias toward alcohol stimuli in the control condition than in the stress condition. No mediating roles of salivary alpha-amylase and anxiety state in the cGxE effect were found. Regarding self-reported drinking urge, individuals with high cumulative genetic score reported greater drinking urge than those with low genetic score regardless of experimental conditions.

Conclusions

Although replication is necessary, the findings suggest that the association of a psychosocial stressor on implicit (but not explicit, self-reported) alcohol outcomes may differ as a function of the collective effects of five monoamine genes.

Maladaptive Coping Strategies and Neuroticism Mediate the Relationship Between 5HTT-LPR Polymorphisms and Symptoms of Anxiety in Elite Athletes

OBJECTIVE

Previous studies have suggested that genetic factors, personality traits and coping strategies might play both independent and interacting roles when influencing stress-related anxiety symptoms. The aim of this study was to examine whether Neuroticism and maladaptive coping strategies mediate the association between the serotonin transporter gene-linked polymorphic region (5HTT-LPR) and symptoms of anxiety and depression in elite athletes who experience high levels of competitive stress.

METHOD

One hundred and thirty-three participants were genotyped for the 5-HTTLPR polymorphism and then asked to complete the Cope Orientation to Problems Experienced Inventory and the NEO Five-Factor Inventory. A path analysis was used to test this hypothesis.

RESULTS

The 5HTT-LPR was significantly associated with Neuroticism, the coping strategy of Focus on and Venting of Emotions' (FVE) and symptoms of anxiety. FVE and Neuroticism mediated the association between the 5HTT-LPR and symptoms of anxiety (i.e., Cognitive Anxiety and Emotional Arousal Control). Also, Neuroticism was a mediator of the association between the 5HTT-LPR and FVE. Finally, FVE also mediated effects on the relationship between Neuroticism and symptoms of anxiety.

CONCLUSIONS

The 5HTT-LPR may affect the susceptibility to develop symptoms of anxiety in elite athletes indirectly through mediation by maladaptive coping strategies and Neuroticism.

Influence of Serotonin Transporter SLC6A4 Genotype on the Effect of Psychosocial Stress on Cognitive Performance: An Exploratory Pilot Study

BACKGROUND AND OBJECTIVE

Previous research has shown an effect of various psychosocial stressors on unconstrained cognitive flexibility, such as searching through a large set of potential solutions in the lexical-semantic network during verbal problem-solving. Functional magnetic resonance imaging has shown that the presence of the short (S) allele (lacking a 43-base pair repeat) of the promoter region of the gene (SLC6A4) encoding the serotonin transporter (5-HTT) protein is associated with a greater amygdalar response to emotional stimuli and a greater response to stressors. Therefore, we hypothesized that the presence of the S-allele is associated with greater stress-associated impairment in performance on an unconstrained cognitive flexibility task, anagrams.

METHODS

In this exploratory pilot study, 28 healthy young adults were genotyped for long (L)-allele versus S-allele promoter region polymorphism of the 5-HTT gene, SLC6A4. Participants solved anagrams during the Trier Social Stress Test, which included public speaking and mental arithmetic stressors. We compared the participants' cognitive response to stress across genotypes.

RESULTS

A Gene×Stress interaction effect was observed in this small sample. Comparisons revealed that participants with at least one S-allele performed worse during the Stress condition.

CONCLUSIONS

Genetic susceptibility to stress conferred by SLC6A4 appeared to modulate unconstrained cognitive flexibility during psychosocial stress in this exploratory sample. If confirmed, this finding may have implications for conditions associated with increased stress response, including performance anxiety and cocaine withdrawal. Future work is needed both to confirm our findings with a larger sample and to explore the mechanisms of this proposed effect.

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.

Dating violence victimization and substance use: The role of a serotonin transporter gene polymorphism (5HTTLPR)

While there is developing research on how genes moderate the effect of stressful life events on substance use, the limited research has yet to focus on specific stressors. As adolescent dating violence victimization has been linked to various substance use behaviors, the current research seeks to further examine the longitudinal outcomes of adolescent dating violence victimization and the role that genes play in moderating these effects. Specifically, using data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), a series of logistic and negative binomial regressions are run to analyze the direct and interactive effects of adolescent dating violence victimization and a polymorphism (5HTTLPR) in the promoter region of the serotonin transporter gene on both alcohol use problems and marijuana use. The results find that 5HTTLPR interacts with adolescent dating violence victimization to increase odds of marijuana use for the sample. However, the interaction between 5HTTLPR and adolescent dating violence has differential effects for males and females, suggesting sex differences regarding the susceptibility properties of 5HTTLPR. Implications of these findings are discussed.

Serotonin Transporter Gene Polymorphism in Women With Suspected Ischemia

Introduction:

Association of serotonin transporter gene ( 5-HTTLPR) polymorphisms with adverse cardiovascular (CV) events in women with suspected ischemia has not yet been reported. We hypothesized an association of 5-HTTLPR polymorphisms with risk of adverse CV events in women with suspected ischemic heart disease (IHD) referred for coronary angiography enrolled in the Women’s Ischemia Syndrome Evaluation (WISE).

Method:

We studied clinical and angiographic data and DNA from a cohort of 437 Caucasian women enrolled in the WISE genotyped for the long (L) and short (S) variant of the 5-HTTLPR polymorphism. Women were followed yearly for adverse CV events (defined as first occurrence of all-cause death, myocardial infarction, stroke, or heart failure hospitalization) with data collected at WISE 10-year follow-up. Exploratory analyses compared outcomes between genotype groups.

Results:

A total of 437 women, with baseline, angiographic, and long-term follow-up data, were successfully genotyped. Their mean age was 58 ± 11 years and body mass index 29 ± 6; 54% had hypertension, 18% diabetes, 50% dyslipidemia, 20% depression history, and only 34% had obstructive CAD. At 8.9 years median follow-up, the SS genotype was associated with significantly increased risk of adverse CV event versus LL + LS (1.93, confidence interval [CI]: 1.03-3.61, P = .03). Results were not significant for all-cause death (hazard ratio: 1.63, CI: 0.91-2.93, P = .09).

Conclusion:

Among a cohort of Caucasian women with suspected IHD enrolled in the WISE, the SS homozygous genotype for the 5-HTTLPR polymorphism was associated with increased risk of adverse CV outcomes.

Behavioral Genetics in Criminal and Civil Courts

Although emerging findings in psychiatric and behavioral genetics create hope for improved prevention, diagnosis, and treatment of disorders, the introduction of such data as evidence in criminal and civil proceedings raises a host of ethical, legal, and social issues. Should behavioral and psychiatric genetic data be admissible in judicial proceedings? If so, what are the various means for obtaining such evidence, and for what purposes should its admission be sought and permitted? How could-and should-such evidence affect judicial outcomes in criminal and civil proceedings? And what are the potential implications of using behavioral and psychiatric genetic evidence for individuals and communities, and for societal values of equality and justice? This article provides an overview of the historical and current developments in behavioral genetics. We then explore the extent to which behavioral genetic evidence has-and should-affect determinations of criminal responsibility and sentencing, as well as the possible ramifications of introducing such evidence in civil courts, with a focus on tort litigation and child custody disputes. We also consider two ways in which behavioral genetic evidence may come to court in the future-through genetic theft or the subpoena of a litigant's biospecimen data that was previously obtained for clinical or research purposes-and the concerns that these possibilities raise. Finally, we highlight the need for caution and for approaches to prevent the misuse of behavioral genetic evidence in courts.

Latent trajectories of alcohol use from early adolescence to young adulthood: Interaction effects between 5-HTTLPR and parenting quality and gender differences

Using a large and nationally representative sample, we examined how adolescents’ 5-HTTLPR genotype and perceived parenting quality independently and interactively associated with trajectories of alcohol use from early adolescence to young adulthood and whether/how gender may moderate these associations. The sample for this study included 13,749 adolescents (53.3% female; 56.3% non-Hispanic White, 21.5% Black, 16.0% Hispanic, and 6.1% Asian) followed prospectively from adolescence to young adulthood. Using growth mixture modeling, we identified four distinct trajectories of alcohol use (i.e., persistent heavy alcohol use, developmentally limited alcohol use, late-onset heavy alcohol use, and non/light alcohol use). Results indicated that the short allele of 5-HTTLPR was associated with higher risk of membership in the persistent and the late-onset heavy alcohol use trajectories. Parenting quality was associated with lower likelihoods of following the persistent heavy and the developmentally limited alcohol use trajectories but was not associated with risk of membership for the late-onset heavy drinking trajectory. 5-HTTLPR interacted with parenting quality to predict membership in the persistent heavy alcohol use trajectory for males but not for females. Findings highlighted the importance of considering the heterogeneity in trajectories of alcohol use across development and gender in the study of Gene Environment interactions in alcohol use.

Effect of socioeconomic status on behavioral problems from preschool to early elementary school - A Japanese longitudinal study

Purpose

Social inequalities are widely accepted to have a deleterious effect on children’s mental health, and those with lower socioeconomic status generally experience more mental health issues. In this study, we examine the impact of socioeconomic situations of children’s families during their early childhood on the children’s social adaptation in Japanese elementary school.

Methods

The current investigation consisted of two sets of data relating to two separate years (with a one-year interval). The participants included preschoolers aged five years at Time 1 (the first year) and first graders aged six years at Time 2 (the second year); 1,712 met the inclusion criteria for both years. Parents of the participants completed a self-reported questionnaire regarding their SES (i.e., family economy and mother’s education) and their children’s mental health. Mental health was assessed using the Child Behavior Checklist/4–18, Parent Report.

Results

For each SES indicator, we found an inverse relationship across all the symptom dimensions. Specifically, bivariate analyses revealed that lower family income, maternal education level, and paternal education level predict all three domains of behavioral problems (i.e., internalized problems, externalized problems, and total behavioral problems). Further, multivariate analyses revealed that lower family income consistently predicts all domains of behavioral problems, lower maternal education level predicted externalized problems and total behavioral problems, and paternal education level did not predict any clinically significant behavioral problems.

Conclusion

In this sample, we found that, for children, family income and parental education when entering preschool were significant predictors of mental health problems after elementary school enrollment; in particular, low income and low maternal educational achievement predicted a high probability of the development of a psychiatric disorder. A greater understanding of the mechanisms of these associations could contribute to improvements in interventions aimed at preventing child maladjustment.

Individual biological sensitivity to environmental influences: testing the differential susceptibility properties of the 5HTTLPR polymorphism in relation to depressive symptoms and delinquency in two adolescent general samples

The gene–environment interaction research field in psychiatry has traditionally been dominated by the diathesis–stress framework, where certain genotypes are assumed to confer increased risk for adverse outcomes in a stressful environment. In later years, theories of differential susceptibility, or biological sensitivity, suggest that candidate genes that interact with environmental events do not exclusively confer a risk for behavioural or psychiatric disorders but rather seem to alter the sensitivity to both positive and negative environmental influences. The present study investigates the susceptibility properties of the serotonin transporter-linked polymorphic region (5HTTLPR) in relation to depressive symptoms and delinquency in two separate adolescent community samples: n = 1457, collected in 2006; and n = 191, collected in 2001. Two-, three-, and four-way interactions between the 5HTTLPR, positive and negative family environment, and sex were found in relation to both depressive symptoms and delinquency. However, the susceptibility properties of the 5HTTLPR were distinctly less pronounced in relation to depressive symptoms. If the assumption that the 5HTTLPR induces differential susceptibility to both positive and negative environmental influences is correct, the previous failures to measure and control for positive environmental factors might be a possible explanation for former inconsistent findings within the research field.

Personality as an intermediate phenotype for genetic dissection of alcohol use disorder

Genetic and environmental interactive influences on predisposition to develop alcohol use disorder (AUD) account for the high heterogeneity among AUD patients and make research on the risk and resiliency factors complicated. Several attempts have been made to identify the genetic basis of AUD; however, only few genetic polymorphisms have consistently been associated with AUD. Intermediate phenotypes are expected to be in-between proxies of basic neuronal biological processes and nosological symptoms of AUD. Personality is likely to be a top candidate intermediate phenotype for the dissection of the genetic underpinnings of different subtypes of AUD. To date, 38 studies have investigated personality traits, commonly assessed by the Cloninger's Tridimensional Personality Questionnaire (TPQ) or Temperament and Character Inventory (TCI), in relation to polymorphisms of candidate genes of neurotransmitter systems in alcohol-dependent patients. Particular attention has been given to the functional polymorphism of the serotonin transporter gene (5-HTTLPR), however, leading to contradictory results, whereas results with polymorphisms in other candidate monoaminergic genes (e.g., tryptophan hydroxylase, serotonin receptors, monoamine oxidases, dopamine receptors and transporter) are sparse. Only one genome-wide association study has been performed so far and identified the ABLIM1 gene of relevance for novelty seeking, harm avoidance and reward dependence in alcohol-dependent patients. Studies investigating genetic factors together with personality could help to define more homogenous subgroups of AUD patients and facilitate treatment strategies. This review also urges the scientific community to combine genetic data with psychobiological and environmental data to further dissect the link between personality and AUD.

Neurological and neuropsychological effects of low and moderate prenatal alcohol exposure

Several explanations for the diverse results in research on foetal alcohol spectrum disorders or alcohol-related neurodevelopmental disorder might be at hand: timing, amount and patterns of alcohol exposure, as well as complex epigenetic responses. The genetic background of the offspring and its interaction with other prenatal and post-natal environmental cues are likely also of importance. In the present report, key findings about the possible effects of low and moderate doses of maternal alcohol intake on the neuropsychological development of the offspring are reviewed and plausible mechanisms discussed. Special focus is put on the serotonergic system within developmental and gene-environment frameworks. The review also suggests guidelines for future studies and also summarizes some of to-be-answered questions of relevance to clinical practice. Contradictory findings and paucity of studies on the effects of exposure to low alcohol levels during foetal life for the offspring's neuropsychological development call for large prospective studies, as well as for studies including neuroimaging and multi-omics analyses to dissect the neurobiological underpinnings of alcohol exposure-related phenotypes and to identify biomarkers. Finally, it remains to be investigated whether any safe threshold of alcohol drinking during pregnancy can be identified.

Associations between stress and depression symptom profiles vary according to serotonin transporter polymorphism in rural Australians

PURPOSE

Depression remains difficult to treat in all cases, and further investigation of the role of genetic and environmental factors may be valuable. This study was designed to investigate the association between the short (s) versus non-short (non-s) 5HTTLPR variants, presence of childhood stressors and recent life stressors, and depression, and to do so at two levels that would expose the associations between total depression scores and also individual depression items.

MATERIALS AND METHODS

Two hundred and forty-nine volunteers from one of the Australian Electoral Office electorates covering a large rural land area completed a series of questionnaires about childhood and recent life stress and depression, and provided a buccal cell sample for genotyping the 5-HTTLPR polymorphism into s versus non-s carriers.

RESULTS

Although there were no significant differences in the depression scores of the s-carriers versus the non-s carriers, each subtype of the 5-HTTLPR polymorphism showed different patterns of association between childhood stress and depression symptoms, and between recent life stress and depression symptoms.

CONCLUSION

Individualization of therapy for depression may be achieved through consideration of the specific associations that patients exhibit between life stress, 5-HTTLPR polymorphism, and depression symptomatology.

Sex differences modulating serotonergic polymorphisms implicated in the mechanistic pathways of risk for depression and related disorders

Despite consistent observations of sex differences in depression and related emotional disorders, we do not yet know how these sex differences modulate the effects of genetic polymorphisms implicated in risk for these disorders. This Mini-Review focuses on genetic polymorphisms of the serotonergic system to illustrate how sex differences might modulate the neurobiological pathways involved in the development of depression. We consider the interacting role of environmental factors such as early-life stress. Given limited current knowledge about this topic, we highlight methodological considerations, challenges, and guidelines for future research. © 2016 Wiley Periodicals, Inc.

Biological embedding of childhood adversity: from physiological mechanisms to clinical implications

BACKGROUND

Adverse psychosocial exposures in early life, namely experiences such as child maltreatment, caregiver stress or depression, and domestic or community violence, have been associated in epidemiological studies with increased lifetime risk of adverse outcomes, including diabetes, heart disease, cancers, and psychiatric illnesses. Additional work has shed light on the potential molecular mechanisms by which early adversity becomes "biologically embedded" in altered physiology across body systems. This review surveys evidence on such mechanisms and calls on researchers, clinicians, policymakers, and other practitioners to act upon evidence.

OBSERVATIONS

Childhood psychosocial adversity has wide-ranging effects on neural, endocrine, immune, and metabolic physiology. Molecular mechanisms broadly implicate disruption of central neural networks, neuroendocrine stress dysregulation, and chronic inflammation, among other changes. Physiological disruption predisposes individuals to common diseases across the life course.

CONCLUSIONS

Reviewed evidence has important implications for clinical practice, biomedical research, and work across other sectors relevant to public health and child wellbeing. Warranted changes include increased clinical screening for exposures among children and adults, scale-up of effective interventions, policy advocacy, and ongoing research to develop new evidence-based response strategies.

Relationships Between Self-Reported and Observed Parenting Behaviour, Adolescent Disordered Eating Attitudes and Behaviours, and the 5-HTTLPR Polymorphism: Data From the Australian Temperament Project

This study examined whether self-reported and observationally measured parental behaviours were associated with disordered eating, and investigated possible moderation by a serotonin-transporter polymorphism (5-HTTLPR). Study 1 included 650 adolescents from the Australian Temperament Project who completed the Eating Disorder Inventory-2 Drive for Thinness and Bulimia scales at 15/16 years and were genotyped for 5-HTTLPR. Parents completed an Australian Temperament Project-devised measure of parental warmth and harsh punishment. Study 2 included a subgroup of 304 participants who also engaged in a video-recorded family interaction, with observed parental warmth and hostility coded by the Iowa Family Interaction Rating Scale. Greater self-reported parental warmth was associated with lower bulimia scores. Conversely, observationally measured parental warmth was associated with lower drive for thinness, but not bulimia. Self-reported parental harsh punishment was associated with bulimia only, with observed parental hostility associated with neither outcome. 5-HTTLPR genotype did not moderate the relationship between parent behaviours and adolescent disordered eating. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

The triallelic serotonin transporter gene polymorphism is associated with depressive symptoms in adults with chronic pain

BACKGROUND

The serotonin (5-HT) transporter-linked polymorphic region (5-HTTLPR) moderates the relationship between stressful life events and depression. Given the high prevalence of depression in chronic pain, the primary aim of this preliminary study was to investigate the associations between the 5-HTTLPR and the severity of depressive symptoms in a cohort of adults with chronic pain.

METHODS

Adults with chronic pain who were consecutively admitted to an outpatient pain rehabilitation program and met inclusion criteria were recruited for study participation (n=277). Individuals were genotyped for the 5-HTTLPR (including rs25531) and categorized as high, intermediate, or low expressors of the 5-HT transporter. The severity of depressive symptoms at admission was measured by using the Center for Epidemiologic Depression scale (CES-D).

RESULTS

The distribution of the high-, intermediate-, and low-expressing genotypes was 61 (22%), 149 (54%), and 67 (24%), respectively. The Hardy-Weinberg P-value was 0.204, which indicated no departure from equilibrium. A main effect of 5-HTTLPR was observed for depressive symptoms (P=0.040) where Center for Epidemiologic Depression scale (CES-D) scores were significantly greater in the low-expressing group compared to the high- (P=0.019) and intermediate (P=0.029)-expressing groups. In multivariate multinomial logistic regression analysis adjusted for age, sex, pain severity, pain catastrophizing, and pain anxiety, greater CES-D scores were significantly associated with the 5-HTTLPR low-expressing group compared to the high-expressing group (P=0.023), but not for the low-expressing group compared to the intermediate-expressing group (P=0.056).

CONCLUSION

These preliminary findings suggest that the triallelic 5-HTTLPR could influence the severity of depressive symptoms in adults with chronic pain. Individuals with chronic pain may be particularly vulnerable to the moderating effects of 5-HTTLPR due to high levels of pain-related stress that are inherently present in this population.

Fluoxetine effects on molecular, cellular and behavioral endophenotypes of depression are driven by the living environment

Selective serotonin reuptake inhibitors (SSRIs) represent the most common treatment for major depression. However, their efficacy is variable and incomplete. In order to elucidate the cause of such incomplete efficacy, we explored the hypothesis positing that SSRIs may not affect mood per se but, by enhancing neural plasticity, render the individual more susceptible to the influence of the environment. Consequently, SSRI administration in a favorable environment promotes a reduction of symptoms, whereas in a stressful environment leads to a worse prognosis. To test such hypothesis, we exposed C57BL/6 mice to chronic stress in order to induce a depression-like phenotype and, subsequently, to fluoxetine treatment (21 days), while being exposed to either an enriched or a stressful condition. We measured the most commonly investigated molecular, cellular and behavioral endophenotypes of depression and SSRI outcome, including depression-like behavior, neurogenesis, brain-derived neurotrophic factor levels, hypothalamic-pituitary-adrenal axis activity and long-term potentiation. Results showed that, in line with our hypothesis, the endophenotypes investigated were affected by the treatment according to the quality of the living environment. In particular, mice treated with fluoxetine in an enriched condition overall improved their depression-like phenotype compared with controls, whereas those treated in a stressful condition showed a distinct worsening. Our findings suggest that the effects of SSRI on the depression- like phenotype is not determined by the drug per se but is induced by the drug and driven by the environment. These findings may be helpful to explain variable effects of SSRI found in clinical practice and to device strategies aimed at enhancing their efficacy by means of controlling environmental conditions.

The Serotonin Transporter Promoter Variant, Stress, and Attentional Biases in Middle Childhood

Although evidence suggests that 5-HTTLPR variants may shape risk for depression, the influence is likely complex, and involves effects on endophenotypes. We examined associations between 5-HTTLPR and biases in attention to affective stimuli in a sample of girls and a sample of both boys and girls. Children with at least one short (S) variant of the 5-HTTLPR polymorphism had lower positive attentional bias scores in both samples. This association was qualified by an interaction with stress in one sample, such that links between the S allele and decreased positive attentional bias was significant only when life stress was elevated. This difference in findings between the two samples was explained by sex differences in samples; the GXE interaction was significant only in boys. Findings are discussed in the context of sex differences in GXE.

Interactive effect of 5-HTTLPR genotype and age on sources of cortical rhythms in healthy women

This study was aimed to localize the effects of 5-HTTLPR (serotonin-transporter-linked polymorphic region) on the age differences of spontaneous EEG activity in women using neuroimaging analysis sLORETA (Standardized Low Resolution brain Electromagnetic Tomography). DNA samples extracted from cheek swabs and resting-state EEG recorded at 60 standard leads were collected from young (YW, N=86, 18-35years) and older (OW, N=45; 55-80years) healthy women. We have shown that advanced age was associated with increased posterior EEG desynchronization in S'/S'. S' (LG allele was grouped with S alleles owing to its functional equivalence and this group was labeled as S') genotype carriers denoted by decrease of delta - beta1 current source density, and to a lesser extent in L/L homozygotes denoted by decrease in delta activity. In heterozygotes OW, as compared with heterozygotes YW, higher source density estimates of beta1 in frontal and temporal cortex were observed. Age differences were more pronounced in the right hemisphere in S'/S' and L/L carriers and in the left hemisphere in heterozygotes. We also found that in OW, current source density estimates of theta, alpha1, alpha2, alpha3 and beta1 sources in the right occipital lobe were higher in S'/L than in S'/S' carriers. These results may have implications for understanding 5-HTT-dependent variation in the effect of aging on brain activity.

The Relationship between Personality Traits, the 5HTT Polymorphisms, and the Occurrence of Anxiety and Depressive Symptoms in Elite Athletes

The purpose of this study was to determine the relationship between personality, the serotonin transporter (5HTT) polymorphisms and the occurrence of anxiety and depressive symptoms in elite athletes. 133 healthy participants completed the NEO Five-Factor Inventory (NEO-FFI). The mood states were assessed using the Profile of Mood States (POMS) questionnaire. The athlete's mental skills were assessed through the Sport Performance Psychological Inventory (IPPS-48). The occurrence of psychiatric and personality disorders was assessed using the Clinical Interview for DSM-IV Disorders. A polymerase chain reaction was employed to identify genotypes at the 5HTTLPR polymorphism. The 5HTTLPR s/s genotype was associated with both neuroticism (p< 0.001) and tension/anxiety symptoms according to the POMS (p<0.02), cognitive anxiety and emotional arousal control according to the IPPS-48 (p<0.01). Significant correlations were proved between neuroticism and symptoms of anxiety and depression (p<0.05). Neuroticism mediates the association between the 5HTTLPR polymorphism and symptoms of cognitive anxiety and emotional arousal control (p<0.05). These results suggest a significant interaction between the 5HTTLPR polymorphism, neuroticism and sport related stress that predict adverse mental health outcomes in athletes. Identification of homogeneous groups of athletes having predispositions to anxiety and depressive symptoms may help to implement early prevention programs.

Genetic Moderators of the Impact of Physical Activity on Depressive Symptoms

BACKGROUND

Converging evidence suggests that physical activity is an effective intervention for both clinical depression and sub-threshold depressive symptoms; however, findings are not always consistent. These mixed results might reflect heterogeneity in response to physical activity, with some subgroups of individuals responding positively, but not others.

OBJECTIVES

1) To examine the impact of genetic variation and sex on changes in depressive symptoms in older adults after a physical activity (PA) intervention, and 2) to determine if PA differentially improves particular symptom dimensions of depression.

DESIGN

Randomized controlled trial.

SETTING

Four field centers (Cooper Institute, Stanford University, University of Pittsburgh, and Wake Forest University).

PARTICIPANTS

396 community-dwelling adults aged 70-89 years who participated in the Lifestyle Interventions and Independence for Elders Pilot Study (LIFE-P).

INTERVENTION

12-month PA intervention compared to an education control.

MEASUREMENTS

Polymorphisms in the serotonin transporter (5-HTT), brain-derived neurotrophic factor (BDNF), and apolipoprotein E (APOE) genes; 12-month change in the Center for Epidemiologic Studies Depression Scale total score, as well as scores on the depressed affect, somatic symptoms, and lack of positive affect subscales.

RESULTS

Men randomized to the PA arm showed the greatest decreases in somatic symptoms, with a preferential benefit in male carriers of the BDNF Met allele. Symptoms of lack of positive affect decreased more in men compared to women, particularly in those possessing the 5-HTT L allele, but the effect did not differ by intervention arm. APOE status did not affect change in depressive symptoms.

CONCLUSIONS

Results of this study suggest that the impact of PA on depressive symptoms varies by genotype and sex, and that PA may mitigate somatic symptoms of depression more than other symptoms. The results suggest that a targeted approach to recommending PA therapy for treatment of depression is viable.

Financial difficulties but not other types of recent negative life events show strong interactions with 5-HTTLPR genotype in the development of depressive symptoms

Several studies indicate that 5-HTTLPR mediates the effect of childhood adversity in the development of depression, while results are contradictory for recent negative life events. For childhood adversity the interaction with genotype is strongest for sexual abuse, but not for other types of childhood maltreatment; however, possible interactions with specific recent life events have not been investigated separately. The aim of our study was to investigate the effect of four distinct types of recent life events in the development of depressive symptoms in a large community sample. Interaction between different types of recent life events measured by the List of Threatening Experiences and the 5-HTTLPR genotype on current depression measured by the depression subscale and additional items of the Brief Symptom Inventory was investigated in 2588 subjects in Manchester and Budapest. Only a nominal interaction was found between life events overall and 5-HTTLPR on depression, which failed to survive correction for multiple testing. However, subcategorising life events into four categories showed a robust interaction between financial difficulties and the 5-HTTLPR genotype, and a weaker interaction in the case of illness/injury. No interaction effect for the other two life event categories was present. We investigated a general non-representative sample in a cross-sectional approach. Depressive symptoms and life event evaluations were self-reported. The 5-HTTLPR polymorphism showed a differential interaction pattern with different types of recent life events, with the strongest interaction effects of financial difficulties on depressive symptoms. This specificity of interaction with only particular types of life events may help to explain previous contradictory findings.

Stressful Life Events and Risk of Depression 25 Years Later: Race and Gender Differences

BACKGROUND

Although stressful life events (SLEs) predict subsequent risk of developing a major depressive episode (MDE), limited information exists on whether or not race and gender alters the predictive role of SLE on risk of MDE over a long-term period. The current study explored race and gender differences in the long-term predictive role of SLE at baseline (1986) on subsequent risk of MDE 25 years later (2011) in a nationally representative cohort in the United States.

METHODS

Using a life course epidemiological approach, this longitudinal study borrowed data from the Americans' Changing Lives (ACL) Study 1986-2011. Main predictor of interest was baseline SLE over the last 3 years measured at 1986. Main outcome was risk of MDE [Composite International Diagnostic Interview (CIDI)] 25 years later (2011). Covariates included demographics, socioeconomics, depressive symptoms [Center for Epidemiological Studies-Depression Scale (CES-D)], chronic medical conditions, and health behaviors measured at baseline (1986). Gender and race were the focal moderators. We employed logistic regressions in the pooled sample, and specific to race and gender, to test whether or not SLE × race and SLE × gender interactions are significant.

RESULTS

In the pooled sample, baseline SLE (1986) predicted risk of MDE 25 years later (2011). We also found a gender by SLE interaction, suggesting a stronger predictive role of SLE for subsequent clinical depression for men compared to women. Race did not modify the predictive role of SLE on subsequent risk of MDE 25 years later.

CONCLUSION

How SLE predicts MDE 25 years later differs for men and women, with a stronger predictive role for men compared to women. More research is needed to better understand the complex links between gender, sex, stress, and depression.

Depression, Stressful Life Events, and the Impact of Variation in the Serotonin Transporter: Findings from the National Longitudinal Study of Adolescent to Adult Health (Add Health)

Background

The low transcriptionally efficient short-allele of the 5HTTLPR serotonin transporter polymorphism has been implicated to moderate the relationship between the experience of stressful life events (SLEs) and depression. Despite numerous attempts at replicating this observation, results remain inconclusive.

Methods

We examined this relationship in young-adult Non-Hispanic white males and females between the ages of 22 and 26 (n = 4724) participating in the National Longitudinal Study of Adolescent to Adult Health (Add Health) with follow-up information every six years since 1995.

Results

Linear and logistic regression models, corrected for multiple testing, indicated that carriers of one or more of the S-alleles were more sensitive to stress than those with two L-alleles and at a higher risk for depression. This relationship behaved in a dose-response manner such that the risk for depression was greatest among those who reported experiencing higher numbers of SLEs. In post-hoc analyses we were not able to replicate an interaction effect for suicide ideation but did find suggestive evidence that the effects of SLEs and 5HTTLPR on suicide ideation differed for males and females. There were no effects of childhood maltreatment.

Discussion

Our results provide partial support for the original hypothesis that 5-HTTLPR genotype interacts with the experience of stressful life events in the etiology of depression during young adulthood. However, even with this large sample, and a carefully constructed a priori analysis plan, the results were still not definitive. For the purposes of replication, characterizing the 5HTTLPR in other large data sets with extensive environmental and depression measures is needed.

Latent trajectories of adolescent antisocial behavior: Serotonin transporter linked polymorphic region (5-HTTLPR) genotype influences sensitivity to perceived parental support

Although prevailing theories of antisocial behavior (ASB) emphasize distinct developmental trajectories, few studies have explored gene–environment interplay underlying membership in empirically derived trajectories. To improve knowledge about the development of overt (e.g., aggression) and covert (e.g., delinquency) ASB, we tested the association of the 44-base pair promoter polymorphism in the serotonin transporter linked polymorphic region gene (5-HTTLPR), perceived parental support (e.g., closeness and warmth), and their interaction with ASB trajectories derived using latent class growth analysis in 2,558 adolescents followed prospectively into adulthood from the National Longitudinal Study of Adolescent Health. Three distinct trajectories emerged for overt (low desisting, adolescent peak, and late onset) and covert ASB (high stable, low stable, and nonoffending). Controlling for sex, parental support inversely predicted membership in the adolescent-peak overt ASB trajectory (vs. low desisting), but was unrelated to class membership for covert ASB. Furthermore, the 5-HTTLPR genotype significantly moderated the association of parental support on overt ASB trajectory membership. It is interesting that the pattern of Gene × Environment interaction differed by trajectory class: whereas short allele carriers were more sensitive to parental support in predicting the late-onset trajectory, the long/long genotype functioned as a potential “plasticity genotype” for the adolescent-peak trajectory group. We discuss these preliminary findings in the context of the differential susceptibility hypothesis and discuss the need for future studies to integrate gene–environment interplay and prospective longitudinal designs.

5-HTTLPR and gender differences in affective disorders: A systematic review

BACKGROUND

Serotonin transporter-linked polymorphic region (5-HTTLPR) variants have been extensively studied in psychiatric disorders. Although gender effects have been reported, they have not been comprehensively reviewed. The aim of our study was to summarize literature findings on 5-HTTLPR and gender differences in affective disorders.

METHODS

A systematic search of PubMed, ISI Web of Knowledge, and PsycINFO databases was performed for dates until January 2015. The included articles (n=78) analyzed the association between 5-HTTLPR and affective spectrum disorders, taking into account gender. The quality of each study was assessed through STROBE and CONSORT.

RESULTS

5-HTTLPR modulation of affective disorders varied by gender. The S allele (or SS genotype) seemed to be differently associated with an increased risk of depression, depressive symptoms, anxiety traits and symptoms, and symptoms of internalizing behavior among women and an increased risk of aggressiveness, conduct disorder and symptom counts of externalizing behavior among men. Moreover, the presence of stressful life events reinforced the association. Interestingly, these differences seemed to begin with adolescence and were not consistent among the elderly, suggesting a plausible role of hormonal fluctuations.

LIMITATIONS

The review is limited by the small number of included papers, due to the paucity of information in the literature regarding 5-HTTLPR and gender.

CONCLUSIONS

5-HTTLPR variants may exert a differential modulation on a number of features depending on gender. Further studies are needed to more deeply investigate the effect of 5-HTTLPR×gender on the modulation of affective disorders.

Genetic Susceptibility and Sleep Disturbance in Black Mothers of Preterm Infants: An Exploratory Study

Serotonin (5HT) is involved in emotion and sleep regulation and the 5HT transporter (5HTT) regulates 5HT function. A common 44-base pair deletion (short allele) or insertion (long allele) polymorphism in the promoter region of 5HTT (5-HTTLPR) is differentially associated with 5HTT transcription efficiency. Under stressful conditions, the short allele of 5-HTTLPR has been associated with depression and sleep disturbance. Black women are at higher risk for preterm labor and depressive symptoms. Thus, this exploratory study aimed to examine whether depressive symptoms and sleep disturbance in Black mothers would vary as a function of the 5-HTTLPR genotype when they faced the stress of infant hospitalization after preterm birth at early postpartum. A total of 30 Black mothers filled out a battery of questionnaires, including the Perceived Stress Scale, Edinburgh Postnatal Depression Scale, and General Sleep Disturbance Scale. A wrist actigraph was used to assess total sleep time and circadian activity rhythms. Buccal cells from saliva were collected to test the 5-HTTLPR genotype. Results showed that about 38% of the mothers were heterozygous for the short (S/L) allele, and 62% were homozygous for the long (L/L) allele. Mothers’ perceived global stress, depressive symptoms, and circadian activity rhythms did not vary with their 5-HTTLPR genotypes. Unexpectedly, mothers with the L/L allele reported greater sleep disturbances than those with the S/L allele. Ethnic specificity in genetic susceptibility to stress was discussed.

Genetic associations with reflexive visual attention in infancy and childhood

This study elucidates genetic influences on reflexive (as opposed to sustained) attention in children (aged 9-16 years; N = 332) who previously participated as infants in visual attention studies using orienting to a moving bar (Dannemiller, 2004). We investigated genetic associations with reflexive attention measures in infancy and childhood in the same group of children. The genetic markers (single nucleotide polymorphisms and variable number tandem repeats on the genes APOE, BDNF, CHRNA4, COMT, DRD4, HTR4, IGF2, MAOA, SLC5A7, SLC6A3, and SNAP25) are related to brain development and/or to the availability of neurotransmitters such as acetylcholine, dopamine, or serotonin. This study shows that typically developing children have differences in reflexive attention associated with their genes, as we found in adults (Lundwall, Guo & Dannemiller, 2012). This effort to extend our previous findings to outcomes in infancy and childhood was necessary because genetic influence may differ over the course of development. Although two of the genes that were tested in our adult study (Lundwall et al., 2012) were significant in either our infant study (SLC6A3) or child study (DRD4), the specific markers tested differed. Performance on the infant task was associated with SLC6A3. In addition, several genetic associations with an analogous child task occurred with markers on CHRNA4, COMT, and DRD4. Interestingly, the child version of the task involved an interaction such that which genotype group performed poorer on the child task depended on whether we were examining the higher or lower infant scoring group. These findings are discussed in terms of genetic influences on reflexive attention in infancy and childhood.

5-HTTLPR Expression Outside the Skin: An Experimental Test of the Emotional Reactivity Hypothesis in Children

Background

There is increasing evidence that variation in the promoter region of the serotonin transporter gene SLC6A4 (i.e., the 5-HTTLPR polymorphism) moderates the impact of environmental stressors on child psychopathology. Emotional reactivity −the intensity of an individual’s response to other’s emotions− has been put forward as a possible mechanism underlying these gene-by-environment interactions (i.e., G×E). Compared to children homozygous for the L-allele (LL-genotypes), children carrying an S-allele (SS/SL-genotypes), specifically when they have been frequently exposed to negative emotions in the family environment, might be more emotionally reactive and therefore more susceptible to affective environmental stressors. However, the association between 5-HTTLPR and emotional reactivity in children has not yet been empirically tested. Therefore, the goal of this study was to test this association in a large-scale experiment.

Methods

Children (N = 521, 52.5% boys, Mage = 9.72 years) were genotyped and randomly assigned to happy, angry or neutral dynamic facial expressions and vocalizations. Motor and affective emotional reactivity were assessed through children’s self-reported negative and positive affect (n = 460) and facial electromyography activity (i.e., fEMG: the zygomaticus or “smile” muscle and the corrugator or “frown” muscle, n = 403). Parents reported on their negative and positive parenting behaviors.

Results

Children mimicked and experienced the emotion they were exposed to. However, neither motor reactivity nor affective reactivity to these emotions depended on children’s 5-HTTLPR genotype: SS/SL-genotypes did not manifest any stronger response to emotional stimuli than LL-genotypes. This finding remained the same when taking the broader family environment into account, controlling for kinship, age, gender and genetic ancestry, and when including a tri-allelic factor.

Conclusions

We found no evidence for an association between the 5-HTTLPR polymorphism and children’s emotional reactivity. This finding is important, in discounting one potential underlying endophenotype of G×E between the 5-HTTLPR and affective environmental stressors.

Effects of Recent Stress and Variation in the Serotonin Transporter Polymorphism (5-HTTLPR) on Depressive Symptoms: A Repeated-Measures Study of Adults Age 50 and Older

Depending on genetic sensitivity to it, stress may affect depressive symptomatology differentially. Applying the stress-diathesis hypothesis to older adults, we postulate: (1) recent stress will associate with increased depressive symptom levels and (2) this effect will be greater for individuals with at least one short allele of the serotonin transporter gene promoter region (5-HTTLPR). Further, we employ a design that addresses specific limitations of many prior studies that have examined the 5-HTTLPR × SLE relation, by: (a) using a within-person repeated-measures design to address fluctuations that occur within individuals over time, increase power for detecting G × E, and address GE correlation; (b) studying reports of exogenous stressful events (those unlikely to be caused by depression) to help rule out reverse causation and negativity bias, and in order to assess stressors that are more etiologically relevant to depressive symptomatology in older adults. The sample is drawn from the Health and Retirement Study, a U.S. population-based study of older individuals (N = 28,248; mean age = 67.5; 57.3 % female; 80.7 % Non-Hispanic White, 14.9 % Hispanic/Latino, 4.5 % African American; genetic subsample = 12,332), from whom measures of depressive symptoms and exogenous stressors were collected biannually (1994-2010). Variation in the 5-HTTLPR was characterized via haplotype, using two single nucleotide polymorphisms (SNPs). Ordered logit models were constructed to predict levels of depressive symptoms from 5-HTTLPR and stressors, comparing results of the most commonly applied statistical approaches (i.e., comparing allelic and genotypic models, and continuous and categorical predictors) used in the literature. All models were stratified by race/ethnicity. Overall, results show a main effect of recent stress for all ethnic groups, and mixed results for the variation in 5-HTTLPR × stress interaction, contingent upon statistical model used. Findings suggest there may be a differential effect of stressors and 5-HTTLPR on depressive symptoms by ethnicity, but further research is needed, particularly when using a haplotype to characterize variation in 5-HTTLPR in population-based sample with a diverse ethnic composition.