Daily stress reactivity and serotonin transporter gene (5-HTTLPR) variation: internalizing responses to everyday stress as a possible transdiagnostic phenotype

Neurobiological and psychological factors to depression

Major Depressive Disorder (MDD) is a common condition with complex psychological and biological background. While its aetiology is still unclear, chronic stress stands amongst major risk factors to MDD pathogenesis. When researching on MDD, it is necessary to be familiar with the neurobiological effects of several prominent contributors to the chronic stress factor experienced across hypothalamic-pituitary-adrenal (HPA) axis, neurotransmission, immune system reflexivity, and genetic alterations. Bi-directional flow of MDD pathogenesis suggests that psychological factors produce biological effects. Here, a summary of how the MDD expresses its mechanisms of action across an overactive HPA axis, the negative impacts of reduced neurotransmitter functions, the inflammatory responses and their gene x environment interactions. This paper builds on these conceptual factors and their input towards the MDD symptomatology with a purpose of synthesising the current findings and create an integrated view of the MDD pathogenesis. Finally, relevant treatment implications will be summarised, along with recommendations to a multimodal clinical practice.

Association of Computer Vision Syndrome with Depression/Anxiety among Lebanese Young Adults: The Mediating Effect of Stress

Computers have become indispensable in daily activities. With this excess use of electronics, computer vision syndrome (CVS), a highly prevalent condition, is associated with various symptoms. Although understanding the relationship between CVS and mental health has been reported, the impact of CVS has not been explored on more than one psychological aspect. We hypothesize that higher CVS symptoms could be associated with higher levels of anxiety and depression, mediated by higher stress. Therefore, the objective of this study was to determine the association between CVS and depression and anxiety among a sample of Lebanese young adults, along with evaluating the mediating effect of stress on these associations. Between August 2020 and April 2021, 749 participants completed an online questionnaire for this cross-sectional study. Females compared to males (Beta = 3.73) and those with CVS compared to those who did not (Beta = 3.14) were significantly associated with more anxiety, whereas having a university level of education compared to secondary or less (Beta = -3.02) was significantly associated with less anxiety. Females compared to males (Beta = 2.55) and those with CVS compared to those without (Beta = 2.61) were significantly associated with more depression, whereas being of an older age (Beta = -0.18) was significantly associated with less depression. Stress partially mediated the association between CVS and anxiety and between CVS and depression. More CVS was significantly associated with more stress (Beta = 3.05). Higher stress was significantly associated with more anxiety (Beta = 0.70) and depression (Beta = 0.71), whereas more CVS was significantly and directly associated with more anxiety (Beta = 3.14) and depression (Beta = 2.61). This study is the first worldwide to evaluate an association between CVS and mental health. Our results serve as a starting point for healthcare providers (psychiatrists and psychologists, most importantly) to look deeper into CVS when looking for reasons behind mental health issues. Further studies are warranted to confirm our results and look for more factors and mediators in such associations.

Oxytocin reactivity to a lab-based stressor predicts support seeking after stress in daily life: Implications for the Tend-and-Befriend theory

Social relationships play an important role in mental and physical health, particularly during times of stress. However, little is known about the biological mechanisms underlying the tendency to seek support following stress. The Tend-and-Befriend theory suggests that oxytocin (OT) may enhance the desire for social contact in response to stress. Yet, no studies in humans have provided empirical support for the connection between stress-induced changes in endogenous OT and increased support seeking after stress. In the present study, 94 participants performed a standardized laboratory stressor and then completed two weeks of daily assessments of support seeking after stress. In line with preregistered hypotheses, stress-induced plasma OT reactivity to the laboratory stressor was associated with more frequent support seeking behaviors following stress in daily life (i.e., outside of the laboratory). Additional results suggested that attachment anxiety (but not avoidance) strengthened this association. Our findings implicate the OT system in affiliative behaviors following stress, providing empirical support for the Tend-and-Befriend theory.

The 5-HTTLPR-rs25531 S-A-S-A Haplotype and Chronic Stress Moderate the Association Between Acute Stress and Internalizing Mental Disorders Among HIV+ Children and Adolescents in Uganda

Background: Internalizing mental disorders (IMDs) among HIV-positive (HIV+) children and adolescents are associated with poor disease outcomes, such as faster HIV disease progression. Although it has been suggested that the development of IMDs is moderated by interaction of stressful life events and vulnerability factors, the underlying etiology is largely unknown. Serotonin transporter gene [solute carrier family 6 member A4 (SLC6A4)] and human tryptophan hydroxylase 2 gene (TPH2) polymorphisms have been implicated in the development of IMDs. This study investigated the association between acute stress and IMDs, and moderation by chronic stress and genetic variants in SLC6A4 and TPH2. Hypothesis: Acute stress acts through genetic and environmental vulnerability factors to increase the risk of developing IMDs. Methods: Polymorphisms in SLC6A4 (5-HTTLPR, rs25531, 5-HTTLPR-rs25531, and STin2 VNTR) and TPH2 (rs1843809, rs1386494, rs4570625, and rs34517220) were genotyped in 368 HIV+ children and adolescents (aged 5-17 years) with any internalizing mental disorder (depression, anxiety disorders, or posttraumatic stress disorder), and 368 age- and sex-matched controls, who were also HIV+. Chronic and acute stress categories were derived by hierarchical cluster analysis. Logistic regression analysis was used to assess the independent moderating effect of chronic stress and each selected polymorphism on the association between acute stress and IMDs. Results: We observed a statistically significant association between severe acute stress and IMDs (p = 0.001). Children and adolescents who experienced severe acute stress were twice as likely to develop IMDs, compared to children and adolescents who experienced mild acute stress (p = 0.001). Chronic stress interacted with severe acute stress to increase the risk of IMDs (p = 0.033). Acute stress was found to interact with 5-HTTLPR-rs25531 S-A-S-A haplotype to increase the risk for IMDs among Ugandan HIV+ children and adolescents (p = 0.049). We found no evidence for a combined interaction of acute stress, chronic stress, and 5-HTTLPR-rs25531 on IMDs. Conclusion: The odds of having an internalizing mental disorder (IMD) were higher among HIV+ children and adolescents who experienced severe acute stress compared to HIV+ children and adolescents who experienced mild acute stress. Chronic stress and 5-HTTLPR-rs25531 independently moderated the association between acute stress and IMDs.

Highs and lows: Genetic susceptibility to daily events

Why people differ in their susceptibility to external events is essential to our understanding of personality, human development, and mental disorders. Genes explain a substantial portion of these differences. Specifically, genes influencing the serotonin system are hypothesized to be differential susceptibility factors, determining a person’s reactivity to both positive and negative environments. We tested whether genetic variation in the serotonin transporter (5-HTTLPR) is a differential susceptibility factor for daily events. Participants (N = 326, 77% female, mean age = 25, range = 17–36) completed smartphone questionnaires four times a day over four to five days, measuring stressors, uplifts, positive and negative affect. Affect was predicted from environment valence in the previous hour on a within-person level using three-level autoregressive linear mixed models. The 5-HTTLPR fulfilled all criteria of a differential susceptibility factor: Positive affect in carriers of the short allele (S) was less reactive to both uplifts and stressors, compared to homozygous carriers of the long allele (L/L). This pattern might reflect relative affective inflexibility in S-allele carriers. Our study provides insight into the serotonin system’s general role in susceptibility and highlights the need to assess the whole spectrum of naturalistic experiences.

Effect of Gender, Physical Activity and Stress-Related Hormones on Adolescent's Academic Achievements

BACKGROUND

Physical activity (PA) has been shown to develop better fitness and body function in children. Various studies have shown that as the age of students increases, its correlation with school achievement decreases. Different hormonal changes during adolescence make it difficult to adjust in his/her environment, causing stress. To the best of our knowledge, no study has studied the correlation between stress-related hormones and school performance among adolescents. This study was conducted to evaluate physical activity and stress-related hormones, cortisol and serotonin, among school adolescents aged 12-18 years old and find their association with academic achievements.

METHODS

A total of 300 students were invited to participate in this study. Physical activity of the participants was assessed in relation to the time spent performing various physical activities. End of the academic year grades were obtained from the school as a collective measure of academic achievement and executive function. The levels of cortisol and serotonin were measured using the competitive immunoassay techniques.

RESULTS

There was a significant correlation between age, gender, BMI, cortisol, serotonin, physical activity score; and academic achievement, and executive functioning among participants. Academic achievement and executive functioning scores correlated positively with gender, serotonin, physical activity score, but negatively with age, BMI and salivary cortisol. Stepwise regression analysis showed that physical activity and demographic parameters and stress-related hormones, cortisol and serotonin, explained around 61.9-77.9% of academic performance and executive functioning variation in school adolescents, especially females.

CONCLUSIONS

Optimal physical activity and release of stress-related hormones could be the determining factor for performance in school and other activities. These results should be taken into consideration while planning the school curriculum.

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.

Automatic approach-avoidance tendencies as a candidate intermediate phenotype for depression: Associations with childhood trauma and the 5-HTTLPR transporter polymorphism

Depression risk genes in combination with childhood events have been associated with biased processing as an intermediate phenotype for depression. The aim of the present conceptual replication study was to investigate the role of biased automatic approach-avoidance tendencies as a candidate intermediate phenotype for depression, in the context of genes (5-HTTLPR polymorphism) and childhood trauma. A naturalistic remitted depressed patients sample (N = 209) performed an Approach-Avoidance Task (AAT) with facial expressions (angry, sad, happy and neutral). Childhood trauma was assessed with a questionnaire. Genotype groups were created based on allele frequency: L_aL_a versus S/L_g-carriers. The latter is associated with depression risk. We found that remitted S/L_g-carriers who experienced childhood trauma automatically avoided sad facial expressions relatively more than L_aL_a homozygotes with childhood trauma. Remitted L_aL_a-carriers who had not experienced childhood trauma, avoided sad faces relatively more than L_aL_a homozygotes with childhood trauma. We did not find a main effect of childhood trauma, nor differential avoidance of any of the other facial expressions. Although tentative, the results suggest that automatic approach-avoidance tendencies for disorder-congruent materials may be a fitting intermediate phenotype for depression. The specific pattern of tendencies, and the relation to depression, may depend on the genetic risk profile and childhood trauma, but replication is needed before firm conclusions can be drawn.

Forgiveness, Stress, and Health: a 5-Week Dynamic Parallel Process Study

BACKGROUND

Psychological stress is a well-known risk factor for poor health, and recent research has suggested that the emotion-focused coping process of forgiveness may help mitigate these effects. To date, however, no studies have examined how levels of forgiveness, stress, and health fluctuate and interrelate over time.

PURPOSE

We addressed this issue by examining how forgiveness, stress, and mental and physical health symptoms change and relate to one another over 5 weeks. We hypothesized that increases in state levels of forgiveness would be associated with decreases in perceptions of stress, which would in turn be related to decreases in mental and physical health symptoms. A reverse effects model was also tested.

METHODS

We recruited a large, community-based sample of 332 young, middle-aged, and older adults (16-79 years old; M _age = 27.9). Each week for 5 weeks, participants reported on their levels of state forgiveness, perceived stress, and mental and physical health symptoms.

RESULTS

Levels of forgiveness, stress, and mental and physical health symptoms each showed significant change and individual variability in change over time. As hypothesized, increases in forgiveness were associated with decreases in stress, which were in turn related to decreases in mental (but not physical) health symptoms (i.e., forgiveness → stress → health). The reverse effects model (i.e., health → stress → forgiveness) provided a relatively poorer fit.

CONCLUSIONS

This study is the first to provide prospective, longitudinal evidence showing that greater forgiveness is associated with less stress and, in turn, better mental health. Strategies for cultivating forgiveness may thus have beneficial effects on stress and health.

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

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

Depressive Symptoms and the Anticipation and Experience of Uplifting Events in Everyday Life

OBJECTIVE

Despite proliferation of laboratory-based studies examining reward functioning in depression, few studies have examined these processes in everyday life. We addressed this shortcoming by exploring experience and anticipation of uplifting experiences under ecologically valid conditions METHOD: One hundred fifty-seven young adults, oversampled for depressive symptoms, completed a 14-day diary tracking mood in relation to recent and anticipated positive events RESULTS: Consistent with studies supporting "mood-brightening" effects in depression, participants with greater baseline dysphoria showed stronger associations between elevated daily uplifts and lower daily depressive symptoms, particularly when events were interpersonal in nature. Baseline dysphoria was associated with lower daily anticipation of positive next-day experiences; however, when dysphoric individuals did anticipate positive experiences, they experienced greater reductions in depressed mood CONCLUSION: Results suggest that despite reward processing deficits found in laboratory studies, dysphoric individuals show improvements in mood in conjunction with anticipation and consumption of uplifting events in daily life.

Vulnerability or Sensitivity to the Environment? Methodological Issues, Trends, and Recommendations in Gene-Environment Interactions Research in Human Behavior

Research on the potential role of gene-environment interactions (GxE) in explaining vulnerability to psychopathology in humans has witnessed a shift from a diathesis-stress perspective to differential susceptibility approaches. This paper critically reviews methodological issues and trends in this body of research. Databases were screened for studies of GxE in the prediction of personality traits, behavior, and mental health disorders in humans published between January 2002 and January 2015. In total, 315 papers were included. Results showed that 34 candidate genes have been included in GxE studies. Independent of the type of environment studied (early or recent life events, positive or negative environments), about 67-83% of studies have reported significant GxE interactions, which is consistent with a social susceptibility model. The percentage of positive results does not seem to differ depending on the gene studied, although publication bias might be involved. However, the number of positive findings differs depending on the population studied (i.e., young adults vs. older adults). Methodological considerations limit the ability to draw strong conclusions, particularly as almost 90% (n = 283/315) of published papers are based on samples from North America and Europe, and about 70% of published studies (219/315) are based on samples that were also used in other reports. At the same time, there are clear indications of methodological improvements over time, as is shown by a significant increase in longitudinal and experimental studies as well as in improved minimum genotyping. Recommendations for future research, such as minimum quality assessment of genes and environmental factors, specifying theoretical models guiding the study, and taking into account of cultural, ethnic, and lifetime perspectives, are formulated.

Establishing the situated features associated with perceived stress

We propose that the domain general process of categorization contributes to the perception of stress. When a situation contains features associated with stressful experiences, it is categorized as stressful. From the perspective of situated cognition, the features used to categorize experiences as stressful are the features typically true of stressful situations. To test this hypothesis, we asked participants to evaluate the perceived stress of 572 imagined situations, and to also evaluate each situation for how much it possessed 19 features potentially associated with stressful situations and their processing (e.g., self-threat, familiarity, visual imagery, outcome certainty). Following variable reduction through factor analysis, a core set of 8 features associated with stressful situations-expectation violation, self-threat, coping efficacy, bodily experience, arousal, negative valence, positive valence, and perseveration-all loaded on a single Core Stress Features factor. In a multilevel model, this factor and an Imagery factor explained 88% of the variance in judgments of perceived stress, with significant random effects reflecting differences in how individual participants categorized stress. These results support the hypothesis that people categorize situations as stressful to the extent that typical features of stressful situations are present. To our knowledge, this is the first attempt to establish a comprehensive set of features that predicts perceived stress.

When Support Seeking Backfires: Co-Rumination, Excessive Reassurance Seeking, and Depressed Mood in the Daily Lives of Young Adults

Research has linked depression to maladaptive variants of support seeking, including co-rumination (CR) and excessive reassurance seeking (ERS), which may contribute to symptom onset and maintenance. Although both CR and ERS are associated with depression, insufficient research has examined how daily behaviors and experiences interact with trait-level CR and ERS to predict daily mood. Fifty-one undergraduates, over-selected for internalizing symptoms, completed baseline assessments, followed by a 14-day daily diary assessing behaviors, stressors, and mood. Daily problem-related talk was associated with elevations in depressed mood for participants with high (but not low) trait CR, particularly for those with major depression. Trait ERS similarly moderated the association between daily reassurance seeking and depressed mood. CR, ERS, and daily reassurance seeking each predicted greater affective reactivity to daily stressors. Results align with daily processes hypothesized by CR and ERS models, and suggest that both constructs may be best understood within a diathesis-stress framework.

Effects of lifetime stress exposure on mental and physical health in young adulthood: How stress degrades and forgiveness protects health

To examine risk and resilience factors that affect health, lifetime stress exposure histories, dispositional forgiveness levels, and mental and physical health were assessed in 148 young adults. Greater lifetime stress severity and lower levels of forgiveness each uniquely predicted worse mental and physical health. Analyses also revealed a graded Stress × Forgiveness interaction effect, wherein associations between stress and mental health were weaker for persons exhibiting more forgiveness. These data are the first to elucidate the interactive effects of cumulative stress severity and forgiveness on health, and suggest that developing a more forgiving coping style may help minimize stress-related disorders.