Perceived parental rejection mediates the influence of serotonin transporter gene (5-HTTLPR) polymorphisms on impulsivity in Japanese adults

Rethinking minority stress: A social safety perspective on the health effects of stigma in sexually-diverse and gender-diverse populations

For over two decades, the minority stress model has guided research on the health of sexually-diverse individuals (those who are not exclusively heterosexual) and gender-diverse individuals (those whose gender identity/expression differs from their birth-assigned sex/gender). According to this model, the cumulative stress caused by stigma and social marginalization fosters stress-related health problems. Yet studies linking minority stress to physical health outcomes have yielded mixed results, suggesting that something is missing from our understanding of stigma and health. Social safety may be the missing piece. Social safety refers to reliable social connection, inclusion, and protection, which are core human needs that are imperiled by stigma. The absence of social safety is just as health-consequential for stigmatized individuals as the presence of minority stress, because the chronic threat-vigilance fostered by insufficient safety has negative long-term effects on cognitive, emotional, and immunological functioning, even when exposure to minority stress is low. We argue that insufficient social safety is a primary cause of stigma-related health disparities and a key target for intervention.

Serotonin receptor 1A promoter polymorphism, rs6295, modulates human anxiety levels via altering parasympathetic nervous activity

OBJECTIVE

The G-allele of the -1019C/G (rs6295) promoter polymorphism of the serotonin receptor 1A (HTR1A) gene has been implicated in anxiety; however, the underlying neurophysiological processes are still not fully understood. Recent evidence indicates that low parasympathetic (vagal) tone is predictive of anxiety. We thus conducted a structural equation model (SEM) to examine whether the HTR1A rs6295 variant can affect anxiety by altering parasympathetic nervous activity.

METHOD

A sample of 1141 drug-free healthy Han Chinese was recruited for HTR1A genotyping. Autonomic nervous function was assessed by short-term spectral analysis of heart rate variability (HRV). Anxiety and stress levels were evaluated by the Beck Anxiety Inventory (BAI) and the Perceived Stress Scale (PSS) respectively.

RESULTS

The number of the HTR1A G allele was inversely correlated with high-frequency power (HF), a parasympathetic index of HRV. The HF index was negatively associated with BAI scores. Furthermore, the good-fitting SEM, adjusting for confounding variables (e.g., age and PSS levels), revealed a significant pathway linking rs6295 variant to BAI scores via HF index modulation.

CONCLUSION

These results are the first to show that HTR1A -1019C/G polymorphism influences anxiety levels by modulating parasympathetic tone, providing a neurophysiological insight into the role of HTR1A in human anxiety.

Perceived parental rejection mediates the effects of previous maltreatment on emotional and behavioural outcomes in Chinese adolescents whereas mental illness has no moderating effect

Objective

This study assessed the mediating role of perceived parental rejection in the relationship between childhood maltreatment experience and behavioural problems in Chinese adolescents.

Methods

A total of 2484 adolescents (1305 males and 1179 females; aged 12–16 years) from Hunan Province, China, participated in the study. Behavioural problems, parental rejection scores and child abuse experiences were evaluated by the Child Behavior Checklist (parental version), the Memories of Parental Rearing Behavior Scale and the Childhood Trauma Questionnaire, separately. Mediating effects were examined by structural equation modelling using Amos 20 software.

Results

The study found that perceived maternal rejection partially mediated the association between abuse and internalising behaviours in the male cohort, whereas perceived father’s rejection partially mediated this association in the female cohort. However, mental illness had no moderating effect on these relationships.

Conclusion

These results are consistent with the literature on maltreatment and parent-child relationships and provide empirical support for the view that emotional and behavioural problems related to perceived parental rejection underlie the development of psychosocial problems in adolescents.

Testing differential susceptibility: Plasticity genes, the social environment, and their interplay in adolescent response inhibition

OBJECTIVES

Impaired inhibitory control is a key feature of attention-deficit/hyperactivity disorder (ADHD). We investigated gene-environment interaction (GxE) as a possible contributing factor to response inhibition variation in context of the differential susceptibility theory. This states individuals carrying plasticity gene variants will be more disadvantaged in negative, but more advantaged in positive environments.

METHODS

Behavioural and neural measures of response inhibition were assessed during a Stop-signal task in participants with (N = 197) and without (N = 295) ADHD, from N = 278 families (age M = 17.18, SD =3.65). We examined GxE between candidate plasticity genes (DAT1, 5-HTT, DRD4) and social environments (maternal expressed emotion, peer affiliation).

RESULTS

A DRD4 × Positive peer affiliation interaction was found on the right fusiform gyrus (rFG) activation during successful inhibition. Further, 5-HTT short allele carriers showed increased rFG activation during failed inhibitions. Maternal warmth and positive peer affiliation were positively associated with right inferior frontal cortex activation during successful inhibition. Deviant peer affiliation was positively related to the error rate.

CONCLUSIONS

While a pattern of differential genetic susceptibility was found, more clarity on the role of the FG during response inhibition is warranted before firm conclusions can be made. Positive and negative social environments were related to inhibitory control. This extends previous research emphasizing adverse environments.

Perceived Parenting Mediates Serotonin Transporter Gene (5-HTTLPR) and Neural System Function during Facial Recognition: A Pilot Study

This study examined changes in prefrontal oxy-Hb levels measured by NIRS (Near-Infrared Spectroscopy) during a facial-emotion recognition task in healthy adults, testing a mediational/moderational model of these variables. Fifty-three healthy adults (male = 35, female = 18) aged between 22 to 37 years old (mean age = 24.05 years old) provided saliva samples, completed a EMBU questionnaire (Swedish acronym for Egna Minnen Beträffande Uppfostran [My memories of upbringing]), and participated in a facial-emotion recognition task during NIRS recording. There was a main effect of maternal rejection on RoxH (right frontal activation during an ambiguous task), and a gene × environment (G×E) interaction on RoxH, suggesting that individuals who carry the SL or LL genotype and who endorse greater perceived maternal rejection show less right frontal activation than SL/LL carriers with lower perceived maternal rejection. Finally, perceived parenting style played a mediating role in right frontal activation via the 5-HTTLPR genotype. Early-perceived parenting might influence neural activity in an uncertain situation i.e. rating ambiguous faces among individuals with certain genotypes. This preliminary study makes a small contribution to the mapping of an influence of gene and behaviour on the neural system. More such attempts should be made in order to clarify the links.

The serotonin transporter (5-HTTLPR) but not serotonin receptor (5-HT2C Cys23Ser) variant is associated with bipolar I disorder in Kurdish population from Western Iran

The role of 5-HTTLPR and 5-HT2C Cys23Ser polymorphisms in the psychopathology of mood disorders and suicide behavior is controversial. The aim of present study was to investigate the association between 5-HTTLPR and 5-HT2C Cys23Ser variants and susceptibility to bipolar I disorder (BID). The 5-HT2C genotypes were studied in 152 patients with BID and 173 gender- and age-matched healthy individuals with Kurds ethnic background from Western Iran using PCR and PCR-RFLP methods. In recessive model (SS vs. LL+LS) the SS genotype was associated with 1.79-fold increased risk of BID (p=0.018). Also, the presence of S allele increased the risk of adult-onset BID by 1.76-fold (p=0.027). No association was detected between 5-HTTLPR genotypes and alleles with suicide attempt. The frequency of 5-HT2C Ser allele in patients and controls were 12.3 and 12.5%, respectively. Mutant allele of HT2C Ser had higher frequency in female (14.7%) than male (10.5%, p=0.27) patients. The frequency of HT2C Ser allele in patients with a family history of BID tended to be higher (15.7%) than those without a family history of the disease (11.8%). The frequency of HT2C Ser allele in suicide attempter women was higher (16.7%) than those without a suicide attempt (14.3%). Our findings demonstrate 5-HTTLPR polymorphism might be a risk factor for BID and adult-onset BID in Kurds population. However, we found the lack of an association between 5-HT2C Cys/Ser variants and the risk of BID.

Increased severity of suicidal behavior in impulsive aggressive patients exposed to familial adversities

BACKGROUND

The mechanisms by which childhood abuse and family history of suicidal behavior (FHS) lead to an increased risk of suicidal behavior are still unknown. Impulsive aggression may play an intermediate role. We investigated whether greater scores for aggression and impulsivity might be associated with the effects of FHS and/or childhood abuse on the severity of suicidal behavior.

METHOD

We examined the scores of three scales measuring impulsive aggression in a sample of 696 suicide attempters. We compared the highest and lowest scores with regard to reports of childhood abuse and FHS using adjusted multinomial regression models. Genetic polymorphisms of the serotonergic system known to be associated with impulsive aggression were also analyzed.

RESULTS

Patients with high impulsive aggressive scores showed significant differences in sociodemographic, clinical and suicidal features compared with patients with low impulsive aggressive scores. Adjusted results showed that combinations of some types of childhood abuse and FHS, particularly emotional abuse and emotional neglect, are associated with high impulsivity and hostility scores. The SS genotype of the serotonin transporter gene (5-HTTLPR) was associated with high levels of impulsivity when the subjects reported emotional abuse [odds ratio (OR) 5.55, 95% confidence interval (CI) 1.75-17.5] or physical abuse (OR 5.03, 95% CI 1.50-16.9) in their childhood.

CONCLUSIONS

Our results support the role of impulsive aggression as one of the links that may connect childhood abuse and FHS with severity of suicidal behavior.

Role of 5-HTTLPR polymorphism in the development of the inward/outward personality organization: a genetic association study

Reciprocity with primary caregivers affects subjects' adaptive abilities toward the construction of the most useful personal meaning organization (PMO) with respect to their developmental environment. Within cognitive theory the post-rationalist approach has outlined two basic categories of identity construction and of regulation of cognitive and emotional processes: the Outward and the Inward PMO. The presence of different, consistent clinical patterns in Inward and Outward subjects is paralleled by differences in cerebral activation during emotional tasks on fMRI and by different expression of some polymorphisms in serotonin pathways. Since several lines of evidence support a role for the 5-HTTLPR polymorphism in mediating individual susceptibility to environmental emotional stimuli, this study was conducted to investigate its influence in the development of the Inward/Outward PMO.

PMO was assessed and the 5-HTTLPR polymorphism investigated in 124 healthy subjects who were subdivided into an Inward (n = 52) and an Outward (n = 72) group.

Case-control comparisons of short allele (S) frequencies showed significant differences between Inwards and Outwards (p = 0.036, χ2 test; p = 0.026, exact test). Genotype frequencies were not significantly different although values slightly exceeded p≤0.05 (p = 0.056, χ2 test; p = 0.059, exact test). Analysis of the 5-HTTLPR genotypes according to the recessive inheritance model showed that the S/S genotype increased the likelihood of developing an Outward PMO (p = 0.0178, χ2 test; p = 0.0143, exact test; OR = 3.43, CI (95%) = 1.188–9.925). A logistic regression analysis confirmed the association between short allele and S/S genotypes with the Outward PMO also when gender and age were considered. However none of the differences remained significant after correction for multiple testing, even though using the recessive model they approach significance.

Overall our data seem to suggest a putative genetic basis for interindividual differences in PMO development.

No interaction between serotonin transporter gene (5-HTTLPR) polymorphism and adversity on depression among Japanese children and adolescents

BACKGROUND

Identification of gene × environment interactions (G × E) for depression is a crucial step in ascertaining the mechanisms underpinning the disorder. Earlier studies have indicated strong genetic influences and numerous environmental risk factors. In relation to childhood and adolescent depression, evidence is accumulating that the quality of the parental environment is associated with serotonin biology in children. We hypothesized that maternal depression is a crucial environmental risk factor associated with serotonin-regulating genes.

METHODS

This study was designed to ascertain the G × E interaction for diagnosis of depression in a Japanese pediatric sample. DNA samples from 55 pediatric patients with depression and 58 healthy schoolchildren were genotyped for the 5-HTT (2 short (S) alleles at the 5-HTT locus) promoter serotonin-transporter-linked polymorphic region (5-HTTLPR) polymorphism. We examined whether an adverse parental environment, operationalized as the mother's history of recurrent major depressive disorder, interacts with 5-HTTLPR polymorphism to predict patients' depression symptoms.

RESULTS

Binary logistic regression analyses revealed that maternal depression (adversity), gender, and FSIQ significantly affect the diagnosis of depression among children and adolescents. However, no main effect was found for adversity or genotype. Results of multivariable logistic regression analyses using stepwise procedure have elicited some models with a good fit index, which also suggests no interaction between 5-HTTLPR and adversity on depression.

CONCLUSIONS

To assess G × E interaction, data obtained from children and adolescents who had been carefully diagnosed categorically and data from age-matched controls were analyzed using logistic regression. Despite an equivocal interaction effect, adversity and gender showed significant main effects.