Oxytocin receptors (OXTR) and early parental care: An interaction that modulates psychiatric disorders

Decreased oxytocin levels related to social cognition impairment in borderline personality disorder

INTRODUCTION

Dysfunctions in the oxytocin system have been reported in patients with borderline personality disorder (BPD). Deficits could be related to interpersonal hypersensitivity, which has been previously associated with failures in social cognition (SC) in this disorder, especially in Theory of Mind (ToM) skills. The aim of this work is to study the links between the oxytocin system and SC impairments in patients with BPD.

METHOD

Plasma oxytocin levels (OXT) and protein expression of oxytocin receptors in blood mononuclear cells (OXTR) were examined in 33 patients with a diagnosis of BPD (age: M 28.85, DT = 8.83). Social cognition was assessed using the Movie for the Assessment of Social Cognition (MASC). Statistical associations between biochemical factors and different response errors in MASC were analyzed through generalized linear regression controlling for relevant clinical factors.

RESULTS

Generalized linear regression showed a significant relationship between lower OXTR and overmentalization in BPD patients (OR = 0.90).

CONCLUSIONS

This work supports the relationship between alterations in the oxytocin system and ToM impairments observed in BPD patients, enhancing the search for endophenotypes related to the phenotypic features of the disorder to improve current clinical knowledge and address more specific therapeutic targets.

Oxytocin system polymorphisms rs237887 and rs2740210 variants increase the risk of depression in pregnant women with early abuse

Prepartum depression is associated with early adversity, pregnancy complications, preterm delivery, postpartum depression, and long-term effects on child neurodevelopment. The oxytocin (OXT) system is affected by early adverse experiences and has been associated with depression. In the current study, we investigated risk factors for prenatal depressive symptoms, mainly the effects of early childhood and adolescence trauma, in combination with the presence of certain variants of polymorphisms of OXT and OXT receptor (OXTR) genes. We hypothesized that early childhood and adolescence trauma has higher negative effects in carriers of genetic variants of the OXT/OXTR system, increasing their risk for depression. Early in pregnancy (8-14 weeks), 141 pregnant women from a Uruguayan population were asked to provide DNA samples and complete questionnaires that assessed their experience of child abuse, depression symptoms, and other variables that included demographic information. Our results showed that 23.5% of pregnant women had depressive symptoms. Several OXT and OXTR genetic variants were associated with higher risk of prepartum depression only in those pregnant women who suffered emotional abuse during infancy or adolescence. Logistic regression (Nagelkerke's R2  = .33) revealed that women who suffered early abuse and were carriers of the variants CC of rs2740210 (OXT) or AA of rs237887 (OXTR) had significantly higher risk of experiencing depressive symptoms. Antecedents of psychiatric disorders also contributed to the risk of depression. We conclude that emotional abuse contributes to the risk of depression in different ways in women carrying different OXT and OXTR genetic variants. Early detection and closer follow-up of women with child abuse and certain OXT genetic variants, among other risk factors, could reduce the long-term impact of prepartum depression.

Resilience by design: How nature, nurture, environment, and microbiome mitigate stress and allostatic load

Resilience to psychological stress is defined as adaption to challenging life experiences and not the absence of adverse life events. Determinants of resilience include personality traits, genetic/epigenetic modifications of genes involved in the stress response, cognitive and behavioral flexibility, secure attachment with a caregiver, social and community support systems, nutrition and exercise, and alignment of circadian rhythm to the natural light/dark cycle. Therefore, resilience is a dynamic and flexible process that continually evolves by the intersection of different domains in human’s life; biological, social, and psychological. The objective of this minireview is to summarize the existing knowledge about the multitude factors and molecular alterations that result from resilience to stress response. Given the multiple contributing factors in building resilience, we set out a goal to identify which factors were most supportive of a causal role by the current literature. We focused on resilience-related molecular alterations resulting from mind-body homeostasis in connection with psychosocial and environmental factors. We conclude that there is no one causal factor that differentiates a resilient person from a vulnerable one. Instead, building resilience requires an intricate network of positive experiences and a healthy lifestyle that contribute to a balanced mind-body connection. Therefore, a holistic approach must be adopted in future research on stress response to address the multiple elements that promote resilience and prevent illnesses and psychopathology related to stress allostatic load.

Influence of oxytocin on parenting behaviors and parent-child bonding: A systematic review

Oxytocin (OT) plays a pivotal role in early parent-child relationship formation and bonding that is critical for the social, cognitive, and emotional development of the child. Therefore, this systematic review aims to consolidate all available evidence regarding the associations of parental OT concentration levels with parenting behavior and bonding within the past 20 years. A systematic search was conducted in five databases from 2002 to May 2022, and 33 studies were finalized and included. Due to the heterogeneity of the data, findings were presented narratively based on the type of OT and parenting outcomes. Current evidence strongly suggests that parental OT levels are positively related to parental touch and parental gaze and affect synchrony and observer-coded parent-infant bonding. No gender difference in OT levels was observed between fathers and mothers, but OT strengthens affectionate parenting in mothers and stimulatory parenting in fathers. Child OT levels were also positively associated with parental OT levels. Family and healthcare providers could encourage more positive touch and interactive play between parent and child to strengthen parent-child relationships.

Genetic and epigenetic effects on couple adjustment in context of romantic relationship: A scoping systematic review

Introduction: Couples' relationships defined by a complex interaction between the two partners and their intrapersonal traits. Romantic; relationships and love are associated with marital satisfaction and stability, as well as couples' happiness and health. Personality traits influence romantic relationships and, personality influenced by genetical and non-genetically factors. The roles of non-genetically factors such as socioeconomic position and external appearance have revealed in determining the quality of romantic relationships. Methods: We; performed a scoping systematic review to assess the association between genetics and epigenetic factors and romantic relationship. Relevant articles were identified by PubMed, EMBASE, Web of Science, Scopus, and the APA PsycInfo searching between inception and 4 June 2022. Results: Different studies evaluated the associated polymorphisms in 15 different genes or chromosomal regions. In the first step; we classified them into four groups: (1) Oxytocin-related signaling pathway (OXTR, CD38, and AVPR1A); (2) Serotonin-related signaling pathway (SLC6A4, HTR1A, and HTR2A); (3) Dopamine and catecholamine-related signaling pathway (DRD1, DRD2, DRD4, ANKK1, and COMT); and (4) other genes (HLA, GABRA2, OPRM1, and Y-DNA haplogroup D-M55). Then, we evaluated and extracted significant polymorphisms that affect couple adjustment and romantic relationships. Discussion: Overall, the findings suggest that genetic and epigenetics variants play a key role in marital adjustment and romantic relationships over time.

Candidate Biological Markers for Social Anxiety Disorder: A Systematic Review

Social anxiety disorder (SAD) is a common psychiatric condition associated with a high risk of psychiatric comorbidity and impaired social/occupational functioning when not promptly treated. The identification of biological markers may facilitate the diagnostic process, leading to an early and proper treatment. Our aim was to systematically review the available literature about potential biomarkers for SAD. A search in the main online repositories (PubMed, ISI Web of Knowledge, PsychInfo, etc.) was performed. Of the 662 records screened, 61 were included. Results concerning cortisol, neuropeptides and inflammatory/immunological/neurotrophic markers remain inconsistent. Preliminary evidence emerged about the role of chromosome 16 and the endomannosidase gene, as well as of epigenetic factors, in increasing vulnerability to SAD. Neuroimaging findings revealed an altered connectivity of different cerebral areas in SAD patients and amygdala activation under social threat. Some parameters such as salivary alpha amylase levels, changes in antioxidant defenses, increased gaze avoidance and QT dispersion seem to be associated with SAD and may represent promising biomarkers of this condition. However, the preliminary positive correlations have been poorly replicated. Further studies on larger samples and investigating the same biomarkers are needed to identify more specific biological markers for SAD.

[Effects of oxytocin pathway gene polymorphisms and adverse childhood experiences on emotion recognition in schizophrenia spectrum disorders]

OBJECTIVE

To study a role of the interaction of oxytocin pathway gene polymorphisms and adverse childhood experiences (ACE) in facial emotion recognition (FER) deficits in schizophrenia.

MATERIAL AND METHODS

Patients with schizophrenia spectrum disorders (n=699) completed cognitive testing, which included a FER task. We determined patients' genotypes for common polymorphisms in three of the oxytocin pathway genes which were previously associated with face perception: OXTR (rs53576, rs7632287), CD38 (rs3796863) and ARNT2 (rs4778599). The presence of ACE in the patient's history was assessed via an analysis of medical records.

RESULTS

In our sample, 49% of participants experienced ACE. ANCOVA adjusted for age and gender revealed a significant interaction effect of OXTR rs53576 with ACE on FER scores (F=11.51; p<0.001; η2p=0.02). The effect remained significant when accounting for cognitive functioning and negative symptoms. Carriers of the A allele without ACE recognized emotions worse than GG homozygotes without ACE (p=0.039) and carriers of the A allele with ACE (p=0.009).

CONCLUSION

The results are consistent with the notion of the A (rs53576) allele's role in sensitivity to childhood experiences that influence the psychosocial development and can be used in further studies of the oxytocin treatment of social cognition and social adaptation of patients with schizophrenia.

Involvement of oxytocin receptor deficiency in psychiatric disorders and behavioral abnormalities

Oxytocin and its target receptor (oxytocin receptor, OXTR) exert important roles in the regulation of complex social behaviors and cognition. The oxytocin/OXTR system in the brain could activate and transduce several intracellular signaling pathways to affect neuronal functions or responses and then mediate physiological activities. The persistence and outcome of the oxytocin activity in the brain are closely linked to the regulation, state, and expression of OXTR. Increasing evidence has shown that genetic variations, epigenetic modification states, and the expression of OXTR have been implicated in psychiatric disorders characterized by social deficits, especially in autism. Among these variations and modifications, OXTR gene methylation and polymorphism have been found in many patients with psychiatric disorders and have been considered to be associated with those psychiatric disorders, behavioral abnormalities, and individual differences in response to social stimuli or others. Given the significance of these new findings, in this review, we focus on the progress of OXTR's functions, intrinsic mechanisms, and its correlations with psychiatric disorders or deficits in behaviors. We hope that this review can provide a deep insight into the study of OXTR-involved psychiatric disorders.

Associations of air PM2.5 level with gut microbiota in Chinese Han preschoolers and effect modification by oxytocin receptor gene polymorphism

Variations in the single nucleotide polymorphisms (SNPs) of the oxytocin receptors (OXTR) indicate individual differences in stress response, social behavior, and psychopathology, but very few paper mentioned OXTR as part of the mechanism linking exposure to air pollution and poor social interactions. The authors investigated the moderating role of Oxytocin receptor (OXTR) rs53576 polymorphism in the relationship between PM_2.5 level and gut microbiota in children, in an attempt to provide some reference for the evidence linking biological and environmental factors to children brain development. The study included 86 healthy Chinese preschoolers (50 males, 36 females) from two campuses of a kindergarten with different air PM_2.5 levels. Atmospheric PM_2.5 values released by air quality monitoring stations where the two campuses are located were collected for 30 days. The genotypes of OXTR rs53576 were determined by PCR and restriction fragment length polymorphism. The gut microbiota situation was evaluated by determining urinary concentrations of short-chain fatty acids. Urinary levels of cortisone and cortisol were determined to assess the impact of air pollution on the HPA axis. Urinary 2'-Deoxy-7,8-dihydro-8-oxoguanosine and 8-oxo-7,8-dihydroguanosine were measured to evaluate the oxidative stress state. The genotype distribution frequency of rs53576 polymorphism was consistent with Hardy-Weinberg equilibrium. The average urinary concentrations of cortisone, cortisol and 8-OHdG in high pollution campus preschoolers were significantly higher than those in low pollution campus preschoolers, while situations were opposite for acetic acid, propionic acid, isobutyric acid, butyric acid and valeric acid. The interaction between OXTR rs53576 and air pollution had a significant effect on urinary acetic acid. Allele G of rs53576 may be a risk factor for gut microbiota disorder caused by air pollution, and children with GA/GG genotype may be more susceptible than those with AA genotype.

Polymorphisms in the oxytocin receptor and their association with apathy and impaired social cognition in Huntington's disease

BACKGROUND

Huntington's disease (HD) is a neurodegenerative disorder characterized by cognitive, motor, and neuropsychiatric manifestations. Oxytocin is a neuropeptide studied for its role as a neuromodulator regulating multiple behaviors linked to social cognition. Genetic variation of oxytocin receptor (OXTR) might interact in the etiology and development of several impaired social behaviors. Our aim was to study OXTR polymorphisms and their relationship with apathy and social cognition in HD.

METHODS

OXTR was sequenced in 21 cases and 22 controls. We assessed apathy, anxiety, depression, and irritability (Hospital Anxiety and Depression Scale-Snaith Irritability scale, HADS-SIS) and social cognition (Ekman 60 faces test), motor symptoms and functionality with the total functional capacity (TFC), and the Unified HD rating Scale (UHDRS).

RESULTS

We identified ten variants in OXTR. Three variants were classified as possibly damaging (p.Arg40Gly) or probably damaging (p.Leu46Pro, p.Thr102Asn). Subjects carrying the wild-type genotype of the synonymous variant p.Val45 showed a significantly lower score in the HADS-SIS scale, related to lower irritability (p = 0.013). The only subject carrying the heterozygous genotype of the synonymous variant p.Leu62 showed a significantly higher score on Ekman scale, compared to wild-type (p = 0.049); however, this finding was not confirmed after bootstrapping.

CONCLUSION

Variations in OXTR could have a relevant role in the correct development of social and cognitive functions. Future approaches will include the molecular study of p.Arg40Gly, p.Leu46Pro, and p.Thr102Asn to confirm their pathogenicity, as well as the validation of the influence of p.Val45 and p.Leu62 variants for their involvement in irritability and social cognition in HD.

Gene-Environment Interactions in Face Categorization: Oxytocin Receptor Genotype x Childcare Experience Shortens Reaction Time

Human faces capture attention, provide information about group belonging, and elicit automatic prepared responses. Early experiences with other-race faces play a critical role in acquiring face expertise, but the exact mechanism through which early experience exerts its influence is still to be elucidated. Genetic factors and a multi-ethnic context are likely involved, but their specific influences have not been explored. This study investigated how oxytocin receptor gene (OXTR) genotypes and childcare experience interacted to regulate face categorization in adults. Information about single nucleotide polymorphisms of OXTR (rs53576) and experiences with own- and other-race child caregivers was collected from 89 Singaporean adults, who completed a visual categorization task with own- versus other-race faces. Participants were grouped into A/A homozygotes and G carriers and assigned a score to account for their type of child caregiver experience. A multivariate linear regression model was used to estimate the effect of genetic group, child caregiver experience, and their interaction on categorization reaction time. A significant interaction of genetic group and child caregiver experience (t = 2.48, p = 0.015), as well as main effects of both genetic group (t = −2.17, p = 0.033) and child caregiver experience (t = −4.29, p < 0.001) emerged. Post-hoc analysis revealed that the correlation between categorization reaction time and child caregiver experience was significantly different between the two genetic groups. A significant gene x environment interaction on face categorization appears to represent an indirect pathway through which genes and experiences interact to shape mature social sensitivity to faces in human adults.

The Interaction Effect of Parental Rejection and Oxytocin Receptor Gene Polymorphism on Depression: A Cross-Cultural Study in Non-Clinical Samples

Parental rejection has been consistently empirically implicated in a wide array of developmental, behavioural and psychological problems worldwide. However, the interaction effect between parental rejection in childhood and the oxytocin receptor genotype on psychological adjustment has yet to be investigated. The present study aimed to investigate gene–environment interaction effects between parental rejection (maternal and paternal) and oxytocin receptor (OXTR) gene polymorphisms (rs53576 and rs2254298) on depressive symptoms in adults in different cultural contexts. Adults from Italy and Japan (N = 133, age = 18–27 years, females = 68) were preliminarily genotyped and then completed the Parental Acceptance-Rejection Questionnaire for mothers and fathers and the Beck Depression Inventory. Hierarchical multiple regression analysis showed that paternal rejection was related to self-reported depression and that the effect of parental rejection was moderated by OXTR gene polymorphisms and nationality. Among Italians, OXTR rs2254298 A-carriers showed resilience to negative early parental care, whereas among Japanese, OXTR rs53576 non-A-carriers showed resistance to negative early paternal care. These findings align with expected relations between perceived acceptance–rejection and an individual’s psychological adjustment, as proposed by interpersonal acceptance–rejection theory, and indicate the need for future studies adopting a multicultural and multilevel approach to better understand how the effects of parental rejection extend into adulthood.

The Interaction between Serotonin Transporter Allelic Variation and Maternal Care Modulates Instagram Sociability in a Sample of Singaporean Users

Human social interactions ensure recognition and approval from others, both in offline and online environments. This study applies a model from behavioral genetics on Instagram sociability to explore the impact of individual development on behavior on social networks. We hypothesize that sociable attitudes on Instagram resulted from an interaction between serotonin transporter gene alleles and the individual’s social relationship with caregivers. We assess the environmental and genetic components of 57 Instagram users. The self-report questionnaire Parental Bonding Instrument is adopted to determine the quality of parental bonding. The number of posts, followed users (“followings”), and followers are collected from Instagram as measures of online social activity. Additionally, the ratio between the number of followers and followings (“Social Desirability Index”) was calculated to estimate the asymmetry of each user’s social network. Finally, buccal mucosa cell samples were acquired, and the polymorphism rs25531 (T/T homozygotes vs. C-carriers) within the serotonin transporter gene was examined. In the preliminary analysis, we identified a gender effect on the number of followings. In addition, we specifically found a gene–environment interaction on the standardized Instagram “Social Desirability Index” in line with our predictions. Users with the genotype more sensitive to environmental influences (T/T homozygotes) showed a higher Instagram “Social Desirability Index” than nonsensitive ones (C-carriers) when they experienced positive maternal care. This result may contribute to understanding online social behavior from a gene*environment perspective.

Epigenetic Mechanism of 5-HT/NE/DA Triple Reuptake Inhibitor on Adult Depression Susceptibility in Early Stress Mice

Major depressive disorder (MDD) is a chronic, remitting and debilitating disease and the etiology of MDD is highly complicated that involves genetic and environmental interactions. Despite many pharmacotherapeutic options, many patients remain poorly treated and the development of effective treatments remains a high priority in the field. LPM570065 is a potent 5-hydroxytryptamine (5-HT), norepinephrine (NE) and dopamine (DA) triple reuptake inhibitor and both preclinical and clinical results demonstrate significant efficacy against MDD. This study extends previous findings to examine the effects and underlying mechanisms of LPM570065 on stress vulnerability using a "two-hit" stress mouse model. The "two-hit" stress model used adult mice that had experienced early life maternal separation (MS) stress for social defeat stress (SDS) and then they were evaluated in three behavioral assays: sucrose preference test, tail suspension test and forced swimming test. For the mechanistic studies, methylation-specific differentially expressed genes in mouse hippocampal tissue and ventral tegmental area (VTA) were analyzed by whole-genome transcriptome analysis along with next-generation bisulfite sequencing analysis, followed by RT-PCR and pyrophosphate sequencing to confirm gene expression and methylation. LPM570065 significantly reversed depressive-like behaviors in the mice in the sucrose preference test, the tail suspension test, and the forced swimming test. Morphologically, LPM570065 increased the density of dendritic spines in hippocampal CA1 neurons. Hypermethylation and downregulation of oxytocin receptor (Oxtr) in the hippocampal tissues along with increased protein expression of Dnmt1 and Dnmt3a in mice that experienced the "two-hit" stress compared to those that only experienced adulthood social defeat stress, and LPM570065 could reverse these changes. Combined, these results suggest that methylation specificity of the gene Oxtr in the hippocampus may play an important role in early life stress-induced susceptibility to depression and that the5-HT/NE/DA triple reuptake inhibitor LPM570065 may reduce depression susceptibility via the reversal of the methylation of the gene Oxtr.

Oxytocin receptor gene (OXTR) polymorphisms and social, emotional and behavioral functioning in children and adolescents: a systematic narrative review

This study systematically reviewed available evidence regarding associations between polymorphisms of the oxytocin receptor (OXTR) gene and socio-emotional and behavioral functioning in children and adolescents. The search yielded 69 articles, which were grouped into nine categories: depression, anxiety, and internalizing symptoms, alcohol abuse, borderline personality disorder, conduct disorder symptoms or diagnosis, autism spectrum disorder, Attention deficit hyperactivity disorder, early childhood attachment and behavior, pro-social skills, and resilience. Direct and/or gene x environment interactions were identified in over half of the studies. ASD and conduct disorder (including callous unemotional traits) were the diagnoses that were most studied and for which there was the strongest evidence of direct links with OXTR polymorphisms. In most studies identifying gene x environment interactions, the candidate OXTR polymorphism was rs53576. Results suggest that OXTR polymorphisms are associated with social, emotional or behavioural functioning in children and adolescents. The mixed findings do, however, highlight the need for further research.

The oxytocin system and early-life experience-dependent plastic changes

Early-life experience influences social and emotional behaviour in adulthood. Affiliative tactile stimuli in early life facilitate the development of social and emotional behaviour, whereas early-life adverse stimuli have been shown to increase the risk of various diseases in later life. On the other hand, oxytocin has been shown to have organizational actions during early-life stages. However, the detailed mechanisms of the effects of early-life experience and oxytocin remain unclear. Here, we review the effects of affiliative tactile stimuli during the neonatal period and neonatal oxytocin treatment on the activity of the oxytocin-oxytocin receptor system and social or emotional behaviour in adulthood. Both affiliative tactile stimuli and early-life adverse stimuli in the neonatal period acutely activate the oxytocin-oxytocin receptor system in the brain but modulate social behaviour and anxiety-related behaviour apparently in an opposite direction in adulthood. Accumulating evidence suggests that affiliative tactile stimuli and exogenous application of oxytocin in early-life stages induce higher activity of the oxytocin-oxytocin receptor system in adulthood, although the effects are dependent on experimental procedures, sex, dosages and brain regions examined. On the other hand, early-life stressful stimuli appear to induce reduced activity of the oxytocin-oxytocin receptor system, possibly leading to adverse actions in adulthood. It is possible that activation of a specific oxytocin system can induce beneficial actions against early-life maltreatments and thus could be used for the treatment of developmental psychiatric disorders.

Oxytocin receptor polymorphism influences characterization of harm avoidance by moderating susceptibility to affectionless control parenting

INTRODUCTION

Oxytocin receptor (OXTR) gene polymorphism reportedly moderates effects of negative environments during childhood on mental function and behavior such as depressive symptoms and externalizing problems. This study examined OXTR gene polymorphism effects on personality traits in healthy participants, considering interaction effects of polymorphism with affectionless control (AC) parenting which is one of the dysfunctional and pathogenic parenting styles.

METHODS

For 496 Japanese volunteers, personality was evaluated using the Temperament and Character Inventory. The Parental Bonding Instrument, which has subscales of care and protection, was used to assess perceived parental rearing. AC parenting was defined as low care and high protection. A/G polymorphism of the OXTR gene (rs53576) was detected using TaqMan SNP Genotyping Assay.

RESULTS

Two-way analysis of covariance revealed significant interaction effects between the genotype and the number of AC parents on scores of harm avoidance, with no significant main effect of genotype on any personality. Post-hoc analysis revealed that the harm avoidance scores were increased in a stepwise manner with respect to the increase of the number of AC parents in the A allele carriers. No similar association was observed in the A allele noncarriers.

CONCLUSION

The results of this study suggest that OXTR polymorphism influences characterization of harm avoidance by moderating susceptibility to AC parenting.

The relation between oxytocin receptor gene polymorphisms, adult attachment and Instagram sociability: An exploratory analysis

Oxytocin is a primary neuropeptide which coordinates affiliative behavior. Previous researchers pointed to the association between genetic vulnerability on Oxytocin Receptor Gene (OXTR) and environmental factors (e.g., social relationships) to comprehend social behavior. Although an extensive knowledge of in-person social interactions has been obtained, little is known about online sociability. A gene-environment perspective is adopted to examine how OXTR and adult attachment moderate Instagram behavior. The genetic factors within the regions OXTR/rs53576 (A/A homozygotes vs G-carriers) and OXTR/rs2254298 (G/G homozygotes vs A-carriers) were assessed. The Experience in Close Relationships-Revised (ECR-R) questionnaire was used to collect participants' (N = 57, 16 males) attachment with a partner. The number of posts, followed people ("followings") and followers were obtained from Instagram, and the Social Desirability Index (SDI) was calculated as the ratio of followers to followings. Interaction effects between OXTR groups and ECR-R scores on the number of posts and SDI were hypothesized. Results showed an effect of rs53576 on the number of Instagram followings. Specifically, people with A/A OXTR/rs53576 genotype had more followings than G-carriers independent of the anxiety or avoidance felt towards their partner. These preliminary results offer insights into future investigations on social media behavior.

Serotonin Transporter Gene Polymorphisms and Maternal Overprotection Regulate Adult Social Expectations on Close Relationships

Humans are evolutionary-driven to adult mating and conceive social expectations on the quality of their affiliations. The genetic susceptibility to adverse environments in critical periods can alter close relationships. The current research investigates how the promoter region of the Serotonin Transporter Gene (5-HTTLPR) and perceived caregiving behavior in childhood could influence the social expectations on close adult relationships. For this purpose, 5-HTTLPR data was collected from the buccal mucosa of 65 Italian individuals (33 males). The participants filled (a) the Parental Bonding Instrument (PBI) to provide the levels of care and overprotection from mother and father, and (b) the Experience in Close Relationships-Revised (ECR-R) to report the social expectations on the intimate relationship assessed in terms of anxiety and avoidance from the partner. An interaction effect between 5-HTTLPR and PBI dimensions on the ECR-R scores was hypothesized. Results confirmed that the interplay between the genetic groups and history of maternal overprotection predicted avoidance experienced in romantic relationships in adulthood. Moreover, both adult anxiety and avoidance felt in an intimate relationship were found to covary as a function of maternal overprotection. The present work proposes further evidence of the genetic and parental mechanisms regulating social expectations involved in close relationships.

OXTR moderates adverse childhood experiences on depressive symptoms among incarcerated males

OBJECTIVES

This study examined the moderation of an oxytocin receptor (OXTR) gene in the link between childhood adversity and depressive symptoms among incarcerated males.

METHODS

Questionnaires about adverse childhood experiences and depressive symptoms, as well as genomic DNA from blood were collected among 608 incarcerated males (M_age = 32.4 years, SD = 9.41, 18-74 years). Moderation analysis was applied to examine the interaction between adverse childhood experiences (including abuse, neglect, and household dysfunction) and the OXTR polymorphisms (rs2254298, rs53576) in predicting depressive symptoms.

RESULTS

Incarcerated males had relatively higher prevalence of childhood adversity (70.2%) and depressive symptoms (49.8%). Higher childhood adversity was associated with increased depressive symptoms, and the effect was more pronounced in the GG homozygotes of OXTR rs2254298 (b = 0.406, p < .001), as compared with the AA/AG carriers (b = 0.236, p < .001). By contrast, the OXTR rs53576 did not interact with childhood adversity in predicting depressive symptoms.

CONCLUSIONS

Chinese incarcerated males with the GG genotype of OXTR rs2254298 have higher vulnerability in the effect of childhood adversity on depressive symptoms.

Review of eating disorders and oxytocin receptor polymorphisms

BACKGROUND AND AIMS

Oxytocin, a nine amino acid peptide synthesised in the hypothalamus, has been widely recognised for its role in anxiolysis, bonding, sociality, and appetite. It binds to the oxytocin receptor (OXTR)-a G-protein coupled receptor-that is stimulated by the actions of oestrogen both peripherally and centrally. Studies have implicated OXTR genotypes in conferring either a risk or protective effect in autism, schizophrenia, and eating disorders (ED). There are numerous DNA variations of this receptor, with the most common DNA variation being in the form of the single nucleotide polymorphisms (SNPs). Two OXTR SNPs have been most studied in relation to ED: rs53576 and rs2254298. Each SNP has the same allelic variant that produces genotypes AA, AG, and GG. In this critical review we will evaluate the putative role of rs53576 and rs2254298 SNPs in ED. Additionally, this narrative review will consider the role of gene-environment interactions in the development of ED pathology.

FINDINGS

The OXTR SNPs rs53576 and rs2254298 show independent associations between the A allele and restrictive eating behaviours. Conversely, the G allele of the OXTR rs53576 SNP is associated with binging behaviours, findings that were also evident in neuroanatomy. One study found the A allele of both OXTR SNPs to confer risk for more severe ED symptomatology while the G allele conferred some protective effect. An interaction between poor maternal care and rs2254298 AG/AA genotype conferred increased risk for binge eating and purging in women.

CONCLUSIONS

Individual OXTR SNP are unlikely in themselves to explain complex eating disorders but may affect the expression of and/or effectiveness of the OXTR. A growing body of G x E work is indicating that rs53576G homozygosity becomes disadvantageous for later mental health under early adverse conditions but further research to extend these findings to eating pathology is needed. The GWAS approach would benefit this area of knowledge.

The association of oxytocin with major depressive disorder: role of confounding effects of antidepressants

Major depressive disorder is a genetic susceptible disease, and a psychiatric syndrome with a high rate of incidence and recurrence. Because of its complexity concerning etiology and pathogenesis, the cure rate of first-line antidepressants is low. In recent years, accumulative evidences revealed that oxytocin act as a physiological or pathological participant in a variety of complex neuropsychological activities, including major depressive disorder. Six electronic databases (Web of Science, PubMed, Scopus, Google Scholar, CNKI, and Wanfang) were employed for researching relevant publications. At last, 226 articles were extracted. The current review addresses the correlation of the oxytocin system and major depressive disorder. Besides, we summarize the mechanisms by which the oxytocin system exerts potential antidepressant effects, including regulating neuronal activity, influencing neuroplasticity and regeneration, altering neurotransmitter release, down regulating hypothalamic-pituitary-adrenal axis, anti-inflammatory, antioxidation, and genetic effects. Increasing evidence shows that oxytocin and its receptor gene may play a potential role in major depressive disorder. Future research should focus on the predictive ability of the oxytocin system as a biomarker, as well as its role in targeted prevention and early intervention of major depressive disorder.

Beyond maternal care: The effects of extra-maternal influences within the maternal environment on offspring neurodevelopment and later-life behavior

The early-life maternal environment has a profound and persistent effect on offspring neuroendocrine function, neurotransmitter systems, and behavior. Studies using rodent models suggest that early-life maternal care can influence the 'developmental programming' of offspring in part through altered epigenetic regulation of specific genes. The exploration of epigenetic regulation of these genes as a biological mechanism has been important to our understanding of how animals adapt to their environments and how these developmental trajectories may be altered. However, other non-maternal factors have been shown to act directly, or to interact with maternal care, to influence later-life phenotype. Based on accumulating evidence, including our research, we discuss other important influences on the developmental programming of offspring. We highlight early-life variations in temperature exposure and offspring genotype x environment interactions as prominent examples. We conclude with recommendations for future investigations on how early-life maternal care and extra-maternal influences lead to persistent changes in the brain and behavior of the offspring throughout development.

Recalled Parental Bonding Interacts with Oxytocin Receptor Gene Polymorphism in Modulating Anxiety and Avoidance in Adult Relationships

Early interactions with significant individuals affect social experience throughout the course of a lifetime, as a repeated and prolonged perception of different levels of care, independence, or control influences the modulation of emotional regulatory processes. As many factors play a role in shaping the expectations and features of social interaction, in this study, we considered the influence of parental bonding and genetic allelic variation of oxytocin receptor gene polymorphism (rs53576) over levels of experienced anxiety and avoidance in 313 young adults belonging to two different cultural contexts, namely Italy and Singapore. Results highlighted a major effect of maternal characteristics, care, and overprotection, with differences between the two cultural groups. Additionally, the interaction between rs53576 and maternal overprotection suggested different environmental susceptibility in the Italian sample and the Singaporean one. Implications for clinical work and future steps are described in the Conclusion.

Natural variation in the oxytocin receptor gene and rearing interact to influence reproductive and nonreproductive social behavior and receptor binding

Individual variation in social behavior offers an opportunity to explore gene-by-environment interactions that could contribute to adaptative or atypical behavioral profiles (e.g., autism spectrum disorders). Outbred, socially monogamous prairie voles provide an excellent model to experimentally explore how natural variations in rearing and genetic diversity interact to shape reproductive and nonreproductive social behavior. In this study, we manipulated rearing (biparental versus dam-only), genotyped the intronic NT213739 single nucleotide polymorphism (SNP) of the oxytocin receptor gene (Oxtr), and then assessed how each factor and their interaction related to reciprocal interactions and partner preference in male and female adult prairie voles. We found that C/T subjects reared biparentally formed more robust partner preferences than T/T subjects. In general, dam-only reared animals huddled less with a conspecific in reproductive and nonreproductive contexts, but the effect of rearing was more pronounced in T/T animals. In line with previous literature, C/T animals exhibited higher densities of oxytocin receptor (OXTR) in the striatum (caudoputamen, nucleus accumbens) compared to T/T subjects. There was also a gene-by-rearing interaction in the striatum and insula of females: In the insula, T/T females expressed varying OXTR densities depending on rearing. Overall, this study demonstrates that significant differences in adult reproductive and nonreproductive social behavior and OXTR density can arise due to natural differences in Oxtr, experimental manipulations of rearing, and their interaction.

A systematic review of human paternal oxytocin: Insights into the methodology and what we know so far

With the consolidation of fathers' engagement in caregiving, understanding the neuroendocrine and hormonal mechanisms underlying fatherhood becomes a relevant topic. Oxytocin (OT) has been linked with maternal bonding and caregiving, but less is known about the role of OT in human fatherhood and paternal caregiving. A systematic review of methods and findings of previous OT research in human fathers was carried. The literature search on PubMed and Scopus yielded 133 records. Twenty-four studies were included and analyzed. Significant variability emerged in OT methodology, including laboratory tasks, assessment methods, and outcome measures. Fathers' OT levels appear to increase after childbirth. OT was significantly correlated with less hostility and with the quality of paternal physical stimulation in play interactions, but not with paternal sensitivity. Fathers' and children's OT levels were significantly correlated in a limited subset of studies, intriguingly suggesting that cross-generational OT regulation may occur during the early years of life. This study highlights relevant issues and limitations of peripheral OT assessment in human subjects, especially in fathers. Although the study of paternal neuroendocrinology appears promising, coping with these issues requires dedicated efforts and methodological suggestions are provided to guide future advances in this field.

The etiology of maternal postpartum depressive symptoms: Childhood emotional maltreatment, couple relationship satisfaction, and genes

There is a call for integrative studies examining the roles of biological and psychosocial factors and their interrelations in shaping maternal postpartum psychopathology. Using longitudinal data from 198 primiparous mothers, we tested a biopsychosocial model for the etiology of maternal postpartum depressive symptoms that integrated childhood emotional maltreatment, couple relationship satisfaction, and oxytocin and dopamine D4 receptor genes (i.e., OXTR rs53576 and DRD4). Results indicate (a) two indirect effects from childhood emotional maltreatment and DRD4 to depressive symptoms at 1 year postpartum through couple relationship satisfaction at 6 months postpartum; (b) an interactive effect between DRD4 and couple relationship satisfaction at 6 months postpartum in predicting depressive symptoms at 1 year postpartum, which is in concert with the differential susceptibility hypotheses; and (c) no mediating effects or moderating effects (after adjusting for multiple testing with Bonferroni correction) involving OXTR rs53576. Notably, all associations were identified after controlling for several key covariates (e.g., maternal prenatal depressive symptoms). Last, robustness of the currently identified interactive effect involving DRD4 was demonstrated by an extensive set of additional analyses considering the effects of rGE, G × Covariates, and/or E × Covariates. Taken altogether, this study represents one of the initial efforts for a more sophisticated portrayal of how nature and nurture forces may work in conjunction with each other to shape new mothers' psychopathology. Yet given the current modest sample size and candidate gene approach, our findings are preliminary, should be cautiously interpreted, and need to be replicated with more rigorous designs. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

A variation in the infant oxytocin receptor gene modulates infant hippocampal volumes in association with sex and prenatal maternal anxiety

Genetic variants in the oxytocin receptor (OTR) have been linked to distinct social phenotypes, psychiatric disorders and brain volume alterations in adults. However, to date, it is unknown how OTR genotype shapes prenatal brain development and whether it interacts with maternal prenatal environmental risk factors on infant brain volumes. In 105 Finnish mother-infant dyads (44 female, 11-54 days old), the association of offspring OTR genotype rs53576 and its interaction with prenatal maternal anxiety (revised Symptom Checklist 90, gestational weeks 14, 24, 34) on infant bilateral amygdalar, hippocampal and caudate volumes were probed. A sex-specific main effect of rs53576 on infant left hippocampal volumes was observed. In boys compared to girls, left hippocampal volumes were significantly larger in GG-homozygotes compared to A-allele carriers. Furthermore, genotype rs53576 and prenatal maternal anxiety significantly interacted on right hippocampal volumes irrespective of sex. Higher maternal anxiety was associated both with larger hippocampal volumes in A-allele carriers than GG-homozygotes, and, though statistically weak, also with smaller right caudate volumes in GG-homozygotes than A-allele carriers. Our study results suggest that OTR genotype enhances hippocampal neurogenesis in male GG-homozygotes. Further, prenatal maternal anxiety might induce brain alterations that render GG-homozygotes compared to A-allele carriers more vulnerable to depression.

Oxytocin Pathway Gene (CD38, OXTR) Variants Are Not Related to Psychosocial Characteristics Defined by Strengths and Difficulties Questionnaire in Adolescents: A Field School-Based Study

Background: CD38 is a transmembrane glycoprotein that regulates oxytocin (OT) production and influences social interactions. The oxytocin receptor (OXTR) has been studied intensively regarding its association with human psychosocial functions. Many studies have demonstrated a link between CD38 rs3796863 and OXTR rs53576 polymorphic regions and psychosocial characteristics as well as various psychiatric disorders in adolescents. Some studies, however, have reported null findings. Methods: The Strengths and Difficulties Questionnaire (SDQ) is a brief psychopathologic screening tool recommended for detecting psychosocial problems and psychiatric disorders in adolescents. The current field school-based study, conducted among urban Siberian adolescents (n = 298 aged 12-18), explored the SDQ scales in relation to polymorphisms of the CD38 and the OXTR genes (rs3796863 and rs53576, respectively). Results: None of the studied genotypes were associated with the SDQ results for the complete sample with presumed statistical power as 0.80 to detect a medium-size effect (Cramer's V = 0.3) at α = 0.0083. Post-hoc analysis in subgroups showed that OT pathway high activity may cause some negative consequences, such as emotional instability in older (aged 15-18) adolescent boys who are carriers of the rs53576 GG variant. Conclusion: Variations at the CD38 rs3796863 and OXTR rs53576 loci were not associated with psychosocial characteristics of adolescents assessed with the SDQ. In studies with a similar design, we recommend replication with larger samples and greater power to detect small effects, especially in age-sex subgroups of adolescents.

Oxytocin Receptor Gene Polymorphisms and Early Parental Bonding Interact in Shaping Instagram Social Behavior

Human beings engage in multiple social interactions daily, both in person and online. There are, however, individual differences in the frequency and quality of these interactions. This exploratory study focuses on online interactions and aims to model these differences by looking at potential environmental and genetic factors. The environmental factor is the childhood parental relationship, as reported by the participants in the dimensions of the Parental Bonding Instrument (N = 57, 41 females). At a genetic level, buccal mucosa cell samples were collected to assess participants' genetic susceptibility, and OXTr regions rs2254298 (G/G homozygotes vs. A-carriers) and rs53576 (A/A homozygotes vs. G-carriers) were analyzed. To capture participants' online activity, Instagram was probed. The number of people that the individual follows ("followings"), followers, and posts were used as a proxy for the quantity of interaction, and a Social Desirability Index (SDI) was computed as the ratio of followers to followings. An interaction between OXTr groups and parental bonding scores on the number of followings and posts was hypothesized. A gene-environment interaction for OXTr/rs2254298 on the number of Instagram posts was identified. In line with the hypothesis, participants with a genetic risk factor (A-carriers) and a history of low paternal care showed fewer Instagram posts than those without this risk factor (G/G genotype). Moreover, an interaction effect between maternal overprotection and OXTr/rs2254298 on the Instagram SDI was detected. These findings could represent an indirect pathway through which genes and parental behavior interact to shape social interactions on Instagram.

Decreased oxytocin plasma levels and oxytocin receptor expression in borderline personality disorder

INTRODUCTION

Borderline personality disorder (BPD) is characterized by intense affective reactions with underlying social and interpersonal cognitive deficits. Oxytocin has largely been associated with both stress regulation and social cognition in psychiatric patients and in non-clinical populations in previous studies. Finally, abnormal oxytocin levels have been preliminary reported in BPD patients.

METHODS

53 patients with moderate-severe BPD and 31 healthy control subjects were investigated for plasma levels of oxytocin and protein expression of oxytocin receptor in blood mononuclear cells. Clinical assessments were made for severity, functionality, and comorbidity with axis I and II conditions.

RESULTS

Oxytocin plasma levels were significantly lower in BPD patients compared with controls. In addition, protein expression of oxytocin receptor was significantly reduced in the BPD group. A positive correlation was found between plasma oxytocin levels and the activity index score of the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ). Oxytocin receptor protein expression, on the contrary, had a negative correlation with the ZKPQ sociability index score.

CONCLUSIONS

Results support the evidence of a dysfunction of the oxytocin system in borderline personality disorder, which could be involved in emotional dysregulation and interpersonal disturbances in these patients.

Oxytocin receptor gene, childhood maltreatment and borderline personality disorder features among male inmates in China

BACKGROUND

Borderline personality disorder (BPD) is caused by a variety of biological and environmental factors. Accumulating evidence suggests that childhood maltreatment is a risk environmental factor in the development of BPD, but research on the genetic pathology of BPD is still in its early stages, and very little is known about the oxytocin receptor (OXTR) gene. The purpose of this study is to further explore the interactive effects between OXTR gene polymorphisms and childhood maltreatment on BPD risk.

METHODS

Among the 1804 Chinese Han male inmates, 765 inmates who had BPD or antisocial personality disorder (ASPD) or highly impulsive or violent crime were considered as high-risk inmates and included in this study. Childhood maltreatment, BPD, antisocial personality disorder (ASPD) and impulsivity were measured by self-reported questionnaires. Peripheral venous blood was collected for the genotype test.

RESULTS

Analyses revealed that the BP group (inmates with BPD features) had higher rs53576 AA genotype frequency and rs237987 AA genotype frequency than the non-BP group, while the statistical significances were lost after Bonferroni correction. Total childhood maltreatment score, emotional abuse and neglect could positively predict BPD risk. Among the high-risk samples, rs53576 GG genotype carriers had higher BPD scores at higher levels of physical abuse and sexual abuse and had lower BPD scores at lower levels of physical abuse and sexual abuse.

CONCLUSIONS

The findings suggest that the interaction between OXTR gene variations and childhood maltreatment is an important mechanism for the development of BPD. The moderating role of the OXTR gene provides evidence for gene plasticity.

Oxytocin receptor gene and parental bonding modulate prefrontal responses to cries: a NIRS Study

The ability to interpret and regulate emotions relies on experiences of emotional socialization, obtained firstly through the interaction with the parents, and on genetic features that affect how individuals take on social situations. Evidence from the genetic field states that specific allelic variations of the oxytocin receptor gene polymorphisms regulate physiological modulation of human behavior, especially concerning responses to social cues and affiliative behaviors. Starting from this gene-by-environment interaction frame, we assessed 102 young adults for OXTr rs53576 and rs2254298, recalled parental bonding (using the Parental Bonding Instrument), and recorded participants' neural responses to social stressors using Near InfraRed Spectroscopy (NIRS). The results highlight that higher genetic susceptibility (G/G homozygous) to familiar context and positive early life interactions modulate more optimal neural responses to general social cues, in terms of promptness to action. With regards to the dimensions of parental bonding, we found lateralized effects, with greater activation in the right prefrontal cortex for Care subscales, and on the left side of the prefrontal cortex for Overprotection. Results provide evidence to understand the neurological mechanisms behind the negative impact of poor parenting practices on the child.

Interactions of OXTR rs53576 and emotional trauma on hippocampal volumes and perceived social support in adolescent girls

Oxytocin (OXT) is a neuropeptide involved in social behaviour and is sensitive to environmental influences to alter individual vulnerability or resilience to stress resulting in both negative and positive outcomes. The effects of the OXT receptor (OXTR) single nucleotide polymorphism (SNP) rs53576 on hippocampal and amygdala structure and functions in adults are differentially associated with susceptibility to adversity and social behaviours, but this evidence is lacking in healthy adolescents. Adolescence is a developmental period characterised by neurobiological and psychosocial changes resulting in higher susceptibility to mood disorders, particularly among girls. As the brain is highly plastic at this stage, to understand psychosocial and emotional development, clarity of the interactions between rs53576 and adversity on hippocampal and amygdala volumes and social behaviours is needed. In this study, we investigated the interactions between rs53576 and emotional trauma (ET) exposure on hippocampal and amygdala volumes of adolescent girls, and associations with parenting style, perceived social support and bullying behaviour. Based on an unbiased and corrected analytical approach, we found smaller left hippocampal volumes in higher (hET) compared to minimally (mET) exposed AA homozygotes, but no differences in G allele carriers nor in the amygdala. Within the mET AA group, larger volumes were associated with peer perceived social support, but in their hET counterparts, smaller volumes were associated with familial perceived social support. This evidence supports an important role for the hippocampus in social behaviours but extends current knowledge to suggest that hippocampal social behavioural features are contextually dependent on rs53576.

Social Media Usage and Development of Psychiatric Disorders in Childhood and Adolescence: A Review

Social media platforms, such as Facebook, Twitter, and Instagram, are now part of almost everyone's social life, especially for the newer generations. Children and teenagers grew up together with these Internet-based services, which have become an integral part of their personal and social life. However, as reported in various studies, psychological and psychiatric problems are sometimes associated with problematic usage of social media. The primary purpose of this review is to provide an overview of the cognitive, psychological, and social outcomes correlated with a problematic use of social media sites during the developmental stages, from age 10 to 19 years. With a specific focus on depression, anxiety, eating, and neurodevelopmental disorders, the review also discusses evidence related to genetic and neurobiological issues, together with the implications in clinical work and future directions under a multidisciplinary perspective. While the scientific community has made significant progress in enhancing our understanding of the impact of social media on teenagers' lives, more research integrating biological and environmental factors is required to fully elucidate the development of these disorders.

Infancy onset maltreatment and the development of suicide ideation: An investigation of moderation by oxytocin-related gene polymorphisms

BACKGROUND

Suicide ideation and behavior remains a significant public policy concern. The interpersonal-psychological theory of suicide posits that thwarted belongingness potentiates risk for suicide. Early disruptions in caregiving have documented effects on lifespan social and interpersonal development, and therefore warrants further investigation in suicide research. This novel study investigates risk for suicide ideation conferred by infant-onset child maltreatment and oxytocin genotypes (OXTR and CD38) and tests interactive effects of genetics and early maltreatment experiences.

METHODS

Participants (N = 251) were from a longitudinal follow-up study of emerging adults who participated in a research summer camp program as children (wave 1). Childhood maltreatment was coded from child protective service records and buccal cells were obtained from children and genotyped. At wave 2, self-reported suicide ideation and internalizing symptomatology were obtained.

RESULTS

Maltreatment onset in infancy was significantly related to lifetime suicide ideation. The CD38 gene variation moderated this association such that early onset maltreatment was related to suicide ideation among C-carriers only. The OXTR gene did not relate to lifetime suicide ideation, nor did it moderate early onset maltreatment risk.

LIMITATIONS

This study was conducted with a relatively small sample, necessitating the combination of genotypes into binary groups. Replication is necessary.

CONCLUSIONS

Child maltreatment experienced early in development confers significant risk for lifetime suicide ideation. Furthermore, greater risk for suicide ideation was present for those with specific oxytocin genotypes. These findings further emphasize the importance of preventive interventions aimed at decreasing the incidence of maltreatment and increasing support for high risk families.

Oxytocin is a principal hormone that exerts part of its effects by active fragments

Oxytocin is a nonapeptide consisting of a cyclic six amino-acid structure and a tail of three amino acids. It was originally known for its ability to induce milk ejection and to stimulate uterine contractions. More recently, oxytocin has been shown to stimulate social behaviors, and exert pain-relieving, anti-stress/anti-inflammatory and restorative effects. We hypothesize that oxytocin is a principal hormone that, in part, exerts its effects after degradation to active fragments with more specific effect profiles. Experimental findings on rats show that administered oxytocin exerts biphasic effects. For example, after an initial increase in pain threshold, a second more long-lasting increase follows. Blood pressure and cortisol levels initially increase and then reverse into a long-lasting decrease in blood pressure and cortisol. Whereas the initial effects are, the second-phase effects are not blocked by an oxytocin antagonist, but by an opioid mu-antagonist and by an alpha 2-adrenoreceptor antagonist, respectively, suggesting that other receptors are involved. Repeated administration of oxytocin induces multiple anti-stress effects, which are mediated by alpha 2-adrenoreceptors. Repeated administration of linear oxytocin and linear oxytocin fragments with a retained C-terminal reduce spontaneous motor activity, a sedative or anti-stress effect, suggesting that alpha 2-adrenoreceptors have been activated. In contrast, linear mid-fragments stimulate motor activity. Low-intensity stimulation of cutaneous nerves in rats, as well as breastfeeding and skin-to-skin contact between mothers and babies, trigger immediate anti-stress effects. Some of these effects are likely caused by open ring/linear C-terminal fragments activating alpha 2-adrenoreceptors. Oxytocin fragments may be pre-formed and released in the brain or created by metabolic conversion of the principal hormone oxytocin in the central nervous system. Oxytocin and its fragments may also be released from peripheral sites, such as peripheral nerves, the gastrointestinal tract, and blood vessels in response to decreased sympathetic or increased parasympathetic nervous tone. Smaller fragments of oxytocin produced in the periphery may easily pass the blood-brain barrier to induce effects in the brain. In conclusion, oxytocin is linked to many different, sometimes opposite effects. The intact cyclic molecule may act to initiate social interaction and associated psychophysiological effects, whereas linear oxytocin and C-terminal fragments may induce relaxation and anti-stress effects following social interaction. In this way, the principal hormone oxytocin and its fragments may take part in a behavioral sequence, ranging from approach and interaction to calm and relaxation. Linear fragments, with an exposed cysteine-residue, may exert anti-inflammatory and antioxidant effects and thereby contribute to the health-promoting effects of oxytocin.

Interaction effect of oxytocin receptor (OXTR) rs53576 genotype and maternal postpartum depression on child behavioural problems

Previous studies have reported interaction effects of oxytocin receptor genotype (rs53576) and environmental factors on mental health in youth. However, the findings are mixed, especially regarding the type of allele (i.e., A vs. G), and it remains unanswered whether such an interaction presents at an early stage of development. Thus, using a unique longitudinal birth cohort sample in Japan (n = 568), we examined whether there was an effect of the interaction between the OXTR rs53576 genotype and maternal postpartum depression, as an environmental risk, on behavioural problems in children. Child behavioural problems (internalising and externalising problems) were ascertained using the Strengths and Difficulties Questionnaire when children were 6 years old. Maternal postpartum depression was measured using the Edinburgh Postnatal Depression Scale when children were at 2 months and 10 months of age. The results revealed a significant effect in the interaction between OXTR rs53576 genotype and maternal postpartum depression on externalising problems in children with AA genotype (β = 0.136, 95% CI 0.032 to 0.240), but not in those with GG/GA genotype. This indicates that an interaction of vulnerable genotypes (i.e., A allele of OXTR rs53576) with an environmental burden (i.e. maternal postpartum depression) may be one of the potential elements that predisposes the infant to developing behavioural problems early in life. Hence, special attention needs to be paid to children exposed to environmental risks such as maternal postpartum depression, to facilitate the provision of appropriate care.

The Influences of Drug Abuse on Mother-Infant Interaction Through the Lens of the Biopsychosocial Model of Health and Illness: A Review

Women who abuse illicit drugs often engage in atypical parenting behaviors that interfere with the natural development of mother-infant interaction and attachment. Maternal caregiving deficits leave pronounced adverse consequences in the wake of drug abuse relapse, which often occurs and in early infancy. These are times when the child requires optimal parental care. The contemporary literature documents long-term implications of illicit drug-abuse in parenting on infants. However, factors that drive and sustain the influence of drug abuse on parent-infant outcomes remain elusive. This review adopts a biopsychosocial approach to synthesizing the existing state of knowledge on this issue. Mother-infant interaction is a dynamic socio-relational process that occurs at multiple levels of organization. As such, a biopsychosocial perspective enables us to uncover: (i) roles of specific physiological mechanisms and biological characteristics of atypical parenting in mothers who abuse drugs, (ii) the influence of drugs on maternal psychological state (i.e., beliefs regarding parenting practices, emotional regulation), and (iii) social relationships (i.e., relationships with spouse and other drug abusers) and contextual cues (i.e., triggers) that moderate non-optimal maternal caregiving. A comprehensive review of these key domains provides a nuanced understanding of how these several sources interdependently shape atypical parent-infant interaction amongst drug abusing mothers. Systematic elucidation of major factors underlying drug-abused maternal behaviors facilitates the development of targeted and more effective interventions.

Development of Neuroimaging-Based Biomarkers in Psychiatry

This chapter presents an overview of accumulating neuroimaging data with emphasis on translational potential. The subject will be described in the context of three disease states, i.e., schizophrenia, bipolar disorder, and major depressive disorder, and for three clinical goals, i.e., disease risk assessment, subtyping, and treatment decision.

Gene × Environment Interaction in Developmental Disorders: Where Do We Stand and What's Next?

Although the field of psychiatry has witnessed the proliferation of studies on Gene × Environment (G×E) interactions, still limited is the knowledge we possess of G×E interactions regarding developmental disorders. In this perspective paper, we discuss why G×E interaction studies are needed to broaden our knowledge of developmental disorders. We also discuss the different roles of hazardous versus self-generated environmental factors and how these types of factors may differentially engage with an individual's genetic background in predicting a resulting phenotype. Then, we present examplar studies that highlight the role of G×E in predicting atypical developmental trajectories as well as provide insight regarding treatment outcomes. Supported by these examples, we explore the need to move beyond merely examining statistical interactions between genes and the environment, and the motivation to investigate specific genetic susceptibility and environmental contexts that drive developmental disorders. We propose that further parsing of genetic and environmental components is required to fully understand the unique contribution of each factor to the etiology of developmental disorders. Finally, with a greater appreciation of the complexities of G×E interaction, this discussion will converge upon the potential implications for clinical and translational research.

The Neuropeptide Hormone Oxytocin in Eating Disorders

PURPOSE OF REVIEW

The neurohormone oxytocin (OXT) impacts food intake as well as cognitive, emotional, and social functioning-all of which are central to eating disorder (ED) pathology across the weight spectrum. Here, we review findings on endogenous OXT levels and their relationship to ED pathology, the impact of exogenous OXT on mechanisms that drive ED presentation and chronicity, and the potential role of genetic predispositions in the OXT-ED link.

RECENT FINDINGS

Current findings suggest a role of the OXT system in the pathophysiology of anorexia nervosa. In individuals with bulimia nervosa, endogenous OXT levels were comparable to those of healthy controls, and exogenous OXT reduced food intake. Studies in other ED are lacking. However, genetic studies suggest a broad role of the OXT system in influencing ED pathology. Highlighting findings on why OXT represents a potential biomarker of and treatment target for ED, we advocate for a systematic research approach spanning the entire ED spectrum.

Borderline personality disorder

Caretakers are often intimidated or alienated by patients with borderline personality disorder (BPD), compounding the clinical challenges posed by the severe morbidity, high social costs and substantial prevalence of this disorder in many health-care settings. BPD is found in ∼1.7% of the general population but in 15-28% of patients in psychiatric clinics or hospitals and in a large proportion of individuals seeking help for psychological problems in general health facilities. BPD is characterized by extreme sensitivity to perceived interpersonal slights, an unstable sense of self, intense and volatile emotionality and impulsive behaviours that are often self-destructive. Most patients gradually enter symptomatic remission, and their rate of remission can be accelerated by evidence-based psychosocial treatments. Although self-harming behaviours and proneness to crisis can decrease over time, the natural course and otherwise effective treatments of BPD usually leave many patients with persistent and severe social disabilities related to depression or self-harming behaviours. Thus, clinicians need to actively enquire about the central issues of interpersonal relations and unstable identity. Failure to correctly diagnose patients with BPD leads to misleading pharmacological interventions that rarely succeed. Whether the definition of BPD should change is under debate that is linked to not fully knowing the nature of this disorder.