A common oxytocin receptor gene (OXTR) polymorphism modulates intranasal oxytocin effects on the neural response to social cooperation in humans

Intranasal Oxytocin and Pain Reduction: Testing a Social Cognitive Mediation Model

Oxytocin is well known for its role in relationships and social cognition and has more recently been implicated in pain relief and pain perception. Connections between prosocial feelings and pain relief are also well documented; however, the effects of exogenous oxytocin on social cognition and pain have not been explored. The current study tested whether intranasally delivered oxytocin affects pain perception through prosocial behaviors. Additionally, moderation of the effects of oxytocin by life history or genetic polymorphisms is examined. Young adults (n = 43; 65% female) were administered intranasal oxytocin (24 IU) or placebo in a crossover design on two visits separated by a one-week washout period. Pain was delivered via cold pressor. Baseline measures for decision-making and social cognition were collected, as well as pain sensitivity and medication history. Saliva samples were collected for analysis of genetic markers, and urine samples were collected to assess oxytocin saturation. Following oxytocin administration, participants reported increased prosocial cognition and decision-making. Pain perception appeared to be adaptive, with procedural order and expectation affecting perception. Finally, behavioral trust and cooperation responses were significantly predicted by genetic markers. Oxytocin may increase a patient's trust and cooperation and reduce pain sensitivity while having fewer physiological side effects than current pharmaceutical options.

Can the Ability to Recognize Facial Emotions in Individuals With Neurodegenerative Disease be Improved? A Systematic Review and Meta-analysis

BACKGROUND

Facial emotion recognition (FER) is commonly impaired in individuals with neurodegenerative disease (NDD). This impairment has been linked to an increase in behavioral disorders and caregiver burden.

OBJECTIVE

To identify interventions targeting the improvement of FER ability in individuals with NDD and investigate the magnitude of the efficacy of the interventions. We also wanted to explore the duration of the effects of the intervention and their possible impacts on behavioral and psychological symptoms of dementia and caregiver burden.

METHOD

We included 15 studies with 604 individuals who had been diagnosed with NDD. The identified interventions were categorized into three types of approach (cognitive, neurostimulation, and pharmacological) as well as a combined approach (neurostimulation with pharmacological).

RESULTS

The three types of approaches pooled together had a significant large effect size for FER ability improvement (standard mean difference: 1.21, 95% CI = 0.11, 2.31, z = 2.15, P = 0.03). The improvement lasted post intervention, in tandem with a decrease in behavioral disorders and caregiver burden.

CONCLUSION

A combination of different approaches for FER ability improvement may be beneficial for individuals with NDD and their caregivers.

Oxytocinergic modulation of speech production-a double-blind placebo-controlled fMRI study

Many socio-affective behaviors, such as speech, are modulated by oxytocin. While oxytocin modulates speech perception, it is not known whether it also affects speech production. Here, we investigated effects of oxytocin administration and interactions with the functional rs53576 oxytocin receptor (OXTR) polymorphism on produced speech and its underlying brain activity. During functional magnetic resonance imaging, 52 healthy male participants read sentences out loud with either neutral or happy intonation, a covert reading condition served as a common baseline. Participants were studied once under the influence of intranasal oxytocin and in another session under placebo. Oxytocin administration increased the second formant of produced vowels. This acoustic feature has previously been associated with speech valence; however, the acoustic differences were not perceptually distinguishable in our experimental setting. When preparing to speak, oxytocin enhanced brain activity in sensorimotor cortices and regions of both dorsal and right ventral speech processing streams, as well as subcortical and cortical limbic and executive control regions. In some of these regions, the rs53576 OXTR polymorphism modulated oxytocin administration-related brain activity. Oxytocin also gated cortical-basal ganglia circuits involved in the generation of happy prosody. Our findings suggest that several neural processes underlying speech production are modulated by oxytocin, including control of not only affective intonation but also sensorimotor aspects during emotionally neutral speech.

The relationship between oxytocin and empathy for others' pain: Testing the mediating effect of first-hand pain sensitivity

Although previous studies have shown that oxytocin attenuates first-hand pain sensitivity, studies of its effects on empathic reactions to the observation of others' pain have yielded inconsistent and controversial results. Given the link between first-hand pain and empathy for others' pain, we hypothesized that oxytocin affects empathy for others' pain by modulating first-hand pain sensitivity. Using a double-blind, placebo-controlled, between-participant experimental design, healthy participants (n = 112) were randomly assigned to either an intranasal oxytocin or placebo group. Pain sensitivity was evaluated by pressure pain threshold, and empathic responses were assessed by ratings in response to viewing video clips depicting others in physically painful scenarios. Results showed that pressure pain thresholds decreased over time in both groups, indicating increased sensitivity to first-hand pain after repeated measurements. However, this decrease was smaller for participants who received intranasal oxytocin, indicative of oxytocin-induced attenuation of first-hand pain sensitivity. In addition, although empathic ratings were comparable between oxytocin and placebo groups, first-hand pain sensitivity fully mediated the impact of oxytocin on pain empathetic ratings. Thus, intranasal oxytocin can indirectly affect pain empathic ratings by reducing first-hand pain sensitivity. These findings expand our understanding of the relationship among oxytocin, pain, and empathy.

The neural basis of smile authenticity judgments and the potential modulatory role of the oxytocin receptor gene (OXTR)

Accurate perception of genuine vs. posed smiles is crucial for successful social navigation in humans. While people vary in their ability to assess the authenticity of smiles, little is known about the specific biological mechanisms underlying this variation. We investigated the neural substrates of smile authenticity judgments using functional magnetic resonance imaging (fMRI). We also tested a preliminary hypothesis that a common polymorphism in the oxytocin receptor gene (OXTR) rs53576 would modulate the behavioral and neural indices of accurate smile authenticity judgments. A total of 185 healthy adult participants (Neuroimaging arm: N = 44, Behavioral arm: N = 141) determined the authenticity of dynamic facial expressions of genuine and posed smiles either with or without fMRI scanning. Correctly identified genuine vs. posed smiles activated brain areas involved with reward processing, facial mimicry, and mentalizing. Activation within the inferior frontal gyrus and dorsomedial prefrontal cortex correlated with individual differences in sensitivity (d') and response criterion (C), respectively. Our exploratory genetic analysis revealed that rs53576 G homozygotes in the neuroimaging arm had a stronger tendency to judge posed smiles as genuine than did A allele carriers and showed decreased activation in the medial prefrontal cortex when viewing genuine vs. posed smiles. Yet, OXTR rs53576 did not modulate task performance in the behavioral arm, which calls for further studies to evaluate the legitimacy of this result. Our findings extend previous literature on the biological foundations of smile authenticity judgments, particularly emphasizing the involvement of brain regions implicated in reward, facial mimicry, and mentalizing.

Oxytocin receptor single nucleotide polymorphism predicts atony-related postpartum hemorrhage

BACKGROUND

Postpartum hemorrhage remains a key contributor to overall maternal morbidity in the United States. Current clinical assessment methods used to predict postpartum hemorrhage are unable to prospectively identify about 40% of hemorrhage cases. Oxytocin is a first-line pharmaceutical for preventing and treating postpartum hemorrhage, which acts through oxytocin receptors on uterine myocytes. Existing research indicates that oxytocin function is subject to variation, influenced in part by differences in the DNA sequence within the oxytocin receptor gene. One variant, rs53576, has been shown to be associated with variable responses to exogenous oxytocin when administered during psychological research studies. How this variant may influence myometrial oxytocin response in the setting of third stage labor has not been studied. We tested for differences in the frequency of the oxytocin receptor genotype at rs53576 in relationship to the severity of blood loss among a sample of individuals who experienced vaginal birth.

METHODS

A case-control prospective design was used to enroll 119 postpartum participants who underwent vaginal birth who were at least 37 weeks of gestation. Cases were defined by either a 1000 mL or greater blood loss or instances of heavier bleeding where parturients were given additional uterotonic treatment due to uterine atony. Controls were matched to cases on primiparity and labor induction status. Genotype was measured from a maternal blood sample obtained during the 2^nd postpartum month from 95 participants. Statistical analysis included bivariate tests and generalized linear and Poisson regression modeling.

RESULTS

The distribution of the genotype across the sample of 95 participants was 40% GG (n = 38), 50.5% AG (n = 48) and 9.5% AA (n = 9). Blood loss of 1000 mL or greater occurred at a rate of 7.9% for GG, 12.5% for AG and 55.6% for AA participants (p = 0.005). Multivariable models demonstrated A-carriers (versus GG) had 275.2 mL higher blood loss (95% CI 96.9-453.4, p < 0.01) controlling for parity, intrapartum oxytocin, self-reported ancestry, active management of third stage or genital tract lacerations. Furthermore, A-carrier individuals had a 79% higher risk for needing at least one second-line treatment (RR = 1.79, 95% CI = 1.08-2.95) controlling for covariates. Interaction models revealed that A-carriers who required no oxytocin for labor stimulation experienced 371.4 mL greater blood loss (95% CI 196.6-546.2 mL).

CONCLUSIONS

We provide evidence of a risk allele in the oxytocin receptor gene that may be involved in the development of postpartum hemorrhage among participants undergoing vaginal birth, particularly among those with fewer risk factors. The findings, if reproducible, could be useful in studying pharmacogenomic strategies for predicting, preventing or treating postpartum hemorrhage.

Formulation considerations for improving intranasal delivery of CNS acting therapeutics

One of the principal impediments for the treatment of neurological conditions is the lack of ability of most of the medicinal agents to evade the blood–brain barrier. Among all the novel approaches to bypass the blood–brain barrier, nose to brain transport is the most patient compliant, non-invasive and effective approach. It directly transports drugs to the CNS via the trigeminal and olfactory nerves present in the nasal cavity. This review article focuses on anatomy and physiology of nasal cavity, potential of intranasal drug delivery, mechanisms of drug transport to brain, its advantages and limitations, novel intranasal formulations, marketed products, factors affecting nose to brain transport, formulation consideration of intranasal products and the future perspectives of CNS targeting via intranasal drug administration.

Enhanced endogenous oxytocin signaling in the brain modulates neural responses to social misalignment and promotes conformity in humans: A multi-locus genetic profile approach

The neuropeptide oxytocin (OT) is known to promote social conformity. However, the specific neurocognitive mechanisms underlying OT-induced conformity remain unclear. We aimed to address this gap by examining how genetic variation in the oxytocin receptor gene (OXTR) is linked with behavioral conformity and its underlying neural systems. Specifically, we utilized the genotype-tissue expression database (GTEx) to create a novel multi-locus genetic profile score (MPS) that reflects the level of OXTR expression in the human brain. A total of 194 participants (Neuroimaging N = 50, Behavioral N = 144) performed a novel conformity task in which they viewed a series of word pairs depicting various moral values and virtues widely recognized in the United States. In each trial, participants indicated the relative importance of these words and subsequently learned about the majority opinion. Participants later rated the same word pairs a second time. Changes in participants' ratings between the first and second sessions were measured and analyzed with respect to social feedback, blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signals, and OXTR MPS. We found that participants adjusted their ratings in accordance with the majority opinions. Social misalignment between self and others activated brain areas such as the striatum and the posterior medial frontal cortex (pMFC). However, unlike most findings from previous studies, activation in the pMFC during the inconsistent social feedback negatively, rather than positively, predicted behavioral conformity. Notably, those with higher OXTR MPS had reduced pMFC activation in the face of social misalignment, which led to greater conformity. Our findings suggest that OT may promote conformity by dampening the conflict-related signals in the pMFC. They also show that OXTR MPS may be useful for studying the effect of genes on highly complex human social traits, such as conformity.

Sex-specific and social experience-dependent oxytocin-endocannabinoid interactions in the nucleus accumbens: implications for social behaviour

Oxytocin modulates social behaviour across diverse vertebrate taxa, but the precise nature of its effects varies across species, individuals and lifetimes. Contributing to this variation is the fact that oxytocin's physiological effects are mediated through interaction with diverse neuromodulatory systems and can depend on the specifics of the local circuits it acts on. Furthermore, those effects can be influenced by both genetics and experience. Here we discuss this complexity through the lens of a specific neuromodulatory system, endocannabinoids, interacting with oxytocin in the nucleus accumbens to modulate prosocial behaviours in prairie voles. We provide a survey of current knowledge of oxytocin-endocannabinoid interactions in relation to social behaviour. We review in detail recent research in monogamous female prairie voles demonstrating that social experience, such as mating and pair bonding, can change how oxytocin modulates nucleus accumbens glutamatergic signalling through the recruitment of endocannabinoids to modulate prosocial behaviour toward the partner. We then discuss potential sex differences in experience-dependent modulation of the nucleus accumbens by oxytocin in voles based on new data in males. Finally, we propose that future oxytocin-based precision medicine therapies should consider how prior social experience interacts with sex and genetics to influence oxytocin actions. This article is part of the theme issue 'Interplays between oxytocin and other neuromodulators in shaping complex social behaviours'.

Oxytocin: An Old Hormone, A Novel Psychotropic Drug And Possible Use In Treating Psychiatric Disorders

BACKGROUND

Oxytocin is a nonapeptide synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Historically, this molecule has been involved as a key factor in the formation of infant attachment, maternal behavior and pair bonding and, more generally, in linking social signals with cognition, behaviors and reward. In the last decades, the whole oxytocin system has gained a growing interest as it was proposed to be implicated in etiopathogenesis of several neurodevelopmental and neuropsychiatric disorders.

METHODS

With the main goal of an in-depth understanding of the oxytocin role in the regulation of different functions and complex behaviors as well as its intriguing implications in different neuropsychiatric disorders, we performed a critical review of the current state of art. We carried out this work through PubMed database up to June 2021 with the search terms: 1) "oxytocin and neuropsychiatric disorders"; 2) "oxytocin and neurodevelopmental disorders"; 3) "oxytocin and anorexia"; 4) "oxytocin and eating disorders"; 5) "oxytocin and obsessive-compulsive disorder"; 6) "oxytocin and schizophrenia"; 7) "oxytocin and depression"; 8) "oxytocin and bipolar disorder"; 9) "oxytocin and psychosis"; 10) "oxytocin and anxiety"; 11) "oxytocin and personality disorder"; 12) "oxytocin and PTSD".

RESULTS

Biological, genetic, and epigenetic studies highlighted quality and quantity modifications in the expression of oxytocin peptide or in oxytocin receptor isoforms. These alterations would seem to be correlated with a higher risk of presenting several neuropsychiatric disorders belonging to different psychopathological spectra. Collaterally, the exogenous oxytocin administration has shown to ameliorate many neuropsychiatric clinical conditions.

CONCLUSION

Finally, we briefly analyzed the potential pharmacological use of oxytocin in patient with severe symptomatic SARS-CoV-2 infection due to its anti-inflammatory, anti-oxidative and immunoregulatory properties.

A randomized trial shows dose-frequency and genotype may determine the therapeutic efficacy of intranasal oxytocin

BACKGROUND

The neuropeptide oxytocin is proposed as a promising therapy for social dysfunction by modulating amygdala-mediated social-emotional behavior. Although clinical trials report some benefits of chronic treatment, it is unclear whether efficacy may be influenced by dose frequency or genotype.

METHODS

In a randomized, double-blind, placebo-controlled pharmaco-functional magnetic resonance imaging trial (150 male subjects), we investigated acute and different chronic (every day or on alternate days for 5 days) intranasal oxytocin (24 international units) effects and oxytocin receptor genotype-mediated treatment sensitivity on amygdala responses to face emotions. We also investigated similar effects on resting-state functional connectivity between the amygdala and prefrontal cortex.

RESULTS

A single dose of oxytocin-reduced amygdala responses to all face emotions but for threatening (fear and anger) and happy faces, this effect was abolished after daily doses for 5 days but maintained by doses given every other day. The latter dose regime also enhanced associated anxious-arousal attenuation for fear faces. Oxytocin effects on reducing amygdala responses to face emotions only occurred in AA homozygotes of rs53576 and A carriers of rs2254298. The effects of oxytocin on resting-state functional connectivity were not influenced by either dose-frequency or receptor genotype.

CONCLUSIONS

Infrequent chronic oxytocin administration may be therapeutically most efficient and its anxiolytic neural and behavioral actions are highly genotype-dependent in males.

Intranasal oxytocin administration impacts the acquisition and consolidation of trauma-associated memories: a double-blind randomized placebo-controlled experimental study in healthy women

Intrusive memories are a hallmark symptom of post-traumatic stress disorder (PTSD) and oxytocin has been implicated in the formation of intrusive memories. This study investigates how oxytocin influences the acquisition and consolidation of trauma-associated memories and whether these effects are influenced by individual neurobiological and genetic differences. In this randomized, double-blind, placebo-controlled study, 220 healthy women received either a single dose of intranasal 24IU oxytocin or a placebo before exposure to a trauma film paradigm that solicits intrusive memories. We used a "general random forest" machine learning approach to examine whether differences in the noradrenergic and hypothalamic-pituitary-adrenal axis activity, polygenic risk for psychiatric disorders, and genetic polymorphism of the oxytocin receptor influence the effect of oxytocin on the acquisition and consolidation of intrusive memories. Oxytocin induced significantly more intrusive memories than placebo did (t(188.33) = 2.12, p = 0.035, Cohen's d = 0.30, 95% CI 0.16-0.44). As hypothesized, we found that the effect of oxytocin on intrusive memories was influenced by biological covariates, such as salivary cortisol, heart rate variability, and PTSD polygenic risk scores. The five factors that were most relevant to the oxytocin effect on intrusive memories were included in a Poisson regression, which showed that, besides oxytocin administration, higher polygenic loadings for PTSD and major depressive disorder were directly associated with a higher number of reported intrusions after exposure to the trauma film stressor. These results suggest that intranasal oxytocin amplifies the acquisition and consolidation of intrusive memories and that this effect is modulated by neurobiological and genetic factors. Trial registration: NCT03031405.

Social partner cooperativeness influences brain oxytocin transcription in Trinidadian guppies (Poecilia reticulata)

For non-kin cooperation to be maintained, individuals need to respond adaptively to the cooperative behaviour of their social partners. Currently, however, little is known about the biological responses of individuals to experiencing cooperation. Here, we quantify the neuroregulatory response of Trinidadian guppies (Poecilia reticulata) experiencing cooperation or defection by examining the transcriptional response of the oxytocin gene (oxt; also known as isotocin), which has been implicated in cooperative decision-making. We exposed wild-caught females to social environments where partners either cooperated or defected during predator inspection, or to a control (non-predator inspection) context, and quantified the relative transcription of the oxt gene. We tested an experimental group, originating from a site where individuals are under high predation threat and have previous experience of large aquatic predators (HP), and a control group, where individuals are under low predation threat and naïve to large aquatic predators (LP). LP, but not HP, fish showed different behavioural responses to the behaviour of their social environment, cooperating with cooperative partners and defecting when paired with defecting ones. In HP, but not LP, fish brain mid-section oxt relative transcription varied depending on social partner behaviour. HP fish experiencing cooperation during predator inspection had lower oxt transcription than those experiencing defection. This effect was not present in the control population or in the control context, where the behaviour of social partners did not affect oxt transcription. Our findings provide insight into the neuromodulation underpinning behavioural responses to social experiences, and ultimately to the proximate mechanisms underlying social decision-making.

Intranasal oxytocin administration but not peripheral oxytocin regulates behaviors of attachment insecurity: A meta-analysis

In light of the roles of oxytocin (OT) in social bonding and interpersonal relationship, studies have examined the roles of OT in human attachment, but by and large previous findings are inconsistent. Here, we conducted - meta-analyses to estimate the associations between peripheral OT level (e.g., blood and salivary OT) and attachment (i.e., attachment dimensions and behaviors of attachment insecurity) and examine the effects of intranasal OT administration on behaviors of attachment insecurity. The analyses indicated that: (1) Peripheral OT level was not significantly associated with attachment dimensions (e.g., attachment anxiety and attachment avoidance) and behaviors of attachment insecurity; (2) intranasal OT administration significantly reduced behaviors of attachment insecurity of neutral contexts, particularly behaviors of attachment avoidance. The findings suggest that intranasal OT administration is an available approach for reducing behaviors of attachment insecurity of interpersonal situations with ambiguous social cues, which implicates suggestions for therapeutic treatments of attachment-related dysfunctions.

The Comprehensive Neural Mechanism of Oxytocin in Analgesia

Oxytocin (OXT) is a nine amino acid neuropeptide hormone that has become one of the most intensively studied molecules in the past few decades. The vast majority of OXT is synthesized in the periventricular nucleus and supraoptic nucleus of the hypothalamus, and a few are synthesized in some peripheral organs (such as the uterus, ovaries, adrenal glands, thymus, pancreas, etc.) OXT modulates a series of physiological processes, including lactation, parturition, as well as some social behaviors. In addition, more and more attention has recently been focused on the analgesic effects of oxytocin. It has been reported that OXT can relieve tension and pain without other adverse effects. However, the critical role and detailed mechanism of OXT in analgesia remain unclear. This review aims to summarize the mechanism of OXT in analgesia and some ideas about the mechanism.

Randomized clinical trial shows no substantial modulation of empathy-related neural activation by intranasal oxytocin in autism

Evidence suggests that intranasal application of oxytocin facilitates empathy and modulates its underlying neural processes, which are often impaired in individuals with autism spectrum disorders (ASD). Oxytocin has therefore been considered a promising candidate for the treatment of social difficulties in ASD. However, evidence linking oxytocin treatment to social behavior and brain function in ASD is limited and heterogeneous effects might depend on variations in the oxytocin-receptor gene (OXTR). We examined 25 male ASD patients without intellectual disability in a double-blind, cross-over, placebo-controlled fMRI-protocol, in which a single dose of oxytocin or placebo was applied intranasally. Patients performed three experiments in the MRI examining empathy for other's physical pain, basic emotions, and social pain. All participants were genotyped for the rs53576 single-nucleotide polymorphism of the OXTR. Oxytocin increased bilateral amygdala responsiveness during the physical pain task for both painful and neutral stimuli. Other than that, there were no effects of oxytocin treatment. OXTR genotype did not significantly interact with oxytocin treatment. Our results contribute to the growing body of empirical literature suggesting heterogenous effects of oxytocin administration in ASD. To draw clinically relevant conclusions regarding the usefulness of oxytocin treatment, however, empirical studies need to consider methods of delivery, dose, and moderating individual factors more carefully in larger samples.

The role of oxytocin signaling in depression and suicidality in returning war veterans

Many war veterans struggle with depression and suicidality, and separation from the military is a time of particularly high risk. Based on research in non-human animals, we hypothesized that reduced oxytocin signaling would mediate symptoms of depression and suicidality in war veterans recently separated from their close comrades. We also hypothesized that veterans with more frequent contact with comrades would have fewer symptoms of depression and suicidality. In this cross-sectional study, male veterans from the Iraq and Afghanistan wars (n = 86) provided blood and urine samples for measurement of peripheral oxytocin (OT) levels, as well as saliva samples for DNA extraction followed by genotyping of oxytocin receptor gene (OXTR) Single Nucleotide Polymorphisms, and CpG-methylation assessment. Participants also completed a series of mental health questionnaires and interviews. Veterans reported feeling very close to their comrades during war, and missing them greatly upon returning home. Neither peripheral OT levels nor OXTR genotypes were related to symptoms of depression or suicidality. On the other hand, methylation at OXTR CpG -924 was negatively correlated with depressive symptomology, after controlling for possible confounds. Veterans who socialized with comrades more frequently had higher levels of urinary, but not plasma OT, as well as less depressive symptomology. Social connectedness was a strong negative predictor of symptoms of both depression and suicidality, eclipsing the predictive power of other variables such as post-deployment social support, the degree to which participants reported missing their comrades, and the frequency with which they socialized with comrades. Our results suggest that veteran mental health is more impacted by lack of social connectedness than by separation from close comrades per se. While there is some evidence that OXTR methylation relates to depressive symptomology, decreased OT signaling does not appear to mediate the relationship between social disconnectedness and depression or suicidality. Sleep quality and anxiety disorders were also significantly associated with mental health symptoms, independent of social connectedness. Our findings suggest that efforts aimed at alleviating the burden of depression and suicidality in returning war veterans should focus on re-integrating veterans into society and establishing a feeling of social connectedness, as well as on treating anxiety disorders and sleep problems.

Heterogeneity in response to repeated intranasal oxytocin in schizophrenia and autism spectrum disorders: A meta-analysis of variance

Intranasal oxytocin (OT) has been suggested as a putative adjunctive treatment for patients with schizophrenia and autism spectrum disorders (ASD). Here, we examine available evidence from trials investigating the effects of repeated administrations of intranasal OT on the core symptoms of patients with schizophrenia and ASD, focusing on its therapeutic efficacy and heterogeneity of response (meta-ANOVA). Repeated administration of intranasal OT does not improve most of the core symptoms of schizophrenia and ASD, beyond a small tentative effect on schizophrenia general symptoms. However, we found significant moderator effects for dose in schizophrenia total psychopathology and positive symptoms, and percentage of included men and duration of treatment in schizophrenia general symptoms. We found evidence of heterogeneity (increased variance) in the response of schizophrenia negative symptoms to intranasal OT compared with placebo, suggesting that subgroups of responsive and non-responsive patients might coexist. For other core symptoms of schizophrenia, or any of the core symptom dimensions in ASD, the response to repeated treatment with intranasal OT did not show evidence of heterogeneity.

Neurobiobehavioral responses to virtual social rejection in females-exploring the influence of oxytocin

In recent years, especially adolescents and young adults interact frequently via social media and digital communication. Mimicking an online communication platform where participants could initiate short conversations with two computerized interlocutors, the Verbal Interaction Social Threat Task (VISTTA) was used to induce feelings of social rejection. Motivational and physiological reactions were investigated in 43 healthy young women undergoing functional magnetic resonance imaging (fMRI), of which 22 received 24 international units (IU) intranasal oxytocin and 21 received placebo. Replicating previous findings, social rejection entailed a lower willingness to cooperate with the two peers. Increased activation in the anterior cingulate cortex and bilateral insula/inferior frontal gyrus was observed when receiving negative feedback from others, and in the precuneus when subsequently rating one's willingness to cooperate with them in the future. Oxytocin did not seem to alter responses to social rejection. The current findings provide validation of the VISTTA for examining consequences of rejection in a virtual social interaction that bears a strong resemblance to online communication platforms.

Chronic oxytocin administration in older men modulates functional connectivity during animacy perception

While aging is associated with social-cognitive change and oxytocin plays a crucial role in social cognition, oxytocin's effects on the social brain in older age remain understudied. To date, no study has examined the effects of chronic intranasal oxytocin administration on brain mechanisms underlying animacy perception in older adults. Using a placebo-controlled, randomized, double-blinded design in generally healthy older men (mean age (SD) = 69(6); n = 17 oxytocin; n = 14 placebo), this study determined the effects of a four-week intranasal oxytocin administration (24 international units/twice a day) on functional MRI (fMRI) during the Heider-Simmel task. This passive-viewing animacy perception paradigm contains video-clips of simple shapes suggesting social interactions (SOCIAL condition) or exhibiting random trajectories (RANDOM condition). While there were no oxytocin-specific effects on brain fMRI activation during the SOCIAL compared to the RANDOM condition, pre-to-post intervention change in the SOCIAL-RANDOM difference in functional connectivity (FC) was higher in the oxytocin compared to the placebo group in a network covering occipital, temporal, and parietal areas, and the superior temporal sulcus, a key structure in animacy perception. These findings suggest oxytocin modulation of circuits involved in action observation and social perception. Follow-up analyses on this network's connections suggested a pre-to-post intervention decrease in the SOCIAL-RANDOM difference in FC among the placebo group, possibly reflecting habituation to repeated exposure to social cues. Chronic oxytocin appeared to counter this process by decreasing FC during the RANDOM and increasing it during the SOCIAL condition. This study advances knowledge about oxytocin intervention mechanisms in the social brain of older adults.

No association between genetic variants in MAOA, OXTR, and AVPR1a and cooperative strategies

The effort to understand the genetic basis of human sociality has been encouraged by the diversity and heritability of social traits like cooperation. This task has remained elusive largely because most studies of sociality and genetics use sample sizes that are often unable to detect the small effects that single genes may have on complex social behaviors. The lack of robust findings could also be a consequence of a poor characterization of social phenotypes. Here, we explore the latter possibility by testing whether refining measures of cooperative phenotypes can increase the replication of previously reported associations between genetic variants and cooperation in small samples. Unlike most previous studies of sociality and genetics, we characterize cooperative phenotypes based on strategies rather than actions. Measuring strategies help differentiate between similar actions with different underlaying social motivations while controlling for expectations and learning. In an admixed Latino sample (n = 188), we tested whether cooperative strategies were associated with three genetic variants thought to influence sociality in humans—MAOA-uVNTR, OXTR rs53576, and AVPR1 RS3. We found no association between cooperative strategies and any of the candidate genetic variants. Since we were unable to replicate previous observations our results suggest that refining measurements of cooperative phenotypes as strategies is not enough to overcome the inherent statistical power problem of candidate gene studies.

Lack of association of common polymorphisms linked to empathic behavior with self-reported trait empathy in healthy volunteers

BACKGROUND

In a previously specified sample of 421 healthy subjects, we found associations of a common oxytocin receptor (OXTR) polymorphism with self-reported trait empathy. In this study, we used this sample to explore polymorphisms in other genes which have been frequently linked to empathic behavior for associations with self-reported trait empathy: CD38 (CD38), involved in oxytocin secretion, the serotonin transporter (SLC6A4), the Catechol-O-Methyltransferase (COMT) and the corticotropin releasing hormone receptor 1 (CRHR1).

METHODS

We genotyped our sample for the following common polymorphisms: rs3796863 in the CD38 gene, 5-HTTLPR in the SLC6A4 gene, rs4680 in the COMT gene and rs242924 in the CRHR1 gene. Dispositional empathy was tested using Davis' Interpersonal Reactivity Index (IRI). We used a Bonferroni corrected alpha level of p = 0.002 to adjust for multiple comparisons.

RESULTS

None of the genotypes were associated with any of the IRI scales for the complete sample (n = 421) or for the sub-groups of male (n = 213) and female (n = 190) participants. Our sample of 421 participants achieved 95% power to detect effects greater than r = ±0.18. For smaller effects, however, false negatives could not be rejected with equal confidence as false positives.

CONCLUSIONS

We conclude that an association between the four polymorphisms with trait empathy measured by the IRI may not be present. We propose that the associations that have been found in other studies can be largely explained by differences in empathy-related constructs and measurements.

Intranasal oxytocin modulates brain responses to voice-identity recognition in typically developing individuals, but not in ASD

Faces and voices are prominent cues for person-identity recognition. Face recognition behavior and associated brain responses can be enhanced by intranasal administration of oxytocin. It is unknown whether oxytocin can also augment voice-identity recognition mechanisms. To find it out is particularly relevant for individuals who have difficulties recognizing voice identity such as individuals diagnosed with autism spectrum disorder (ASD). We conducted a combined behavioral and functional magnetic resonance imaging (fMRI) study to investigate voice-identity recognition following intranasal administration of oxytocin or placebo in a group of adults diagnosed with ASD (full-scale intelligence quotient > 85) and pairwise-matched typically developing (TD) controls. A single dose of 24 IU oxytocin was administered in a randomized, double-blind, placebo-controlled and cross-over design. In the control group, but not in the ASD group, administration of oxytocin compared to placebo increased responses to recognition of voice identity in contrast to speech in the right posterior superior temporal sulcus/gyrus (pSTS/G) - a region implicated in the perceptual analysis of voice-identity information. In the ASD group, the right pSTS/G responses were positively correlated with voice-identity recognition accuracy in the oxytocin condition, but not in the placebo condition. Oxytocin did not improve voice-identity recognition performance at the group level. The ASD compared to the control group had lower right pSTS/G responses to voice-identity recognition. Since ASD is known to have atypical pSTS/G, the results indicate that the potential of intranasal oxytocin to enhance mechanisms for voice-identity recognition might be variable and dependent on the functional integrity of this brain region.

Kinetics of oxytocin effects on amygdala and striatal reactivity vary between women and men

Accumulating evidence suggests that intranasal oxytocin (OXT; 24 IU) reduces amygdala responses to fear-related stimuli in men, while exerting inverse effects in women. However, OXT enhances activity of the brain reward system in both sexes. Importantly, a crucial and still open question is whether there are sex-specific dose-response relationships for the amygdala and striatal regions. To address this question, a total of 90 healthy women participated in a double-blind, placebo-controlled crossover functional magnetic resonance imaging (fMRI) study and the results were compared with our previous findings from men. Participants were randomly assigned to three doses of OXT (6 IU, 12 IU, and 24 IU) and completed an emotional face recognition task including fearful and happy faces of varying emotional intensities. Across doses, OXT enhanced amygdala reactivity to low fearful faces compared to placebo and increased responses to happy faces in the dorsal striatum in women. While treatment effects on amygdala reactivity were evident at each given dose, the OXT effect on striatal responses to social stimuli was more pronounced with higher doses, but this dose-dependent effect did not survive correction for multiple comparisons. Importantly, OXT effects on amygdala and striatal activation significantly differed between sexes and striatal baseline sexual-dimorphic response patterns were diminished after administration of OXT. Our findings suggest that OXT increases the salience of social signals by strengthening the sensitivity for these signals in the amygdala and in the striatum in women, while OXT may primarily induce anxiolysis by reducing amygdala responses in men.

A Novel Role of CD38 and Oxytocin as Tandem Molecular Moderators of Human Social Behavior

Oxytocin is an important modulator of human affiliative behaviors, including social skills, human pair bonding, and friendship. CD38 will be discussed as an immune marker and then in more detail the mechanisms of CD38 on releasing brain oxytocin. Mention is made of the paralogue of oxytocin, vasopressin, that has often overlapping and complementary functions with oxytocin on social behavior. Curiously, vasopressin does not require CD38 to be released from the brain. This review discusses the social salience hypothesis of oxytocin action, a novel view of how this molecule influences much of human social behaviors often in contradictory ways. The oxytocinergic-vasopressinergic systems are crucial modulators of broad aspects of human personality. Of special interest are studies of these two hormones in trust related behavior observed using behavioral economic games. This review also covers the role of oxytocin in parenting and parental attachment. In conclusion, the effects of oxytocin on human behavior depend on the individual's social context and importantly as well, the individual's cultural milieu, viz. East and West. ACRONYMS: ACC = Anterior Cingulate ADP = Adenosine diphosphate AQ = Autism Quotient cADPR = Cyclic ADP-ribose CNS = Central nervous system DA = Dopamine eQTLC = Expression Quantitative Trait Loci LC-NE = Locus Coeruleus-Norepinephrine MRI = Magnetic Resonance Imaging OFC = Orbitofrontal cortices OXT = Oxytocin RAGE = Receptor for advanced glycation end-products SARM1 = Sterile Alpha and toll/interleukin-1 receptor motif-containing 1 TRPM2= Transient Receptor Potential Cation Channel Subfamily M Member 2 AVP = Vasopressin.

Imaging-genetics of sex differences in ASD: distinct effects of OXTR variants on brain connectivity

Autism spectrum disorder (ASD) is more prevalent in males than in females, but the neurobiological mechanisms that give rise to this sex-bias are poorly understood. The female protective hypothesis suggests that the manifestation of ASD in females requires higher cumulative genetic and environmental risk relative to males. Here, we test this hypothesis by assessing the additive impact of several ASD-associated OXTR variants on reward network resting-state functional connectivity in males and females with and without ASD, and explore how genotype, sex, and diagnosis relate to heterogeneity in neuroendophenotypes. Females with ASD who carried a greater number of ASD-associated risk alleles in the OXTR gene showed greater functional connectivity between the nucleus accumbens (NAcc; hub of the reward network) and subcortical brain areas important for motor learning. Relative to males with ASD, females with ASD and higher OXTR risk-allele-dosage showed increased connectivity between the NAcc, subcortical regions, and prefrontal brain areas involved in mentalizing. This increased connectivity between NAcc and prefrontal cortex mirrored the relationship between genetic risk and brain connectivity observed in neurotypical males showing that, under increased OXTR genetic risk load, females with ASD and neurotypical males displayed increased connectivity between reward-related brain regions and prefrontal cortex. These results indicate that females with ASD differentially modulate the effects of increased genetic risk on brain connectivity relative to males with ASD, providing new insights into the neurobiological mechanisms through which the female protective effect may manifest.

The role of oxytocin on self-serving lying

INTRODUCTION

The effects of intranasal administration of the neuropeptide oxytocin on social cognition and behavior are highly specific. Potentially situational and personal variables influence these effects. The aim of the present study was to investigate effects of oxytocin administration on self-serving lying, including situational effects.

METHODS

A total of 161 adult males participated in a randomized double-blind placebo-controlled between-subject intranasal oxytocin administration (24 international units) study. Self-serving lying was assessed using three subsequent rounds of the die-in-a-cup paradigm, in which different degrees of lying can be implemented by the participants that can be determined on group level.

RESULTS

Oxytocin administration seemed to promote self-serving lying, particularly in the third (last) round and only to a certain degree (not to the maximum possible).

CONCLUSIONS

Our findings demonstrate that oxytocin administration can promote self-serving lying when given repeated opportunities to lie. Moreover, exploratory results presented in the Supplementary Material indicate that the sensitivity to the effects of intranasal oxytocin in this domain might be moderated by individual differences in the oxytocin receptor gene.

Oxytocin modulation of self-referential processing is partly replicable and sensitive to oxytocin receptor genotype

Intranasal oxytocin (OXT) has been associated with effects on diverse social-emotional domains in humans, however progress towards a therapeutic application of OXT in disorders with social-emotion impairments is currently hampered by poor replicability. Limited statistical power and individual differences in biological factors, such as oxytocin receptor (OXTR) genetics, may have contributed to these variable findings. To this end, employing a validated oxytocin-sensitive trait judgment paradigm, we present a pharmaco-genetic study aiming at (1) replicating previous findings suggesting that intranasal oxytocin (24 IU) reduces the self-referential bias in a large sample of n = 170 male subjects, (2) determining whether variations in common receptor polymorphisms (rs237887, rs2268491, rs2254298, rs53576, rs2268498) influence sensitivity to oxytocin's behavioral effects. We confirmed that in the whole sample oxytocin influenced self-other distinction in terms of reduced decision time. However, oxytocin only influenced decision time in rs53576 G carriers, whereas effects on subsequent memory performance were only found in rs2268498 TT homozygotes. In summary, the current study partially replicates our previous findings showing that oxytocin reduces the self-referential bias and suggests that sensitivity to its effects in this domain are receptor genotype dependent.

Oxytocin receptor gene polymorphisms moderate the relationship between job stress and general trust in Chinese Han university teachers

BACKGROUND

Chronic exposure to stressful work environments can influence general trust. High job stress is associated with low trust in others. Both environmental and genetic factors contribute to general trust; however, few empirical studies have explored the important role of gene-environment interactions on general trust. In this study, the moderating roles of the polymorphisms OXTR rs53576 and OXTR rs2268490 in the relationship between job stress and general trust were evaluated.

METHODS

362 healthy Chinese Han university teachers (196 males, 165 females, and 1 undisclosed) were included (M_age = 39.80, SD = 9.16). Standardized questionnaires about demographic characteristics, job stress, and general trust scale were collected. Blood samples were collected for OXTR rs53576 and rs2268490 genotyping.

RESULTS

Job stress scores showed a significant negative main effect on general trust (p < 0.001), while OXTR rs53576 and rs2268490 did not (p > 0.05). The effect of the interaction between job stress and OXTR rs53576 or rs2268490 on general trust was significant, even after controlling for gender and age. High job stress was associated with low general trust in OXTR rs53576 homozygous individuals (GG/AA) or OXTR rs2268490 CT individuals, demonstrating that the GA genotype in OXTR rs53576 and CC/TT genotype in OXTR rs2268490 are protective genotype of general trust.

LIMITATIONS

This study used a cross-sectional design, only considered Chinese Han university teachers, and only examined two polymorphisms in OXTR.

CONCLUSIONS

Our findings provide evidence that gene-environment interactions influence general trust and identify a new locus (rs2268490) underlying this phenotype.

Reduced DNA Methylation of the Oxytocin Receptor Gene Is Associated With Anhedonia-Asociality in Women With Recent-Onset Schizophrenia and Ultra-high Risk for Psychosis

Negative symptoms are recognized as a fundamental feature of schizophrenia throughout the disease course. Epigenetic alterations in the oxytocin receptor gene (OXTR) may be a key mechanism involved in social-emotional disturbances of schizophrenia. Here, we investigated OXTR methylation and its association with clinical and brain network connectivity phenotypes of negative symptoms, particularly anhedonia-asociality, in individuals with recent-onset schizophrenia (ROS) and at ultrahigh risk (UHR) for psychosis. Sixty-four ROS (39 women), 46 UHR (19 women), and 98 healthy individuals (52 women) participated in this study. OXTR methylation was quantified using the pyrosequencing method. A subset of participants (16 ROS, 23 UHR, and 33 healthy controls [HCs]) underwent a 5.5-minute resting-state functional magnetic resonance imaging to determine the relationship between OXTR methylation and the striatal-amygdala network functional connectivity (FC) underlying anhedonia-asociality. Both men and women with ROS and UHR showed significantly decreased OXTR methylation compared to HCs. In women with ROS and UHR, decreased OXTR methylation showed a significant correlation with increased anhedonia-asociality. FC of the striatal-amygdala network, positively associated with the severity of anhedonia-asociality, showed an inverse correlation with OXTR methylation. This study suggests that epigenetic alterations of OXTR, which can be detected before the development of full-blown psychosis, confer susceptibility to schizophrenia and play a crucial role in the manifestation of anhedonia-asociality, particularly in women.

Cumulative Risk of the Oxytocin Receptor Gene Interacts with Prenatal Exposure to Oxytocin Receptor Antagonist to Predict Children's Social Communication Development

Compelling evidence for the far-reaching role of oxytocin (OT) in social cognition and affiliative behaviors set the basis for examining the association between genetic variation in the OT receptor (OXTR) gene and risk for autism spectrum disorder (ASD). In the current study, gene-environment interaction between OXTR and prenatal exposure to either OT or OXTR antagonist (OXTRA) in predicting early social communication development was examined. One hundred and fifty-three children (age: M = 4.32, SD = 1.07) were assigned to four groups based on prenatal history: children whose mothers prenatally received OXTRA and Nifedipine to delay preterm labor (n = 27); children whose mothers received Nifedipine only to delay preterm labor (n = 35); children whose mothers received OT for labor augmentation (n = 56), and a no intervention group (n = 35). Participants completed a developmental assessment of intelligence quotient (IQ), adaptive behavior, and social communication abilities. DNA was extracted via buccal swab. A genetic risk score was calculated based on four OXTR single nucleotide polymorphisms (rs53576, rs237887, rs1042778, and rs2254298) previously reported to be associated with ASD symptomatology. OXTRrisk-allele dosage was associated with more severe autism diagnostics observation schedule (ADOS) scores only in the OXTRA group. In contrast, in the Nifedipine, OT, and no intervention groups, OXTRrisk-allele dosage was not associated with children's ADOS scores. These findings highlight the importance of both genetic and environmental pathways of OT in signaling early social development and raise the need for further research in this field. Autism Res 2019, 12: 1087-1100. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: In the current study, we examined if the association between prenatal exposure to an oxytocin receptor antagonist (OXTRA) and autism spectrum disorder (ASD) related impairments are dependent on an individual's genetic background for the oxytocin receptor gene (OXTR). Children who carried a greater number of risk alleles for the OXTR gene and whose mothers received OXTRA to delay preterm labor showed more ASD-related impairments. The results highlight the importance of both genetic and environmental pathways of oxytocin in shaping early social development.

Mixed support for a causal link between single dose intranasal oxytocin and spiritual experiences: opposing effects depending on individual proclivities for absorption

Intranasal oxytocin (OT) has previously been found to increase spirituality, an effect moderated by OT-related genotypes. This pre-registered study sought to conceptually replicate and extend those findings. Using a single dose of intranasal OT vs placebo (PL), we investigated experimental treatment effects, and moderation by OT-related genotypes on spirituality, mystical experiences, and the sensed presence of a sentient being. A more exploratory aim was to test for interactions between treatment and the personality disposition absorption on these spirituality-related outcomes. A priming plus sensory deprivation procedure that has facilitated spiritual experiences in previous studies was used. The sample (N = 116) contained both sexes and was drawn from a relatively secular context. Results failed to conceptually replicate both the main effects of treatment and the treatment by genotype interactions on spirituality. Similarly, there were no such effects on mystical experiences or sensed presence. However, the data suggested an interaction between treatment and absorption. Relative to PL, OT seemed to enhance spiritual experiences in participants scoring low in absorption and dampen spirituality in participants scoring high in absorption.

Affective Language, Interpretation Bias and Its Molecular Genetic Variations: Exploring the Relationship Between Genetic Variations of the OXTR Gene (rs53576 and rs2268498) and the Emotional Evaluation of Words Related to the Self or the Other

Several studies have demonstrated links between oxytocin and socio-emotional information processing. Regarding the frequently studied single nucleotide polymorphism (SNP) rs53576 and the less studied, functional polymorphism rs2268498 of the oxytocin receptor (OXTR) gene, previous research suggested that their variants might be associated with different proficiency in the processing of social information. Differences between the genotype variants are not restricted to non-verbal stimulus processing but have also been reported in the verbal domain. Moreover, there is evidence that oxytocin expression influences empathic communication and language development during childhood, indicating that language-based theory-of-mind abilities may be affected by interindividual differences in OXTR genotypes as well. The present study therefore investigates whether two prominent SNPs of the OXTR gene (rs53576 GG vs. A+; rs2268498 TT vs. C+) also play a role in the affective evaluation of verbal stimuli varying in emotional valence and in self-other reference. Participants (N = 149 Caucasian participants, 104 females; A+: n = 80, GG: n = 69; C+: n = 98, TT: n = 51) were presented a series of written, self-, other-, and unreferenced words of positive, negative, and neutral valence and asked to affectively evaluate each word pair as positive, negative, or neutral by button press. In line with previous research, reaction times and accuracy (number of valence-congruent responses) showed a self-positivity bias (i.e., preferential processing of self-related positive words), which, however, was unaffected by participants' genotype. Regarding affective evaluation of neutral words (interpretation bias), A+ carriers displayed a weaker positive interpretation bias compared to GG carriers in the other- and unreferenced stimulus categories. C+ carriers showed a weaker positive interpretation bias than TT carriers in the self-reference condition and in the other-reference condition. These effects were independent from participants' gender. The present results suggest that the OXTR genotype and hence participants' genetic oxytocin sensitivity may cause an interpretation bias in the spontaneous appraisal of neutral words.

Genetic and epigenetic regulatory mechanisms of the oxytocin receptor gene (OXTR) and the (clinical) implications for social behavior

Oxytocin and the oxytocin receptor (OXTR) play an important role in a large variety of social behaviors. The oxytocinergic system interacts with environmental cues and is highly dependent on interindividual factors. Deficits in this system have been linked to mental disorders associated with social impairments, such as autism spectrum disorder (ASD). This review focuses on the modulation of social behavior by alterations in two domains of the oxytocinergic system. We discuss genetic and epigenetic regulatory mechanisms and alterations in these mechanisms that were found to have clinical implications for ASD. We propose possible explanations how these alterations affect the biological pathways underlying the aberrant social behavior and point out avenues for future research. We advocate the need for integration studies that combine multiple measures covering a broad range of social behaviors and link these to genetic and epigenetic profiles.

Sex-dependent regulation of social reward by oxytocin: an inverted U hypothesis

The rewarding properties of social interactions are essential for the expression of social behavior and the development of adaptive social relationships. Here, we review sex differences in social reward, and more specifically, how oxytocin (OT) acts in the mesolimbic dopamine system (MDS) to mediate the rewarding properties of social interactions in a sex-dependent manner. Evidence from rodents and humans suggests that same-sex social interactions may be more rewarding in females than in males. We propose that there is an inverted U relationship between OT dose, social reward, and neural activity within structures of the MDS in both males and females, and that this dose-response relationship is initiated at lower doses in females than males. As a result, depending on the dose of OT administered, OT could reduce social reward in females, while enhancing it in males. Sex differences in the neural mechanisms regulating social reward may contribute to sex differences in the incidence of a large number of psychiatric and neurodevelopmental disorders. This review addresses the potential significance of a sex-dependent inverted U dose-response function for OT's effects on social reward and in the development of gender-specific therapies for these disorders.

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

Oxytocin plays an important role in the modulation of social behavior in both typical and atypical contexts. Also, the quality of early parental care sets the foundation for long-term psychosocial development. Here, we review studies that investigated how oxytocin receptor (OXTR) interacts with early parental care experiences to influence the development of psychiatric disorders. Using Pubmed, Scopus and PsycInfo databases, we utilized the keyword "OXTR" before subsequently searching for specific OXTR single nucleotide polymorphisms (SNPs), generating a list of 598 studies in total. The papers were catalogued in a database and filtered for gene-environment interaction, psychiatric disorders and involvement of parental care. In particular, rs53576 and rs2254298 were found to be significantly involved in gene-environment interactions that modulated risk for psychopathology and the following psychiatric disorders: disruptive behavior, depression, anxiety, eating disorder and borderline personality disorder. These results illustrate the importance of OXTR in mediating the impact of parental care on the emergence of psychopathology.

A Precision Medicine Approach to Oxytocin Trials

In this chapter, we introduce a new area of social pharmacology that encompasses the study of the role of neuromodulators in modulating a wide range of social behaviors and brain function, with the interplay of genetic and epigenetic factors. There are increasing evidences for the role of the neuropeptide oxytocin in modulating a wide range of social behaviors, in reducing anxiety, and in impacting the social brain network. Oxytocin also promotes social functions in patients with neuropsychiatric disorders, such as autism and reduces anxiety and fear in anxiety disorders. In this chapter, we will emphasize the importance of integrating basic research and clinical human research in determining optimal strategies for drug discoveries for social dysfunctions and anxiety disorders. We will highlight the significance of adopting a precision medicine approach to optimize targeted treatments with oxytocin in neuropsychiatry. Oxytocin effects on social behavior and brain function can vary from one individual to another based on external factors, such as heterogeneity in autism phenotype, childhood experiences, personality, attachment style, and oxytocin receptor polymorphisms. Hence, targeted therapies for subgroups of patients can help alleviating some of the core symptoms and lead to a better future for these patients and their families.

Effect of the interaction between oxytocin receptor gene polymorphism (rs53576) and stressful life events on aggression in Chinese Han adolescents

OBJECTIVES

Accumulating evidence suggests that stressful life events are associated with increased risk for aggressive behavior in adolescents; however, aggressive reactions to life stressors exhibit large individual differences. The present study sought to examine whether the interaction between a single nucleotide polymorphism (SNP [rs53576]) within the oxytocin receptor gene (OXTR) and stressful life events is related to aggression in Chinese Han adolescents.

METHODS

A total of 197 Chinese Han adolescents (14-17 years of age) were included in this study. Aggression was assessed using the 12-item short version of Buss and Perry Aggression Questionnaire. Stressful life events during the past 12 months were assessed using the Adolescent Self-Rating Life Events Checklist. Genomic DNA was extracted from saliva and buccal cells from each individual.

RESULTS

Multivariate analysis of variance yielded a significant interaction between OXTR rs53576 SNP and life stress (F = 2.449, p = 0.043, partial η2 = 0.051) and of sex × SNP × life stress (F = 3.144, p = 0.016, partial η2 = 0.064). High life stress during the past 12 months was associated with high levels of physical aggression and hostility in OXTR rs53576 homozygous AA adolescents but not in G-carrier adolescents. In boys, homozygous AA individuals in the high life stress group reported significantly higher levels of physical aggression than participants in the other three groups; the interaction, however, was not significant in girls.

CONCLUSIONS

This study, which analyzed a specific gene-environment interaction, demonstrated that AA OXTR rs53576 homozygosity may correlate with higher levels of aggression under high life stress conditions with a sample of healthy Chinese Han adolescents. These findings promote the etiological understanding of adolescent aggression, highlighting the complex effect of stressful life events on aggression, and adding evidence supporting the relationship between the oxytocin system and aggressive behavior in adolescents.

Epigenetic Modification of OXTR is Associated with Openness to Experience

Oxytocin is a neuropeptide known to influence social and cognitive processing across several mammalian species. There currently exists a mixed and controversial pattern of evidence that oxytocin pathway genes confer individual differences in social cognition and personality in humans. Inconsistencies across studies may in part be explained by the presence of intermediary, epigenetic, variables that exist between genotype and phenotype. This study was designed to investigate the association between epigenetic modification of the Oxytocin Receptor Gene (OXTR), via DNA methylation, and Big-5 personality traits. Genetic data were collected via saliva samples and analyzed to quantify DNA methylation within the promoter region of OXTR. The results indicate that Openness to Experience is associated with OXTR DNA methylation, while controlling for the remaining Big-5 personality dimensions (Neuroticism, Extraversion, Agreeableness, and Conscientiousness) and sex and age. This finding provides additional support for models associating oxytocin with individual differences in personality and identity in humans.

Intranasal Oxytocin Does Not Modulate Responses to Alcohol in Social Drinkers

BACKGROUND

Preclinical and clinical evidence suggest that the neuropeptide oxytocin may be of value in treating alcohol use disorder, by either reducing the rewarding effects of alcohol or reducing negative affect induced by alcohol withdrawal. However, the effect of a single dose of oxytocin on subjective and psychomotor responses to alcohol in social drinkers is not known.

METHODS

This study examined the effect of intranasal oxytocin on subjective, behavioral, and physiological responses to a moderate dose of alcohol (0.8 g/kg) in young adult social drinkers. Participants (N = 35) completed 2 study sessions at which they consumed beverages containing alcohol (ALC; N = 20) or placebo (NoALC; N = 15) in combination with intranasal oxytocin (40 IU with a 20 IU booster) or placebo. They received oxytocin at one session and placebo at the other session (order counterbalanced) 20 minutes before consuming beverages. Subjective mood and drug effects ratings, heart rate and blood pressure, and 4 behavioral tasks (flanker task, digit span, go/no-go, and pursuit rotor) were the primary outcome measures.

RESULTS

ALC produced its expected subjective and behavioral effects; including feeling intoxicated and impaired performance on the digit span and go/no-go tasks. Oxytocin alone had no significant subjective or physiological effects, and it did not affect responses to alcohol on any measure.

CONCLUSIONS

We can conclude that, under these conditions, a single dose of intranasal oxytocin does not alter the effects of acute alcohol in healthy young adult social drinkers. Further research is needed to determine whether oxytocin alters responses to alcohol under different conditions, and to determine its potential as an aid in treatment for substance use disorders.

Effects of Intranasal Oxytocin on Emotion Recognition in Korean Male: A Dose-Response Study

OBJECTIVE

Research has shown that intranasal oxytocin affects social cognition and behavior; however, its effects vary based on social context, individual characteristics and dose. The present study aimed to determine effective dose of oxytocin spray on emotion recognition in healthy Korean males.

METHODS

The study followed a randomized, double-blind, placebo-controlled design. Thirty-seven Korean males underwent two experimental sessions, with one week in between. They received either 32 (n=19) or 40 (n=18) international units (IU) of oxytocin and placebo, and then completed a face emotion recognition task. The effect of oxytocin on emotion recognition was examined using repeated measures analysis of variance (ANOVA) for each dose condition.

RESULTS

The higher dose (40 IU) was found to improve recognition of happy faces, while the lower dose (32 IU) had no effect. There were no statistical differences in age, education, attachment style or empathic ability between the two dose groups.

CONCLUSION

The results suggest that oxytocin increases the ability of Korean males to recognize positive emotion, and this effect is dose-dependent. Additional studies evaluating the effect of higher doses of oxytocin on social cognition will help to determine the optimal dose for Korean populations.

Oxytocin selectively modulates brain processing of disgust in Huntington's disease gene carriers

People with Huntington's disease (HD) exhibit altered processing of emotional information, especially disgust and other negative emotions. These impairments are likely due to the effects of the disease on underlying brain networks. We examined whether oxytocin, when given intranasally, would normalise aberrant brain reactivity to emotional faces in participants with the gene-expansion for HD. In a double-blind placebo-controlled cross-over design, we measured brain activity, using functional magnetic resonance imaging, whilst nine medication-free HD carriers, and ten control participants viewed emotional (disgust, fear, angry, sad, surprise, happy) and neutral faces, following acute intranasal oxytocin (24IU) and placebo. Subjective mood changes were assessed before and after the neuroimaging on each visit. Permutation-based non-parametric statistical testing for the whole brain, showed significant group×drug interactions (p's<0.05, TFCE corrected) in areas of the left frontal pole, superior frontal, and middle frontal gyri cortically, and left putamen and thalamus sub-cortically. Parameter estimates extracted from the middle frontal gyrus and putamen showed that, under placebo, the HD group had lower brain activity to disgust stimuli, compared with controls. After intranasal oxytocin, the pattern of activation to disgust stimuli was normalised in the HD group to similar levels as controls; eight of the nine HD carriers showed increased response in the middle frontal gyrus, and seven of the nine HD carriers showed increased response in the putamen. The observed effects of oxytocin occurred in the absence of changes in subjective mood or state anxiety. These findings provide early evidence for a physiological role of oxytocin in the neuropathology of HD. Our findings are the first reported oxytocin effects in a neurodegenerative disease. Further research should examine the therapeutic benefits of oxytocin in alleviating emotional and social cognition deficits in HD and related disorders.