Sex-Related Differences in Plasma Oxytocin Levels in Humans

An exploration of blood-based biomarkers of negative symptoms of psychosis in men

Negative symptoms in the context of psychosis are still poorly understood and diagnosed, which impairs the treatment efficacy of current therapies and patient's integration in society. In this study, we aimed to test hypothesis-based and exploratory associations of negative symptom domains, as defined by the Brief Negative Symptom Scale (BNSS), with hormonal and hematological variables, and, complementarily, with standard psychological/cognitive and psychopathological measures. Fifty-one male patients diagnosed with a psychotic disorder underwent a structured interview and blood collection. Standard Spearmen bivariate correlations were used for data analysis. We obtained evidence of hypothesis-based associations between specific negative symptoms and oxytocin, thyroid stimulating hormone levels and neutrophil-to-lymphocyte ratio; as well as novel and hypothesis-free associations with erythrocyte and lymphocyte count, mean corpuscular volume and red cell distribution width. Complementarily, we also obtained some validation of previous associations of negative symptoms with illness resolution, cognitive symptom severity and social performance, and a novel association with anger contagion. We hope our results can generate new hypotheses in psychosis research. Our work suggests further avenues in research on erythrocytic, inflammatory, thyroid and oxytocin-related markers and abnormalities in psychosis, especially in regards to specific negative symptoms, towards more precise and comprehensive etiological, diagnostic and therapeutic models.

Neuroimaging and behavioral evidence of sex-specific effects of oxytocin on human sociality

Although the social role of oxytocin came to light due to sex-specific interactions such as mother-offspring bonding, current understanding of sex differences in the effects of oxytocin on human sociality is limited because of the predominance of all-male samples. With the increasing inclusion of females in intranasal oxytocin research, it is now possible to explore such patterns. Neuroimaging studies reveal relatively consistent sex-differential effects of oxytocin on the activation of brain regions associated with processing social stimuli - particularly the amygdala. Findings from behavioral research are varied but suggest that oxytocin more often facilitates social cognition and positive social interactions in males, with context-dependent effects in each sex. We discuss potential biological and psychological mechanisms underlying the reported sex differences, and conclude with considerations for future research and clinical applications of oxytocin.

Neuropeptides affecting social behavior in mammals: Oxytocin

Oxytocin (OXT), a neuropeptide consisting of only nine amino acids, is synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Although OXT is best known for its role in lactation and parturition, recent research has shown that it also has a significant impact on social behaviors in mammals. However, a comprehensive review of this topic is still lacking. In this paper, we systematically reviewed the effects of OXT on social behavior in mammals. These effects of OXT from the perspective of five key behavioral dimensions were summarized: parental behavior, anxiety, aggression, attachment, and empathy. To date, researchers have agreed that OXT plays a positive regulatory role in a wide range of social behaviors, but there have been controversially reported results. In this review, we have provided a detailed panorama of the role of OXT in social behavior and, for the first time, delved into the underlying regulatory mechanisms, which may help better understand the multifaceted role of OXT. Levels of OXT in previous human studies were also summarized to provide insights for diagnosis of mental disorders.

An overview of the differences in the pharmacological management of post-traumatic stress disorder between women and men

INTRODUCTION

Post-traumatic stress disorder (PTSD) is a disabling psychiatric condition with a worldwide prevalence between 6% and 9%, and more common in the female than in the male sex. The aim of this paper is to review and comment on the different factors that might explain the discrepancies in the pharmacological management of women and men.

AREAS COVERED

The available literature shows that there exists a vulnerability of women to develop PTSD that may depend on neurobiological as well as environmental/cultural factors. These variables might influence the clinical picture, the outcome and the response to specific treatments, given their consequences on the pharmacokinetics of commonly prescribed drugs. Women suffering from PTSD are more prone to consult and receive more prescriptions of psychotropic drugs than men. However, it is evident that the particular stages of a women's life such as pregnancy or breastfeeding might require a specific evaluation and care.

EXPERT OPINION

It is necessary to explore the pharmacokinetics of compounds highlighting sex-related differences, and their safety during pregnancy and lactation. Taking care of differences between women and men should represent a main focus of research, while being a primary target towards a really tailored pharmacological treatment of PTSD.

Cumulative Genetic Scores Interact with Maternal and Paternal Parenting in Predicting Parent-Adolescent Cohesion and Conflict

Previous research concerning the interplay between genetics and parenting in the development of the parent-child relationship during adolescence has been extremely scarce, predominantly adopting single-gene designs. This limited body of work has largely overlooked the distinct effects of maternal and paternal roles, as well as potential gender differences. Additionally, existing gene-by-environment (G × E) studies have mainly concentrated on adverse environmental factors and associated negative outcomes, somewhat neglecting positive environments and outcomes. The present study examined the interactions of cumulative genetic scores (CGS, dopamine receptor D2 TaqIA and oxytocin receptor gene rs53576 polymorphisms) with both positive and negative parenting on parent-adolescent cohesion and conflict. Furthermore, this study aimed to ascertain with which gene-environment model the potential G × E interactions would align. A total of 745 Chinese Han adolescents (Mage = 13.36 ± 0.96 years; 46.8% girls) from grades 7 to 9 participated in this study. Results revealed a significant effect of CGS and negative maternal parenting on mother-adolescent conflict among males, consistent with the weak differential susceptibility model. As CGS increased, the effects of negative maternal parenting on mother-son conflict were magnified. These findings have implications for the timing and focus of interventions aimed at improving parent-adolescent relationships.

Main Biological Models of Resilience

Objective

Resilience is a complex process of adaptation to new conditions that would permit a positive outcome after adversities, traumas or other sources of stress. However, despite the growing interest in this topic, there is no universally accepted definition and no comprehensive bio-behavioural model. This systematic review aims to provide an overview of the main biological models that have been theorized to date, with a focus on new alternative theories to improve our understanding of the mechanisms underlying the development and strengthening of resilience, with potential implications for the prevention of some psychopathological disorders.

Method

This review was conducted according to PRISMA guidelines and includes 185 studies published in English in PubMed and Embase up to December 2023.

Results

Most studies use the stress-related model, which conceptualizes resilience as the absence of symptoms after the stressful event and mainly deal with the differences between stress-prone and resilient phenotypes in animals exposed to stress. However, the results of this search seem to suggest that resilience might be an independent construct with biological bases rooted in the stress system and the social brain, and widely sculptured by individual and environmental factors, especially early life events and affiliation.

Conclusions

This work contributes to ongoing efforts to understand the intricate mechanisms of resilience, while highlighting the potential of improving social relationships since our birth to promote coping strategies towards stress and traumas, and even a peaceful world.

Linking childhood trauma to the psychopathology of schizophrenia: the role of oxytocin

Childhood trauma has been linked to schizophrenia, but underlying biological mechanisms remain elusive. This study explored the potential role of plasma oxytocin as a mediator in the relationship between childhood trauma and the psychopathology of schizophrenia. 160 patients with schizophrenia and 80 age- and sex-matched healthy controls were assessed for childhood trauma experiences using the Childhood Trauma Questionnaire and structured interviews. Psychopathology was evaluated using the Positive and Negative Syndrome Scale and plasma oxytocin levels were measured. Results showed that patients with schizophrenia had lower oxytocin levels and higher childhood trauma scores than healthy controls. There was a significant correlation between childhood trauma scores and psychopathology, with plasma oxytocin levels being inversely associated with psychopathology, except for positive symptoms. Hierarchical regression analysis indicated that both childhood trauma scores and plasma oxytocin levels significantly predicted psychopathology. Plasma oxytocin levels partially mediated the relationship between childhood trauma and schizophrenia psychopathology. This study underscores the potential role of oxytocin in bridging the gap between childhood trauma and schizophrenia.

Sex differences in the rapid detection of neutral faces associated with emotional value

BACKGROUND

Rapid detection of faces with emotional meaning is essential for understanding the emotions of others, possibly promoting successful interpersonal relationships. Although few studies have examined sex differences in the ability to detect emotional faces, it remains unclear whether faces with emotional meaning capture the attention of females and males differently, because emotional faces have visual saliency that modulates visual attention. To overcome this issue, we tested the rapid detection of the neutral faces associated with and without learned emotional value, which are all regarded as free from visual saliency. We examined sex differences in the rapid detection of the neutral female and male faces associated with emotional value.

METHODS

First, young adult female and male participants completed an associative learning task in which neutral faces were associated with either monetary rewards, monetary punishments, or no monetary outcomes, such that the neutral faces acquired positive, negative, and no emotional value, respectively. Then, they engaged in a visual search task in which previously learned neutral faces were presented as discrepant faces among newly presented neutral distractor faces. During the visual search task, the participants were required to rapidly identify discrepant faces.

RESULTS

Female and male participants exhibited comparable learning abilities. The visual search results demonstrated that female participants achieved rapid detection of neutral faces associated with emotional value irrespective of the sex of the faces presented, whereas male participants showed this ability only for male faces.

CONCLUSIONS

Our results demonstrated that sex differences in the ability to rapidly detect neutral faces with emotional value were modulated by the sex of those faces. The results suggest greater sensitivity to faces with emotional significance in females, which might enrich interpersonal communication, regardless of sex.

A long and winding road: My personal journey to oxytocin with no return

The present paper is the personal narration of the author reviewing her scientific pathways that led her toward the study of oxytocin. My work began with a pioneering study showing a decreased number of the serotonin transporter proteins in romantic lovers. This unexpected finding promoted my interest in the neurobiology of human emotions and feelings, and significantly shifted my research focus from diseases to physiological states that underlie "love." During this time increasing experimental data broadened the spectrum of activities of oxytocin from female functions, such as parturition and lactation, to modulation of the stress and immune system. The literature also began to reveal an important role for oxytocin in a sense of safety and wellbeing, processes that are critical to both love and survival. I suggest here that future studies should disentangle different emerging questions regarding the exact role of oxytocin within human nature, as well as its possible therapeutic applications in different physiological conditions and pathological states. Understanding these, in turn, holds the potential to improve the lives of both individuals and societies.

Relationship between BDNF and oxytocin

Converging, albeit scattered data mainly gathered in animals indicate that the neurotrophin brain-derived neurotrophic factor (BDNF) and the nonapeptide oxytocin (OT) interact in a cooperative way. Data in humans are really limited and indirect. Therefore, the aim of the present study was to explore the possible existence of a link between OT and BDNF in humans, by means of two peripheral markers, the platelet-poor-plasmatic-BDNF (PPP-BDNF) and the platelet BDNF (PLT-BDNF) and OT levels. Twenty-six young healthy controls of both sexes who volunteered for the study were included in the study. Fifty ml of peripheral venous blood were drawn from one-night fasting subjects between 8.00 and 9.00 a.m. The BDNF and OT assays were carried out according to common methods. Comparisons for continuous variables were performed by the Student's t-test for variables that follow a normal distribution, and by the Wilcoxon-Mann-Whitney test for variables not normally distributed. The correlations between biological markers were explored by calculating the Pearson's correlation coefficient or Spearman's rank correlation. The results showed that PLT-BDNF (pg/mg proteins, mean ± SD) and PPP-BDNF (pg/ml, mean ± SD) were 1546 ± 1844 and 10111 ± 1892, respectively. The OT levels (pg/ml, mean ± SD) were 13.92 ± 4.54. The OT levels were significantly higher in women than in men. The Spearman's analysis revealed a statistically significant and negative correlation between OT levels and PLT-BDNF (R = -0.543, p = 0.004). The findings of this study highlight the presence of a significant and negative correlation between OT and PLT-BDNF in a small group of healthy controls of both sexes. In any case, despite all the limits of peripheral biomarkers, they suggest that this reciprocal influence might have a downstream homeostatic function dampening one activity when the other is activated or no longer necessary, maybe at the level of the stress and/or immune systems.

Novel Pharmacological Targets of Post-Traumatic Stress Disorders

Post-traumatic stress disorder (PTSD) is a psychopathological condition with a heterogeneous clinical picture that is complex and challenging to treat. Its multifaceted pathophysiology still remains an unresolved question and certainly contributes to this issue. The pharmacological treatment of PTSD is mainly empirical and centered on the serotonergic system. Since the therapeutic response to prescribed drugs targeting single symptoms is generally inconsistent, there is an urgent need for novel pathogenetic hypotheses, including different mediators and pathways. This paper was conceived as a narrative review with the aim of debating the current pharmacological treatment of PTSD and further highlighting prospective targets for future drugs. The authors accessed some of the main databases of scientific literature available and selected all the papers that fulfilled the purpose of the present work. The results showed that most of the current pharmacological treatments for PTSD are symptom-based and show only partial benefits; this largely reflects the limited knowledge of its neurobiology. Growing, albeit limited, data suggests that the hypothalamic-pituitary-adrenal axis, opioids, glutamate, cannabinoids, oxytocin, neuropeptide Y, and microRNA may play a role in the development of PTSD and could be targeted for novel treatments. Indeed, recent research indicates that examining different pathways might result in the development of novel and more efficient drugs.

Mentalization, Oxytocin, and Cortisol in the General Population

Although evidence suggests the role of oxytocin and cortisol in social cognition and emotion regulation, it is less known how their peripheral levels are related to social perception (biological motion detection) and mentalization (self-reflection, emotional awareness, and affect regulation) in the general population. We assessed 150 healthy individuals from the general community on a mentalization questionnaire, a scale measuring the intensity of positive and negative emotions, and measured oxytocin and cortisol levels in the saliva. Oxytocin but not cortisol level and biological motion detection predicted mentalization abilities. There was a positive correlation between mentalization and positive emotions and between mentalization and biological motion detection. These results suggest that oxytocin, but not cortisol, plays a role in low-level perceptual and self-reflective aspects of social cognition.

Effects of mesotocin manipulation on the behavior of male and female common waxbills

The oxytocin family of neuropeptides is implicated in the regulation of sociality across vertebrates. Non-mammalian homologs of oxytocin, such as isotocin in fish and mesotocin in amphibians, reptiles and birds, all play crucial roles modulating social and reproductive behavior. In this study, we exogenously manipulated the mesotocinergic system in a highly social bird, the common waxbill Estrild astrild, and tested the effects on affiliative and aggressive behavior by performing tests of competition over food. Birds treated with mesotocin showed a sedative state, decreasing almost all the behaviors we studied (movement, feeding, allopreening), while birds treated with an oxytocin antagonist showed a decrease only in social behaviors (aggressions and allopreening). We also found two sex-specific effects: mesotocin reduced allopreening more in males than females, and the oxytocin antagonist reduced aggressiveness only in females. Our results suggest sex-specific effects in the modulation of affiliative and aggressive behaviors via mesotocinergic pathways.

Adverse childhood experiences mediate the negative association between borderline personality disorder symptoms and plasma oxytocin

Background Interpersonal dysfunction is a core symptom of borderline personality disorder (BPD) and may be closely linked to adverse childhood experiences. According to a recent model on the pathology of BPD, the neuropeptide oxytocin might play an important role in the development and maintenance of the disorder. However, so far, only few studies with small adult samples have reported reduced baseline oxytocin levels in BPD that may be linked to adverse childhood experiences. Methods We examined baseline plasma oxytocin levels in 131 female patients with BPD and 124 non-BPD female controls across a large age span (12-50 years). Additionally, 113 female patients with less than five DSM-IV BPD features were included to examine the association between plasma oxytocin levels and the number of fulfilled BPD criteria. We also explored associations between plasma oxytocin and adverse childhood experiences as well as depressive symptoms in BPD. Results Patients with BPD had reduced plasma oxytocin levels compared to non-BPD controls and this was independent of age. Plasma oxytocin was negatively associated with the number of fulfilled BPD criteria. The exploratory regression model revealed no association between plasma oxytocin and depressive symptoms but an association between plasma oxytocin and adverse childhood experiences, which in fact mediated the relationship between BPD criteria und plasma oxytocin. Conclusion In a large sample of individuals with BPD across a large age span, our results replicate and extend previous reports of reduced plasma oxytocin levels that might be related to adverse childhood experiences thus providing further evidence for a prominent role of oxytocin in BPD.

Temporal profile of intranasal oxytocin in the human autonomic nervous system at rest: An electrocardiography and pupillometry study

BACKGROUND

Human social behavior is modulated by oxytocin (OT). Intranasal administration of OT (IN-OT) is a noninvasive route shown to elicit changes in the autonomic nervous system (ANS) activity; however, IN-OT's effect on the temporal profile of ANS activity at rest is yet to be described.

AIMS

We aimed to describe the temporal profile of IN-OT at six 10-min time windows from 15- to 100-min post-administration in 20 male participants at rest while continuously recording their pupillary in an eyes-open condition and cardiac activity in eyes-open and eyes-closed conditions.

METHODS

We used a double-blind, placebo-controlled, within-subjects design study where we extracted two proxies of parasympathetic nervous system (PNS) activity: high-frequency heart rate variability (HF-HRV) and pupillary unrest index (PUI); and a proxy of sympathetic nervous system activity: sample entropy of the pupillary unrest.

RESULTS

In the eyes-open condition, we found an effect of IN-OT on the proxies of PNS activity: decreased PUI in the three-time windows post-administration spanning 65-100 min, and as an exploratory finding, an increased HF-HRV in the 80-85 min time window.

CONCLUSIONS

We suggest there is a role of OT in PNS regulation that may be consistent with OT's currently theorized role in the facilitation of alertness and approach behavior.

Genetic and epigenetic signatures associated with plasma oxytocin levels in children and adolescents with autism spectrum disorder

Oxytocin (OT), the brain's most abundant neuropeptide, plays an important role in social salience and motivation. Clinical trials of the efficacy of OT in autism spectrum disorder (ASD) have reported mixed results due in part to ASD's complex etiology. We investigated whether genetic and epigenetic variation contribute to variable endogenous OT levels that modulate sensitivity to OT therapy. To carry out this analysis, we integrated genome-wide profiles of DNA-methylation, transcriptional activity, and genetic variation with plasma OT levels in 290 participants with ASD enrolled in a randomized controlled trial of OT. Our analysis identified genetic variants with novel association with plasma OT, several of which reside in known ASD risk genes. We also show subtle but statistically significant association of plasma OT levels with peripheral transcriptional activity and DNA-methylation profiles across several annotated gene sets. These findings broaden our understanding of the effects of the peripheral oxytocin system and provide novel genetic candidates for future studies to decode the complex etiology of ASD and its interaction with OT signaling and OT-based interventions. LAY SUMMARY: Oxytocin (OT) is an abundant chemical produced by neurons that plays an important role in social interaction and motivation. We investigated whether genetic and epigenetic factors contribute to variable OT levels in the blood. To this, we integrated genetic, gene expression, and non-DNA regulated (epigenetic) signatures with blood OT levels in 290 participants with autism enrolled in an OT clinical trial. We identified genetic association with plasma OT, several of which reside in known autism risk genes. We also show statistically significant association of plasma OT levels with gene expression and epigenetic across several gene pathways. These findings broaden our understanding of the factors that influence OT levels in the blood for future studies to decode the complex presentation of autism and its interaction with OT and OT-based treatment.

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.

The Association Between Peripheral Oxytocin Levels and Depressive Symptoms in People With HIV

OBJECTIVE

Depression is common in people with HIV (PWH), yet little is known about the mechanisms contributing to depressive symptoms in PWH. Previous research across a range of populations has suggested a relationship between the neuropeptide oxytocin and depressive symptoms, with variable directionality. This article investigated the association between peripheral oxytocin levels and depressive symptoms in PWH.

METHODS

Unextracted oxytocin serum concentrations were assayed in 79 PWH (44% female, mean age = 34.35 [8.5], mean body mass index = 25.69 [5.46], mean CD4 = 516.60 [271.15]) who also completed the Center for Epidemiologic Studies Depression Scale (CES-D). CES-D items were evaluated in an exploratory factor analysis (EFA), and the relationships between oxytocin, total CES-D score, and the resulting EFA factors were analyzed with multivariate linear regressions conducted in R. Multiple regression models were used to adjust for age, sex, body mass index, CD4, and education.

RESULTS

Contrary to hypothesized, higher peripheral oxytocin levels were associated with higher CES-D total scores with a small-to-moderate effect size ( β = 0.26, p = .009). Following Bonferroni correction, oxytocin was not significantly associated with any of the five factors identified from the EFA: depressed affect, positive affect, appetite, cognitive symptoms, or perceived failure ( p values > .042). Small effect sizes were found for the depressed affect ( β = 0.22) and perceived failure ( β = 0.21) factors ( p values > .042).

CONCLUSIONS

In a sample of predominately Black or African American individuals with HIV, higher oxytocin was associated with higher total depressive symptoms. In addition, this relationship was slightly stronger than those of specific depressive symptoms. These findings warrant further study into the role of oxytocin in mood symptoms within PWH.

Temporal Dynamics of Intranasal Oxytocin in Human Brain Electrophysiology

Oxytocin (OT) is a key modulator of human social cognition, popular in behavioral neuroscience. To adequately design and interpret intranasal OT (IN-OT) research, it is crucial to know for how long it affects human brain function once administered. However, this has been mostly deduced from peripheral body fluids studies, or uncommonly used dosages. We aimed to characterize IN-OT's effects on human brain function using resting-state EEG microstates across a typical experimental session duration. Nineteen healthy males participated in a double-blind, placebo-controlled, within-subject, cross-over design of 24 IU of IN-OT in 12-min windows 15 min-to-1 h 42min after administration. We observed IN-OT effects on all microstates, across the observation span. During eyes-closed, IN-OT increased duration and contribution of A and contribution and occurrence of D, decreased duration and contribution of B and C; and increased transition probability C-to-B and C-to-D. In eyes-open, it increased A-to-C and A-to-D. As microstates A and D have been related to phonological auditory and attentional networks, respectively, we posit IN-OT may tune the brain for reception of external stimuli, particularly of social nature-tentatively supporting current neurocognitive hypotheses of OT. Moreover, we contrast our overall results against a comprehensive literature review of IN-OT time-course effects in the brain, highlighting comparability issues.

Possible oxytocin-related biomarkers in anxiety and mood disorders

Anxiety and mood disorders are prevalent, disabling, and frequently difficult to treat. Such disorders are often comorbid and share similar characteristics. For more accurate diagnosis and improved treatment, a deeper understanding of the pathophysiology of anxiety and mood disorders is important. Oxytocin, a neuropeptide synthesized in the hypothalamus, affects human psychology and behaviors such as social and affiliative behaviors, fear and emotion processing, and stress regulation. Thus, oxytocin is believed to exert anxiolytic and antidepressant-like effects. This review article provides an overview of clinical studies on relationships between the oxytocin system and anxiety and mood disorders, focusing on oxytocin-related biomarker findings. Biomarkers used in such studies include central and peripheral oxytocin levels, analysis of oxytocin-related genes, and expression levels of oxytocin and oxytocin receptor genes in postmortem brains. Although a growing number of studies support the presence of oxytocinergic effects on anxiety and mood disorders, study results are heterogeneous and inconclusive. Moderating factors such as the characteristics of study populations, including sex, age, context, early life adversity, and attachment styles in patient cohorts, might affect the heterogeneity of the study results. Limitations in existing research such as small sample sizes, large dependence on peripheral sources of oxytocin, and inconsistent results between immunoassay methods complicate the interpretation of existing findings.

Decreased CSF oxytocin relates to measures of social cognitive impairment in Huntington's disease patients

OBJECTIVE

Huntington's disease (HD) is an inherited neurodegenerative disease with motor, cognitive and psychiatric symptoms. Non-motor symptoms like depression and altered social cognition are proposed to be caused by dysfunction of the hypothalamus. We measured the hypothalamic neuropeptide oxytocin in plasma and cerebrospinal fluid (CSF) in a cohort of HD gene expansion carriers (HDGECs), compared the levels to healthy HD family controls and correlated oxytocin levels to disease progression and social cognition.

METHODS

We recruited 113 HDGECs and 33 controls. Psychiatric and cognitive symptoms were evaluated, and social cognition was assessed with the Emotion Hexagon test, Reading the Mind in the Eyes and The Awareness of Social Inference Test. The levels of oxytocin in CSF and blood were analyzed by radioimmunoassay.

RESULTS

We found the level of oxytocin in CSF to be significantly lower by 33.5% in HDGECs compared to controls (p = 0.016). When dividing the HDGECs into groups with or without cognitive impairment, we found the oxytocin level to be significantly lower by 30.3% in the HDGECs with cognitive symptoms (p = 0.046). We found a statistically significant correlation between the level of oxytocin and scores on social cognition (Reading the Mind in the Eyes p = 0.0019; Emotion Hexagon test: p = 0.0062; The Awareness of Social Inference Test: p = 0.002).

CONCLUSIONS

This is the first study to measure oxytocin in the CSF of HDGECs. We find that HDGECs have a significantly lower level of oxytocin compared to controls, and that the level of oxytocin may represent an objective and comparable measure that could be used as a state biomarker for impairment of social cognition. We suggest treatment trials to evaluate a potential effect of oxytocin on social cognition in HD.

Oxytocin and Vasopressin Levels and Related Factors in Adolescents with Social Phobia and Other Anxiety Disorders

Objective

This study aimed to determine whether a difference exists in plasma oxytocin and vasopressin levels among social anxiety disorder, other anxiety disorders, and healthy control groups in adolescents. The relationship between several psychiatric variables (i.e., state and trait anxiety, social anxiety, childhood trauma, and behavioral inhibition) and oxytocin or vasopressin levels were also investigated in adolescents with anxiety disorders.

Methods

The study included three groups of adolescents: social anxiety disorder (n = 29), those with other anxiety disorders (n = 27), and the control group (n = 28). The participants filled out self-report scales to determine various psychological variables. Oxytocin and vasopressin levels were determined from the blood samples of the participants.

Results

The oxytocin levels did not show a significant difference between the social anxiety disorder group and the other anxiety disorders group. However, the oxytocin levels were significantly higher in the social anxiety disorder and other anxiety disorders groups than in the control group. The vasopressin levels did not show a significant difference among the groups. According to the hierarchical regression analysis, the state and trait anxiety levels predicted oxytocin in opposite directions. Oxytocin showed positive and negative relationship with trait and state anxiety respectively. No predictive factors were found for the vasopressin levels.

Conclusion

We found that the oxytocin levels of adolescents with social anxiety disorder were not different from those of adolescents with other anxiety disorders. Further studies can improve our knowledge of the relationship among anxiety disorders and oxytocin or vasopressin.

Endogenous oxytocin, cortisol, and testosterone in response to group singing

Humans have sung together for thousands of years. Today, regular participation in group singing is associated with benefits across psychological and biological dimensions of human health. Here we examine the hypothesis that a portion of these benefits stem from changes in endocrine activity associated with affiliation and social bonding. Working with a young adult choir (n = 71), we measured changes salivary concentrations of oxytocin, cortisol, and testosterone from before and after four experimental conditions crossing two factors: vocal production mode (singing vs. speaking) and social context (together vs. alone). Salivary oxytocin and cortisol decreased from before to after the experimental manipulations. For oxytocin the magnitude of this decrease was significantly smaller after singing compared to speaking, resulting in concentrations that were significantly elevated after singing together compared to speaking together, after controlling for baseline differences. In contrast, the magnitude of the salivary cortisol decreases was the same across experimental manipulations, and although large, could not be separated from diurnal cycling. No significant effects were found in a low-powered exploratory evaluation of testosterone (tested only in males). At a psychological level, we found that singing stimulates greater positive shifts in self-perceived affect compared to speaking-particularly when performed together-and that singing together enhances feelings of social connection more than speaking together. Finally, measurements of heart rate made for a subset of participants provide preliminary evidence regarding physical exertion levels across conditions. These results are discussed in the context of a growing multidisciplinary literature on the endocrinological correlates of musical behavior. We conclude that singing together can have biological and psychological effects associated with affiliation and social bonding, and that these effects extend beyond comparable but non-musical group activities. However, we also note that these effects appear heavily influenced by broader contextual factors that shape social dynamics, such as stress levels, the intimacy of interactions, and the status of existing relationships.

Oxytocin receptor expression and epigenetic regulation in the anterior cingulate cortex of individuals with a history of severe childhood abuse

Childhood abuse significantly increases the lifetime risk of negative mental health outcomes. The oxytocinergic system, which plays a role in complex social and emotional behaviors, has been shown to be sensitive to early-life experiences. While previous studies have investigated the relationship between early-life adversity and oxytocin, they did so with peripheral samples. We, therefore, aimed to characterize the relationship between early-life adversity and oxytocin receptor (OXTR) expression in the brain, using post-mortem human samples, as well as a rodent model of naturally occurring variation in early-life environment. Focusing on the dorsal anterior cingulate cortex, we compared OXTR expression and epigenetic regulation between MDD suicides with (N = 26) and without history of childhood abuse (N = 24), as well as psychiatrically healthy controls (N = 23). We also compared Oxtr expression in the cingulate cortex of adult rats raised by dams displaying high (N = 13) and low levels (N = 12) of licking and grooming (LG) behavior. Overall, our results indicate that childhood abuse associates with an upregulation of OXTR expression, and that similarly, this relationship is also observed in the cingulate cortex of adult rats raised by low-LG dams. Additionally, we found an effect of rs53576 genotype on expression, showing that carriers of the A variant also show upregulated OXTR expression. The effects of early-life adversity and rs53576 genotype on OXTR expression are, however, not explained by differences in DNA methylation within and around the MT region of the OXTR gene.

The glial cell's role in antinociceptive differential effects of oxytocin upon female and male rats

BACKGROUND

Sex plays a crucial role in pain processing and response to analgesic drugs. Indeed, spinal glia seems to be significant in the sexual dimorphism observed in the above effects. Recently, studies have associated oxytocin with antinociceptive effects, but these have been mainly performed in male animals; consequently, the influence of sex has been poorly explored.

METHODS

Using a model of spinal nociception that produces pain through activation of the spinal glia, that is, intrathecal (i.t.) lipopolysaccharide (LPS) injection, we analysed the changes in the analgesic response to i.t. oxytocin in female and male rats by behavioural (punctate mechanical hypersensitivity), electrophysiological (unitary extracellular recordings of wide dynamic range [WDR] cells) and molecular biology (real-time PCR of proinflammatory genes) experiments.

RESULTS

We found that LPS-induced hypersensitivity was longer in female (>96 h) than in male (≈4 h) rats. Besides, spinal oxytocin preferentially prevents the LPS-induced hypersensitivity in male rather than female rats. Indeed, LPS increases the spinal neuronal-evoked activity associated with the activation of peripheral Aδ- and C-fibres and post-discharge in males, whereas only C-fibre discharge was enhanced in females. The electrophysiological data correlate with the fact that spinal oxytocin only prevented TNF-α and IL-1β synthesis in male rats.

CONCLUSIONS

Therefore, these data suggest that oxytocin-mediated analgesia depends on a sexual dimorphism involving activation of the spinal glia. These results reinforced the idea that different strategies are required to treat pain in men and women, and that oxytocin could be used preferentially to treat pain with a significant inflammatory component in men.

SIGNIFICANCE STATEMENT

Oxytocin is a molecule that emerges as a potent analgesic in preclinical and clinical studies. We investigated the contribution of glia to the response of oxytocin-induced analgesia and how sex influences in this response show that different strategies are required to treat pain in men and women, and that oxytocin could be used preferentially to treat pain with a significant inflammatory component in men.

Consequences of pandemic-associated social restrictions: Role of social support and the oxytocin system

During pandemics, governments take drastic actions to prevent the spreading of the disease, as seen during the present COVID-19 crisis. Sanctions of lockdown, social distancing and quarantine urge people to exclusively work and teach at home and to restrict social contacts to a minimum; lonely people get into further isolation, while families` nerves are strained to the extreme. Overall, this results in a dramatic and chronic increase in the level of psychosocial stress over several months mainly caused by i) social isolation and ii) psychosocial stress associated with overcrowding, social tension in families, and domestic violence. Moreover, pandemic-associated social restrictions are accompanied by loss of an essential stress buffer and important parameter for general mental and physical health: social support. Chronic psychosocial stress and, in particular, social isolation and lack of social support affect not only mental health, but also the brain oxytocin system and the immune system. Hence, pandemic-associated social restrictions are expected to increase the risk of developing psychopathologies, such as depression, anxiety-related and posttraumatic stress disorders, on the one hand, but also to induce a general inflammatory state and to impair the course of infectious disorders on the other. Due to its pro-social and stress-buffering effects, resulting in an anti-inflammatory state in case of disease, the role of the neuropeptide oxytocin will be discussed and critically considered as an emerging treatment option in cases of pandemic-induced psychosocial stress, viral infection and during recovery. In this review, we aim to critically focus on possible short- and long-term consequences of social restrictions on mental health and the immune system, while discussion oxytocin as a possible treatment option.

Oxytocin blood concentrations in alcohol use disorder: A cross-sectional, longitudinal, and sex-separated study

Alcohol use disorder (AUD) is a severe illness, for which we lack sufficient mechanistic understanding. Preliminary evidence associates AUD with the oxytocin (OXT) system. Here we investigated alterations in endogenous OXT blood concentrations in patients with AUD and their association with alcohol drinking and prospective course. In sex-separated analyses, OXT serum concentrations of 200 in-patients with AUD (56.5% male; baseline, 24-72 h of abstinence) were compared with those of 240 age-matched healthy controls (55.4% male), investigated longitudinally (follow-up, 5 days later), and tested for associations with alcohol drinking behavior and prospective 24-month alcohol-related hospital readmissions. At baseline, the patients showed increased OXT concentrations relative to controls (men, 156%, P < 0.001; women, 124%, P = 0.002). The elevations normalized at follow-up. In male patients, baseline OXT concentrations correlated positively with alcohol concentration at admission, the amount of alcohol consumption per drinking year, and the number of previous withdrawal treatments (Rho > 0.195, P < 0.044). In beverage type-specific analysis, baseline OXT concentrations correlated with liquor consumption positively in male and negatively in female patients (|Rho| > 0.277, P < 0.017). Higher baseline OXT concentrations predicted more readmissions and fewer days to the first readmission (|Rho| > 0.185, P < 0.050) in male patients. This study provides novel and sex-separated insights into the role of the OXT system in AUD. We identified a mechanism that might underlie the sex-separated choice of beverage type and established that increased OXT concentrations during early abstinence predict a worse outcome in male patients with AUD.

Specificity of plasma oxytocin immunoassays: A comparison of commercial assays and sample preparation techniques using oxytocin knockout and wildtype mice

Oxytocin has garnered much interest due to its role in affective states, social behaviors, and diverse physiological functions. However, approaches for measuring endogenous oxytocin concentrations have generated considerable controversy and debate. Common procedures for measuring oxytocin often produce uncorrelated results, and the detected concentrations frequently vary across two orders of magnitude. These findings have led some researchers to argue that immunoassays of plasma oxytocin may be unreliable and nonspecific, particularly when samples are not first processed using an extraction procedure. Here, we assess the specificity of oxytocin immunoassays using plasma samples from wildtype (WT) and oxytocin knockout (KO) mice. Plasma samples from both genotypes were measured using immunoassay and were measured with or without a solid-phase extraction. Using a commercially available kit from Arbor Assays, we demonstrate that both techniques generate a clear contrast between genotypes, with wildtype samples containing high concentrations of oxytocin (unextracted mean = 468 pg/ml; extracted mean = 381 pg/ml), while knockout samples measured below the lower limit of detection. Analytical validations demonstrated good parallelism and spike recovery for both methods. Furthermore, the same wildtype samples measured with both procedures were highly correlated (r = 0.95), although unextracted samples measured at significantly higher concentrations (p = 2.0 ×10-7, Cohen's d = 2.65). To test the generalizability of these results across immunoassay kits, we performed additional assays with kits from Cayman Chemical and Enzo Life Sciences. The Cayman Chemical kit produced results similar to Arbor Assays with a clean signal differentiating WT and KO plasma, both with and without an extraction step. The Enzo kit also differentiated the genotypes, with correlation between extracted and unextracted samples, but was considerably more susceptible to interference without the extraction, as evidenced by false positive signal in KO plasma samples. The extent to which these results generalize to other species remains unknown and challenging to assess.

Decreased Plasma Oxytocin Levels in Patients With PTSD

Introduction

Although the pathophysiology of post-traumatic stress disorder (PTSD) is still unclear, growing preclinical evidences suggest that oxytocin (OT), a pleiotropic hormone, is possibly involved. However, direct studies on OT levels or clinical trials with this exogenous hormone in patients with PTSD led to inconsistent findings. Therefore, the aim of the present study was at exploring and comparing the plasma OT levels in a group of patients with PTSD and matched healthy subjects as the control group.

Materials and Methods

Twenty-six outpatients (13 men, 13 women, mean age: 40.3 ± 11.5 years) suffering from PTSD, according to the Diagnostic and Statistical Manual for Mental Disorders, fifth edition (DSM-5), and 26 healthy subjects (13 men, 13 women, mean age: 43.8 ± 12.7 years) were included. The patients were assessed through the structured clinical interview for DSM-5 research version, patient edition (SCID-I/P), and the Impact for Event Scale revised (IES-R). All fasting subjects underwent three venous blood samples for the subsequent oxytocin radioimmunoassay. We used unpaired Student’s t-test to assess OT levels and the intergroup difference of demographic characteristics, while anxiety, avoidance, and hyperarousal scores were compared among groups adjusting for the effect of gender and age by means of analysis of covariance (ANCOVA). The correlations between different variables were investigated by Pearson’s method.

Results

The most common traumatic events of patients with PTSD were the following: severe car accident, physical violence, sexual violence, sudden death of a loved one, and natural disaster. The IES total score was 55 ± 15. Student’s t-test revealed that the patients showed significantly lower OT levels (mean ± SD, pg/ml) than healthy control subjects (4.37 ± 1.61 vs 5.64 ± 2.17, p < 0.001). We detected no correlation between the IES total score, subscales, or single items and OT plasma levels. Again, no difference between men and women was detected in the patients’ group, while healthy control women showed higher OT levels than men.

Discussion

Our study, while reporting the presence of decreased plasma OT levels in outpatients with PTSD of both sexes, as compared with healthy control subjects, would support the possible involvement of OT in the pathophysiology of PTSD. However, given the complexity of the clinical picture, future investigations are necessary to better deepen the role and level of OT in PTSD.

How Relevant is the Systemic Oxytocin Concentration for Human Sexual Behavior? A Systematic Review

Introduction

Despite its role in social cognition and affiliative behavior, less is known about the role played by oxytocin in human sexual behavior.

Aim

In the present systematic review, we aimed to find the levels of oxytocin related to human sexual arousal and orgasm.

Methods

We conducted the study according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We performed a systematic search in the principal databases for studies that reported collection of salivary or plasmatic samples, with dosage of oxytocin in relation to sexual activity during induction of sexual arousal and orgasm.

Results

414 articles were obtained. After duplicates removal and the application of pre exclusion criteria, 16 articles were considered eligible and 13 articles were included with a Cohen's k of 0.827. Most of the studies used sexual self-stimulation and collected plasmatic or salivary samples to measure oxytocin. The sexual arousal and orgasm were assessed based on subjective reports.

Main Outcome Measure

The primary outcomes were the oxytocin levels collected during the induction of sexual arousal and orgasm.

Conclusions

Several studies collected only subjective reports about the sexual arousal and the orgasm. Most of the studies found higher levels of oxytocin during the orgasm or ejaculation. Given the sexual arousal evoked by self-stimulation in which sexual fantasies play an important role, it should be possible to postulate for a role of the oxytocin in sexual desire. In particular, we hypothesize a complex role of the oxytocin in the modulation of sexual fantasies and thoughts that are relevant in the sexual desire and help to trigger genital and sexual arousal.

Cera N, Vargas-Cáceres S, Oliveira C, et al. How Relevant is the Systemic Oxytocin Concentration for Human Sexual Behavior? A Systematic Review. Sex Med 2021;9:100370.

The Relationship Between Plasma Oxytocin and Executive Functioning in Huntington's Disease: A Pilot Study

The role of oxytocin (OT) in social cognition of patients with Huntington's disease (HD) has been studied, but its impact on executive functioning has not been explored yet. Healthy controls, premanifest HD, and manifest HD participants underwent executive functioning assessment and OT plasma measurement. There were no significant group differences in plasma OT levels. Higher OT levels were associated with better executive functioning in premanifest HD participants. Our findings revealed an association between OT levels and depressive symptoms in premanifest and manifest HD participants. The potential role of OT in HD deserves further investigation.

The evolutionary biology of endometriosis

We provide the first analysis and synthesis of the evolutionary and mechanistic bases for risk of endometriosis in humans, structured around Niko Tinbergen's four questions about phenotypes: phylogenetic history, development, mechanism and adaptive significance. Endometriosis, which is characterized by the proliferation of endometrial tissue outside of the uterus, has its phylogenetic roots in the evolution of three causally linked traits: (1) highly invasive placentation, (2) spontaneous rather than implantation-driven endometrial decidualization and (3) frequent extensive estrogen-driven endometrial proliferation and inflammation, followed by heavy menstrual bleeding. Endometriosis is potentiated by these traits and appears to be driven, proximately, by relatively low levels of prenatal and postnatal testosterone. Testosterone affects the developing hypothalamic-pituitary-ovarian (HPO) axis, and at low levels, it can result in an altered trajectory of reproductive and physiological phenotypes that in extreme cases can mediate the symptoms of endometriosis. Polycystic ovary syndrome, by contrast, is known from previous work to be caused primarily by high prenatal and postnatal testosterone, and it demonstrates a set of phenotypes opposite to those found in endometriosis. The hypothesis that endometriosis risk is driven by low prenatal testosterone, and involves extreme expression of some reproductive phenotypes, is supported by a suite of evidence from genetics, development, endocrinology, morphology and life history. The hypothesis also provides insights into why these two diametric, fitness-reducing disorders are maintained at such high frequencies in human populations. Finally, the hypotheses described and evaluated here lead to numerous testable predictions and have direct implications for the treatment and study of endometriosis. Lay summary: Endometriosis is caused by endometrial tissue outside of the uterus. We explain why and how humans are vulnerable to this disease, and new perspectives on understanding and treating it. Endometriosis shows evidence of being caused in part by relatively low testosterone during fetal development, that 'programs' female reproductive development. By contrast, polycystic ovary syndrome is associated with relatively high testosterone in prenatal development. These two disorders can thus be seen as 'opposite' to one another in their major causes and correlates. Important new insights regarding diagnosis, study and treatment of endometriosis follow from these considerations.

The supraoptic and paraventricular nuclei in healthy aging and neurodegeneration

The supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus undergo structural and functional changes over the course of healthy aging. These nuclei and their connections are also heterogeneously affected by several different neurodegenerative diseases. This chapter reviews the involvement of the SON and PVN, the hypothalamic-pituitary axes, and the peptide hormones produced in both nuclei in healthy aging and in neurodegeneration, with a focus on Alzheimer's disease (AD), frontotemporal dementia (FTD), amyotrophic lateral sclerosis, progressive supranuclear palsy, Parkinson's disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy, and Huntington's disease. Although age-related changes occur in several regions of the hypothalamus, the SON and PVN are relatively preserved during aging and in many neurodegenerative disorders. With aging, these nuclei do undergo some sexually dimorphic changes including changes in size and levels of vasopressin and corticotropin-releasing hormone, likely due to age-related changes in sex hormones. In contrast, oxytocinergic cells and circulating levels of thyrotropin-releasing hormone remain stable. A relative resistance to many forms of neurodegenerative pathology is also observed, in comparison to other hypothalamic and brain regions. Mirroring the pattern observed in aging, pathologic hallmarks of AD, and some subtypes of FTD are observed in the PVN, though to a milder degree than are observed in other brain regions, while the SON is relatively spared. In contrast, the SON appears more vulnerable to alpha-synuclein pathology of DLB and PD. The consequences of these alterations may help to inform several of the physiologic changes observed in aging and neurodegenerative disease.

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.

Childhood Trauma and Aggression in Persons Convicted for Homicide: An Exploratory Study Examines the Role of Plasma Oxytocin

Evidence has demonstrated the association between childhood trauma and criminality in adulthood, however, less is known about how best to explain the route from childhood trauma to adulthood aggression. Results from both human and animal studies have generated the hypothesis that dysfunction of the oxytocinergic system may correlate with pathological aggression. The current study represents a first exploratory examination to investigate the trajectory from childhood trauma to aggression, specifically, plasma oxytocin's role in this association. We assessed the childhood trauma experiences in a total of 108 participants, including 33 persons convicted for homicide and 75 non-offending healthy participants, using the Childhood Trauma Questionnaire, with in-depth clarification interviews for cross-validation. All participants were checked for aggression using the Modified Overt Aggression Scale and their plasma oxytocin levels were obtained. Results indicated that persons convicted for homicide had higher childhood trauma scores and lower plasma oxytocin levels than healthy controls. The plasma oxytocin levels were inversely correlated with childhood trauma in all participants. Further mediation models were constructed to explore these associations, in the best-fit model, the relationship between childhood trauma and aggression is mediated by plasma oxytocin levels in persons convicted for homicide. In conclusion, the association between childhood trauma and aggression of persons convicted for homicide is mediated by their plasma oxytocin levels. With leading to further theoretical consideration in the causality on how best to explain the interaction between childhood trauma and aggression, the current study may assist in developing further research and preventive strategies for aggression, particularly the importance of early identification of childhood trauma.

Relation of promoter methylation of the structural oxytocin gene to critical life events in major depression: A case control study

BACKGROUND

Stressful life events (SLEs) are associated with hyper(re-)activity of the HPA-axis. HPA-axis hyper(re-)activity is thought to be a major risk factor for depression development. SLEs may induce changes in an organism's stress system via epigenetic mechanisms. The neuropeptide oxytocin (OT) is able to attenuate the stress response, and OT pathways are dysregulated in individuals suffering from Major Depressive Disorder (MDD). Therefore, the gene coding for oxytocin (OXT) is a possible target for the investigation of depression development.

METHODS

We collected data on SLEs, OXT promoter methylation (Sequenom Epityper MassArray) and depression severity from 90 MDD inpatients and 90 matched healthy controls.

RESULTS

We found MDD inpatients to have a significantly lower OXT methylation than healthy controls. Methylation status was significantly negatively associated with SLEs but only in the group of MDD inpatients. There were no associations between methylation status and depression severity.

LIMITATIONS

Methylation in blood samples is only a proxy for epigenetic profiles in brain tissue. We did not assess mRNA or protein levels and cannot draw conclusions regarding the functionality or specificity of differences in OXT methylation between groups.

CONCLUSION

SLEs leave their traces in the epigenetic profiles of the OT system of MDD inpatients. Alterations in epigenetic profiles of the OXT system could constitute a vulnerability factor predisposing individuals for depression development. Better understanding of DNA methylation profiles of depression-associated genes could serve as basis for a personalized medicine, in which pharmacological or psychotherapeutic treatment of depression is tailored to the patient's individual characteristics.

Oxytocin in the Male Reproductive Tract; The Therapeutic Potential of Oxytocin-Agonists and-Antagonists

In this review, the role of oxytocin and oxytocin-like agents (acting via the oxytocin receptor and belonging to the oxytocin-family) in the male reproductive tract is considered. Previous research (dating back over 60 years) is revised and connected with recently found aspects of the role oxytocin plays in male reproductive health. The local expression of oxytocin and its receptor in the male reproductive tract of different species is summarized. Colocalization and possible crosstalk to other agents and receptors and their resulting effects are discussed. The role of the newly reported oxytocin focused signaling pathways in the male reproductive tract, other than mediating contractility, is critically examined. The structure and effect of the most promising oxytocin-agonists and -antagonists are reviewed for their potential in treating male disorders with origins in the male reproductive tract such as prostate diseases and ejaculatory disorders.

Social Feedback During Sensorimotor Synchronization Changes Salivary Oxytocin and Behavioral States

In humans and animal models, oxytocin increases social closeness, attachment and prosocial behaviors, while decreasing anxiety and stress levels. Efficiently triggering the release of endogenous oxytocin could serve as a powerful therapeutic intervention for disorders of social behavior and for anxiety. We designed a new version of a social sensorimotor synchronization task to investigate the role of social approval in inducing biochemical and psychological changes following behavioral synchrony in a sample of 80 college students. Social approval in the form of real time positive feedback increased well-being only in women, while increasing social closeness in both genders. Social disapproval in the form of real time negative feedback prevented a decrease in stress levels that otherwise women reported following engagement in either social or non-social synchronization. Surprisingly, for certain personality traits, negative social feedback during sensorimotor synchronization was psychologically beneficial irrespective of gender. Salivary oxytocin levels increased only in women after the social but not the non-social synchronization tasks. Oxytocin dynamics were independent of the type of real time feedback that subjects received, indicating the existence of distinct mechanisms for hormonal versus behavioral changes following synchronization. Nevertheless, changes in salivary oxytocin after positive social feedback correlated with changes in well-being and predicted changes in prosocial attitudes. Our findings show evidence of distinct mechanisms for behavioral versus hormonal changes following social sensorimotor synchronization, and indicate that gender and personality traits should be carefully considered when designing behavioral therapies for improving social attitudes and for stress management.

Oxytocin and elderly MRI-based hippocampus and amygdala volume: a 7-year follow-up study

Oxytocin is deeply involved in human relations. In recent years, it is becoming clear that oxytocin is also involved in social cognition and social behaviour. Oxytocin receptors are also thought to be present in the hippocampus and amygdala, and the relationship between oxytocin and the structure and function of the hippocampus and amygdala has been reported. However, a few studies have investigated oxytocin and its relationship to hippocampus and amygdala volume in elderly people. The aim of this study is to investigate the association between serum oxytocin levels and hippocampus and amygdala volume in elderly people. The survey was conducted twice in Kurokawa-cho, Imari, Saga Prefecture, Japan, among people aged 65 years and older. We collected data from 596 residents. Serum oxytocin level measurements, brain MRI, Mini–Mental State Examination and Clinical Dementia Rating were performed in Time 1 (2009–11). Follow-up brain MRI, Mini–Mental State Examination and Clinical Dementia Rating were performed in Time 2 (2016–17). The interval between Time 1 and Time 2 was about 7 years. Fifty-eight participants (14 men, mean age 72.36 ± 3.41 years, oxytocin 0.042 ± 0.052 ng/ml; 44 women, mean age 73.07 ± 4.38 years, oxytocin 0.123 ± 0.130 ng/ml) completed this study. We analysed the correlation between serum oxytocin levels (Time 1) and brain volume (Time 1, Time 2 and Times 1–2 difference) using voxel-based morphometry implemented with Statistical Parametric Mapping. Analysis at the cluster level (family-wise error; P < 0.05) showed a positive correlation between serum oxytocin levels (Time 1) and brain volume of the region containing the left hippocampus and amygdala (Time 2). This result suggests that oxytocin in people aged 65 years and older may be associated with aging-related changes in hippocampus and amygdala volume.

Oxytocin, A Possible Treatment for Covid-19? Everything to Gain, Nothing to Lose

After comparing the morbidity patterns of COVID-19 infections, variations of oxytocin levels and some properties of the neurohormone oxytocin, the authors put forward their hypothesis that oxytocin might constitute a safe, inexpensive and readily available treatment for this disease.

Antidepressant Use During Development May Impair Women's Sexual Desire in Adulthood

INTRODUCTION

Although antidepressants are well known to cause sexual side effects in adults, the long-term effects of antidepressant use during development on adult sexual function is unknown.

AIM

To explore differences in sexual desire and sexual behavior between adults who did vs did not use antidepressants during childhood or adolescence.

METHODS

An online survey of 610 young adults (66% women) assessed childhood and current mental health and use of antidepressants and other psychiatric medications before the age of 16 years and currently, partnered and solitary sexual desire, and frequency of masturbation and partnered sexual activity. Antidepressants were coded into either selective serotonin reuptake inhibitors (SSRIs) or non-SSRI antidepressants.

MAIN OUTCOME MEASURE

Scores on the Sexual Desire Inventory, and self-reported frequency of masturbation and partnered sexual activity.

RESULTS

For women, childhood SSRI use was associated with significantly lower solitary sexual desire, desire for an attractive other, and frequency of masturbation. This was true even when controlling for childhood mental health concerns, current mental health, and current antidepressant use. However, there was no effect of childhood SSRI use on women's partnered sexual desire or partnered sexual activity. There was no significant effect of childhood antidepressant use on men's sexual desire or masturbation. However, in men, childhood use of non-SSRI antidepressants was associated with significantly higher frequency of partnered sexual activity. Childhood use of non-SSRI antidepressants, or nonantidepressant psychiatric medication, was not associated with adult sexual desire or behavior in either women or men.

CLINICAL IMPLICATIONS

It is possible that SSRI use during childhood interrupts the normal development of sexual reward systems, which may be a risk factor for sexual desire dysfunction in adult women.

STRENGTHS & LIMITATIONS

Strengths include a large sample, use of attention checks and validated measures, and careful assessment of childhood mental health history; however, generalizability is limited by a predominantly white, young adult sample. These data are cross-sectional, and therefore, causal explanations for the association between childhood SSRI use and adult sexual well-being should be considered preliminary, warranting replication.

CONCLUSION

These findings point to a critical need for well-controlled, prospective research on possible long-term effects of antidepressant use, particularly SSRI use, on the development of adult sexual well-being. Lorenz TK. Antidepressant Use During Development May Impair Women's Sexual Desire in Adulthood. J Sex Med 2020;17:470-476.

Validation of the Mexican Spanish Version of the Scale of Positive and Negative Experience in a Sample of Medical and Psychology Students

The Scale of Positive and Negative Experience (SPANE) aims to measure affect with high transcultural validity. The bifactor model is the best theoretical option to represent affective balance, although it is not typically used in validation studies. The objectives of this research were to test a bifactor model vis-à-vis the traditional model composed of two correlated factors, to prove its invariance across sexes, and to provide evidence of concurrent validity. A nonprobability sample composed of 600 Mexican students of psychology and medicine was recruit. One-group and multigroup confirmatory factor analyses were carried out. The SPANE and the scales selected to assess depression, perceived stress, and satisfaction with life were applied. The bifactor model showed better goodness-of-fit indices than the two correlated factors model: Δχ²(11) = 121.436, p < . 001, Δχ²/Δdf = 11.04 > 5, ΔGFI = .034, ΔNFI = .025, ΔNNFI = .022, and ΔCFI = .023 >.01. The internal consistency for the general factor as well as for the factor of positive affect was excellent, whereas it was good for the factor of negative affect. The measurement model was valid across sexes. The general factor of affective balance had a very high correlation with depression, high with perceived stress, and medium with satisfaction with life. It is concluded that SPANE is reliable and shows evidence of validity among Mexican student of psychology and medicine, and the bifactor model is adequate to represent affective balance.