Effects of oxytocin on empathy, introspective accuracy, and social symptoms in schizophrenia: A 12-week twice-daily randomized controlled trial

Potential Delayed Positive Effects of tDCS on Improving Introspective Accuracy in Social Cognition in Schizophrenia

BACKGROUND AND HYPOTHESIS

Impairments in introspective accuracy (IA) are prominent among schizophrenia patients and detrimentally affect daily functioning, making IA a potential therapeutic target. Recent research highlights the role of the right rostrolateral prefrontal cortex (rlPFC) in IA and suggests that transcranial direct current stimulation (tDCS) to this region may improve it. Therefore, we tested whether applying tDCS to the right rlPFC could enhance IA for schizophrenia patients and explored the potential order/delayed effects.

STUDY DESIGN

A randomized, double-blind, sham-controlled crossover design was used. Patients with a schizophrenia spectrum disorder (N = 40) underwent 2 tDCS sessions targeting right rlPFC (one was active stimulation and the other was sham) about a week apart. After each session, participants completed executive function and emotion recognition tasks for evaluating IA.

STUDY RESULTS

When ignoring order effects, tDCS did not affect performance, IA, or confidence ratings across 3 tasks, except for increased confidence ratings in the cognitive task after active stimulation versus sham. However, considering order effects revealed significant interaction effects between condition and order for both task performance and IA. The group receiving active stimulation at visit 1 (Active First) generally improved over time in both cognitive and social cognitive task performance and in social cognitive IA, specifically for emotion recognition ability. In contrast, the group receiving sham stimulation at visit 1 (Sham First) showed no change in performance or IA over time.

CONCLUSIONS

Our findings provide preliminary evidence for potential positive, but delayed, effects of tDCS in improving task performance and IA in schizophrenia.

Social Psychopharmacology: Novel Approaches to Treat Deficits in Social Motivation in Schizophrenia

BACKGROUND AND HYPOTHESIS

Diminished social motivation is a negative symptom of schizophrenia and leads to severe functional consequences for many patients suffering from the illness. However, there are no effective medications available to treat this symptom. Despite the lack of approved treatments for patients, there is a growing body of literature on the effects of several classes of drugs on social motivation in healthy volunteers that may be relevant to patients. The aim of this review is to synthesize these results in an effort to identify novel directions for the development of medications to treat reduced social motivation in schizophrenia.

STUDY DESIGN

In this article, we review pharmacologic challenge studies addressing the acute effects of psychoactive drugs on social motivation in healthy volunteers and consider how these findings may be applied to deficits in social motivation in schizophrenia. We include studies testing amphetamines and 3,4-methylenedioxymethamphetamine (MDMA), opioids, cannabis, serotonergic psychedelics, antidepressants, benzodiazepines, and neuropeptides.

STUDY RESULTS

We report that amphetamines, MDMA, and some opioid medications enhance social motivation in healthy adults and may represent promising avenues of investigation in schizophrenia.

CONCLUSIONS

Given the acute effects of these drugs on behavioral and performance-based measures of social motivation in healthy volunteers, they may be particularly beneficial as an adjunct to psychosocial training programs in patient populations. It remains to be determined how these medications affect patients with deficits in social motivation, and in which contexts they may be most effectively administered.

Intranasal oxytocin as a treatment for obesity: safety and efficacy

INTRODUCTION

Known for its effect on labor and lactation and on emotional and social functions, oxytocin has recently emerged as a key modulator of feeding behavior and indeed suggested as a potential treatment for obesity. The potential positive effect of oxytocin on both metabolic and psychological-behavioral complications of hypothalamic lesions makes it a promising tool in the management of these conditions.

AREAS COVERED

The aim of the present review article is to provide an overview of the mechanism of action and clinical experience of the use of oxytocin in different forms of obesity.

EXPERT OPINION

Current evidence suggests a potential role of oxytocin in the treatment of obesity with different causes. Several challenges remain: an improved understanding of the physiological regulation, mechanisms of action of oxytocin, and interplay with other endocrine axes is fundamental to clarify its role. Further clinical trials are needed to determine the safety and efficacy of oxytocin for the treatment of different forms of obesity. Understanding the mechanism(s) of action of oxytocin on body weight regulation might also improve our understanding of obesity and reveal possible new therapeutic targets - as well as promoting advances in other fields in which oxytocin might be used.

Racial disparities and predictors of functioning in schizophrenia

Black Americans are diagnosed with schizophrenia spectrum disorders at more than twice the rate of White individuals and experience significantly worse outcomes following diagnosis. Little research has examined specific factors that may contribute to worse functional outcomes among Black Americans diagnosed with schizophrenia. One approach to understanding why racial disparities emerge is to examine established predictors of functioning in this population: neurocognition, social cognition, and symptom severity. The present study aims to broaden existing literature on racial differences within these domains by (a) examining racial differences in functioning and these established predictors of functioning (i.e., neurocognition, social, and symptom severity) and (b) investigating whether cognition and symptom domains similarly predict functioning between Black and White Americans with schizophrenia. Sixty-six participants' baseline neurocognition, social cognition, symptom severity, and functioning were assessed. Black participants demonstrated lower neurocognition scores and higher levels of disorganized symptoms relative to White participants. No racial differences in functioning or social cognition were observed. Further, race did not moderate the relationship between any of these established predictors and functioning outcomes. The largely nonsignificant differences in known predictors of functioning highlight the need to explore further domains that may be more relevant for understanding racial disparities in schizophrenia. Considering that psychosocial treatments for schizophrenia spectrum disorders often focus on cognition, these results underscore the importance of identifying whether these domains or other treatment targets may be better in addressing racial disparities in functioning. Possible areas of exploration for future work (e.g., structural factors, racism-related stress) are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Exploring a Possible Interplay between Schizophrenia, Oxytocin, and Estrogens: A Narrative Review

Schizophrenia is characterized by symptoms of psychosis and sociocognitive deficits. Considering oxytocin’s antipsychotic and prosocial properties, numerous clinical, and preclinical studies have explored the neuropeptide’s therapeutic efficacy. Sex differences in the clinical course of schizophrenia, as well as in oxytocin-mediated behaviors, indicate the involvement of gonadal steroid hormones. The current narrative review aimed to explore empirical evidence on the interplay between schizophrenia psychopathology and oxytocin’s therapeutic potential in consideration of female gonadal steroid interactions, with a focus on estrogens. The review was conducted using the PubMed and PsychINFO databases and conforms to the Scale for the Assessment of Narrative Review Articles (SANRA) guidelines. The results suggest a potential synergistic effect of the combined antipsychotic effect of oxytocin and neuroprotective effect of estrogen on schizophrenia. Consideration of typical menstrual cycle-related hormonal changes is warranted and further research is needed to confirm this assumption.

Intranasal Peptide Therapeutics: A Promising Avenue for Overcoming the Challenges of Traditional CNS Drug Development

The central nervous system (CNS) has, among all organ systems in the human body, the highest failure rate of traditional small-molecule drug development, ranging from 80-100% depending on the area of disease research. This has led to widespread abandonment by the pharmaceutical industry of research and development for CNS disorders, despite increased diagnoses of neurodegenerative disorders and the continued lack of adequate treatment options for brain injuries, stroke, neurodevelopmental disorders, and neuropsychiatric illness. However, new approaches, concurrent with the development of sophisticated bioinformatic and genomic tools, are being used to explore peptide-based therapeutics to manipulate endogenous pathways and targets, including "undruggable" intracellular protein-protein interactions (PPIs). The development of peptide-based therapeutics was previously rejected due to systemic off-target effects and poor bioavailability arising from traditional oral and systemic delivery methods. However, targeted nose-to-brain, or intranasal (IN), approaches have begun to emerge that allow CNS-specific delivery of therapeutics via the trigeminal and olfactory nerve pathways, laying the foundation for improved alternatives to systemic drug delivery. Here we review a dozen promising IN peptide therapeutics in preclinical and clinical development for neurodegenerative (Alzheimer's, Parkinson's), neuropsychiatric (depression, PTSD, schizophrenia), and neurodevelopmental disorders (autism), with insulin, NAP (davunetide), IGF-1, PACAP, NPY, oxytocin, and GLP-1 agonists prominent among them.

Oxytocin administration versus emotion training in healthy males: considerations for future research

Identifying emotions correctly is essential for successful social interaction. There is therefore a keen interest in designing therapeutic interventions to improve emotion recognition in individuals who struggle with social interaction. The neuropeptide oxytocin has been proposed as a potential physiological intervention due to its important role in emotion recognition and other aspects of social cognition. However, there are a number of caveats to consider with the current form of intranasal oxytocin commonly used in the literature. Psychological interventions, on the other hand, do not carry the same caveats, and there is, therefore, a need to understand how intranasal oxytocin administration compares to psychological interventions designed to target the same psychological phenomena; and whether a combined intervention approach may provide additive benefits. Here we present a pilot, proof-of-concept study in healthy volunteers comparing the effect of intranasal oxytocin against a validated emotion training programme, finding that the psychological intervention, and not intranasal oxytocin, improved emotion recognition specifically for angry expressions. We discuss the theoretical implications of the research for future clinical trials. 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.

An Update on Clinical Insight, Cognitive Insight, and Introspective Accuracy in Schizophrenia-Spectrum Disorders: Symptoms, Cognition, and Treatment

INTRODUCTION

Poor insight, or unawareness of morbid changes in cognition, emotional states, or behavior, is commonly observed among people with schizophrenia. Poor insight represents a persistent barrier to wellness because it interferes with treatment and self-direction. Paradoxically, good insight may also be a barrier to health when awareness of these changes leads to depression or self-stigma.

AREAS COVERED

This paper builds upon this previous work by exploring these issues in schizophrenia separately as they have appeared in published research over the last three years in three different kinds of insight: clinical, cognition, and introspective accuracy. Specifically, studies are reviewed that address: the adverse effects of poor insight, the paradoxical effects of good insight, correlates with other forms of cognition, and emerging treatments.

EXPERT OPINION

The evidence continues to offer a nuanced picture of the complex effects of good insight in schizophrenia. Incremental improvements were also found in the development of novel integrative treatment approaches. This work also highlights the intricacy of the concept of insight, the need for further exploration of the effects of culture, and conceptual work that distinguishes the points of convergence and divergence of these forms of insight.

Multiple Aspects of Inappropriate Action of Renin-Angiotensin, Vasopressin, and Oxytocin Systems in Neuropsychiatric and Neurodegenerative Diseases

The cardiovascular system and the central nervous system (CNS) closely cooperate in the regulation of primary vital functions. The autonomic nervous system and several compounds known as cardiovascular factors, especially those targeting the renin-angiotensin system (RAS), the vasopressin system (VPS), and the oxytocin system (OTS), are also efficient modulators of several other processes in the CNS. The components of the RAS, VPS, and OTS, regulating pain, emotions, learning, memory, and other cognitive processes, are present in the neurons, glial cells, and blood vessels of the CNS. Increasing evidence shows that the combined function of the RAS, VPS, and OTS is altered in neuropsychiatric/neurodegenerative diseases, and in particular in patients with depression, Alzheimer's disease, Parkinson's disease, autism, and schizophrenia. The altered function of the RAS may also contribute to CNS disorders in COVID-19. In this review, we present evidence that there are multiple causes for altered combined function of the RAS, VPS, and OTS in psychiatric and neurodegenerative disorders, such as genetic predispositions and the engagement of the RAS, VAS, and OTS in the processes underlying emotions, memory, and cognition. The neuroactive pharmaceuticals interfering with the synthesis or the action of angiotensins, vasopressin, and oxytocin can improve or worsen the effectiveness of treatment for neuropsychiatric/neurodegenerative diseases. Better knowledge of the multiple actions of the RAS, VPS, and OTS may facilitate programming the most efficient treatment for patients suffering from the comorbidity of neuropsychiatric/neurodegenerative and cardiovascular diseases.

Introspective accuracy for substance use across a year of treatment for first episode psychosis

Substance use exacerbates psychosis, mania, depression, and poor functioning in people with first episodes of psychosis (FEP) and is associated with poor treatment outcomes, even when it does not reach the level of a formal disorder. Impaired insight and substance use are common issues that may interfere with treatment outcomes among people experiencing FEP, yet both are treatable. Improvements in these domains are associated with better outcomes. Low insight could increase risk for substance use by impairing the ability to self-appraise and assess consequences. Introspective accuracy (IA) is understudied in this area and is one way of considering self-appraisal. This study is an archival review using data collected from NAVIGATE, a coordinated specialty care program treating people with FEP. IA was operationalized as the difference between clinician and client ratings of substance use. We tested whether IA changed over one year of treatment and whether those changes occurred alongside changes in symptoms and illness self-management. No changes in IA were detected in relation to illness self-management. Changes in IA for substance use occurred midway through treatment-individuals with greater symptom remission had more overconfident IA. Prior research on insight has shown a paradox where greater insight accompanies more symptoms. However, past research has also shown a relationship between IA and functional outcomes, like illness self-management, and that overconfidence in one domain can positively bias clinician ratings in another. Our findings suggest either a positive bias for ratings associated with overconfident IA or an insight paradox type effect.

Oxytocin increases physiological linkage during group therapy for methamphetamine use disorder: a randomized clinical trial

Patients and psychotherapists often exhibit behavioral, psychological, and physiological similarity. Here, we test whether oxytocin—a neuropeptide that can enhance expressivity and social perception—influences time-lagged “linkage” of autonomic nervous system responses among participants and facilitators during group therapy. Physiological linkage estimates (n = 949) were created from ten cohorts, each with two facilitators (n = 5) and four to six participants (n = 48), over six weekly sessions of group therapy for methamphetamine use disorder. All participants of a cohort received oxytocin or placebo intranasally in a randomized double-blind procedure before each session. Cardiac interbeat intervals (IBI) were measured continuously during sessions to estimate physiological linkage, operationalized as one cohort-mate’s IBI reactivity during one minute predicting another cohort-mate’s IBI reactivity during the following minute. In oxytocin cohorts, participants and facilitators experienced significant physiological linkage to their cohort-mates (i.e., their physiological responses were predicted by the prior responses of their cohort-mates) and significantly more linkage than people in placebo cohorts. Both effects occurred during the first and second sessions but not later sessions. Results suggest that oxytocin may enhance psychosocial processes often associated with linkage—such as social engagement—in groups and highlight oxytocin’s potential to improve group cohesion during group therapy.

Clinical Trials Registration: NCT02881177, First published on 26/08/2016.

Associations between oxytocin and empathy in humans: A systematic literature review

This is a systematic review about the association between empathic behavior and oxytocin (OXT). Searches were conducted in the electronic databases PubMed, Web of Science, PsycINFO, SciELO, and LILACS using the search terms "oxytocin", "empathy", and "empathic". Forty-four studies were reviewed. Scarce findings point to a lack of association between baseline endogenous OXT levels and empathy traits, and for a trend towards a direct relationship between oxytocinergic reactivity and empathic functioning. The results showed that variations in empathy were related to polymorphisms in the OXT receptor gene, especially in rs53576, and that this relationship seems to mediated by individual, ethnic, and cultural characteristics. Most studies on the exogenous administration of OXT tested a single dose (24 IU) with positive effects mainly on the affective domain of empathy. At the neural level, findings were inconsistent. Taken together, the results of the studies reviewed support the existence of a relationship between OXT and empathy that is complex and multifaceted. Robust evidence is still needed to elucidate existing links. Future investigations could benefit from methodological improvements aimed at increasing the reproducibility and applicability of findings, as well as the systematic assessment of the effects of exogenous OXT considering dose and frequency of administration, genotyping, and hormonal availability at the peripheral and central levels. This should lead to significant progress in the understanding of the therapeutic possibilities of OXT in the domain of empathic behavior.

Oxytocin in Schizophrenia: Pathophysiology and Implications for Future Treatment

Schizophrenia is a form of mental disorder that is behaviorally characterized by abnormal behavior, such as social function deficits or other behaviors that are disconnected from reality. Dysregulation of oxytocin may play a role in regulating the expression of schizophrenia. Given oxytocin’s role in social cognition and behavior, a variety of studies have examined the potential clinical benefits of oxytocin in improving the psychopathology of patients with schizophrenia. In this review, we highlight the evidence for the role of endogenous oxytocin in schizophrenia, from animal models to human studies. We further discuss the potential of oxytocin as a therapeutic agent for schizophrenia and its implication in future treatment.

Experimental empathy induction promotes oxytocin increases and testosterone decreases

Oxytocin and testosterone coordinate adaptive social behaviors with stimuli in the environment. Administration of oxytocin and testosterone is associated with increased and reduced indicators of empathy, respectively, but how levels of these hormones are jointly affected by naturalistic empathy-inducing stimuli remains unclear. In this study, salivary oxytocin and testosterone levels were measured in 173 healthy adults before and after watching a video involving a gravely ill child. Participants also completed questionnaires to assess psychological variables predicted to affect oxytocin reactivity (Autism-Spectrum Quotient, Interpersonal Reactivity Index, Empathy and Systemizing Quotients). On average, there was a 14% increase in oxytocin (p = 0.003) and 4% decrease in testosterone (p = 0.001) pre- to post-video. Opposite directional changes in hormone levels occurred together, as supported by a chi-square test (p < 0.001) and a circular statistics test (p < 0.05). Considered separately, psychological traits did not predict hormone levels or changes to any appreciable degree. However, oxytocin and testosterone changes were linked with empathy relative to systemizing such that: (1) 'Empathy Bias' was associated with a large oxytocin increase but little change in testosterone, while (2) 'Systemizing Bias' and 'Balance' between empathy and systemizing were associated with a decrease in testosterone but little change in oxytocin. These findings suggest that participants were divisible into 'high oxytocin responders' (relatively empathetic) and 'high testosterone responders' (balanced or systemizing-biased). These findings support a model of joint, opposite changes in oxytocin and testosterone under experimental empathy induction, with high, somewhat predictable, diversity in individual responses.

What Do You Have in Mind? Measures to Assess Mental State Reasoning in Neuropsychiatric Populations

Social interaction is closely associated with both functional capacity and well-being. Previous research has not only revealed evidence of social dysfunction in individuals with a wide range of psychiatric and neurological disorders but also generated an abundance of potential measures for assessing social cognition. This review explores the most popular measures used within neuropsychiatric populations to investigate the ability to recognize or reason about the mental states of others. Measures are also critically analyzed in terms of strengths and limitations to aid task selection in future clinical studies. The most frequently applied assessment tools use verbal, visual or audiovisual forms of presentation and assess recognition of mental states from facial features, self-rated empathy, the understanding of other's cognitive mental states such as beliefs and intentions, or the ability to combine knowledge of other's thoughts and emotions in order to understand subtle communications or socially inappropriate behavior. Key weaknesses of previous research include limited investigation of relationships with clinical symptoms, and underutilization of measures of everyday social functioning that offer a useful counterpart to traditional "lab" tasks. Future studies should aim to carefully select measures not only based on the range of skills to be assessed but also taking into account potential difficulties with interpretation and the need to gain insight into the application of social cognitive skills as well as ability per se. Some of the best measures include those with well-matched control trials (e.g., Yoni Task) or those that restrict the influence of verbal deficits (e.g., intentions comic strip task), elicit spontaneous mentalizing (e.g., Animations Task), and possess greater ecological validity (e.g., Movie for the Assessment of Social Cognition). Social cognitive research within psychiatric populations will be further enhanced through the development of more closely matched control tasks, and the exploration of relationships between task performance, medication, strategy use, and broader emotional and motor functions.