A meta-analysis and theoretical critique of oxytocin and psychosis: prospects for attachment and compassion in promoting recovery

Adjunctive intranasal oxytocin for schizophrenia: A meta-analysis of randomized, double-blind, placebo-controlled trials

OBJECTIVE

Findings on the efficacy of intranasal oxytocin (IN-OT) in schizophrenia have been inconsistent. This meta-analysis of double-blind randomized controlled trials (RCTs) examined the efficacy and tolerability of adjunctive IN-OT in the treatment of schizophrenia.

METHODS

Standardized mean differences or risk ratios (SMDs or RRs) with their 95% confidence intervals (CIs) were used to synthesize the results of studies included in the meta-analysis.

RESULTS

Ten RCTs (n = 344) with 172 schizophrenia subjects on adjunctive IN-OT [range = 40-80 International Units (IU)/day] and 172 schizophrenia subjects on adjunctive placebo over 2-16 weeks were included. No significant differences regarding total psychopathology measured with the total Positive and Negative Syndrome Scale (PANSS) or the Brief Psychiatric Rating Scale (BPRS) [8 RCTs, n = 203; SMD: -0.08 (95%CI: -0.53, 0.37), P = 0.74, I² = 59%] and the positive, negative and general symptom scores [SMD: -0.20 to -0.04 (95%CI: -0.75, 0.36), P = 0.28 to 0.78; I² = 0% to 72%] were found between the IN-OT and placebo groups. Similarly, subgroup analyses for total psychopathology found no group differences. Dose-response effect analyses showed that only 80 IU/day IN-OT had superiority over placebo in improving total psychopathology (P = 0.02) and positive symptom score (P = 0.01). No group differences between adjunctive IN-OT and placebo regarding discontinuation due to any reason [RR: 1.12 (95%CI: 0.67, 1.88), P = 0.67, I² = 0%] and adverse drug reactions were found.

CONCLUSIONS

Although the meta-analysis did not show a positive effect in general, the higher dose of adjunctive IN-OT (80 IU/day) appears to be efficacious and safe in improving total psychopathology and positive symptoms in schizophrenia.

REVIEW REGISTRATION

CRD42017080856.

Associations of oxytocin and vasopressin plasma levels with neurocognitive, social cognitive and meta cognitive function in schizophrenia

Many with schizophrenia experiences deficits in social cognition, neurocognition and metacognition. Yet the biological mechanisms which may underpin these cognitive deficits are poorly understood. Two candidate causes of these deficits are disturbances in oxytocin (OT) and vasopressin (VP). To explore this we assessed plasma OT and VP in 34 schizophrenia patients and 31 healthy controls. We also concurrently assessed social cognition using the Reading the Mind from the Eyes test, neurocognition using the Wisconsin Card Sorting Test and metacognition using the Metacognitive Assessment Scale-Abbreviated. Group comparisons revealed lower plasma OT levels in the schizophrenia group. Plasma VP levels did not differ between groups. Correlations revealed that lower levels of OT were associated with poorer levels of metacognitive functioning in the schizophrenia group but not poorer social cognition or neurocognition. In a stepwise multiple regression, plasma OT level, neurocognition and social cognition contributed uniquely to the prediction of metacognition in the schizophrenia group. Results may suggest that disturbance in OT is linked with deficits in metacognition and may interact with other forms of cognitive deficits, interfering with the person's abilities to form a complex and integrated sense of self and others.

Clinical and therapeutic role of mentalization in schizophrenia-a review

Recent empirical findings from clinical and genetic studies suggest that mentalization, a key area of social cognition, is a distinct construct, although it is closely related to the neurocognitive deficits and symptoms of schizophrenia. Mentalization contributes a great deal to impaired social functioning. Current measures often display methodological problems, and many aspects should be taken into account when assessing mentalization. Moreover, advances in cognitive and affective neurosciences have led to the development of more advanced behavioral methods to assess the relationship between cognitive functions, symptoms, and social cognition based on their underlying neural mechanisms. The development of assessment tools that better examine the neural circuitry of such relationships may lead to the development of new psychosocial and pharmacological treatments.

Oxytocin effects in schizophrenia: Reconciling mixed findings and moving forward

Schizophrenia is a severe mental illness that causes major functional impairment. Current pharmacologic treatments are inadequate, particularly for addressing negative and cognitive symptoms of the disorder. Oxytocin, a neuropeptide known to moderate social behaviors, has been investigated as a potential therapeutic for schizophrenia in recent years. Results have been decidedly mixed, leading to controversy regarding oxytocin's utility. In this review, we outline several considerations for interpreting the extant literature and propose a focused agenda for future work that builds on the most compelling findings regarding oxytocin effects in schizophrenia to date. Specifically, we examine underlying causes of heterogeneity in randomized clinical trials (RCTs) conducted thus far and highlight the complexity of the human oxytocin system. We then review evidence of oxytocin's effects on specific deficits in schizophrenia, arguing for further study using objective, precise outcome measures in order to determine whether oxytocin has the potential to improve functional impairment in schizophrenia.

Genes Related to Oxytocin and Arginine-Vasopressin Pathways: Associations with Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a highly heritable neurodevelopmental disorders characterized by impaired social interactions, communication deficits, and repetitive behavior. Although the mechanisms underlying its etiology and manifestations are poorly understood, several lines of evidence from rodent and human studies suggest involvement of the evolutionarily highly-conserved oxytocin (OXT) and arginine-vasopressin (AVP), as these neuropeptides modulate various aspects of mammalian social behavior. As far as we know, there is no comprehensive review of the roles of the OXT and AVP systems in the development of ASD from the genetic aspect. In this review, we summarize the current knowledge regarding associations between ASD and single-nucleotide variants of the human OXT-AVP pathway genes OXT, AVP, AVP receptor 1a (AVPR1a), OXT receptor (OXTR), the oxytocinase/vasopressinase (LNPEP), and ADP-ribosyl cyclase (CD38).

Data extraction and statistical errors: A quantitative critique of Gumley, Braehler, and Macbeth (2014)

OBJECTIVE

While oxytocin has been identified as having therapeutic properties for schizophrenia, the emerging evidence has been mixed which has resulted in meta-analytic reviews. We identified several errors in one such meta-analysis. Here, we highlight these errors, demonstrate the conclusions were incorrect, and state the importance of this report.

METHODS

We reproduced the methods of Gumley, Braehler, and Macbeth (), including: outcomes (positive, negative, and total symptoms, as well as general psychopathology) and meta-analytic estimates for fixed and random effect models.

RESULTS

Whereas Gumley, Braehler, and Macbeth () reported oxytocin had significant effects on three of four outcomes, we show that all effects were non-significant.

CONCLUSIONS

Based on these null results, we hope this report encourages a re-evaluation of intranasal oxytocin as a treatment for schizophrenia.

Effects of intranasal oxytocin on symptoms of schizophrenia: A multivariate Bayesian meta-analysis

Schizophrenia is a heterogeneous disorder in which psychiatric symptoms are classified into two general subgroups-positive and negative symptoms. Current antipsychotic drugs are effective for treating positive symptoms, whereas negative symptoms are less responsive. Since the neuropeptide oxytocin (OT) has been shown to mediate social behavior in animals and humans, it has been used as an experimental therapeutic for treating schizophrenia and in particular negative symptoms which includes social deficits. Through eight randomized controlled trials (RCTs) and three meta-analyses, evidence for an effect of intranasal OT (IN-OT) has been inconsistent. We therefore conducted an updated meta-analysis that offers several advantages when compared to those done previously: (1) We used a multivariate analysis which allows for comparisons between symptoms and accounts for correlations between symptoms; (2) We controlled for baseline scores; (3) We used a fully Bayesian framework that allows for assessment of evidence in favor of the null hypothesis using Bayes factors; and (4) We addressed inconsistencies in the primary studies and previous meta-analyses. Eight RCTs (n=238) were included in the present study and we found that oxytocin did not improve any aspect of symptomology in schizophrenic patients and there was moderate evidence in favor of the null (no effect of oxytocin) for negative symptoms. Multivariate comparisons between symptom types revealed that oxytocin was not especially beneficial for treating negative symptoms. The effect size estimates were not moderated, publication bias was absent, and our estimates were robust to sensitivity analyses. These results suggest that IN-OT is not an effective therapeutic for schizophrenia.

Effects of Intranasal Oxytocin on Long-Term Memory in Healthy Humans: A Systematic Review

Preclinical Research The neuropeptide oxytocin (Oxt) is implicated in complex emotional and social behaviors and appears to play an important role in learning and memory. Animal studies have shown that the effects of exogenous Oxt on memory vary according to the timing of administration, context, gender, and dose and may improve the memory of social, but not nonsocial stimuli. Oxt is intimately involved in a broad array of neuropsychiatric functions and may therefore be a pharmacological target for several psychiatric disorders. This review summarizes the potential effects of Oxt on long-term memory processes in healthy humans based on a PubMed search over the period 1980-2016. The effects of intranasal Oxt on human memory are controversial and the studies included in this review have applied a variety of learning paradigms, in turn producing variable outcomes. Specifically, data on the long-term memory of nonemotional stimuli found no effect or even worsening in memory, while studies using emotional stimuli showed an improvement of long-term memory performance. In conclusion, this review identified a link between long-term memory performance and exogenous intranasal Oxt in humans, although these results still warrant further confirmation in large, multicenter randomized controlled trials. Drug Dev Res 77 : 479-488, 2016. © 2016 Wiley Periodicals, Inc.

Efficacy and safety of oxytocin augmentation therapy for schizophrenia: an updated systematic review and meta-analysis of randomized, placebo-controlled trials

The aim of this study was to perform a systematic review and an updated and comprehensive meta-analysis of oxytocin augmentation therapy in patients with schizophrenia who received antipsychotic agents. Data published up to 07/11/2015 were obtained from PubMed, PsycINFO, and Cochrane Library databases. We conducted a systematic review and meta-analysis of patients' data from randomized controlled trials (RCTs) comparing oxytocin with placebo. Relative risk (RR), standardized mean difference (SMD), and 95 % confidence intervals (95 % CI) based on the random-effects model were calculated. We included seven RCTs; the total sample size was 206 patients. Oxytocin was superior to placebo for decreasing the Positive and Negative Syndrome Scale (PANSS) general subscale scores (SMD = -0.44, 95 % CI -0.82 to -0.06, p = 0.02, I (2) = 0 %, N = 4, n = 112); however, it was not different from placebo for total symptoms (SMD = -0.46, 95 % CI -1.20 to 0.28, p = 0.22, I (2) = 80 %, N = 6, n = 162), positive symptoms (SMD = -0.18, 95 % CI -0.87 to 0.51, p = 0.60, I (2) = 81 %, N = 6, n = 192), and negative symptoms (SMD = -0.34, 95 % CI -0.76 to 0.08, p = 0.12, I (2) = 55 %, N = 7, n = 214). However, a sensitivity analysis including only oxytocin administration on consecutive days studies was superior to placebo in negative symptoms (SMD = -0.44, 95 % CI -0.87 to -0.01, p = 0.04, I (2) = 51 %, N = 6 n = 192). There were no significant differences for all-cause discontinuation (RR = 1.02) and individual side effects such as headache and dizziness between oxytocin and placebo. Oxytocin may improve PANSS general subscale scores in schizophrenia and seems to be well tolerated. However, because the number of studies in the current analysis was small, further study will be required using larger sample sizes.

Peripheral oxytocin and vasopressin: Biomarkers of psychiatric disorders? A comprehensive systematic review and preliminary meta-analysis

A large array of studies have investigated peripheral oxytocin (OT) and vasopressin (ADH) as potential biomarkers of psychiatric disorders, with highly conflicting and heterogenous findings. We searched Web of KnowledgeSM and Scopus® for English original articles investigating OT and/or ADH levels in different biological fluids (plasma/serum, saliva, urine and cerebrospinal fluid) across several psychiatric disorders. Sixty-four studies were included. We conducted 19 preliminary meta-analyses addressing OT alterations in plasma/serum, saliva, urine and cerebrospinal fluid of 7 psychiatric disorders and ADH alterations in plasma/serum, saliva, urine and cerebrospinal fluid of 6 psychiatric disorders compared to controls. Hedge's g was used as effect size measure, together with heterogeneity analyses, test of publication biases and quality control. None of them (except serum OT in anorexia nervosa) revealed significant differences. There is no convincing evidence that peripheral ADH or OT might be reliable biomarkers in psychiatric disorders. However, the lack of significant results was associated with high methodological heterogeneity, low quality of the studies, small sample size, and scarce reliability of the methods used in previous studies, which need to be validated and standardized.

Altering the course of schizophrenia: progress and perspectives

Despite a lack of recent progress in the treatment of schizophrenia, our understanding of its genetic and environmental causes has considerably improved, and their relationship to aberrant patterns of neurodevelopment has become clearer. This raises the possibility that 'disease-modifying' strategies could alter the course to - and of - this debilitating disorder, rather than simply alleviating symptoms. A promising window for course-altering intervention is around the time of the first episode of psychosis, especially in young people at risk of transition to schizophrenia. Indeed, studies performed in both individuals at risk of developing schizophrenia and rodent models for schizophrenia suggest that pre-diagnostic pharmacotherapy and psychosocial or cognitive-behavioural interventions can delay or moderate the emergence of psychosis. Of particular interest are 'hybrid' strategies that both relieve presenting symptoms and reduce the risk of transition to schizophrenia or another psychiatric disorder. This Review aims to provide a broad-based consideration of the challenges and opportunities inherent in efforts to alter the course of schizophrenia.

Effects of oxytocin and genetic variants on brain and behaviour: Implications for treatment in schizophrenia

Impairments in social cognition and poor social functioning are core features of schizophrenia-spectrum disorders. In recent years, there has been a move towards developing new treatment strategies that specifically target social cognitive and social behavioural deficits. Oxytocin (OXT) is one such strategy that has gained increasing attention. There is a strong rationale for studying OXT in psychosis, from both an evolutionary perspective and neurodevelopmental-cognitive model of schizophrenia. Thus, the aim of this review was to critique and examine the observational and clinical oxytocin trial literature in schizophrenia-spectrum disorders. A handful of clinical trials suggest that OXT treatment may be beneficial for remediating social cognitive impairments, psychiatric symptoms, and improving social outcomes. However, inconsistencies exist in this literature, which may be explained by individual differences in the underlying neural response to OXT treatment and/or variation in the oxytocin and oxytocin receptor genes. Therefore, we additionally reviewed the evidence for structural and functional neural intermediate phenotypes in humans that link genetic variants to social behaviour/thinking, and discuss the implications of such interactions in the context of dysfunctional brain networks in schizophrenia. Factors that pose challenges for future OXT clinical research include the impact of age, sex, and ancestry, task-specific effects, bioavailability and pharmacokinetics, as well as neurotransmitter and drug interactions. While initial findings from OXT single dose/clinical trial studies are promising, more interdisciplinary research in both healthy and psychiatric populations is needed before determining whether OXT is a viable treatment option/adjunct for addressing poor illness outcomes in psychotic disorders.

RETRACTED: Effect of intranasal oxytocin administration on psychiatric symptoms: A meta-analysis of placebo-controlled studies

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the authors and Editor-in-Chief of the journal. It was brought to the authors' attention that there were several significant data analytic errors linked to the data entry and the software program that was used in the published meta-analysis comparing the effect of intranasal oxytocin versus placebo administration on psychiatric symptoms. Correcting these errors changed the main result of this study. The authors greatly apologize to the journal, the reviewers, and readers for the errors in the original article, and would like to thank the readers who brought the errors to their attention.

Associations between attachment and psychopathology dimensions in a large sample of patients with psychosis

Attachment theory is a powerful theoretical framework that complements and extents current models psychosis. We tested the hypothesis that attachment anxiety and avoidance are differentially associated with the severity of positive, negative and general psychopathology symptoms in patients with a diagnosis of psychosis. Five hundred patients with DSM-IV or ICD-10 diagnoses of psychotic disorders (schizophrenia, schizoaffective or non-affective psychosis) from independent samples from Netherlands, United Kingdom and Israel completed the Relationship Questionnaire. Psychopathology was assessed with the Positive and Negative Syndromes Scale. We used both categorical and dimensional approach to attachment data, which were analyzed using ANOVA with post-hoc tests, Pearson's correlations and multiple regression analysis. The conservative level of statistical significance was established (p < 0.001) to control for multiple testing. After adjustment for possible confounders, attachment anxiety predicted severity of positive symptoms as well as affective symptoms. Both attachment anxiety and avoidance were associated with severity of hallucinations and persecution Contrary to predictions, attachment avoidance was not associated with overall scores for negative symptoms, although there was some evidence of relatively weaker association between avoidance and social and emotional withdrawal.

Oxytocin administration selectively improves olfactory detection thresholds for lyral in patients with schizophrenia

BACKGROUND

Olfaction plays an important role in mammalian social behavior. Olfactory deficits are common in schizophrenia and correlate with negative symptoms and low social drive. Despite their prominence and possible clinical relevance, little is understood about the pathological mechanisms underlying olfactory deficits in schizophrenia and there are currently no effective treatments for these deficits. The prosocial neuropeptide oxytocin may affect the olfactory system when administered intranasally to humans and there is growing interest in its therapeutic potential in schizophrenia.

METHODS

To examine this model, we administered 40IU of oxytocin and placebo intranasally to 31 patients with a schizophrenia spectrum illness and 34 age-matched healthy control participants in a randomized, double-blind, placebo-controlled, cross-over study. On each test day, participants completed an olfactory detection threshold test for two different odors: (1) lyral, a synthetic fragrance compound for which patients with schizophrenia have specific olfactory detection threshold deficits, possibly related to decreased cyclic adenosine 3',5'-monophosphate (cAMP) signaling; and (2) anise, a compound for which olfactory detection thresholds change with menstrual cycle phase in women.

RESULTS

On the placebo test day, patients with schizophrenia did not significantly differ from healthy controls in detection of either odor. We found that oxytocin administration significantly and selectively improved olfactory detection thresholds for lyral but not for anise in patients with schizophrenia. In contrast, oxytocin had no effect on detection of either odor in healthy controls.

DISCUSSION

Our data indicate that oxytocin administration may ameliorate olfactory deficits in schizophrenia and suggest the effects of intranasal oxytocin may extend to influencing the olfactory system. Given that oxytocin has been found to increase cAMP signaling in vitro a possible mechanism for these effects is discussed.

Oxytocin and social cognition in affective and psychotic disorders

Impairments in social cognition are now recognized as core illness features in psychotic and affective disorders. Despite the significant disability caused by social cognitive abnormalities, treatments for this symptom dimension are lacking. Here, we describe the evidence demonstrating abnormalities in social cognition in schizophrenia, major depressive disorder, and bipolar disorder, as well as the neurobiology of social cognition including the role of oxytocin. We then review clinical trials of oxytocin administration in psychotic and affective disorders and the impact of this agent on social cognition. To date, several studies have demonstrated that oxytocin may improve social cognition in schizophrenia; too few studies have been conducted in affective disorders to determine the effect of oxytocin on social cognition in these disorders. Future work is needed to clarify which aspects of social cognition may be improved with oxytocin treatment in psychotic and affective disorders.

Do delivery routes of intranasally administered oxytocin account for observed effects on social cognition and behavior? A two-level model

Accumulating evidence demonstrates the important role of oxytocin (OT) in the modulation of social cognition and behavior. This has led many to suggest that the intranasal administration of OT may benefit psychiatric disorders characterized by social dysfunction, such as autism spectrum disorders and schizophrenia. Here, we review nasal anatomy and OT pathways to central and peripheral destinations, along with the impact of OT delivery to these destinations on social behavior and cognition. The primary goal of this review is to describe how these identified pathways may contribute to mechanisms of OT action on social cognition and behavior (that is, modulation of social information processing, anxiolytic effects, increases in approach-behaviors). We propose a two-level model involving three pathways to account for responses observed in both social cognition and behavior after intranasal OT administration and suggest avenues for future research to advance this research field.

The influence of oxytocin on volitional and emotional ambivalence

Moral decisions and social relationships are often characterized by strong feelings of ambivalence which can be a catalyst for emotional distress and several health-related problems. The anterior cingulate cortex (ACC) has been identified as a key brain region in monitoring conflicting information, but the neurobiological substrates of ambivalence processing are still widely unknown. We have conducted two randomized, double-blind, placebo-controlled, functional magnetic resonance imaging experiments involving 70 healthy male volunteers to investigate the effects of the neuropeptide oxytocin (OXT) on neural and behavioral correlates of ambivalence. We chose moral decision-making and the imagery of partner infidelity as examples to probe volitional and emotional ambivalence. In both experiments, intranasal OXT diminished neural responses in the ACC to ambivalence. Under OXT, moral dilemma vignettes also elicited a reduced activation in the orbitofrontal cortex, and the imagery of partner infidelity was rated as less arousing. Interestingly, the OXT-induced differential activation in the ACC predicted the magnitude of arousal reduction. Taken together, our findings reveal an unprecedented role of OXT in causing a domain-general decrease of neural responses to ambivalence. By alleviating emotional distress, OXT may qualify as a treatment option for psychiatric disorders with heightened ambivalence sensitivity such as schizophrenia or obsessive-compulsive disorder.

Brain circuit dysfunction in a distinct subset of chronic psychotic patients

OBJECTIVE

To identify the mechanism of unexplained hyponatremia and primary polydipsia in schizophrenia and its relationship to the underlying psychiatric illness.

METHODS

Briefly review previous studies that led to the conclusion the hyponatremia reflects altered hippocampal inhibition of peripheral neuroendocrine secretion. In greater detail, present the evidence supporting the hypothesis that circuit dysfunction associated with the hyponatremia and the polydipsia contributes to the underlying mental disorder.

RESULTS

Polydipsic patients with and without hyponatremia exhibit enhanced neuroendocrine responses to psychological stress in proportion to structural deformations on their anterior hippocampus, amygdala and anterior hypothalamus. Nonpolydipsic patients exhibit blunted responses and deformations on other hippocampal and amygdala surfaces. The deformations in polydipsic patients are also proportional to diminished peripheral oxytocin levels and impaired facial affect recognition that is reversed by intranasal oxytocin. The anterior hippocampus is at the hub of a circuit that modulates neuroendocrine and other responses to psychological stress and is implicated in schizophrenia. Preliminary data indicate that other measures of stress reactivity are also enhanced in polydipsics and that the functional connectivity of the hippocampus with the other structures in this circuitry differs in schizophrenia patients with and without polydipsia.

CONCLUSION

Polydipsia may identify a subset of schizophrenia patients whose enhanced stress reactivity contributes to their mental illness. Stress reactivity may be a symptom dimension of chronic psychosis that arises from circuit dysfunction that can be modeled in animals. Hence polydipsia could be a biomarker that helps to clarify the pathophysiology and heterogeneity of psychosis as well as identify novel therapies. Clinical investigators should consider obtaining indices of water balance, as these may help them unravel and more concisely interpret their findings. Basic researchers should assess if the polydipsic subset is a patient group particularly suitable to test hypotheses arising from their translational studies.

Compassion-Focused EMDR

Compassion-focused therapy was developed to enhance physiological systems related to well-being, safeness, and connectedness in people where shame and self-criticism inhibited progress in therapy (Gilbert, 2000; Gilbert & Irons, 2005). This system links attachment experiences with emotion regulation capacities, with integrative capacities of the mind and also with the interplay between different motivational systems, which are played out in multiple self-states (Cortina & Liotti, 2010; Cozolino, 2010; Gilbert, 2009; Liotti & Gilbert, 2011). Hence, a compassionate focus could potentially prove valuable in eye movement desensitization and reprocessing (EMDR), particularly where shame or attachment trauma is involved or for those traumas that have impacted on the structure of the self, for example, dissociation. A structured compassion-focused EMDR (CF-EMDR) seems likely to be particularly useful for therapists wishing to pay positive attention to strengths and well-being. The primary task of the CF-EMDR therapist would therefore be to facilitate a warm and wise relationship to the problems that brought the person to EMDR. This article outlines the potential benefit of a compassionate focus in the processing phases of EMDR to address self-critical blocks, giving clinical examples in tables to illustrate the process and language.