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

Objectives
There is now considerable evidence that affiliative processes are linked to oxytocin (OXT), which is linked to a range of social-cognition competences underpinning interpersonal functioning. There is evidence that OXT circuitry is involved in psychosis and emerging evidence for OXT in treatment. Therefore, this study explored studies investigating OXT and improvements in symptoms and social cognition among individuals diagnosed with psychosis.

Method
We conducted a systematic review of randomized controlled trials investigating OXT and psychosis. Specifically we asked, (1) what is the evidence that OXT is associated with improved overall, positive, negative and general symptoms and (2) what is the evidence that OXT is associated with improved social cognition?

Results
There were seven randomized controlled trials that met the inclusion criteria for this review. We conducted an exploratory meta-analysis of data from four of these studies on a total sample size of n = 105. For overall symptoms, using a random-effects model OXT versus placebo was associated with an effect size of d = 0.52 (95% CI = 0.34–0.70; z = 5.66; p < .01). There was evidence of significant heterogeneity (Q = 96.4, p < .001; I2 = 96.5%). Similar patterns of findings were observed for positive, negative, and general symptoms. We found significant evidence of high risk of bias across all studies. We also identified that one particular study had an undue effect on overall effect size estimates. Finally, evidence regarding OXT was linked to improved social cognition was inconsistent.

Conclusions
There are significant problems in interpreting the current evidence base for OXT in psychosis. However, OXT may provide a useful biomarker for exploring mechanisms of change occurring in psychological therapies including compassion-focused therapy (CFT), which through its engagement of the attachment system may directly influence OXT.

Practitioner points
Positive clinical implications

Practitioners should consider the attachment and/or interpersonal context of both psychological and pharmacological therapies.
There may be a specific role CFT in fostering social cognition and mentalization as a context for emotional and psychiatric recovery.
Future clinical trials of CFT in psychosis could consider mapping changes in social cognition onto changes in OXT thereby linking important domains of emotional and social recovery to underlying and salient neurophysiological systems.