Oxytocin to modulate emotional processing in schizophrenia: A randomized, double-blind, cross-over clinical trial

Deficits in social cognition, including emotional processing, are hallmarks of schizophrenia and antipsychotic agents seem to be ineffectual to improve these symptoms. However, oxytocin does seem to have beneficial effects on social cognition. The aim of this study was to examine the effects of four months of treatment with intranasal oxytocin, in 31 patients with schizophrenia, on distinct aspects of social cognition. This was assessed using standardized and experimental tests in a randomized, double-blind, placebo-controlled, cross-over trial. All patients underwent clinical and experimental assessment before treatment, four months after treatment and at the end of treatment. Social cognition abilities were assessed with the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) and the Reading the Mind in the Eyes task (RMET). Furthermore, an Emotional Priming Paradigm (EPP) was developed to examine the effects of oxytocin on implicit perceptual sensitivity to affective information and explicit facial affect recognition. We found that oxytocin improved performance on MSCEIT compared to placebo in Branch 3-Understanding Emotion (p-value=0.004; Cohen׳s d=1.12). In the EPP task, we observed a significant reduction of reaction times for facial affect recognition (p-value=0.021; Cohen׳s d=0.88). No effects were found for implicit priming or for theory of mind abilities. Further study is required in order to highlight the potential for possible integration of oxytocin with antipsychotic agents as well as to evaluate psycho-social treatment as a multi-dimensional approach to increase explicit emotional processing abilities and compensate social cognition deficits related to schizophrenia.