Intranasal oxytocin has not demonstrated efficacy relative to placebo on empathy, introspective accuracy, and self-reported social measures in individuals with schizophrenia, according to a study recently published in Schizophrenia Research.
This double-blind treatment study included 62 individuals randomly assigned to either intranasal oxytocin twice daily (n=32) or placebo (n=30). Introspective accuracy did not differ significantly between the groups, though it did improve slightly at the 3-month mark in the placebo group (P =.02). Those taking oxytocin showed improvement in Interpersonal Reactivity Index relative to placebo (MLS=0.4 vs -1.8; P =.031). Self-reported symptom outcomes did not differ significantly between the groups, and changes within a group were only observed in placebo. Social avoidance had decreased in the placebo group at 3 months (MLS=-2.7; 95% CI, -4.6 to -0.7; P =.007), and at 6 weeks both paranoia (MLS=-4.7; 95% CI, -8.2 to -1.2; P =.008) and total score (MLS=-8.1; 95% CI, -14.6 to -1.7; P =.01) had also improved in placebo.
Participants in this study were diagnosed with either schizoaffective disorder or schizophrenia, and all participants completed visits at weeks 6 and 12 for assessment. Scales including the Specific Level of Functioning Scale, Positive and Negative Syndrome Scale, Interpersonal Perception Task, and Interpersonal Reactivity Index were used. Mixed models were utilized to examine the efficacy of oxytocin on preselected outcomes.
The study researchers “found little support for the effect of twice-daily intranasal oxytocin on self-reported social symptoms, empathy and [introspective accuracy]. Presentation of these tertiary and exploratory outcomes should contribute to any potential file drawer effect in oxytocin treatment research.”
This research was funded by a grant from NIMH.
Halverson T, Jarskog LF, Pedersen C, Penn D. Effects of oxytocin on empathy, introspective accuracy, and social symptoms in schizophrenia: a 12-week twice-daily randomized controlled trial [published online September 19, 2018]. Schizophr Res. doi: 10.1016/j.schres.2018.09.013