Intranasal Oxytocin as an Adjunct to Inpatient Treatment for Anorexia Nervosa: Does a ‘Social Hormone’ Address Social and Interpersonal Difficulties?

Abstract

Anorexia nervosa (AN) is a life-threatening mental illness, for which effective treatments are desperately lacking. Nutritional rehabilitation is considered the cornerstone of treatment, but is often distressing for patients. Intranasal oxytocin (IN-OXT) has been shown to improve anxiety and promote trust in some mental illnesses. This thesis reports on findings from two different aspects of oxytocin (OXT) in AN. Firstly, a systematic review and meta-analysis assessing endogenous levels of OXT in acute AN compared to healthy controls, describes preliminary evidence of low OXT, and a dysregulated OXT system in AN. However, methodological issues limit the conclusions that can be drawn about OXT in AN. Secondly, a randomised double-blind controlled trial examined the use of IN-OXT in female patients with AN undergoing inpatient refeeding over 4 weeks (N=62). Patients were tested on a range of measures at pre- and post-treatment, and 6 months (6-month follow-up also included qualitative interviews). Results indicated significant improvement in weight concern, and a trend toward improvement in shape concern on the Eating Disorder Examination at post-treatment, for those taking IN-OXT compared to placebo. However, any benefits of IN-OXT appeared to taper off with cessation of the nasal spray. Significantly increased interpersonal distress was reported for those taking IN-OXT at 6 month follow up, compared to placebo, which may reflect activation of underlying attachment style. Thematic analysis of interviews (N=18) showed that IN-OXT appeared to produce more profound changes for patients, including increased openness with others, less rumination, and more flexibility in thinking and behaviour compared to placebo. Future research is needed to elucidate any potential benefit of IN-OXT in this cohort.