2026 ECNP Congress

PS03-3195

A randomised controlled trial for intranasal oxytocin versus placebo to treat Body Dysmorphic Disorder (BDD)

Susan L. Rossell — R. Iyer, E. Byrne, K. Holmes a Court, W.L. Toh, D. Meyer, T. Pikoos, P. Sumner, D. Castle · Swinburne University, Centre for Mental Health and Brain Sciences, Melbourne, Australia

2026 ECNP Congress

Background

Body Dysmorphic Disorder (BDD) is a severe and debilitating mental health condition. BDD usually starts in the teenage years, with negative impact on social development; school avoidance is common and impacts academic achievements. BDD is often unremitting, associated with high rates of hospital admissions (48%), suicidal ideation (80%) and suicide attempts (28%). People with BDD experience substantial functional impairments across multiple life domains, including work, leisure or school activities, as well as difficulties with social and romantic relationships. Although existing treatments are effective for some individuals, many patients experience persistent symptoms or show limited response. There is an urgent need for novel targeted interventions. Emerging evidence suggests that intranasal oxytocin may improve social cognition and functioning in BDD. Oxytocin is a neuropeptide that acts as a neurotransmitter. It is a key modulator of complex social behaviours and social cognition throughout mammalian evolution. It is well-known for its role in attachment, social exploration, social recognition, fear extinction and anxiety reduction. This study aimed to evaluate the efficacy and safety of daily intranasal oxytocin (24 IU) as an augmenting treatment in symptomatic adults with BDD.

Methods

This 6-week, single-centre, double-blind, placebo-controlled randomised trial examined the effects of 24 IU (0.6 ml) intranasal oxytocin daily versus placebo. Adults with DSM-5 BDD and moderate-to-severe symptoms (BDD-YBOCS ≥ 20) were randomised. Outcomes were assessed at baseline, 6 weeks (primary endpoint), and 12 weeks (follow-up). The primary outcome was BDD symptom severity (BDD-YBOCS). Secondary outcomes included measures of everyday functioning (including perceived social self-efficacy and global functioning) and the Depression Anxiety Stress Scales (DASS). Data were analysed using mixed linear models.

Results

Fifty-six participants were randomised. The primary outcome of BDD-YBOCS score at 6 weeks was not statistically significant (p = 0.15, d = −0.43, 95% CI [−1.00, 0.15]). However, oxytocin-treated participants showed significant improvements compared with placebo in perceived social self-efficacy (p = .001, d = 0.5, 95% CI [−0.21, −0.79]), global current functioning (p = .01, d = 0.51, 95% CI [0.21, −0.80]), and depression (p = 0.01, d = −0.92, 95% CI [−1.63, −0.21]), but not in quality of life, loneliness, perceived social support, relationship satisfaction, anxiety, or stress. Improvements in global functioning and depression were sustained at 12-week follow-up. Adverse events were minor to moderate and transient, indicating good tolerability.

Discussion

This proof-of-concept trial found that 6 weeks of daily intranasal oxytocin did not significantly reduce core BDD symptoms relative to placebo, although a medium effect size was observed. Oxytocin was associated with significant and sustained benefits in global functioning and depressive symptoms. These findings suggest that targeting the oxytocin system may hold promise for improving the prominent social and functional impairments in BDD. Larger, adequately powered trials, ideally combining oxytocin with evidence-based psychological therapies, are warranted to further evaluate its therapeutic potential.

References

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