Effects of Oxytocin on Amygdala Response to Threat in Generalised Social Anxiety Disorder: A Functional Magnetic Resonance Imaging (fMRI) Study

A placebo-controlled, randomised phase III trial investigating the effects of oxytocin, a neuropeptide, on the neural circuit (i.e. amgydala) involved in threat processing in Generalised Social Anxiety Disorder using functional magnetic resonance imaging (fMRI).

Status

Completed

Phases

Phase 3

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12607000141448

Enrollment

Registered

2007-02-23

Start date

2008-03-12

Completion date

2009-11-17

Last updated

2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

The proposed study will examine if intranasal oxytocin can modulate the neural circuitry (especially the amygdala) response to threat in patients with Generalised Social Anxiety Disorder (GSAD). Two treatment conditions are involved: Oxytocin vs. Placebo. Participants (20 GSAD, 20 healthy controls) are required to undergo two functional magnetic resonsonance imaging (fMRI) sessions during which they will be asked to complete two emotional facial expression tasks. It is hypothesised that under placebo, patients with GSAD will show exaggerated amygdala activity as well as functional connectivity to threatening (i.e. angry and fearful) facial stimuli compared to healthy controls. Under oxytocin, such effects will be absent and amgydala activation and functional connectivity during threat processing will be reduced.

Interventions

Two intranasal treatment conditions: (1) Oxytocin Nasal Spray (24IU or 40.3mg) and (2) Placebo. Administration at 50 mins prior to fMRI scanning procedure. There is a minimum washout period of 1 week in between 2 fMRI sessions. The two groups, involving patients with Generalised Social Anxiety Disorder (GSAD) and healthy controls, will both receive the same interventions (placebo and oxytocin) during the time span of the study, but in different sequences during the study. All participants act as their own control due to placebo condition. However it is also of interest to compare the group of Generalised Social Anxiety Disorder patient with a control/comparison group of healthy controls. The allocation of the conditions is blinded and randomised.

Study design

Allocation

Randomised controlled trial

Intervention model

Crossover

Primary purpose

Treatment

Masking

Blinded (masking used)

Eligibility

Sex/Gender

All

Age

18 Years to 55 Years

Healthy volunteers

Yes

Inclusion criteria

Right-handed, non-smokers, psychotropic medication free for a minimum of 2 weeks (8 weeks for fluoxetine, 4 weeks for monoamine oxidase inhibitors), not taking hormonal contraceptives, and do not have comorbid alcohol or substance abuse or dependence. Additional inclusion for GSAD participants - Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) GSAD as primary diagnosis.

Exclusion criteria

Clinically significant medical or neurologic condition (not applicable to GSAD patients, see inclusion criteria), current/recent depressive episode, life history of bipolar, schizophrenia, obsessive compulsive disorder, post-traumatic stress disorder or presence of organic mental syndrome, mental retardation, or pervasive developmental disorder, pregnancy or lactation, presence of ferrous-containing metals within the body, inability to tolerate small, enclosed spaces without anxiety.

Outcome results