Neural and Behavioral Effects of Oxytocin in Autism Spectrum Disorders

The current trial aims to explore the neural and behavioral effects of oxytocin in autism spectrum disorders (ASD). Oxytocin is a nonapeptide produced by the paraventricular and supraoptic nuclei of the hypothalamus and is known to play a pivotal role in a variety of complex social behaviors. Initial studies showed that intranasal administration of oxytocin can have a positive effect on social functioning in ASD.

However, future studies are necessary to explore whether and how oxytocin effects neural processes in the brain underlying these behavioral improvements. This trial will not only measure behavioral enhancements, but will specifically focus on elucidating the associated neurophysiological changes by guiding the administration of oxytocin with regular neurophysiological assessments.

The present study is a monocentric, between-subjects, randomized, placebo-controlled trial. The investigators will recruit approximately 40 young-adult, male individuals with a clinical diagnosis of Autism Spectrum Disorder (ASD). Participants will be randomly allocated to an experimental group (Oxytocin (OT)) and a control group (Placebo (PL)). All participants will receive the same frequency and duration of intervention. Behavioral and neural outcome measures will be assessed at multiple time points in a period of a year. Participants will be tested at 5 occasions: before and after a single dose of nasal spray, after multiple doses of nasal spray (1 daily dose of nasal spray during 4 weeks), after a 4-week retention period and after a 1-year retention period. At each time point participants will be tested at both the behavioral and neural level. Test performance of both participant groups (OT vs PL) will be compared by measuring reaction times and accuracy rates in a computerized task assessing a person's ability to recognize bodily emotional states from point light displays. In addition, attachment, social functioning, restricted behaviour, general quality of life and mood will be assessed via self-reported questionnaires.

Functional MRI measurements will be performed in a 3T MR Philips Intera scanner. Before scanning, subjects will undergo a training session to familiarize them with the task instructions. In addition to the fMRI measurements, resting state fMRI and Diffusion Tensor Imaging (DTI) will also be performed to reveal alterations of the functional and structural connectivity between critical regions.

Statistical analysis of the behavioral data will have a between-subject factor of group (OT vs PL) and within-subject factors of time (change-from-baseline). Image analysis will be performed with Statistical Parametric Mapping (SPM) software. The investigators will contrast for either decreased or increased activation, as different regions may show divergent changes due to the received nasal spray (either OT or PL).

Eligibility Criteria:
Inclusion Criteria:

* Clinical diagnosis of Autism Spectrum Disorder, Asperger Syndrome or Autism
* Male
* Age between 18 and 40 years old

Exclusion Criteria:

* Associated neuro(psycho)logical disorder (i.e. epilepsy, concussion, stroke)
* Eye sight worse than + or - 7
* Genetic syndrome
* Color blindness
* Any contraindication to neuroimaging research as assessed with the MRI screening list:

MRI contraindications:

pacemaker, implanted defibrillator, ear implant / a cochlear implant, insulin or implanted pump, a neurostimulator or VP shunt, any metallic object in the eyes (metallic fragments)