To investigate whether 24IU oxytocin can result in changes in functional brain connectivity in patients with schizophrenia and healthy individuals using functional magnetic resonance imaging (fMRI). The study will also examine the effect of oxytocin receptor gene polymorphism on the functional connectivity

Inclusion and Exclusion Criteria:

Schizophrenia subjects:

Inclusion criteria 1) Males between 18 and 50 years 2) Diagnosis of DSM-IV schizophrenia, schizoaffective or schizophreniform disorder 3) capacity to provide informed consent, as evaluated by the MacArthur Competence Assessment Tool for Clinical Research Exclusion criteria

1. General impairment in intellectual functioning
2. History of alcohol or substance dependence in the last 12 months (with the exception of nicotine)
3. Contraindication to oxytocin like hypersensitivity, vascular disease, chronic nephritis, epilepsy, asthma
4. Past history of head injury resulting in loss of consciousness or neurosurgery
5. Concomitant severe medical conditions
6. Metal implants or paramagnetic objects within the body or claustrophobia which may interfere with the MRI.

Healthy volunteers:

Inclusion criteria

1. Males between 18 and 50 years
2. Capacity to provide informed consent Exclusion criteria

1) Life-time diagnosis of psychiatric illnesses including substance abuse 2) General impairment in intellectual functioning 3) Past history of head injury resulting in loss of consciousness or neurosurgery 4) Concomitant severe medical or neurological conditions 5) Metal implants or paramagnetic objects or claustrophobia 6) Family history of schizophrenia, schizoaffective or schizophreniform disorder in family member (sibling, parent or offspring) 7) Contraindication to oxytocin like hypersensitivity, vascular disease, chronic nephritis, epilepsy, asthma.