Effects of Intranasal Oxytocin on Satiety Signaling in People With Schizophrenia

Inclusion Criteria:

- DSM-IV diagnosis of schizophrenia or schizoaffective disorder

- Male or Female

- Age: 18 to 54 years

- Caucasian or Non-Caucasian

- Body Mass Index of ≥ 27 kg/m2

- One month of stable antipsychotic treatment (same medication regimen and same dose)

Exclusion Criteria:

- History of organic brain disease

- DSM-IV diagnosis of Mental Retardation

- DSM-IV diagnosis of Alcohol or Substance Dependence within the last six months (except
nicotine)

- DSM-IV diagnosis of Alcohol or Substance Abuse within the last one month (except
nicotine)

- Are pregnant or lactating

- Meet DSM-IV criteria for a past and/or current eating disorder via the SCID, or if
they have a past medical history of an eating disorder, received treatment/counseling
for an eating disorder and/or required hospitalization for an eating disorder. (If an
otherwise undiagnosed eating disorder is detected during screening, referral to
treatment will be provided.)

- Are taking weight-loss medications, whether over-the-counter (i.e. Hydroxycut, Stacker
products, Metabo-Plus, CortiSlim), or prescribed, including appetite suppressants
(Didrex, Tenuate, Sanorex, Mazanor, Adipex-P, Meridia, and Phentermine) and
fat-absorption inhibitors (Xenical).

- Have cognitive impairment severe enough to preclude informed consent or valid
responses on questionnaires. This is defined an as a score of less than 10 on the
Evaluation to Sign Consent (ESC).

- Have a medical illness, dietary restrictions, or food allergies that, in the view of
the investigators, would compromise participation.

- Are taking prostaglandins such as dinoprostone or misoprostol (because they interact
with oxytocin).