Effects of Intranasal Oxytocin on Satiety Signaling in People With Schizophrenia

Phase 4

Completed

Brief Summary: The objective of this study is to test a single dose of intranasal oxytocin, compared to placebo, in a within subjects, crossover design, to see if oxytocin will improve satiety signaling (behaviorally and/or by self report) compared to placebo. If this single dose pilot paradigm shows an increase in satiety, it may be tested in follow-up studies as a prevention or treatment for weight gain and overeating in people with schizophrenia.

Recruitment & Eligibility

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).

Arm && Interventions

Group	Intervention	Description
Oxytocin/Placebo	Placebo	Each participant will receive intranasal oxytocin 24IU or intranasal saline 24IU in random order. All results will be reported by treatment, the sample is too small for order effects.
Placebo/Oxytocin	Placebo	Each participant will receive intranasal oxytocin 24IU or intranasal saline 24IU in random order. All results will be reported by treatment, the sample is too small for order effects.
Oxytocin/Placebo	Oxytocin	Each participant will receive intranasal oxytocin 24IU or intranasal saline 24IU in random order. All results will be reported by treatment, the sample is too small for order effects.
Placebo/Oxytocin	Oxytocin	Each participant will receive intranasal oxytocin 24IU or intranasal saline 24IU in random order. All results will be reported by treatment, the sample is too small for order effects.

Primary Outcome Measures

Name	Time	Method
Food Consumption After Intervention	90 minutes	We hypothesize that participants will have greater satiety signaling, indicated by less consumption of the "Test Meal" consumed 90 minutes after the preload.

Secondary Outcome Measures