Effects of Antipsychotic Medications on Energy Intake and Expenditure
Condition: Schizophrenia; Schizoaffective Disorder; Weight Gain
MeSH terms: Weight Gain; Schizophrenia; Psychotic Disorders
Study type: Observational

Summary: 
      Aim 1: To evaluate the effect of antipsychotic treatment group on Activity Energy
      Expenditure. The project hypothesizes that subjects treated with olanzapine will demonstrate
      a greater decrease in AEE over time than subjects treated with ziprasidone, due at least in
      part to sedating effects of olanzapine.

      Aim 2: To evaluate the effect of antipsychotic treatment group on Energy Intake. The project
      hypothesizes that subjects treated with olanzapine will demonstrate a greater increase in EI
      over time than subjects treated with ziprasidone, based on higher histamine type 1 (H1)
      receptor affinity of olanzapine and the relationship between H1 affinity and hunger and/or
      satiety.
    

Detailed description: 
      The overall purpose of this research is to determine how two commonly prescribed
      antipsychotic medications, olanzapine (Zyprexa) and ziprasidone (Geodon), affect weight gain
      through increasing appetite and/or through increasing sedation that results in decreased
      activity.

      Undesirable changes in body weight, blood sugar control, type 2 diabetes, and blood lipids
      occur more commonly in people who have schizophrenia than in people without psychiatric
      conditions. Although differences in glucose regulation were first reported in schizophrenia
      before the use of antipsychotic medications, antipsychotic treatment may contribute to these
      problems, though just how this happens is not understood. This study proposes to use a
      doubly-labeled water (DLW) method to measure the degree to which weight gain (fat mass) is
      due to increased appetite, decreased physical activity from being tired and sleepy, or some
      combination of both. Doubly-labeled water contains stable isotopes (non-radioactive forms) of
      the hydrogen and oxygen that make up all water, isotopes that will be slowly passed out
      through the urine after participants drink DLW. The number of hydrogen and oxygen isotopes
      found in the urine samples will tell us how many calories the participant's body has been
      using.

      The DLW method has been used in people with obesity and other types of medical problems. It's
      recognized as the most accurate measure of the number of calories burned throughout a typical
      day, and how many calories are taken in from food and drink. By measuring these factors in
      people who take antipsychotic medications, doctors will gain a better understanding of the
      effects of antipsychotic medications on body weight and fat mass. This could lead to the
      development of better ways to prevent or treat weight gain or diabetes in patients who take
      antipsychotic medications.
    

Intervention name(s): H218O and 2H2O, administered as a mixed cocktail
Intervention type(s): Dietary Supplement
Intervention description(s): 0.195 g of H218O and 0.117 g of 2H2O per kg of estimated total body water (TBW), administered as a mixed cocktail
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Males and females, ages 18-80, diagnosed with schizophrenia or schizoaffective disorder
      
Keywords: energy expenditure; schizophrenia