Healthy Volunteers Study of the Effects of Olanzapine and Ziprasidone

Primary Aim: To test the acute effects of olanzapine or ziprasidone administration, in comparison to placebo, on insulin sensitivity in antipsychotic-naïve healthy young men, measured as whole-body dextrose infusion rates (mg/kg/min), hepatic glucose production (glucose rate of appearance \[Ra\]), primarily muscle glucose utilization (glucose rate of disappearance \[Rd\]), and adipose tissue related free fatty acid production (glycerol rate of appearance \[Ra\]). We hypothesize that olanzapine, but not ziprasidone, will result in acute decreases in insulin sensitivity. Secondary Aim: To test the acute effects of olanzapine or ziprasidone on insulin signaling pathways in antipsychotic naïve healthy young men. We hypothesize that olanzapine, but not ziprasidone, will result in acute alterations in insulin signaling.