This study will investigate the molecular mechanisms of atypical-antipsychotic induced insulin resistance. This will be accomplished by administering olanzapine or placebo to healthy subjects for 7 days and analyzing genetic and protein changes in peripheral tissues known to play an important role in insulin resistance pathophysiology.

We will include persons that meet the following criteria:

1. 21-45 years old
2. BMI 18.5-24.9kg/m2
3. No history of drug or alcohol dependence or abuse
4. No current or past history of psychiatric or neurologic disease
5. minimal exercise routine prior or during study (light walking allowed)
6. Normal liver function tests
7. minimal alcohol intake (<1 drink per day).

The following persons will be excluded:

1. Has 1st degree relative with diabetes (I or II)
2. current or re-cent nicotine intake
3. presence of organic/physical disease that could affect glucose
4. currently taking prescription or over-the-counter medications that could affect glucose
5. currently pregnant or lactating
6. unwilling to take acceptable birth control method
7. current or previous exposure to antipsychotics
8. history of unstable weight
9. personal or family history of cardiac arrhythmias or seizures
10. current or past history of eating disorder(s) or restricted diet
11. allergy to lidocaine or drug excipients
12. history of difficulty with intravenous line placement
13. history of fainting.