On the third day of treatment, researchers will record the amount of haloperidol that you had to use in the previous 24 hours. If the amount of haloperidol that you used is greater than a certain amount, your dose of olanzapine will again be increased. As before, if your dose of olanzapine is increased, you may still be able to use haloperidol if needed. If you respond to olanzapine after 3 days of treatment, you will be given the option to continue the drug off-study.