 The hypotheses are as follows: First, based on the known affinity of ziprasidone, the dopamine D2 occupancy 24 hours after the last administered dose of 80 mg will be 60. Second, the difference in dopamine D2 occupancy between scan at 6 hours and 24 hours will be less than 15. Third, the difference in dopamine D2 occupancy between scan at 12 hours and 24 hours will be less than 10. Fourth, ED50 24 hours post dose will be higher that those 6 and 12 hours postdose. 