GROUP 1: If you are assigned to group 1, then you will receive active drug during visit 1 (first inpatient visit) and placebo (inactive drug which is same as receiving no drug) during visit 3 (second inpatient visit). GROUP 2: If you are assigned to group 2, then you will receive placebo (inactive drug which is same as receiving no drug) during visit 1 (first inpatient visit) and active drug for visit 3 (second inpatient visit).