Medicare Psychiatric Hospital Prospective Payment System Act of 1998

Medicare Psychiatric Hospital Prospective Payment System Act of 1998 - Amends title XVIII (Medicare) of the Social Security Act to: (1) provide for a prospective payment system for inpatient psychiatric facility hospital services; and (2) exempt such services from certain reductions under the Balanced Budget Act of 1997, and, instead, limit payment to not less than a certain applicable percentage of the amount that would have been paid if such reductions did not apply.