any significant non-PD CNS disorder; drug abuse or alcoholism; unstable cardiac, pulmonary, renal, hepatic, endocrine or hematologic disease; active infectious disease; AIDS or AIDS-related complex; malignancy within 3 years of screening (other than fully excised non-melanoma skin cancer, cured in situ cervical carcinoma, early stage bladder cancer, or DCIS of breast); psychosis or untreated major depression within 30 days of screening; dementia