Parallel Group, Placebo-Controlled, Tolerability, Safety, and Efficacy Study of OPC-14117 in HIV Dementia

Inclusion Criteria Patients must have: * HIV seropositivity. * Cognitive impairment. Prior Medication: Allowed: * Prior OPC-14117 other than on the current study. * Antiretroviral therapy if stable for 6 weeks prior to study entry (12 weeks for stavudine). Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: * Current opportunistic CNS infection (i.e., toxoplasmosis or cryptococcal meningitis). * Severe pre-morbid psychiatric illness including schizophrenia and major depression that would interfere with protocol compliance. * CNS neoplasms. * Any other clinically significant condition or laboratory abnormality that would interfere with ability to participate on study. * Current participation in other drug studies. Patients with the following prior conditions are excluded: * Past history of opportunistic CNS infection (i.e., toxoplasmosis or cryptococcal meningitis). * History of chronic neurological disorders such as serious head injury, documented stroke, multiple sclerosis, uncontrolled epilepsy, Tourette's syndrome, and other neurodegenerative processes such as Huntington's disease. * History of adverse reaction / allergy to OPC-14117. * Prior participation on this study. Prior Medication: Excluded: * Other investigational drugs within the past 30 days. Alcoholism within past 6 months (more than 2 drinks daily).