General Paresis of the Insane, also known as General Paralysis of the Insane or GPI, is a progressive and irreversible neurological disease that affects the brain and central nervous system. It is caused by syphilis, a bacterial infection that spreads through sexual contact or contaminated blood transfusions. Synonyms for GPI include Progressive Paralysis, Dementia Paralytica, and Neurosyphilis. Other terms used to describe GPI include Tertiary Syphilis and Paralytic Dementia. The disease causes a wide range of symptoms including mental deterioration, memory loss, delusions, hallucinations, and physical weakness. GPI was once a major public health concern, but it became less common after the development of antibiotics and widespread use of penicillin to treat syphilis.