Friedrich Nietzsche suffered from dementia paralytica -or
general paresis- as the results of contracting syphilis (STI),
which left untreated (antibiotics) can cause lasting mental
damages. The bacterium infects the nervous system (brain and spinal
cord) that degenerates into neurosyphilis. The form of
neurosyphilis Nietzsche developed typically became general paresis
that progressed into dementia, then death.