Objective: For a long time it was thought that Nietzsche suffered from general paralysis of the insane (GPI). However, this diagnosis has been questioned recently, and alternative diagnoses have been proposed.

Method: We have charted Friedrich Nietzsche's final fatal illness, and viewed the differential diagnosis in the light of recent neurological understandings of dementia syndromes.

Results: It is unclear that Nietzsche ever had syphilis. He lacked progressive motor and other neurological features of a progressive syphilitic central nervous system (CNS) infection and lived at least 12 years following the onset of his CNS signs, which would be extremely rare for patients with untreated GPI. Finally, his flourish of productivity in 1888 would be quite uncharacteristic of GPI, but in keeping with reports of burgeoning creativity at some point in the progression of frontotemporal dementia (FTD).

Conclusion: We suggest that Nietzsche did not have GPI, but died from a chronic dementia, namely FTD.