The PredictND tool is a clinical decision support system (CDSS) to aid in differential diagnosis of dementia. It provides a comprehensive overview of patient data (demographics, neuropsychological tests, cerebrospinal fluid biomarkers, and visual and computed MRI ratings) and a likelihood index for 5 diagnostic groups: Alzheimer’s disease, vascular dementia, dementia with Lewy bodies, frontotemporal dementia, and subjective cognitive decline. In this study, patients with subjective cognitive decline, mild cognitive impairment, or any type of dementia were followed for at least 12 months. Although the etiological diagnosis changed for some cases, the diagnostic accuracy did not significantly change. Clinicians had increased confidence in the diagnosis with PredictND.