Neuropsychiatric Symptoms in Comorbid Alzheimer's Disease Neuropathologic Change and Frontotemporal Lobar Degeneration

Comorbid presence of ADNC and FTLD neuropathology was associated with greater likelihood of presenting with known neuropsychiatric symptoms of the other disease, irrespective of clinical syndrome. Disinhibition and personality change differentiated comorbid ADNC and FTLD from ADNC alone, while delusions, irritability, and anxiety differentiated comorbid ADNC and FTLD from FTLD alone. These findings highlight the diagnostic value of antemortem behavioral symptoms in comorbid pathology. Moreover, findings are consistent with well-established neuropsychiatric phenotypes of ADNC and FTLD, emphasizing the importance of clinical phenotypes in precision medicine.