Neuropsychiatric predictors of progression from amnestic-mild cognitive impairment to Alzheimer's disease: the role of depression and apathy.
The aim of the study is to evaluate whether depression or apathy in patients with amnestic-mild cognitive impairment (MCI) increases the risk of progressing to Alzheimer's disease (AD). We investigated 131 consecutive memory-clinic outpatients with newly-diagnosed amnestic-MCI (mean age 70.8, SD=6.5). Psychiatric disorders were diagnosed at baseline according to the criteria for depression and apathy in AD. Neuropsychiatric symptoms were assessed with the Neuropsychiatric Inventory (NPI). Follow-up examinations were conducted after six months and annually for four years. Neurologists diagnosed AD at follow-up using NINCDS-ADRDA criteria. Cox proportional hazard models with 95% confidence intervals were used to test the hypothesis that apathy or depression increases the risk of developing AD. At baseline, 36.6% amnestic-MCI patients had a diagnosis of depression and 10.7% had apathy. Patients with both amnestic-MCI and an apathy diagnosis had an almost sevenfold risk of AD progression compared to amnestic-MCI patients without apathy (HR=6.9; 2.3-20.6), after adjustment for age, gender, education, baseline global cognitive and functional status, and depression. Furthermore, the risk of developing AD increased 30% per point on the NPI apathy item (HR=1.3; 1.1-1.4). There was no increased risk of developing AD in amnestic-MCI patients with either a diagnosis or symptoms of depression. In conclusion, apathy, but not depression, predicts which patients with amnestic-MCI will progress to AD. Thus, apathy has an important impact on amnestic-MCI and should be considered a mixed cognitive/psychiatric disturbance related to ongoing AD neurodegeneration.
Palmer
Katie
K
Fondazione Santa Lucia, Instituto di Ricovero e Cura a Carettere Scientifico, Rome, Italy. k.palmer@hsantalucia.it
Di Iulio
Fulvia
F
Varsi
Ambra Erika
AE
Gianni
Walter
W
Sancesario
Giuseppe
G
Caltagirone
Carlo
C
Spalletta
Gianfranco
G
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000209:etiology*; D000647:Amnesia / Q000150:complications* / Q000209:etiology; D001526:Behavioral Symptoms / Q000150:complications* / Q000175:diagnosis / Q000209:etiology*; D003072:Cognition Disorders / Q000150:complications* / Q000175:diagnosis / Q000209:etiology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007558:Italy; D008297:Male; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests