Differential Impact of Apathy and Depression in the Development of Dementia in Mild Cognitive Impairment Patients

BACKGROUND AND AIMS: Neuropsychiatric symptoms may accompany mild cognitive impairment (MCI) and assist in identifying incipient dementia. The aim of this study was to evaluate the role of apathy and depression in the conversion to dementia among MCI subjects. METHODS: 124 MCI outpatients were investigated. Diagnosis of apathy and depression was based on clinical criteria. The main endpoint was the development of dementia within 2 years from the enrolment. RESULTS: 50 (40.3%) subjects were classified as MCI normal, 38 (30.7%) as MCI depressed, 21 (16.9%) as MCI depressed-apathetic and 15 (12.1%) as apathetic. The rates of conversion were 24% for MCI normal, 7.9% for MCI depressed, 19% for MCI depressed-apathetic and 60% for MCI apathetic. Diagnosis of apathy was a risk factor for conversion apart from age, functional and cognitive status at baseline (OR = 7.07; 95% CI 1.9-25.1; p = 0.003). In contrast, MCI depressed subjects had a reduced risk of conversion (OR = 0.10; 95% CI 0.02-0.4; p = 0.001). CONCLUSION: These findings argue for a differential role of apathy and depression in the development of dementia, and suggest the need of dissecting in MCI patients apathy and depression symptoms in the reading of mood disorders.