Depression and progression of cognitive function in Chinese older persons with mild cognitive impairment: A 2-year follow up

Abstract

Mild Cognitive Impairment (MCI) is a high risk condition for subsequent development of clinical dementia. Depression and apathy are common neuropsychiatric symptoms in subjects with MCI. However, reports concerning the significance of depression and apathy in predicting further cognitive deterioration are inconsistent. This study examined the association between depression and apathy with change in cognitive function in a group of Chinese subjects with MCI. 309 Chinese subjects (aged 60 or over) with MCI were recruited from community volunteers and population survey. Amnestic MCI were diagnosed according to the Mayo Clinic criteria, non-amnestic MCI were subjects with global Clinical Dementia Rating (CDR) <1 and >=2 CDR subscale in non-memory domains rated as 0.5 or more. They were followed up at an average of 22(3.8) months. Outcome was defined as either improved (not satisfied criteria for MCI), stable (MCI at follow up) or demented. The presence of depression and apathy was rated by the Chinese version of Neuropsychiatric Inventory (NPI). At follow up, 146(47%) remained stable, 116(38%) improved and 47(15%) became demented. Subjects with depressed mood compared with those without depressed mood at the baseline (25% versus 14%), had a higher chance of deterioration to dementia (Pearson Chi square=3.9, p=0.049). MCI subjects with depressed mood experienced a greater drop in MMSE scores at follow up (drop in z scores = 0.7(1.4)) (t=2.2, p=0.027). The presence of apathy did not correlate significantly with deterioration to dementia at follow up. The findings suggested that depressed mood in Chinese subjects with MCI may be associated with higher chance for further cognitive deterioration. While depressed mood may be a concomitant manifestation of incipient dementia, its effects in accelerating functional decline should be further evaluated.