Cognitive and functional impairment in Chinese elderly with late-onset depression

OBJECTIVES. To investigate cognitive and functional impairment in Chinese elderly subjects with late-onset depression. METHODS. Subjects with late-onset depression and who were clinically non-demented were recruited. Their cognitive and functional scores were compared with those of cognitively normal elderly controls and elderly persons with mild cognitive impairment. Functional ability was assessed by the Disability Assessment for Dementia score. Various cognitive domains were assessed including global cognitive function, delayed episodic memory, working memory, and categorical verbal fluency test. RESULTS. A total of 105 depressed subjects and 324 non-depressed controls (149 normal elderly controls and 175 with mild cognitive impairment) were recruited. The depression group had significantly poorer performance in all cognitive assessments compared to the normal elderly control group. The depression group had a similar cognitive profile to those with mild cognitive impairment, except that its subjects had slightly better performance in the Categorical Verbal Fluency Test, delayed recall testing, and the Chinese version of the Alzheimer's Disease Assessment Scale-Cognitive subscale test. Depressed subjects had significantly lower functional scores in instrumental activities of daily living than the non-depressed, normal elderly controls, and those with mild cognitive impairment. CONCLUSIONS. Our results demonstrate that Chinese elderly with late-onset depression had cognitive impairments in multiple domains similar to those encountered in the age- and sex-matched non-depressed controls with mild cognitive impairment. However, their functional performance was significantly poorer than that in these controls. This study provided extensive characterisation of the range and depth of cognitive and functional impairments in elderly patients with late-onset depression.