Clinical remission of late-onset depression in elderly Chinese: a short-term outcome study

Better understanding of the relationship between executive and memory functions and treatment response in late-onset depression may improve our ability to identify those individuals who are less likely to benefit from traditional pharmacological interventions. This study aimed to investigate the remission rate in elderly Chinese people with late-onset depression, and to examine the predictors of outcomes.

Patients aged 60 years or older with late-onset depression without dementia were recruited into the study. Mood symptoms were assessed by the 24-item Hamilton Rating Scale for Depression and Neuropsychiatric Inventory at 12 and 24 weeks. Cognitive domains assessed included global cognitive function, episodic memory, executive functions, and processing speed. The clinical characteristics and cognitive scores were compared among the early remitters, late remitters, and non-remitters.

Of the 105 subjects, 42 (40%) had remission at 12 weeks and were categorised as early remitters, 41 (39%) who did not remit at 12 weeks achieved remission at 24 weeks (late remitters), and 22 (21%) had not achieved remission at 24 weeks (non-remitters). Executive function, processing speed, episodic memory, apathy and depression severity were related to remission outcomes. Regression analyses found that severity of baseline apathy and depression were predictors of remission at 12 and 24 weeks, respectively.

This study identified 2 subgroups of patients according to outcomes. One group with clinical characteristics similar to vascular depression achieved a late response to treatment. The other group were non-remitters who had features of depression-executive dysfunction syndrome, which might have underlying degenerative process and presented with the co-occurrence of depression and mild cognitive impairment.