One in three with mild cognitive impairment has depression, review findsBMJ 2016; 355 doi: https://doi.org/10.1136/bmj.i6387 (Published 28 November 2016) Cite this as: BMJ 2016;355:i6387
Nearly a third of people with mild cognitive impairment also have depression, a systematic review and meta-analysis has shown.1
Depression has previously been thought to be common in people with mild cognitive impairment, who show greater decline in cognitive function than expected with normal ageing but not to the level of cognitive loss in dementia. Evidence has shown a link between having depression and increased progression to dementia, so the researchers sought to understand this more fully.
Studies assessing the prevalence of depression in patients with mild cognitive impairment have shown inconsistent results, so researchers carried out a systematic review and meta-analysis to provide a better estimate from the currently available information. They analysed 57 studies on the prevalence of depression diagnosed in a total of 20 892 people with mild cognitive impairment on the basis of cognitive criteria or a global measure.
The results, reported in JAMA Psychiatry,1 showed that the overall pooled prevalence of depression in patients with mild cognitive impairment was 32% (95% confidence interval 27% to 37%).
Depression was significantly more prevalent in patients taking part in the 29 clinic based studies (40% (32% to 48%)) than in patients in the 28 community based samples (25% (19% to 30%); P<0.001).
“To our knowledge, this is the largest systematic review and meta-analysis of depression in people with mild cognitive impairment,” said the researchers, led by Zahinoor Ismail, of the University of Calgary, Canada.
“The prevalence of depression in people with mild cognitive impairment is high,” they noted, adding, “A contributor to heterogeneity in the reported literature is the source of the sample, with greater depression burden prevalent in clinical samples compared with community samples.”