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One-third of individuals with mild cognitive impairment have depression

A systematic review and meta-analysis indicated depression among 32% of individuals with mild cognitive impairment.

“Because [mild cognitive impairment (MCI)] and depression can have overlapping symptoms, disentangling and differentiating between them can be problematic. Both depression and MCI tend to be underrecognized in clinical settings,” Zahinoor Ismail, MD, of University of Calgary, Alberta, Canada, and colleagues wrote. “Despite the importance of this association between MCI and depression, to our knowledge, no consensus has emerged around certain foundational elements of knowledge in this area. Among these is the question of prevalence. Many studies examining depression prevalence in patients with MCI have been conducted, but the results have been inconsistent.”

To estimate the prevalence of depression among individuals with MCI and explain heterogeneity in reported results, researchers conducted a systematic review and meta-analysis of 57 studies representing 20,892 individuals.

Overall pooled prevalence of depression among participants with MCI was 32% (95% CI, 27-37), with significant heterogeneity between estimates.

Analysis by source indicated depression prevalence of 25% in community-based samples and 40% in clinic-based samples, indicating a significant difference between sample types (P < .001).

Criteria used for MCI diagnosis or MCI subtype and diagnostic method for depression did not significantly influence prevalence estimates.

“Depression is common in people with MCI, with an overall pooled prevalence of 32%. A contributor to heterogeneity in the reported literature regarding the prevalence of depression in those with MCI is the source of the sample, with greater depression burden prevalent in clinical samples compared with community samples. Other sources of heterogeneity have been explored, but more research on depression in people with MCI is required,” the researchers concluded.” – by Amanda Oldt

Disclosure: Ismail reports receiving support from the Alzheimer Society of Calgary via the Hotchkiss Brain Institute. Please see the study for a full list of relevant financial disclosures.