Patients with mild cognitive impairment (MCI) have a high risk of developing depression, according to a study from JAMA Psychiatry.

Zahinoor Ismail, MD, FRCPC, from the University of Calgary in Alberta, Canada, and colleagues selected articles from 2001-2005 that reported the prevalence of depression in patients with MCI. A total of 255 articles were reviewed, and 57 of them, representing 20,892 patients, met inclusion criteria; 23 studies were from North America, 22 were from Europe, 8 were from Asia, 2 were from Australia, 1 was from Africa, and 1 was from South America.

The overall presence of depression in patients with MCI was pooled using a random-effects model because of assumed heterogeneity among results.

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The effects of study population source (community-based or clinic-based), method of depression diagnosis (informant-rated, self-report, or clinician-administered), method of MCI diagnosis (cognitive or global criteria), and subtype of MCI (amnestic or nonamnestic) on the prevalence of depression in patients with MCI were assessed using random-effects meta-regression.

The overall pooled prevalence of depression in patients with MCI was 32%, with significant heterogeneity between estimates. The prevalence of depression in patients with MCI from the 28 community-based samples was significantly lower than in patients from the 29 studies reporting on clinic-based samples (25% vs 40%). There was no difference in the prevalence of depression in patients with MCI based on how depression was diagnosed or whether MCI was diagnosed based on cognitive criteria or global measure.

The subtype of MCI was reported in 15 studies, all of which reported amnestic subtype. Of these, 8 studies reported depression prevalence for patients with the nonamnestic subtype. The prevalence of depression was higher in patients with amnestic MCI (34%) than in patients with nonamnestic MCI (26%).

The mean age of participants (range, 53.2 to 88.5 years) was not significantly associated with depression in MCI patients. The prevalence of depression in MCI patients was significantly lower in the 2 studies from Australia (13%) compared with 22 from Europe (37%) and the 23 from North America (30%).

According to the authors, “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. More research on depression in people with MCI is required.” 


  1. Ismail Z, Elbayoumi H, Fischer CE, et al. Prevalence of depression in patients with mild cognitive impairment. JAMA Psychiatry. 23 November 2016. doi:10.1001/jamapsychiatry.2016.3162