Cognitive performance in depression in low- and middle-income countries: A systematic review with meta-analytic components.

Background: Depression is highly prevalent in low- and middle- income countries (LMIC) and associated with significant cognitive dysfunction across multiple domains. However, little is known about neurocognitive tests used in people with depression in LMIC. We aimed to investigate cognitive performance and cognitive tests in depression research in LMIC.
Methods: APA PsycInfo, Embase, Ovid MEDLINE, and Global Health were systematically searched for studies that implemented a cognitive performance test in a depressed, LMIC population. Tool quality was assessed using an adapted scale for quality of measures in cross-cultural settings. Data extracted included demographics, depression and cognitive performance measures, and cognitive performance comparisons between depression and control groups.
Results: 29 studies met eligibility criteria, involving a total of 19,100 participants from 11 LMIC. 93.1 % of studies were conducted in upper middle-income countries. 67 cognitive performance tools were implemented. Reliability was reported for 5.6 % of cognitive performance tests and validity was reported for 8.3 %. 36.1 % of tests used were culturally adapted. 75.9 % of included studies implemented at least one memory test. Cognitive deficits were observed in all depressed groups, especially in memory (Cohen's d = -1.60, 95 % CI -2.02 to -1.18).
Limitations: Heterogeneity between studies; averaged results across memory subtypes; no assessment of depression severity and cognitive deficits associations; restrictive search terms.
Conclusions: Cognitive impairments in depression, especially in memory, are prevalent in LMIC. This research has drawn attention to the burden of cognitive dysfunction in depression in LMIC, and to the disparate research gap in LMIC. PROSPERO registration CRD42022315397.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)