The relationship between neurocognitive and psychosocial functioning in major depressive disorder: a systematic review.

OBJECTIVE: Neurocognitive deficits are demonstrated in major depressive disorder (MDD) and most likely contribute to the functional impairment experienced by affected individuals. We systematically reviewed the evidence on neurocognitive deficits and their relationship(s) to psychosocial functioning in MDD. DATA SOURCES: English-language literature was searched in MEDLINE, EMBASE, Science Direct, and PsycInfo databases for the years 1980-October 15, 2013, with the following terms: (depressive disorder or depressive disorder, major) and permutations of (cognitive, neurocognitive, neuropsych*) with (impairment, deficit, performance, test) and (quality of life; functional outcomes; outcome assessment, health care) or (assessment, outcomes; assessment, patient outcomes; outcomes assessment; outcomes assessments, patient). STUDY SELECTION: Inclusion criteria were (1) nongeriatric adults (< 60 years) with a primary diagnosis of MDD by DSM-IV, ICD-9, or ICD-10 criteria; (2) use of neuropsychological tests; and (3) use of a specific measure of social, occupational, or daily functioning. Of 488 articles identified in the initial search, 10 met the inclusion criteria. DATA EXTRACTION: Two independent appraisers assessed eligibility of the studies. Substantial heterogeneity in the samples and methods precluded a quantitative meta-analysis, so we performed a narrative descriptive review.
RESULTS: The included studies employed a variety of neurocognitive tests and assessments of psychosocial functioning. Overall, depressed samples had neurocognitive deficits in various domains that were associated with different measures of psychosocial functioning. However, these findings were constrained by methodological limitations of studies.
CONCLUSIONS: The limited evidence base suggests that neurocognitive functioning appears to be broadly associated with functional impairment in individuals with MDD, but the quality of evidence is weak. Further studies to clarify the relationship(s) between neurocognitive and psychosocial functioning in MDD will benefit from larger and more homogeneous samples, prospective designs with multivariate analyses, and use of comprehensive assessments of psychosocial functioning that are validated in depressed populations. © Copyright 2014 Physicians Postgraduate Press, Inc.