ABSTRACT
BACKGROUND: Psychiatry lags other fields in development of diagnostic tests. METHODS: A literature review and meta-analysis was conducted to ascertain if polysomnographic abnormalities (REM density, REM latency, sleep efficiency, slow wave sleep, stage 1 and stage 2 sleep) warrant additional effort to develop them into a clinical diagnostic test for major depressive disorder (MDD). The 31 publications meeting inclusion criteria were then classified into one of three progressive steps using guidelines for evaluating the clinical usefulness of a diagnostic test. RESULTS: Most of the abnormalities found in MDD patients, when compared to healthy controls, occurred in the expected direction with moderate effect sizes but with substantial publication bias and heterogeneity. Eleven studies compared abnormalities in MDD to other psychiatric disorders (step 2a), and four studies provided data on the sensitivity or specificity of the findings in differentiating among the psychiatric disorders that frequently appear on the same differential diagnostic list as MDD (step 2b). No multicenter trial has been conducted prospectively to test the clinical utility of the diagnostic test (step 3). LIMITATIONS: Only published articles in the English language were used. CONCLUSIONS: Sleep studies for the detection of MDD appear replicable with a moderate effect size. However, additional step 1 studies are needed to define the sensitivity and specificity. The heterogeneity of sleep recording, scoring techniques, and MDD must also be addressed.