Neuropsychological functioning in adolescents and young adults with major depressive disorder--a review.

While neuropsychological dysfunction is a contributor to major depressive disorder (MDD) in adult MDD, little is known about neuropsychological function in MDD during adolescence and early adulthood. The aim of this review is to evaluate literature on neuropsychological function in this young age group. A database search of Medline, the Cochrane database and PsycInfo was conducted. Inclusion/exclusion criteria yielded seven case-control studies on neuropsychological functioning in MDD (12-25 years of age) published since 1995. Effect sizes were calculated. Results show a broader range of statistically significant neuropsychological deficits in MDD compared to controls in the cognitive domains of executive function (EF), working memory (WM), psychomotor and processing speed (PPS), verbal fluency (VF) and visual (-spatial) memory (VM). Most convincingly, three out of four studies investigating WM and three out of four studies investigating PPS found statistically significant impairments in MDD with varying effect sizes. EF deficits were reported only in three out of seven studies with small, medium and large effect sizes. While some evidence was found for impaired VM and VF, no evidence was observed for attention and verbal learning and memory; however, these domains have been less extensively studied. Further research is required to broaden the study base.