Polysomnographic parameters associated with cognitive function in patients with major depression and insomnia.

Objective: To examine whether objective sleep parameters are associated with cognitive function (CF) in patients with major depressive disorder (MDD) with chronic insomnia (CI) and whether the severity of these disorders is related to CF.

Method: Thirty patients with MDD with CI attending a tertiary care institution underwent two consecutive nights of polysomnographic (PSG) recording and a battery of neuropsychological tests, which included episodic memory, sustained attention, working memory, and executive function. The severity of MDD and CI was assessed by clinical scales.