Lisdexamfetamine Dimesylate in Residual Symptoms and Cognitive Impairment in Major Depressive Disorder.

This protocol is designed to test the hypothesis that a cluster of co-occurring residual symptoms sometimes found in treated depression will respond as a group to psychostimulant therapy. This cluster includes apathy, reduced drive, fatigue, impaired executive function and other cognitive measures, and low positive affect. We propose to measure this cluster of symptoms in a population of residually depressed subjects demonstrating them, and then to measure the effect of stimulant therapy on this cluster, and each constituent symptom, as well as to measure its effect on subjects' overall functional impairment, and to document treatment emergent adverse effects. The goal is to gather data about the response of these residual symptoms to stimulant therapy. Since each subject will be exposed to active treatment and matched placebo, a benefit to individual participants will be to learn if their specific symptom burden is ameliorated by stimulant therapy, and what adverse effects may emerge for them. We hope to develop an understanding of the specific symptoms in this clinical population that are likely to improve with stimulant therapy. We also hope to be able to characterize the side effect burden of stimulant therapy in this clinical population.