Effects of a Single Dose of Amisulpride on Functional Brain Changes

Double blind, placebo-controlled, randomized, single dose, parallel-group design The study is designed to investigate effects of a single dose of amisulpride on functional brain changes during reward- and motivation-related processing and at rest. Measurement of functional brain changes will occur after a single dose of amisulpride or placebo in HV and patients with MDD. It is hypothesized that functional brain changes previously linked to reward- and motivation-related processing require dopaminergic signaling and are diminished in MDD compared to HV. In MDD, but not in HV, treatment with a single low dose (100 mg) amisulpride should increase brain activation associated with reward- and motivation-related processing. To test these hypotheses, we will implement a randomized, placebo-controlled, parallel- group design with 4 treatment arms (MDD/placebo, MDD/amisulpride, HV/placebo and HV/ amisulpride). All subjects will undergo MRI scanning sessions at Visit 3 and Visit 4. Treatment with amisulpride or matching placebo will occur 3.5 to 4 hours before the start of each scanning session. Time of treatment will be standardized across subjects. At Visit 3 and Visit 4, blood samples will be taken 30 minutes pre-dose, and 1 hour, 3.5 to 4 hours, and 4.5 to 5 hours after oral drug administration to determine target plasma levels of amisulpride. The study is composed of 4 outpatient visits: Screening, baseline and 2 scanning sessions.