Overview Effect of Nicotine on Brain Reward Pathways Status: Completed Trial end date: 2017-11-01 Target enrollment: Participant gender: Summary The investigators will determine whether an acute dose of nicotine, in the form of the nicotine lozenge, impacts brain and behavioral measures of mood and reward responsiveness in individuals with major depressive disorder. Phase: Phase 1 Details Lead Sponsor: Mclean HospitalCollaborator: National Institute on Drug Abuse (NIDA)Treatments: Nicotine