title: "Mourning" a lost opportunity.
authors.affiliation: Medical University of South Carolina, Columbia, SC, USA, kalivasp@musc.edu.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Kalivas
authors.forename: Cassandra D
authors.initials: CD
authors.lastname: Gipson
mesh_terms: D016739:Behavior, Addictive; D058999:Drug-Seeking Behavior; D006801:Humans; D008960:Models, Psychological; D012201:Reward; D019966:Substance-Related Disorders / Q000209:etiology* / Q000523:psychology*