There is currently no laboratory or clinical evidence from animal or human studies documenting a withdrawal syndrome associated with cocaine dependence, although many users report that withdrawal disturbances are responsible for their repeated use of the drug. In the present study rats self-administered i.v. cocaine and a sweetened drinking solution. When cocaine access was terminated there was a marked suppression in operant behavior reinforced by the sweetened solution, and this withdrawal disruption was immediately reversed when cocaine was reinstated. There were no physical signs of withdrawal, and food intake increased when cocaine was withdrawn. The results suggest that sensitive behavioral tests reveal aspects of drug dependence that may account for persistent abuse.
Bibliographical noteFunding Information:
We gratefully acknowledge the technical assistance of Timothy Newman and Sheryl Nygaard. This work was supported by Grant DA 03240 from the National Institute on Drug Abuse and an Undergraduate Research Oooortunties Proeram u award No. 2433, Univercity of Minnesota. ”