Baclofen has opposite effects on escalation of cocaine self-administration: Increased intake in rats selectively bred for high (HiS) saccharin intake and decreased intake in those selected for low (LoS) saccharin intake

► High (HiS) and low (LoS) drug-prone rats received baclofen during key abuse phases. ► Baclofen increased cocaine intake in HiS rats but decreased it in LoS rats. ► Baclofen blocked reinstatement of drug seeking equally in HiS and LoS rats.