Examining two practical methods for modeling relapse in preclinical studies

Drug addiction is a recurring chronic disease characterized by repeated and compulsive drug use and seeking behavior, despite awareness of its negative consequences. Relapse, which refers to a person's return to old patterns of behavior and drug use after a period of abstinence, is a significant concern in addiction treatment. One of the main concerns in addiction treatment is the high rate of relapse, even during a short period after withdrawal. It is common for individuals to experience relapse shortly after completing treatment. Exposure to the drug itself, drug-related cues and coping with stress are three factors induce relapse. To investigate and address the issue of relapse, significant efforts have been made to develop extinction-reinstatement models in laboratory animals. Modeling a human psychological disorder such as addiction in animals is not possible due to its complexity, laboratory animals can be used to simulate human psychological issues objectively and behaviorally, with measurable parameters. Over the past decades, animal models of relapse have been developed to investigate and address this neurobiological phenomenon. These models primarily focus on seeking behavior and drug taking, using methods such as spontaneous administration of substances and conditional place preference. This review article provides description of these two main models in relation to the "reinstatement" phenomenon.