Drug addiction is a psychiatric disorder that afflicts thousands worldwide. Drug abusers regularly choose to seek substances often at the expense of other beneficial behaviours including fostering healthy relationships and upkeep of good health. Furthermore, many addicts that abstain from using drugs, sometimes for several years, may ultimately relapse, leading to resumption of maladaptive drug seeking. These behaviours are reflective of decision-making deficits that are inherent in substance abuse. To investigate the relationship between poor decision making and drug addiction, we utilize three animal models: the rodent gambling task (rGT), cocaine self-administration, and incubation of craving to determine how baseline choice preferences change as animals acquire drug seeking, escalate cocaine use, and relapse.
Drug self-administration is a well-validated animal paradigm of drug-seeking. In the model, animals are implanted with jugular vein catheters and attached to a drug-delivery system that allows the animal to press a lever for liquid infusions of drugs and associated cues. Animals quickly learn to press for the drug, and if given extended access, will likely escalate to habitual drug seeking similar to that seen in human drug abusers.
Incubation of drug craving is a model used to study relapse. Previous studies have shown that following stable acquisition of drug-seeking in the self administration paradigm, rats that are forced to abstain from the program for longer periods (i.e. 30 days versus 1 day) will lever press for the cue previously associated with drug at a greater rate, showing a likeness to cue-induced drug relapse following an extended period of abstinence.