Table 1.

Stages of the addiction cycle.

Stage	Source of Reinforcement	Animal Models
Binge/Intoxication	positive reinforcement	conditioned place preference drug self-administration decreased reward thresholds
Withdrawal/Negative Affect	negative reinforcement	conditioned place aversion increased self-administration in dependence increased reward thresholds
Preoccupation/Anticipation	conditioned positive and negative reinforcement	drug-induced reinstatement cue-induced reinstatement stress-induced reinstatement protracted abstinence