The Addiction Kindling Effect: The addiction kindling effect is a progressive disorder experienced by addicts after suffering multiple relapses. In simple terms, the kindling effect is the worsening of withdrawal symptoms with progressive relapses. Due to the kindling effect each relapse is followed by a marked increase in the likelihood and the severity of relapsing back into drug abuse (Reoux & Ries, 2001; Becker, 1998). In general, symptoms are more pronounced and longer lasting each time an addict relapses. With each relapse, the addict will return to drug use more quickly, use more heavily, and for longer binge periods. In the stories, we see the kindling effect when Lepus experiences progressively worsening symptoms of drug dependence with each additional experience of drug abstinence. As a result, Lepus relapses over and over again, and with each recurring relapse, Lepus falls deeper and deeper into the downward spiral of addiction.
The Sign-Tracker phenotype is vulnerable to cue-induced relapse: Individuals differ in their vulnerability to cue-induced relapse. With respect to alcohol cues, for example, individuals differ in their reactions to the sight of their favorite alcoholic beverage. Those most tempted by the drug-associated cues exhibited stronger urges to drink alcohol, greater difficulty controlling urges, and increased alcohol consumption (Palfai, 2001). Sign-Trackers (i.e., the ST phenotype) are like Lepus. They are more likely to experience cue-induced cravings for the drug’s effects (Saunders & Robinson, 2013; Saunders, Yager, & Robinson, 2013), and this increases the risk of relapse. Sign-Trackers are more vulnerable to cue-induced relapse, as assessed by post-extinction, cue-induced reinstatement of drug-taking (Saunders & Robinson, 2010). There is also evidence that Sign-Trackers, relative to Goal-Trackers (i.e., the GT phenotype), are more resistant to Pavlovian extinction procedures (Ahrens, Singer, Fitzpatrick, Morrow, & Robinson, 2015). This suggests that Sign-Trackers, relative to Goal-Trackers, will more likely maintain responding during cue-extinction therapy treatments, and, in addition, will more likely relapse into drug-taking when presented with a drug cue.