The automatic pull of drug cues in addiction: Neural correlates and effects of re-training ; Untersuchung des Substanz-Annäherungsbias bei Menschen mit Substanzabhängigkeit: Neuronale Korrelate und Effekte eines Bias- Modifikationstrainings

Addiction is a chronic, relapsing brain disorder, characterized by continuation of drug-use despite knowledge of the negative consequences. One important factor for relapse may be the degree to which drug cues automatically trigger motivational approach responses (i.e., “drug cue reactivity”). This phenomenon is hypothesized to be the result of neuroadaptations in mesocorticolimbic areas. Empirical studies indeed demonstrate that drug-addicted individuals have a tendency to faster approach than avoid drug cues compared to neutral cues (i.e., a drug approach bias), which has been associated with higher drug craving and relapse. Moreover, retraining the drug approach bias with Cognitive Bias Modification training (CBM) in alcohol-dependent patients has been shown to reduce relapse rates one year after training. These findings highlight the clinical importance of the drug approach bias. However, much remains unknown about the persistence of the approach bias after drug abstinence, the neural correlates underlying the approach bias, and neural mechanisms of CBM. The overall aim of this thesis is to study automatic approach/avoidance behaviour in tobacco and alcohol dependence. More specifically, the thesis aims to answer the following four questions: first, do drug-dependent individuals have an automatic approach bias for drug cues and is the strength of this bias related to craving? Second, does the drug approach bias persist after prolonged abstinence? Third, what are the underlying neural correlates of the drug approach bias? Fourth, what are the effects of CBM on neural drug cue reactivity in drug-dependence? For this purpose, three empirical studies were conducted. First, we investigated the approach bias to smoking cues and alcohol cues on the Approach Avoidance Task (AAT) in heavy tobacco smokers and alcohol-dependent patients respectively, and studied its relation to subjective drug craving (experiment I and II). Second, we compared heavy smokers, never-smokers and abstinent heavy smokers (i.e., ex-smokers) ...