Psychophysiological responses to drug-associated stimuli in chronic heavy cannabis use

Due to learning processes originally neutral stimuli become drug-associated and can activate an implicit drug memory, which leads to a conditioned arousing 'drug-seeking' state. This condition is accompanied by specific psychophysiological responses. The goal of the present study was the analysis of changes in cortical and peripheral reactivity to cannabis as well as alcohol-associated pictures compared with emotionally significant drug-unrelated and neutral pictures in long-term heavy cannabis users. Participants were 15 chronic heavy cannabis users and 15 healthy controls. Verbal reports as well as event-related potentials of the electroencephalogram and skin conductance responses were assessed in a cue-reactivity paradigm to determine the psychophysiological effects caused by drug-related visual stimulus material. The evaluation of self-reported craving and emotional processing showed that cannabis stimuli were perceived as more arousing and pleasant and elicited significantly more cannabis craving in cannabis users than in healthy controls. Cannabis users also demonstrated higher cannabis stimulus-induced arousal, as indicated by significantly increased skin conductance and a larger late positivity of the visual event-related brain potential. These findings support the assumption that drug-associated stimuli acquire increased incentive salience in addiction history and induce conditioned physiological patterns, which lead to craving and potentially to drug intake. The potency of visual drug-associated cues to capture attention and to activate drug-specific memory traces and accompanying physiological symptoms embedded in a cycle of abstinence and relapse - even in a 'so-called' soft drug - was assessed for the first time.