Implicit measures of alcohol approach and drinking identity in alcohol use disorder: A preregistered double-blind randomized trial with cathodal transcranial direct current stimulation (tDCS).

Alcohol use disorder (AUD) is a severe and widespread mental disorder with a huge negative impact on the social, economic and health dimensions. The identification of risk factors for the development of AUD and for relapse in existing AUD are crucial for prevention and treatment approaches. Alcohol-related implicit associations have been shown to contribute to drinking and might partially explain sudden relapses. The aims of this study are to investigate implicit associations in abstinent AUD patients and to test whether cathodal transcranial direct current stimulation (tDCS) modulates implicit associations. We measured performance in two alcohol-related implicit association tests (IATs) and two control tasks (flower-insect IAT, Stroop task) in 27 abstinent AUD patients with 31.5 (SD = 36) days of abstinence on average. During the execution of the tasks, we applied 1 mA cathodal or sham tDCS over the left dorsolateral prefrontal cortex (dlPFC) in a sham-controlled within-subject design. Results show an implicit bias of alcohol avoidance and implicit nondrinking identity for abstinent AUD patients. Cathodal tDCS modulated neither alcohol-related implicit associations nor the control tasks. This study complements knowledge about implicit alcohol-related association in AUD patients and shows no effect of a neuromodulatory intervention to alter implicit associations with the present parameters.