Effects of Olfactory Stimuli in Virtual Reality Cue Exposure on Craving and Attentional Bias in Alcohol Use Disorder

Alcohol use disorder (AUD) is a prevalent and burdensome clinical condition with high relapse rates. A central risk factor for relapse is craving for alcohol-often accompanied by an attentional bias toward alcohol-related stimuli-which can be evoked by both real-world and virtual stimuli in immersive virtual reality (VR). In addition to visual and auditory stimuli, olfactory stimuli are increasingly recognized as important for creating realistic, multisensory VR environments. However, no systematic investigation has yet examined how olfactory stimuli embedded in VR-based cue exposure (VR-CE) influence craving and attentional bias in patients with AUD. The goal of this prospective experimental single-arm clinical study, with a 2 (visual stimuli: neutral vs. alcohol-related VR scenarios) × 2 (olfactory stimuli: no odor vs. alcohol-related odor) within-subjects factorial design, is to determine how visual and olfactory stimuli contribute to the outcomes during a multimodal VR-CE in patients with AUD. The main question is whether VR-CE with concurrent visual and olfactory alcohol-related stimuli induces a greater increase in craving and attentional bias from baseline than exposure to a single modality (visual or olfactory), as assessed by subjective and psychophysiological measures in patients with AUD.

Inclusion Criteria: * age between 18-65 years * diagnosis of alcohol dependence according to ICD-10 (F10.2) * complete inpatient detoxification within the last three months * history of alcohol craving * capacity to provide written informed consent Exclusion Criteria: * substance dependences other than alcohol or nicotine * current alcohol intoxication (tested by random breath-alcohol measurements) * alcohol abstinence less than 7 days or on-going alcohol consumption * severe neuropsychiatric disorder (e.g. schizophrenia-spectrum disorder, bipolar affective disorder or substantial cognitive impairment) * severe medical conditions affecting brain or heart function that could influence the parameters under investigation * acute suicidality or risk of harm to others * current pharmacological treatment for alcohol dependence (e.g., benzodiazepines) or for craving (e.g., acamprosate, disulfiram, naltrexone, nalmefene) * other medications that may have a significant influence on heart rate * sinusitis, self-reported problems with smell, or lack of normosmia, assessed both subjectively and objectively * limited ability to understand the study information, the consent form or the study procedures and principles