Effects of Olfactory Stimuli in Virtual Reality Cue Exposure on Craving and Attentional Bias in Alcohol Use Disorder (OLFA-VR)

Effects of Olfactory Stimuli in Virtual Reality Cue Exposure on Craving in Alcohol Dependence

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Alcohol Use Disorder
• Intervention / Treatment: Device: VR-CE

Detailed Description

Sixty patients with AUD, treated in inpatient or outpatient psychiatric clinics, will be enrolled in the study. Participants will receive written and verbal information about the study, and written informed consent for participation will be obtained. A screening for eligibility will then be conducted. This will include, among other things, a history of craving and the confirmation of normosmia. Sociodemographic data, questionnaires on craving, AUD characteristics, and tendency for immersion, as well as potentially confounding variables and factors influencing physiological parameters, will be collected. Participants will then be asked to name a beverage of their choice (beer, red wine, white wine, vodka, or schnaps), which will be presented to them visually and olfactorily during the VR-CE.

Before exposure to the VR scenarios, participants will be familiarized with the VR headset. Eye tracking within the head-mounted display (HMD) will be calibrated, and participants will be allowed to acclimatize to the VR environment. Subsequently, participants will be exposed to each of the four VR-CE conditions for 5 minutes (neutral visual+no odor; neutral visual+alcohol-related odor; alcohol-related visual+no odor; and alcohol-related visual+alcohol-related odor) in randomized order. Randomization will be implemented such that the visual stimuli are presented in blocks (i.e., both neutral or both alcohol-related VR scenarios), while the olfactory stimuli (no odor vs. alcohol-related odor) are randomized within each visual block. Prior to each visual block, participants will undergo a 5-minute VR baseline session in a black virtual room with blue orientation lines, which will serve as the baseline for subjective and psychophysiological parameters.

During exposure, psychophysiological parameters and eye-tracking data will be recorded, self-reported craving will be assessed three times and sense of presence once during each VR-CE condition. After the exposure, questionnaires to assess self-reported craving, attentional bias, sense of presence, affective reaction and cybersickness will be administered.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nadja Ruckser, M.Sc; Phone Number: +49 30 838 67876; Email: nadja.ruckser@charite.de

Study Locations

• Germany
  • State of Berlin
    • Berlin, State of Berlin, Germany, 10115
      • Psychiatric University Hospital Charité at St. Hedwig Hospital, Berlin, Berlin 10115

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: VR-CE; The single-arm clinical study employs a 2 (visual: neutral vs. alcohol-related VR scenarios) × 2 (olfactory: no odor vs. alcohol-related odor) within-subjects factorial design. Each participant will complete all four conditions within the virtual reality cue exposure (VR-CE)	Device: VR-CE; Virtual reality cue exposure (VR-CE) using visual (neutral vs. alcohol-related VR scenarios) and olfactory (no odor vs. alcohol-related odor) stimuli conditions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Self-reported craving (VAS-C)	Self-reported craving will be assessed using the visual analogue scale (VAS-C; range 0-10, higher score indicates higher levels of craving) during the 2 (visual) × 2 (olfactory) virtual reality cue exposure (VR-CE) conditions.	Day 1, at minute 0:30, 2:30 and 4:30 during both VR baseline sessions and each VR-CE condition.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Psychophysiological craving index (heart rate variability, HRV)	For a multimodal craving measurement, heart rate variability (HRV) will be assessed as a psychophysiological craving index during both VR baseline sessions and each VR-CE condition.	Day 1, continuously during both VR baseline sessions and each VR-CE condition.
Psychophysiological craving index (heart rate, HR)	For a multimodal craving measurement, heart rate (HR, in beats per minute (bpm)) will be assessed as a psychophysiological craving index during both VR baseline sessions and each VR-CE condition.	Day 1, continuously during both VR baseline sessions and each VR-CE condition.
Psychophysiological craving index (electrodermal activity, EDA)	For a multimodal craving measurement, electrodermal activity (EDA, in microsiemens) will be assessed as a psychophysiological craving index during both VR baseline sessions and each VR-CE condition.	Day 1, continuously during both VR baseline sessions and each VR-CE condition.
Psychophysiological craving index (respiratory rate, RR)	For a multimodal craving measurement, respiratory rate (RR) will be assessed as a psychophysiological craving index during both VR baseline sessions and each VR-CE condition.	Day 1, continuously during both VR baseline sessions and each VR-CE condition.
Psychophysiological craving index (pupillometry)	For a multimodal craving measurement, pupillometry (pupil dilation in mm) will be assessed as a psychophysiological craving index during both VR baseline sessions and each VR-CE condition.	Day 1, continuously during both VR baseline sessions and each VR-CE condition.
Self-reported craving (AUQ)	In addition to the VAS-C during VR baseline and VR-CE conditions, self-reported craving will be assessed using the Alcohol Urge Questionnaire (AUQ, range: 0-42, higher score indicates higher levels of craving).	Day 1, after both VR baseline sessions and each VR-CE condition.
Self-reported attentional bias (AAS)	The Alcohol Attention Scale (AAS, item-range: 0-10, higher scores indicate higher levels of attention) will be used to assess self-reported attention toward the sight and smell of alcohol, as well as thoughts about drinking during each VR-CE condition with at least one alcohol-related stimulus.	Day 1, after each VR-CE condition, except for the combination of neutral VR scenario and no odor.
Pupillometry indices of attentional bias	Pupillometry indices of attentional bias will be continuously assessed through gaze tracking via eye-tracking of alcohol-related and neutral stimuli during the alcohol-related VR scenario.	Day 1, during the alcohol-related VR scenario.
Sense of presence (VAS-P)	Self-report of sense of presence will be assessed using a visual analogue scale (VAS-P; range 0-10, higher score indicates higher levels of sense of presence).	Day one, during both VR baseline sessions and each VR-CE condition (minute 4:35).
Sense of presence (IPQ)	Self-report of sense of presence will be assessed after both VR baseline sessions and each VR-CE condition via the Igroup Presence Questionnaire (IPQ, range: 0-6, higher scores indicate higher sense of presence).	Day 1, after both VR baseline sessions and each VR-CE condition.
Affective reaction (SAM)	Affective reaction will be assessed non-verbally using the three-item Self-Assessment Manikin (SAM, range: -4-4, higher scores indicate stronger affective reaction).	Day 1, after both VR baseline sessions and each VR-CE condition.
Cybersickness (FMS)	Cybersickness during both VR baseline sessions and each VR-CE condition will be assessed using the Fast Motion Sickness Scale (FMS, range: 0-20, higher scores indicate higher cybersickness).	Day 1, after both VR baseline sessions and each VR-CE condition.
Cybersickness (VRSQ)	In addition to the FMS, the Virtual Reality Sickness Questionnaire (VRSQ, range: 0-27, higher score indicates higher cybersickness) will be used to assess self-reported cybersickness.	Day 1, after both VR baseline sessions and each VR-CE condition.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sociodemographic variables	Sociodemographic variables will be assessed, e.g. age, gender, sex	Day one, before VR-CE
AUD characteristics (AUDIT)	Alcohol use disorder (AUD) characteristics, such as AUD screening score (AUDIT, range: 0-40, higher score indicates greater likelihood of alcohol dependence) will be assessed.	Day 1, before the VR-CE
AUD characteristics (ADS)	Alcohol use disorder (AUD) characteristics, such as addiction severity (Alcohol Dependence Scale, ADS, range: 1-47, higher score indicates greater alcohol dependance severity) will be assessed.	Day 1, before the VR-CE
Self-reported trait craving before VR-CE (OCDS)	Self-reported trait craving prior to VR-CE will be assessed using the Obsessive Compulsive Drinking Scale (OCDS, range: 0-40, higher scores indicate higher craving).	Day 1, before VR-CE
Self-reported trait craving before VR-CE (CAS-A)	Self-reported trait craving prior to VR-CE will be assessed using the Craving Automated Scale for Alcohol (CAS-A, range: 0-75, higher scores indicate higher craving).	Day 1, before VR-CE
Immersive tendencies (ITQ)	Participants ability to feel immersed or "present" in an environment will be assessed as a trait using the Immersive Tendencies Questionnaire (ITQ, range: 18-126, higher scores indicate higher immersive tendencies).	Day 1, before VR-CE

Collaborators and Investigators

• Sponsor: Charite University, Berlin, Germany
• Investigators: Principal Investigator: Alva Lütt, Dr. med., Psychiatric University Hospital Charité at St. Hedwig Hospital, Berlin, Berlin 10115; Principal Investigator: Stefan Gutwinski, Prof. Dr. med., Psychiatric University Hospital Charité at St. Hedwig Hospital, Berlin, Berlin 10115

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): July 1, 2027
• Study Completion (Estimated): July 1, 2027

Study Registration Dates

• First Submitted: May 22, 2026
• First Submitted That Met QC Criteria: June 21, 2026
• First Posted (Actual): June 25, 2026

Study Record Updates

• Last Update Posted (Actual): June 25, 2026
• Last Update Submitted That Met QC Criteria: June 21, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: alcohol use disorder; olfactory; virtual reality cue exposure
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Substance-Related Disorders; Chemically-Induced Disorders; Alcohol-Related Disorders; Sensation Disorders; Olfaction Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Anosmia; Alcoholism
• Other Study ID Numbers: EA1/269/24_trial

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No