Systematic Review and Meta-Analysis of the Effectiveness of Virtual Reality Exposure Therapy for the Treatment of Alcohol and Nicotine Dependence

Background and Purpose:  The use and misuse of alcohol and nicotine is one of the greatest and costliest public health problems in the United States.  Exposure therapy for addiction has significant limitations, including accessibility and feasibility.  One potential solution to address these limitations is virtual reality cue exposure therapy (VRET).  With no consensus on outcomes using habituation through exposure to cues through systematic VRET, the questions guiding this review were 1. To what extent is VRET being utilized for the treatment of alcohol or nicotine use disorders? 2. What are the effects of VRET on craving, dependence, and substance use?

Methods:  Systematic review and meta-analytic procedures were used to assess effects of VRET on alcohol and nicotine cravings and use. VRET is a combination of exposure therapy and virtual simulations to provide a greater sense of presence for eliciting cravings and habituation. VRET may be a series of controlled exposures with or without a paired cognitive or didactic therapeutic intervention. A comprehensive search strategy, comprised of 18 databases and research registers, reference lists, and a gray literature search was undertaken to find experimental, quasi-experimental, and single group design studies conducted between 2000 and January 2018. Study selection and data extraction was conducted by two independent reviewers. The protocol for this review was registered and PRISMA conduct and reporting guidelines were followed. Descriptive analysis was conducted to examine and describe characteristics and outcomes of all included studies. Standardized mean difference effect sizes, adjusted for small sample variance weights, was used to quantitatively synthesize results across the included studies.

Results:  The search yielded 1801 record hits and the full text of 107 studies were screened for inclusion. After full text screening, 13 studies were included, with only two U.S. based studies.  With small treatment sample sizes (M = 26.4, SD = 15.94), few studies were experimental design (n = 3).  Presence of a moderate to high risk of bias was present in most studies. Meta-analytic results point to positive and statistically significant effects at post test for reduction of craving for nicotine (g = 0.42; 95% CI = 0.20, .78) and alcohol (g = 0.36; 95% CI = 0.13, .64) as well as nicotine use (g = 0.28; 95% CI = 0.06, .54) and alcohol use (g = 0.18; 95% CI = 0.08, .32). Heterogeneity was small to moderate. Due to lack of heterogeneity and sufficient power, moderator analyses were not conducted.

Implications: While initial results point to efficacy of VR technology for addressing addictions, limited RCTs, lack of treatment fidelity protocol, sparse discussion about the VR environments and what is needed within them, and unclear expectations related to training for the intervention indicate an number of methodological issues. This systematic review allows a broader understanding of the current effort allowing researchers a road map towards deriving evidence about VRET’s utility in addressing a significant health concern.  Recommendations include further clarification of fidelity of procedures, rigorous study designs with larger samples, and extended outcome measures, both short and long term.