Associations between risky alcohol use, disability, and problem-solving impairment among Veterans with Gulf War Illness: Secondary data analysis of a randomized clinical trial

Objective: Gulf War Illness (GWI) and alcohol use are both major sources of disability among Gulf War Veterans. The goal of this secondary data analysis was to examine associations between risky alcohol use, problem-solving impairment, and disability among Veterans in a randomized clinical trial of problem-solving treatment (PST) for GWI. We examined cross-sectional associations and conducted longitudinal analyses to test if alcohol use moderated treatment outcome of PST. Methods: Participants were 268 United States military Veterans with GWI randomized to PST or a control intervention. Participants were assessed at four timepoints. Measures included the World Health Organization Disability Assessment Schedule 2.0 (WHO-DAS 2.0), Problem Solving Inventory (PSI), and Alcohol Use Disorders Identification Test-Concise (AUDIT-C). We conducted multivariate regression (cross-sectional) and mixed model analyses (longitudinal) with separate models for WHO-DAS 2.0 and PSI. All models included AUDIT-C and household income. This analysis was pre-registered on the Open Science Framework. Results: Cross-sectional analyses revealed a significant negative association with small effect size between AUDIT-C and WHO-DAS 2.0 (p = 0.006; f2 = 0.05); worse disability was associated with less risky alcohol use. There was no evidence that risky alcohol use moderated effects of PST on disability or PSI. Conclusion: If replicated, the cross-sectional findings suggest high levels of disability may deter heavy drinking among Veterans with GWI. We did not find evidence that risky alcohol use moderated treatment outcome of PST for GWI. More research is needed to identify moderators of GWI interventions and to understand risky drinking among Veterans with complex health problems.