World Health Organization risk drinking level reductions are associated with improved functioning and are sustained among patients with mild, moderate and severe alcohol dependence in clinical trials in the United States and United Kingdom.

One- and two-level reductions in WHO risk levels in the last month of treatment were maintained at the 1-year follow-up [adjusted odds ratio (OR), 95% confidence interval (CI) = one-level reduction in COMBINE: 3.51 (2.73, 4.29) and UKATT: 2.65 (2.32, 2.98)] and associated with fewer alcohol-related consequences [e.g. B, 95% CI = one-level reduction COMBINE: -26.22 (-30.62, -21.82)], better mental health [e.g. B, 95% CI = one-level reduction UKATT: 9.53 (7.36, 11.73)] and improvements in γ-glutamyltransferase [e.g. B, 95% CI = one-level reduction UKATT: -89.77 (-122.50, -57.04)] at the end of treatment, even among patients with severe alcohol dependence. Results were similar when abstainers were excluded. Conclusions Reductions in World Health Organization risk levels for alcohol consumption appear to be achievable, associated with better functioning and maintained over time in both the United States and the United Kingdom.