Alcohol-specific inhibition training in patients with alcohol use disorder: a multi-centre, double-blind randomized clinical trial examining drinking outcome and working mechanisms

Aims: For the first time, to our knowledge, in a clinical sample with alcohol use disorder (AUD), this study compared the effects of two versions of alcohol-specific inhibition training (Alc-IT) on drinking outcomes and on experimental parameters assessing two possible working mechanisms: stimulus devaluation and inhibitory enhancement. Design: Multi-centre, double-blind, three-arm clinical RCT with 3-, 6- and 12-month follow-up comparing standard Alc-IT, improved Alc-IT and an active control condition. Setting: Three specialized AUD treatment centres in Switzerland. Participants: A total of 242 detoxified, recently abstinent patients with severe AUD (18-60 years; 29.8% female). Intervention and Comparator: Both interventions [standard Alc-IT (n = 84) and improved Alc-IT (n = 79)] and the comparator [unspecific inhibition training (n = 79)] consisted of six sessions of a modified inhibitory task (Go/NoGo task) with alcohol-related and neutral stimuli. Both versions of Alc-IT required response inhibition in alcohol-related trials but differed in Go/NoGo ratios (standard: 50/50; improved: 75/25), with improved Alc-IT posing higher inhibitory demands. The control condition, an unspecific inhibition training, featured alcohol-related pictures in Go as well as NoGo trials. Measurements: The primary outcome, percentage of days abstinent, was assessed at 3-month follow-up with a time-line follow-back interview. Findings: The group receiving improved Alc-IT showed a significantly higher percentage of days abstinent at 3-month follow-up compared with the control group [gamma(control) = 74.30; gamma(improved) = 85.78; beta = 11.48, 95% confidence interval (CI) = 2.57, 20.40, P = 0.012, adjusted r(2) = 0.062], while for standard Alc-IT no effect significantly different from zero was detected (gamma(standard) = 70.95; beta = -3.35, 95% CI = -12.20, 5.50, P = 0.457, adjusted r(2) = -0.04). Conclusions: Alcohol-specific inhibition training with high inhibitory demands increased days abstinent at 3-month follow-up in patients with severe alcohol use disorder. Such an improved, inhibitory-demanding, alcohol-specific inhibition training outperformed the standard version of alcohol-specific inhibition training, suggesting an inhibitory working mechanism.