Background and aims
Evidence for efficacy of brief alcohol interventions (BAIs) is mainly limited to primary care and at‐risk drinkers. The aim was to test the efficacy of a BAI addressing the full spectrum of alcohol use in a general population sample and across alcohol risk groups.
Design
Two‐parallel‐group randomized controlled trial (allocation ratio 1:1) with post‐baseline assessments at months 3, 6 and 12.
Setting
One municipal registry office in Germany responsible for registration, passport and vehicle admission issues.
Participants
A total of 1646 proactively recruited 18–64‐year‐old adults with past year alcohol use (56% women, 66% low‐risk drinkers) were randomized to intervention (n = 815) or control (n = 831).
Intervention and comparator
The intervention consisted of assessment plus computer‐generated individualized feedback letters at baseline and months 3 and 6. Comparator was assessment only.
Measurements
Primary outcome was change in the self‐reported number of drinks/week from baseline to 12 months. Changes at 3 and 6 months were secondary outcomes. Moderator was alcohol risk group (low‐risk versus at‐risk drinking) according to the Alcohol Use Disorders Identification Test–Consumption, with scores from 1‐3 (women) and from 1‐4 (men) indicating low‐risk drinking.
Findings
For the whole sample, significant group differences were observed neither at 12‐month follow‐up [incidence rate ratio (IRR) = 1.01, 95% confidence interval (CI) = 0.87–1.17, Bayes factor (BE) = 0.52] nor at previous assessments (month 3: IRR = 1.01, 95% CI = 0.92–1.12, BE = 0.41; month 6: IRR = 0.93, 95% CI = 0.81–1.07, BE = 1.10). Moderator analyses revealed that low‐risk drinkers were more likely to benefit from BAI only at month 6 than at‐risk drinkers (IRR = 0.77, 95% CI = 0.70–0.86).
Conclusions
In a randomized controlled trial, there was no clear evidence for efficacy of a computer‐based brief alcohol intervention in a general population sample, but there was some evidence of medium‐term benefits in the large but understudied group of low‐risk drinkers.