# The predictive value of participant subgroups in a temporary alcohol abstinence challenge: compliance with abstinence and changes in drinking behaviour

## TL;DR

This study shows that dividing people into subgroups based on drinking habits can predict success during alcohol abstinence challenges, but not long-term behavior changes.

## Contribution

The study demonstrates the predictive value of subgroups for abstinence but limited value for long-term drinking behavior changes.

## Key findings

- Subgroups predicted abstinence success during the challenge but not long-term behavior changes.
- Some subgroups showed less improvement in weekday drinking frequency and glasses per day.
- No significant differences were found in weekend drinking or excessive volumes.

## Abstract

Dividing participants of Temporary alcohol Abstinence Challenges (TACs) into subgroups can improve intervention effectiveness by identifying individuals who require extra support. In a previous study, participant subgroups were identified based on determinants of behaviour change, including drinking refusal self-efficacy, craving, and behavioural automaticity. However, the predictive value of these subgroups for TAC success remains unknown. This study examined their predictive value for (i) abstinence during a TAC and (ii) changes in drinking behaviour.

Data were analysed from 1800 Dutch TAC participants who completed baseline and eight-month follow-up questionnaires. Binary logistic regression assessed the effect of subgroup on abstinence. Ordinal and binary logistic regressions within Generalized Estimating Equation models examined subgroup effects on drinking behaviour changes, including drinking frequency, glasses per drinking day, and excessive volumes.

TAC subgroups differed in abstinence and in changes in drinking frequency and glasses per drinking day on weekdays. ‘Habitual drinkers with perceived control to refuse’ and ‘drinkers in control’ were more likely to abstain during the challenge than ‘ordinary drinkers’, whereas ‘drinkers not in control’ were less likely to abstain. ‘Drinkers in control’ showed smaller reductions in drinking frequency and glasses per drinking day on weekdays compared with ‘ordinary drinkers’. No significant differences were found in changes in excessive drinking volumes and glasses per drinking day on weekends.

This study demonstrated the predictive value of subgroups for abstinence but found limited predictive value for changes in drinking behaviour after the challenge. Future research could explore personalized support to optimize behaviour change.

Short Summary: The study examined subgroups of Temporary alcohol Abstinence Challenge (TAC) participants. While subgroups predicted abstinence during the TAC, they had limited value in predicting postchallenge changes in drinking behaviour. The participation value for two subgroups may be questionable. Future research could explore personalized support to optimize behaviour change.