INTRODUCTION Identifying subgroups of Temporary (alcohol) Abstinence Challenge (TAC) participants may offer opportunities to enhance intervention effectiveness. However, knowledge about such subgroups is missing. This study aimed to (i) describe a TAC population; (ii) identify subgroups of participants based on determinants of changes in drinking behaviour; and (iii) characterise subgroups in terms of sociodemographic and other characteristics.

METHODS Data from 3803 Dutch TAC participants were analysed to identify subgroups using three-step Latent Class Analysis. Classes were based on determinants of changes in drinking behaviour (i.e., drinking refusal self-efficacy, craving and behavioural automaticity) and were characterised by sociodemographic characteristics, drinking behaviour, previous participation in TACs, self-reported health and life satisfaction.

RESULTS The majority of TAC participants were female, highly educated, employed, 53 years old on average, participated in previous TACs and reported relatively high alcohol use. Four classes of participants were identified: (i) 'ordinary drinkers' (49.0%); (ii) 'drinkers in control' (21.4%); (iii) 'habitual drinkers with perceived control to refuse' (18.4%); and (iv) 'drinkers not in control' (11.2%). Class 2 drank least often and non-excessive volumes, while other classes typically drank 4 or more days per week and 3 to 4 glasses per drinking day, with the highest alcohol use found in class 4.

DISCUSSION AND CONCLUSIONS Different configurations of determinants in this study's four subgroups may require different intervention approaches and might inform personalised support. Future research is needed to examine the predictive value of these subgroups on post-challenge drinking behaviour to assess support needs and participation value.