Psychological and social determinants of reductions in alcohol consumption following participation in Dry January: A prospective observational study

Background and AimsParticipation in Dry January is associated with reductions in alcohol consumption six-months later. Increased drink refusal self-efficacy (DRSE) appears to mediate these reductions. However, little is known about other potential determinants and mechanisms of change. We aimed to overcome limitations of previous studies and examine outcomes of Dry January participation for people who drink at hazardous levels (AUDIT-C >4) and investigate factors that may underpin these reductions, including seasonal variation in alcohol consumption, access to online supports, and other psychological and social constructs.DesignProspective observational study in which we administered a series of online surveys across four timepoints: pre-Dry January, post-January, and three and six months later. SettingData was collected from participants based in the UK using online surveys.ParticipantsThree groups of participants (AUDIT-C>4) were recruited, those who: (1) registered for Dry January with the organisers Alcohol Change UK (‘official’, n=291, mean age = 49.10); (2) attempted an independent alcohol-free January without registering for the official campaign (‘unofficial’, n=115, mean age = 45.09); and (3) did not participate in Dry January at all (‘No Dry January’, n=225, mean age =47.91).MeasurementsThe primary outcome measure was AUDIT-C at six months. Predictors were DRSE, drinker identity, motivation to change, social contagion, level of abstinence during January, and frequency of use of online supports (Try Dry app, emails, Facebook groups).Findings‘Official’ Dry January participants had a significant reduction in AUDIT-C at six-months (baseline mean (SD) = 9.44 (1.92), six-months mean (SD) = 7.65 (3.03); z= -10.42, p<.001, r=.61). Six-month AUDIT-C was lower for ‘official’ participants compared to both ‘No Dry January’ and ‘unofficial’ Dry January groups. Significant pathways of change were identified for ‘official’ Dry January participants: relative to ‘No Dry January’ participants, improvements in DRSE predicted reductions in AUDIT-C at six months (β =-0.04, z= -2.39, p=.017). Greater abstinence during January predicted increased DRSE during January which in turn predicted lower AUDIT-C at six months (β=-0.02, z=-2.29, p=.022). ConclusionPeople who drink at hazardous levels who participate in Dry January report reduced alcohol consumption six months later. Enduring reductions in consumption cannot be fully attributed to seasonal variation in alcohol consumption and are enhanced by registering for the ‘official’ campaign and having access to structured online supports. Pathways between level of abstinence, DRSE, and subsequent alcohol consumption were identified. However, effect sizes were small indicating that other mechanisms of change remain to be identified.