An online tailored intervention targeting heavy drinking in students in secondary vocational education (MBO students)

INTERVENTION: Students who give informed consent will be randomly assigned to the experimental condition (just‐in‐time adaptive tailored feedback about alcohol drinking, and usual alcohol feedback in Testjeleefstijl.nu) or control condition (usual alcohol feedback in Testjeleefstijl.nu). Participants in the experimental condition will receive the tailored feedback over a period of three months by means of an app. CONDITION: Alcohol, Alcohol consumption among young adults ; ; PRIMARY OUTCOME: ‐ Mean weekly alcohol consumption (continuous);; ; ‐ Frequency of binge drinking (dichotomous and continuous);; ; ‐ Frequency of heavy drinking (dichotomous). ; ; ; ; The frequency of binge drinking was measured as the number of days in the past week on which participants had drunk four (women) or six (men) or more glasses of alcohol (continuous) and the percentage of participants that had drunk four (women) or six (men) or more glasses of alcohol at least once per week (dichotomous); . ; The frequency of heavy drinking was measured as the percentage of participants drinking more than the mean weekly alcohol consumption rate of 0 (girls and boys <18 years), 7 (females >=18 years) or 14 (males >=18 years) glasses of alcohol. ; ; ; ; Timepoints: EMA (i.e., daily measurement for 7 consecutive days) every six weeks starting at baseline and ending 43 weeks after baseline (in total 56 EMA's: 8 times x 7 days). SECONDARY OUTCOME: Mood, attitude, intrinsic motivation, self‐efficacy, coping planning and intentions towards drinking less alcohol than usual. ; ; ; ; Timepoints: ; ; ‐ EMA (i.e., daily measurement for 7 consecutive days) every six weeks starting at baseline and ending 43 weeks after baseline (in total 56 EMA's: 8 times x 7 days) for mood, intrinsic motivation and self‐efficacy. ; ; ‐ Online surveys at baseline, and 2 weeks and 6 months follow‐up (i.e., after the intervention period) for attitude, intention, coping planning. INCLUSION CRITERIA: ‐ MBO students aged 16 to 24 years who are heavy drinkers. Heavy drinking is defined as: 1) drinking more than the low‐risk drinking guidelines (Health Council of the Netherlands) recommending for adolescents (aged 16‐17 years) to drink no alcohol and for adults to drink a maximum of 1 (women) or 2 (men) glasses of standard alcohol units daily and/or 2) binge drinking, that is, drinking 4 or more (women) or 6 or more (men) standard alcohol units at one occasion.