Table 1.

Intervention content topics by day of the week.

Day of week	Content area	Example intervention messagesa
Sunday	Coping with stress	Taking time for yourself can help reduce the amount of stress we experience! How, if at all, could you prevent stressing? You are worth it!
Monday	Coping with negative mood	Accepting things that happen in life can be hard. Sometimes to be strong means asking for help. Talk to someone who cares or text 741-741
Tuesday	Prosocial people and activities	What’re three things that used to make you feel excited or happy? Try doing/thinking about these things when you feel bored/down. Good luck!
Wednesday	Alternatives to address motives for substance use	What’re things you used to love doing with friends that you miss? Imagine doing them again. Who has your best interests in mind?
Thursday	Alternative leisure activities	Doing fun or exciting activities can lift your mood! Try thinking of an exciting thing you’d like to do. Making a bucket list can be fun
Friday or Saturday	Tools and protective strategies to reduce substance use	Exercising’s a natural high. Try a new workout & challenge yourself to a fitness goal. Look in the mirror & say 3 things you like about you. Some take breaks between drinks, so they don’t overdo it. Remind yourself that you are the fun and you make the good time. Be true to you! Think about how much money you could save by staying away from too much partying. Sounds like a great way to have extra cash. Nice going!

^aAlthough daily or weekly app data were not saved because of a software error, the intervention messages were tailored based on each participant’s daily responses and weekly reports of prior week substance use.