After being informed about the study and potential risks, participants will complete online screening assessments. Those who are determined to be eligible via online screening will complete a urine drug screen to confirm eligibility. Once eligibility is confirmed, participants will be randomized either to the intervention group or to the wait-list control group. Those who are randomized to the intervention group will receive the 4-week text intervention via smartphone and complete assessments (including urine drug screens) at baseline, 1 month, 3 months, and 6 months. Those who are randomized to the wait-list control group will only complete the assessments (including urine drug screens) at baseline, 1 month, 3 months, and 6 months. Participants who are initially assigned to the wait-list control group can choose to receive the text intervention once their 6-month participation is complete.
