Cost-effectiveness analysis of motivational interviewing with feedback to reduce drinking among a sample of college students.

OBJECTIVE This study evaluated the costs and cost-effectiveness of combining motivational interviewing with feedback to address heavy drinking among university freshmen. METHOD Microcosting methods were used in a prospective cost and cost-effectiveness study of a randomized trial of assessment only (AO), motivational interviewing (MI), feedback only (FB), and motivational interviewing with feedback (MIFB) at a large public university in the southeastern United States. Students were recruited and screened into the study during freshman classes based on recent heavy drinking. A total of 727 students (60% female) were randomized, and 656 had sufficient data at 3-months' follow-up to be included in the cost-effectiveness analysis. Effectiveness outcomes were changes in average drinks per drinking occasion and number of heavy drinking occasions. RESULTS Mean intervention costs per student were $16.51 for MI, $17.33 for FB, and $36.03 for MIFB. Cost-effectiveness analysis showed two cost-effective interventions for both outcomes: AO ($0 per student) and MIFB ($36 per student). CONCLUSIONS This is the first prospective cost-effectiveness study to our knowledge to examine MI for heavy drinking among students in a university setting. Despite being the most expensive intervention, MIFB was the most effective intervention and may be a cost-effective intervention, depending on a university's willingness to pay for changes in the considered outcomes.