People respond to incentives. They don’t need to be large, either; a mere dime (19 cents in today’s dollars) motivated my daughter to break a seemingly intractable bad habit. For nearly 20 years, contingency management, which involves reinforcing desirable behaviors with tangible rewards, such as vouchers, gift cards, or cash, has been found to be a highly effective (1) and cost-effective (2) treatment for patients with substance use disorders (1). In this issue of the Journal, McDonell et al. (3) report that contingency management, when added to treatment as usual, can be highly beneficial for patients with serious mental illness and stimulant dependence who are being treated in a community mental health setting. Half of the patients in this study (those in the “contingent condition”) were randomly assigned to receive contingency management; for these patients, a stimulant-negative urine test would earn them an opportunity to draw from a “fishbowl” containing slips of paper worth varying amounts (most were worth $1, a few were worth $20, and one piece of paper contained a “jumbo” prize of $80; half of the slips of paper contained no monetary value and just read “nice job”). The comparison group received similar opportunities to draw for these prizes, but the opportunities were not contingent on the results of their urine tests (i.e., they were in the “noncontingent condition”). Unsurprisingly, and consistent with many other studies, the patients for whom the reinforcement was linked to their drug abstinence were more than twice as likely to produce a stimulant-negative urine test during treatment and 1.4 times as likely to do so during the follow-up assessment. If that had been the only finding, this would have been a nice study but not particularly noteworthy. However, it was the differences between the two study cohorts in psychiatric functioning and likelihood of hospitalization that stand out in this study. During the 6 months following randomization (3 months of treatment and 3 months of follow-up), nine of the participants in the noncontingent condition were hospitalized psychiatrically, for a total of 152 days, whereas only two participants in the contingent condition were hospitalized, for a total of 14 days. Thus, there was more than a tenfold difference between the two groups in their number of hospital days. Moreover, participants assigned to the contingent condition were 3 times less likely to inject drugs during the treatment period, although these differences were not maintained during the posttreatment follow-up assessment.