The study, led by Dr. Nancy Petry of the University of Connecticut School of Medicine and Dr. Maxine Stitzer of Johns Hopkins University School of Medicine, was published in the October 2005 issue of the Archives of General Psychiatry.

This is the first publication of results from a protocol related to NIDA's Clinical Trials Network (CTN). The CTN is a research infrastructure that tests the effectiveness and usefulness of new and improved interventions in community-based treatment settings with diverse populations. Consisting of 17 research "nodes," the CTN assists NIDA in establishing and maintaining partnerships with drug abuse researchers and community treatment providers. This study included participants from eight CTN sites.

"Behavioral and psychosocial techniques are important components of effective drug abuse and addiction therapies," says NIDA Director Dr. Nora D. Volkow. "A comprehensive and integrated treatment plan can address a broad range of social problems, skills deficits, and co-occurring psychiatric problems that together increase a person's vulnerability to substance abuse. In addition, there are no approved medications for treating certain forms of drug dependence, so behavioral interventions, such as those employed in this study, are essential."

In traditional MI, participants receive vouchers for items or services for staying in treatment and remaining off illicit drugs. But clinics must purchase the vouchers, which can make the therapy costly and increase the difficulty of implementing it into community practice. However, the scientists who conducted the study indicate that the opportunity to win prizes worth as little as $1 offers a successful and economical alternative to both voucher reward programs and those that employ counseling only.

A total of 415 cocaine or methamphetamine abusers participated in this 12-week study. Approximately half were randomly assigned to receive usual care, which consisted of group counseling, and sometimes individual and family sessions. The rest were assigned to the MI program, in which they received counseling plus opportunities to win prizes. The scientists monitored drug abstinence by means of urinalysis.

Members of the usual care group were congratulated when their urinalysis results showed they had not abused cocaine, methamphetamine, and alcohol. But members of the MI group could draw from a container of chips that offered a 50-percent chance of winning a prize ranging in value from $1 to $100. In this study, the average direct costs of the prizes were $203 per participant. According to Dr. Petry, patients in voucher MI programs may earn as much as $600.

The scientists observed that participants in the MI group remained in treatment for a longer period and attended more counseling sessions than those in the usual care group. At the end of 12 weeks, 49 percent of the MI group remained, compared with 35 percent of the usual care group. They also noted that MI members submitted a significantly greater number of negative stimulant and alcohol urine samples. The MI group also was more likely to achieve sustained, continuous abstinence. Almost 19 percent of the MI group achieved 12 weeks of continued abstinence compared with almost 5 percent of the usual care group.

"This study showed that drawing for prizes, even when most of the rewards are worth very little, offered a more cost-effective means of improving abstinence and retention in psychosocial drug treatment programs," notes Dr. Petry. "However, additional research is needed to address the long-term efficacy of this MI program, especially as applied in community settings."