Rewards for abstaining reduce methamphetamine use

NEW YORK (Reuters Health) - When patients are treated for methamphetamine abuse and participate in a program that includes a "contingency management" strategy -- a system that rewards abstinence -- they are less likely to use illicit drugs compared with patients treated with usual care alone, investigators report.

Contingency management has improved the outcomes of patients in cocaine treatment, as well as those beginning treated for other substance use, Dr. John M. Roll and his associates explain in their report, published in the American Journal of Psychiatry for November. However, this approach to methamphetamine abuse has not bee rigorously tested.

Roll, from Washington State University in Spokane, and his group therefore evaluated the efficacy of contingency management based on a subanalysis of data from the Clinical Trials Network initiative of the National Institute on Drug Abuse involving 113 patients dependent on methamphetamine or other drugs.

The subjects were randomly assigned to usual care or usual care plus contingency management for 12 weeks. The programs consisted of 24 study visits during which time participants provided urine specimens to test for cocaine, alcohol, cannabis or opiates, in addition to methamphetamines.

Usual care included established psychosocial treatments, such as cognitive behavioral therapy and relapse prevention, as well as encouragement to participate in 12-step programs.

As part of the contingency management, subjects earned the chance to win prizes each time they tested negative, with the chances increasing with each consecutive period of abstinence. The reinforcers were plastic chips, half of which could be exchanged for prizes, most of which were worth $1 to $5, although a few were worth $20 or $100. The number of chips individuals could take increased with each week of negative samples, but was reset to one after a missed or positive sample.

Participants in the contingency management group submitted significantly more stimulant-negative samples than those in the usual care group (13.9 versus 9.9, retrospectively. This group also had longer periods of documented continuous abstinence (approximately 4.6 weeks versus 2.8 weeks; and was more likely to remain abstinent throughout the entire trial (17.6 percent versus 6.5 percent).

Roll's team observed no difference between groups at 3- and 6-month follow-up. However, they report, "regardless of group assignment, providing all negative samples during the last 4 weeks of treatment significantly increased the likelihood of providing a stimulant-negative urine sample at the 3-month follow-up time."

They conclude that showing that contingency management works "in a 'real world' setting demonstrates the actual clinical utility of the intervention."

SOURCE: American Journal of Psychiatry, November 2006.