Randomized trial comparing two treatment strategies using prize-based reinforcement of abstinence in cocaine and opiate users.

Matson et al. (2008) ran a clinic trial with adults who used both cocaine and opiates. Half got prizes only for cocaine-free urines. The other half got prizes for both cocaine-free and opiate-free urines.

Every clean test earned draws from a prize bowl. Winners got small prizes like snacks or bus tokens. No extra money was added for the second drug.

Both groups cut cocaine use the same amount. Only the combined group kept more opiate-free urines after treatment ended. They also reported less craving for heroin.

More targets meant better opiate outcomes without extra cost.

Bryant et al. (1984) first showed that paying cash and giving take-home methadone for clean urines keeps clients in detox longer. L et al. built on this by adding cocaine testing and prize draws.

Woodman et al. (2025) now extends the idea onto a phone app inside methadone clinics. The core rule is the same: reward every clean test, but the tech is new.

Leigh et al. (2015) found that raising the prize amount over time helps smokers stay abstinent longer. L et al. kept the prize size flat, yet still saw gains by targeting two drugs at once.

If you run a substance-use program, tie prizes to every drug you care about. Adding opiate testing to cocaine testing costs nothing extra yet keeps clients off heroin longer. Try it next week: keep the same prize bowl, just mark two drugs on the cup.