The goal of this randomized control pilot study is to learn about a financial incentives intervention among individuals who use stimulants and take part in a community-based syringe exchange program. The main question it aims to answer is how financial incentives for not using stimulants will impact stimulant use. Participants in the experimental group will have the opportunity to earn financial incentives for providing a negative urine sample for stimulants using a point-of-care test, which indicates abstinence from stimulant use, along with health education on the health risks of stimulant use and substance injection. Researchers will compare the experimental group to the control group who will receive health education on the health risks of stimulants use and injection.

The investigators are proposing a two condition, parallel groups, randomized control pilot study to evaluate the efficacy of a financial incentives intervention among individuals who use stimulants and take part in a community-based syringe exchange program. The study design will include recruiting service recipients who already participate in programs offered by a syringe exchange program.The experimental group will have the opportunity to earn financial incentives contingent on providing a negative urine sample for stimulants using a point-of-care test, which indicates abstinence from stimulant use, in addition to health education on the health risks of stimulant use and substance injection. The control group will receive health education on the health risks of stimulants use and injection. All participants will participate in their syringe exchange services as usual. The investigators chose the health education as the control because participants across both conditions already receive the services provided by the syringe exchange program. Moreover, this control condition will help control for a potential type of between-groups variability.

Inclusion Criteria:

• be 18 years or older
• report using stimulants in the past 30 days
• meet the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis for stimulant use disorder at a moderate or severe level (i.e., 6 or more of the 11 criteria)
• participation in services at syringe exchange program

Exclusion Criteria:

• failure to meet one or more inclusionary criteria
• individuals who are cognitively impaired by their drug use or psychiatric conditions that could preclude informed consent

From enrollment to study completion at 12 weeks

This project was designed as a pilot study with a small sample size. As such, there are limitations of the statistical power due to the small sample size. Although the originally proposed sample size by condition was not met, the results are able to discern patterns of differences in the primary outcome by study condition.