Interest in contingency management and reducing stimulant use among syringe service program participants

Abstract

Introduction:

Expanding access to effective treatment for stimulant use disorder (StimUD) is increasingly urgent as US fatal drug poisonings involving stimulants have rapidly increased. Limited information is available regarding interest in StimUD treatment among syringe service program (SSP) participants including interest in contingency management (CM).

Methods:

We surveyed SSP participants in Burlington, Vermont regarding their interests in reducing and stopping stimulant use, participating in CM, and examined associations between sociodemographics, drug use, and health/treatment variables with interest in reducing and stopping stimulant use using multivariable logistic regression.

Results:

Among 139 participants, 64.6 % reported interest in reducing and 59.7 % in stopping stimulant use. Overall, 82.8 % of participants reported interest in CM to reduce or stop stimulant use. Interest in reducing use was greater (odds ratio[95 % CI]) among participants currently receiving substance use disorder (SUD) treatment (3.84[1.61–9.14], p < .01), without Hepatitis C viral (HCV) infection (2.61[1.14–5.98], p = .02), and being somewhat (19.29[2.25–165.65], p = .01) or very (19.65[2.34–164.84], p = .01) concerned about anxiety. Interest in stopping use was greater among participants currently receiving SUD treatment (4.98[1.97–12.62], p < .01), without HCV infection (2.87[1.22–6.74], p = .02), participants whose primary drug was opioids compared to both stimulants and opioids (28.13[2.95–267.93], p < .01), and participants whose primary drug was stimulants compared to both stimulants and opioids (12.81[1.45–113.43], p = .02).

Conclusions:

Results demonstrate interest in stimulant use treatment among this sample of SSP participants, with strong interest in CM. As community-based programs with high social acceptability for their non-judgmental services, SSPs are a novel setting to examine providing evidence-based CM for StimUD.

Introduction

Expanding access to effective treatment for stimulant use disorder (StimUD) has become increasingly urgent as fatal drug poisonings involving stimulants, such as cocaine and methamphetamine, have rapidly increased in the United States (US; Friedman & Shover, 2023; Mattson, 2021; Ahmad et al., 2025). In the US, stimulant involvement in fatal poisonings has increased from 12,122 deaths in 2015 to 64,778 deaths in 2023 (Ahmad et al., 2025). In Vermont, fatal drug poisonings increased over 500 % between 2010 and 2023 with cocaine being the second most prevalent drug detected in 72 % of fatal poisonings (Vermont Department of Health, 2025). Notably, in Vermont, the proportional involvement of cocaine in drug poisonings has risen over sixfold compared its presence in only 11 % of deaths in 2015 (Vermont Department of Health, 2024).

The most efficacious treatment for StimUD is contingency management (CM), a positive reinforcement-based treatment in which individuals earn financial incentives (e.g., gift cards) for completion of objective goal behavior(s) (e.g., evidence of recent nonuse of stimulants; Bentzley et al., 2021; Bolívar et al., 2021; Higgins et al., 2007; Ronsley et al., 2020). Despite the evidence supporting its efficacy, availability of CM in community clinical settings is limited or non-existent in most of the US (Becker et al., 2023; Higgins et al., 2019). Currently, there are no Food and Drug Administration (FDA) approved medications for StimUD (Brandt et al., 2021).

Expanding access to evidence-based treatment and harm reduction strategies for substance use disorders (SUD) are critical to addressing the ongoing drug poisoning epidemic and represents two of four key areas of the US Overdose Prevention Strategy (US Department of Health and Human Services, 2025). Increasing access to CM to reduce stimulant use in a variety of community settings is one specific activity that would help with increasing access to evidence-based treatment. For example, syringe service programs (SSPs) are community-based harm-reduction programs that provide sterile syringes and a range of other evidence-based services (e.g., drug test strips, overdose education and naloxone distribution) for people who inject drugs (PWID; Devries et al., 2017; Peiper et al., 2019). Indeed, SSPs are a potentially promising setting to provide CM and other evidence-based SUD treatments because their low-barrier approach and nonjudgmental services are well-liked among service recipients (Frost et al., 2022; Jakubowski & Fox, 2020).

To our knowledge, interest in CM has not been examined and limited information is available about interest in StimUD treatment generally among SSP service recipients. SSPs have been reported to be the most preferred setting to receive medication for OUD (MOUD) among a sample of SSP participants (Fox et al., 2015) and low-barrier MOUD has been successfully integrated into SSPs with treatment outcomes comparable to conventional MOUD settings (Bachhuber et al., 2018; Hood et al., 2020). Relatedly, McMahan et al. (2020) examined interest in reducing or stopping drug use among 583 SSP participants in Washington State. Opioids were the primary drug for 76 % of respondents (n = 443) and methamphetamine for 24 % (n = 140). Overall, interest in reducing or stopping use was lower for respondents whose primary drug was methamphetamine (46 %) than opioids (82 %). Counseling (49 %) and medication to reduce use (48 %) were the most endorsed types of treatment of interest for individuals whose primary drug was methamphetamine. Important to the current study, options for the types of treatment for methamphetamine use did not include CM.

In the present study, we sought to examine perspectives of SSP service recipients who use stimulants on interest in CM and to reduce or stop stimulant use with the following three aims: (1) examine general interest in reducing and stopping stimulant use and preferred types of StimUD treatment; (2) examine interest and the potential acceptability of CM treatment for stimulant use; and (3) model associations between sociodemographics, drug use practices, and health- and treatment-variables with preferences to reduce stimulant use, stop stimulant use, and receive CM treatment to reduce or stop stimulant use.

Methods

Study participants and setting

Respondents were 139 individuals participating in harm reduction services at a SSP in Burlington, Vermont who reported stimulant use (e.g., crack cocaine, methamphetamine) in the last three months. To be eligible, individuals had to (a) be 18 years or older, (b) participate in services at the SSP, and (c) report past three-month stimulant use. Of the 150 individuals who participated in survey interviews, 139 met all inclusionary criteria, yielding in an inclusion rate of 92.7 %. The SSP is an on-site program that is open full-time and is Vermont’s largest and oldest SSP, having operated in the community for over two decades. The staff include peer support specialist, social workers, case managers, nursing, and a part-time physician. Services provided by the SSP include sterile syringe provision, same building low-barrier MOUD, free Narcan/overdose reversal kits and prevention training, HIV testing, counseling and care management, as well as other harm reduction services including free drug test strips (e.g., fentanyl, xylazine), wound care kits, and safer smoking supplies. As an anonymous program, the SSP does not collect or store identifiable information about service recipients.

Study procedures and materials

Data were collected using the following two instruments: (1) the University of Washington (UW) Alcohol and Drug Abuse Institute (ADAI) Washington State Syringe Service Program Health Survey (Banta-Green et al., 2018; Frost et al., 2018; McMahan et al., 2020) and (2) a six-item CM questionnaire developed by the authors on interest in CM treatment. All descriptions for the dependent measures and independent variables from the Washington State Syringe Service Program Health Survey are described and reported based on their descriptions in other peer-reviewed studies (Banta-Green et al., 2018; Frost et al., 2018; McMahan et al., 2020). All data were collected in-person using an interview format led by a trained SSP staff member between March and June 2023. Verbal informed consent was obtained from each participant. A form documenting the consent process was completed prior to participation. Each participant earned a $25 gift card for their participation in the survey interview. All surveys were competed on-site at the SSP. This study was approved by the University of Vermont Institutional Review Board.

Dependent measures

Interest in reducing or stopping stimulant use

Respondents completed two questions on reducing and stopping their stimulant use. Interest was assessed by two variations of the question “How interested are you in (reducing; stopping) your stimulant use?” with four response options (very interested, somewhat interested, not sure, not interested).

Preferred types of treatment

For respondents who indicated interest in reducing or stopping their stimulant use, one additional question queried potential types of help they would be interested in. The question asked was “What types of help would you want if they were easy to get?” Response options included financial incentives for abstinence, detoxification, outpatient/residential program, medication that may help reduce stimulant use, mental health medications, someone to help navigate services, and don’t want any help.

Interest in contingency management

A six-item questionnaire examined potential interest in CM treatment and questions related to participation in a CM program. The topics queried included (1) interest in CM to reduce or stop their stimulant use (“How interested would you be in trying CM to reduce or stop your cocaine and/or methamphetamine use?”; 7-point Likert type scale from very uninterested to very interested), (2) interest in stopping their use if they could earn $1200 over 12 weeks (7-point Likert type scale from very uninterested to very interested), (3) the likelihood of coming in once or twice per week for CM visits (7-point Likert type scale from very unlikely to very likely), and (4) whether the goal would be to reduce or completely stop their stimulant use.

Independent variables

Four categories comprised the independent variables of interest: (1) sociodemographics, (2) drug use practices, (3) current and past-year SUD treatment, and (4) mental health, health, and medical service utilization. Sociodemographic variables of interest included age (years old), race (white or not white), gender (female or male), housing status (unhoused/unstable or permanent), employment (unemployed/disability or part-time/full-time work), and past-year incarceration (yes or no).

Regarding drug use, respondents identified their primary (i.e., preferred) drug through an open-ended question in which they were asked “which of the drugs listed is your main drug?” which was categorized into three subgroups: stimulants-primary, opioids-primary, and both stimulants- and opioids-primary. Other drug use variables included the type of drug administration (injecting vs. other [e.g., smoking, snorting]), type of stimulant use (methamphetamine, crack cocaine, powder cocaine [yes or no]), past-year overdose (0 or ≥1), and use of naloxone/Narcan kit in the past three months (yes or no).

Current and past-year SUD treatment was assessed by one question on each topic where respondents indicated the type(s) of treatment received. Response options (yes or no) included MOUD (e.g., methadone, buprenorphine), outpatient, inpatient, 12-step/recovery support, or none.

Mental health variables included one question each on concerns about anxiety and concerns about depression (“How concerned are you about [anxiety; depression]?”), each with three response options (very, somewhat, none). More general health questions included past-year medical care including the Emergency Room (ER), other places of care (e.g., doctor’s office, community clinic, tribal clinic), or none (yes or no). Respondents were also queried on Hepatitis C viral (HCV) infection occurrence, HCV treatment, and past-year occurrence of an abscess or skin infection, blood clot or blood infection, and endocarditis (yes or no).

Data analysis

Regarding interest in reducing and stopping stimulant use and preferred types of help of interest (Aim 1) and interest in CM treatment for stimulant use (Aim 2), descriptive analyses were conducted to examine overall findings and results by primary drug. Again, primary drug was categorized into three subgroups: stimulants-primary, opioids-primary, and both stimulants- and opioids-primary.

For Aim 3, univariable logistic regression analyses were conducted to examine associations between sociodemographic characteristics, drug use, treatment, and mental, health and medical service utilization among all 139 participants on three outcomes: interest (1) to reduce stimulant use, (2) to stop stimulant use, and (3) in CM treatment to reduce or stop stimulant use. Each outcome was coded as a binary variable (very interested versus other) based on an a priori decision to compare those with strong interest versus all others. Each predictor from the univariable logistic regression analysis with an association of p < .10 is reported and was included as a predictor in the multivariable models. Backward stepwise multivariable logistic regression analyses were conducted to determine which sets of variables were significant, independent predictors of each outcome; all variables with an association of p < .05 are reported. All statistical analyses were conducted using SAS ver. 9.4 statistical analysis software (SAS Institute, Inc., Cary, NC, USA).

Results

Among the 139 respondents, 72 (51.8 %) reported their primary drug was stimulants, 50 (36.0 %) reported opioids, and 17 (12.2 %) reported both stimulants and opioids. Participants were 46.0 % female, 89.9 % identified as white, 80.6 % reported currently being unhoused or unstable housing, 86.3 % reported being unemployed or on disability, and 57.6 % currently receiving MOUD treatment. Additional demographic information is reported in Table 1.

Table 1.

Sociodemographics and other participant characteristics.

Variable	All participants (n = 139)
	N	%
Mean age	41.09	-
Gender
Male	73	52.52 %
Female	64	46.04 %
Transgender	1	0.72 %
Not reported	1	0.72 %
Race
White	125	89.93 %
Latinx/Hispanic	3	2.16 %
Black	4	2.88 %
American Indian/Alaska Native	4	2.88 %
Other	7	5.04 %
Housing status
Unhoused	63	45.32 %
Temporary/unstable	49	35.25 %
Permanent	26	18.71 %
Not reported	1	0.72 %
Employment status
Unemployed	90	64.75 %
Disability	30	21.58 %
Casual work	2	1.44 %
Part-time work	4	2.88 %
Full-time work	7	5.04 %
Retired	1	0.72 %
Other	5	3.60 %
Jail or prison in last 12 months
Yes	37	26.62 %
Current treatment
Medication for opioid use disorder	80	57.55 %
Outpatient	21	15.11 %
Inpatient	0	0.00 %
12-step/recovery group	1	0.72 %
None	49	35.25 %
Past year treatment
Medication for opioid use disorder	102	73.38 %
Outpatient	22	15.83 %
Inpatient	15	10.79 %
12-step/recovery group	2	1.44 %
None	29	20.86 %
Primary drug
Opioids primary	50	35.97 %
Stimulants primary	72	51.80 %
Stimulants & opioids primary	17	12.23 %
Type of drug administration
Injection	83	59.71 %
Other	56	40.29 %
Type of stimulant use
Crack cocaine	121	87.05 %
Powder cocaine	47	33.81 %
Methamphetamine	76	54.68 %
Past-year overdose
Yes	39	28.89 %
Use of Naloxone/Narcan in past three months
Yes	105	77.78 %
Concern about anxiety
None	18	13.14 %
Somewhat	50	36.50 %
Very	69	50.36 %
Concern about depression
None	27	19.71 %
Somewhat	63	45.99 %
Very	47	34.31 %
Past-year locations of medical care
Emergency room	68	48.92 %
Other	40	28.78 %
None	41	29.50 %
History of Hepatitis C viral infection
Yes	74	56.49 %
History of Hepatitis C viral infection treatment
Yes	36	25.90 %
Past-year occurrence of a skin infection
Yes	38	27.34 %
Past-year occurrence of a blood clot or blood infection
Yes	11	7.91 %
Past-year occurrence of endocarditis
Yes	5	3.60 %

Interest in reducing and stopping stimulant use and types of help wanted

Fig. 1 depicts the proportion of participants interested in reducing or stopping their stimulant use. Overall, 64.6 % of participants reported interest in reducing and 59.7 % in stopping their stimulant use. Among those whose primary drug was stimulants, 67.6 % reported interest in reducing and 62.7 % in stopping their stimulant use. Among those who primary drug was opioids, 63.0 % reported interest in reducing and 60.9 % in stopping their stimulant use. Among those who primary drug was both stimulants and opioids, 56.3 % reported interest in reducing and 43.8 % in stopping their stimulant use.

Fig. 1.

Interest in reducing and stopping stimulant use for all participants and by primary drug.

The types of help of interests are depicted in Fig. 2. Financial incentives were the most endorsed type of help among participants whose primary drug was stimulants (47.1 %), opioids (47.8 %), and both stimulants and opioids (56.3 %). The next most endorsed types of help were outpatient or residential programs (stimulants-primary, 27.9 %; opioids-primary, 23.9 %; combined stimulants- and opioids-primary, 12.5 %) and 1-on-1 counseling (stimulants-primary, 22.1 %; opioids-primary, 26.1 %; combined stimulants- and opioids-primary, 6.3 %). Approximately 22.0 % of all participants reported not wanting any type of help for their stimulant use.

Fig. 2.

Interest in different types of help wanted for stimulant use.

Interest in contingency management

Overall, interest in CM to reduce or stop stimulant use was reported by 82.8 % of participants; this included 80.0 % of participants whose primary drug was stimulants, 89.4 % of those who primary drug was opioids, and 76.5 % of those who primary drug was both stimulants and opioids. Very interested was the most endorsed response option across all participants (stimulants-primary, 55.7 %; opioids-primary, 70.2 %; combined stimulants- and opioids-primary, 47.1 %). Interest in stopping stimulant use if you could earn $1200 over 12 weeks was reported by 90.9 % of participants whose primary drug was stimulants, 97.6 % of those who primary drug was opioids, and 87.5 % of those who primary drug was both stimulants and opioids. Most participants (83.7 %) reported being likely to come to the SSP twice per week for CM visits. Approximately 59.2 % of participants in the stimulants-primary, 66.0 % in the opioids-primary, and 75.0 % in the combined stimulants- and opioids-primary groups indicated if they were to try CM their goal would be to completely stop their stimulant use (Fig. 3).

Fig. 3.

Percent of participants interested in contingency management to reduce versus completely stop their stimulant use.

Associations between predictor variables and dependent outcomes

Table 2 summarizes the univariable regression analyses for each outcome (for additional descriptive characteristics, see Supplemental Table 1). Four variables were significantly associated with interest in reducing stimulant use: current SUD treatment (X²(1) = 5.86, p = .02), concern about anxiety (X²(2) = 7.64, p = .02), no history of HCV infection (X²(1) = 4.54, p = .03), and current MOUD treatment (X²(1) = 4.26, p = .04). More specifically, the odds of interest were significantly greater among participants currently receiving some type of SUD treatment (OR = 2.53, 95 % CI = 1.19–5.35, p = .02), being somewhat (OR = 16.69, 95 % CI = 2.05–136.15, p = .01) or very (OR = 18.66, 95 % CI = 2.34–149.00, p = .01) concerned about anxiety compared to no concern, reporting no history of HCV infection (OR = 2.21, 95 % CI = 1.07–4.57, p = .03), and currently receiving MOUD treatment (OR = 2.12, 95 % CI = 1.04–4.32, p = .04).

Table 2.

Bivariable logistic regression analysis results for associations (p < .10) of characteristics with interest to reduce stimulant use, stop stimulant use, and in CM to reduce or stop stimulant use among all participants.

	X 2	P value	OR (95 % CI)
Reduce stimulant use
Current treatment	5.86	.02	2.53 (1.19–5.35)
Concern about anxiety	7.64	.02	–
Somewhat vs none	–	.01	16.69 (2.05–136.15)
Very vs none	–	.01	18.66 (2.34–149.00)
Very vs somewhat	–	.77	1.12 (0.53–2.37)
No history of HCV infection	4.54	.03	2.21 (1.07–4.57)
Current MOUD treatment	4.26	.04	2.12 (1.04–4.32)
Stop stimulant use
Current treatment	7.35	.01	2.87 (1.34–6.14)
Current MOUD treatment	5.47	.02	2.36 (1.15–4.85)
Concern about anxiety	7.29	.03	–
Somewhat vs none	–	.02	7.19 (1.48–34.98)
Very vs none	–	.01	8.50 (1.80–40.25)
Very vs somewhat	–	.66	1.18 (0.56–2.51)
Primary drug	6.20	.05	–
Opioids-primary vs stimulant-opioids	–	.01	5.63 (1.41–22.48)
Stimulants-primary vs stimulant-opioids	–	.07	3.51 (0.92–13.48)
Opioids-primary vs stimulants-primary	–	.22	1.60 (0.75–3.42)
No history of HCV infection	3.48	.06	2.00 (0.97–4.14)
CM to reduce or stop stimulant use
Gender (female vs male)	5.19	.02	2.27 (1.12–4.62)

Four variables were significantly associated with interest in stopping stimulant use: current SUD treatment (X²(1) = 7.35, p = .01), current MOUD treatment (X²(1) = 5.47, p = .02), concern about anxiety (X²(2) = 7.29, p = .03), and primary drug type (X²(2) = 6.20, p = .05). More specifically, the odds of interest were significantly greater among participants currently receiving some type of SUD treatment (OR = 2.87, 95 % CI = 1.34–6.14, p = .01), currently receiving MOUD treatment (OR = 2.36, 95 % CI = 1.15–4.85, p = .02), being somewhat (OR = 7.19, 95 % CI = 1.48–34.98, p = .02) or very (OR = 8.50, 95 % CI = 1.80–40.25, p = .01) concerned about anxiety, and those whose primary drug was opioids compared to both stimulants and opioids (OR = 5.63, 95 % CI = 1.41–22.48, p = .01). One variable, gender (X²(1) = 5.19, p = .02), was significantly associated with interest in CM treatment to reduce or stop stimulant use with greater than twice the odds of interest among female participants (OR = 2.27, 95 % CI = 1.12–4.62, p = .02).

Table 3 summarizes the multivariable regression analyses for each outcome. Three variables were independent, significant predictors of interest in reducing stimulant use: current SUD treatment (X²(1) = 9.23, p < .01), concern about anxiety (X²(2) = 7.71, p = .02), and no history of HCV infection (X²(1) = 5.11, p = .02). The odds of interest in reducing use were significantly greater among participants currently receiving some type of SUD treatment (OR = 3.84, 95 % CI = 1.61–9.14, p < .01), being somewhat (OR = 19.29, 95 % CI = 2.25–165.65, p = .01) or very (OR = 19.65, 95 % CI = 2.34–164.84, p = .01) concerned about anxiety, and no history of HCV infection (OR = 2.61, 95 % CI = 1.14–5.98, p = .02). For interest in stopping stimulant use, three variables were independent, significant predictors: current SUD treatment (X²(1) = 11.45, p < .01), primary drug (X²(2) = 9.46, p < .01), and no history of HCV infection (X²(1) = 5.83, p = .02). The odds of interest in stopping stimulant use were significantly greater among participants currently receiving some type of SUD treatment (OR = 4.98, 95 % CI = 1.97–12.62, p < .01), those whose primary drug was opioids compared to both stimulants and opioids (OR = 28.13, 95 % CI = 2.95–267.93, p < .01), those whose primary drug was stimulants compared to both stimulants and opioids (OR = 12.81, 95 % CI = 1.45–113.34, p = .02), and reporting no history of HCV infection (OR = 2.87, 95 % CI = 1.22–6.74, p = .02).

Table 3.

Multivariable logistic regression analysis results for characteristics statistically significantly associated with interest to reduce stimulant use and stop stimulant use among all participants.

	X 2	P value	OR (95 % CI)
Reduce stimulant use
Current treatment	9.23	<.01	3.84 (1.61–9.14)
Concern about anxiety	7.71	.02	–
Somewhat vs none	–	.01	19.29 (2.25–165.65)
Very vs none	–	.01	19.65 (2.34–164.84)
Very vs somewhat	–	.96	1.02 (0.45–2.33)
No history of HCV infection	5.11	.02	2.61 (1.14–5.98)
Stop stimulant use
Current treatment	11.45	<.01	4.98 (1.97–12.62)
Primary drug	9.46	<.01	–
Opioids-primary vs stimulant-opioids	–	<.01	28.13 (2.95–267.93)
Stimulants-primary vs stimulant-opioids	–	.02	12.81 (1.45–113.34)
Opioids-primary vs stimulants-primary	–	.08	2.20 (0.92–5.23)
No history of HCV infection	5.83	.02	2.87 (1.22–6.74)

Discussion

This study examined interest in reducing and stopping stimulant use, types of stimulant treatment of interest, and interest in and the potential acceptability of CM treatment for stimulant use among individuals participating in SSP services. Approximately two-thirds of participants reported interest in reducing or stopping their stimulant use, indicating many individuals who are actively using stimulants and participate in harm reduction services are interested in receiving help for their stimulant use. Financial incentives was the most endorsed among the types of help of interest, followed by outpatient or residential supports and 1-on-1 counseling to a lesser extent.

As a first step in examining potential interest in CM among SSP participants, we primarily focused on the implementation construct of acceptability and the potential appropriateness of CM from the service recipient perspective (Proctor et al., 2011). Over 80 % of participants reported interest in CM treatment to reduce or stop their stimulant use, with most participants reporting they were very interested. These high levels of interest in CM were observed across all participants and similar for those whose primary drug was stimulants, opioids, and both stimulants and opioids. Moreover, approximately two-thirds of participants reported their goal would be to completely stop their stimulant use. Considering this high acceptability, future research is needed that gathers feedback from a more diverse range of perspectives (e.g., service providers, frontline staff, managers, organizational leaders, sponsors) and on a greater number of implementation constructs (e.g., feasibility, adoption, implementation costs; Proctor et al., 2011). In doing so, these efforts could be informed and created using a collaborative, user-center design approach (Becker et al., 2019) to better understand the determinants of implementation in SSP settings.

In examining the potential acceptability of CM among SSP service recipients, we queried interest in a program where the goal behavior was stimulant nonuse (i.e., abstinence). This decision was guided by the extensive empirical support with nonuse as the most commonly reported goal behavior. That said, future research may also seek to examine more harm reduction-oriented goal behaviors, such as reinforcing attendance (e.g., Pfund et al., 2022) and reductions in use (e.g., Preston et al., 2001; Silverman et al., 2007). With respect to the latter, Preston et al. (2001) offer a methodological approach for reinforcing reductions in stimulant use (i.e., decreases ≥25 % in cocaine metabolite levels) and found less cocaine use among individuals in the condition that reinforced successive decreases in cocaine metabolite levels towards nonuse compared to a standard CM condition that reinforced only nonuse throughout.

Initiatives to expand the availability of CM for StimUD are currently ongoing across the US. This work includes numerous statewide efforts in states such as California, Washington, Montana, Maine, Michigan, and Vermont among others. The funding mechanism varies across states, with some states funding CM via Medicaid 1115 waivers (e.g., California, Washington), Opioid Settlement Funds (e.g., Vermont, Michigan), and state or county level grants (e.g., Maine) (Freese et al., 2023; Parent et al., 2023). In each statewide program, implementation is occurring in traditional SUD treatment settings (e. g., intensive outpatient, opioid treatment programs) and to our knowledge, no current projects provide funding for CM to be implemented in harm reduction settings. Thus, to further maximize reach, our results suggest future efforts should consider expanding CM implementation to more types of community settings including low-barrier harm reduction programs and SSPs using these already adopted funding mechanisms. This proposed expansion is a potential opportunity to provide evidence-based StimUD treatment to individuals interested in help but not currently connected to other treatment and recovery services.

With the emerging implementation of CM across the US, there has also been updated guidance and advisory reports from multiple federal agencies including from the Office of the Assistant Secretary for Planning and Evaluation (ASPE, 2023) and Substance Abuse and Mental Health Services Administration (SAMHSA, 2025). For example, in January 2025, SAMHSA released an updated advisory report, “Using SAMHSA funds to implement evidence-based CM services”. Key updates in this advisory report included increasing the cap for CM incentives from $75 to $750 per patient per year, outlining updated safeguards to help promote evidence-based practice and minimize the risk for fraud and abuse, and updating guidance for clinical settings and goal behaviors. A commonality across these reports is guidance to prioritize the use of CM for StimUD because of its strong empirical evidence and the lack of FDA-approved medications (ASPE, 2023). We chose to query interest in a CM program with maximal earnings of up to $1200, which is above the SAMHSA cap, to better align the potential incentive magnitude with evidence from the extant literature and the research team’s extensive experiences using CM incentives of similar dollar amounts (Higgins et al., 1991; Higgins et al., 1993; Higgins et al., 1994; Rawson et al., 2002, 2004, 2006).

Multivariable regression analyses indicated several notable predictors differentiating interest in reducing or stopping stimulant use. Expanding services in SSP settings to include StimUD treatment may be of particular interest to those already in SUD treatment in that participants currently in treatment were approximately four to five times more likely to report interest in reducing and stopping stimulant use. Participants without a history of HCV infection were over twice as likely to report interest in reducing and stopping stimulant use. Participants reporting concerns about anxiety were significantly more interested in reducing stimulant use, with odds nineteen times greater for participants reporting somewhat or very concerned compared to no concern. This result corresponds with previous evidence indicating a robust relation between anxiety and stimulant use (Edinoff et al., 2022; Raines et al., 2021). One’s primary drug was also significantly associated with interest in stopping stimulant use. Participants whose primary drug was an opioid were most likely to be interested, followed by those whose primary drug was a stimulant, and then those whose primary drug was both stimulants and opioids.

Gender was significantly associated with interest in CM to reduce or stop stimulant use, with twice the odds of interest for female participants. This result aligns with Brecht et al. (2004) who found statistically significantly longer durations of initial treatment episodes for females with methamphetamine use disorder than males, and lower but not statistically significant differences in relapse within six months.

This study has several limitations to note when interpreting these results. As an observational study, these data do not support causal inferences and describe findings from the time period when the survey interviews were conducted. All data was collected via self-report which could affect the findings in that there is potential for social desirability bias to occur (e.g., to report interest in treatment). Relatedly, querying self-reported interest in CM treatment and to reduce or stop stimulant use may not fully correspond with the behavior of participating in CM treatment. The mental health variables of anxiety and depression were based on single-item questions and not from validated diagnostic instruments; thus, these results should not be interpreted as indicative of a mental health diagnosis. With our focus on SSP service recipient acceptability, absent from these results is acceptability data from other perspectives such as SSP staff and sponsors. Finally, this study was conducted at one SSP in Burlington, Vermont and the results may not be representative of all individuals who participate in SSP services or use drugs in Vermont and may not be generalizable to other geographic settings.

Conclusion

These results demonstrate that individuals participating in harm reduction services at a SSP in Burlington, Vermont are interested in treatment for their stimulant use, but acceptability is variable and based on the type of treatment service offered. Notably, this sample of SSP service recipients indicated high levels of interest in CM treatment, an evidence-based intervention for StimUD with strong empirical support although still limited accessibility in community settings to date. As community-based programs with high social acceptability among service recipients for their non-judgmental services, SSPs are a novel potential setting in which to provide CM treatment for StimUD. Such CM implementation for StimUD could be viewed as a parallel to providing low-barrier MOUD treatment for OUD in SSP settings (CDC, 2023), with a shared goal of making evidence-based treatment for SUDs readily available for interested service recipients as part of the continuum of supports.

Supplementary Material

Supplementary data to this article can be found online at https://doi.org/10.1016/j.josat.2025.209763.

Data availability

The datasets generated and/or analyzed during the current study are not publicly available due to institutionally approved protocols but can be made available from the corresponding author on reasonable request.