Supporting Patients with Stimulant Use Disorder During and After Hospitalization with a Mobile App-Based Contingency Management Intervention: a Feasibility and Acceptability Study

Abstract

Objectives

Contingency management (CM) is the most effective intervention for stimulant use disorder (StUD) but is underutilized. This study examined the feasibility and acceptability of a novel mobile-app-based CM intervention for patients with StUD during and after hospitalization.

Methods

We recruited hospitalized patients with moderate to severe StUD and an expected hospital length of stay >2 weeks or heart failure diagnosis. Patients received gift cards for participating in incentivized activities (counseling, drug testing, and recovery-oriented reflections) through the mobile app. Patients could participate for 2 months (including after hospital discharge), earning up to $330. An in-person nurse supported implementation. We collected intervention engagement data (app usage, rewards earned) and conducted qualitative interviews on participants’ experiences.

Results

56 participants (68% male, 70% with unstable housing) completed intake. Average hospital length of stay was 33 days with 64% admitted for infection. Participants engaged for an average of 33.9 days. Engagement varied widely—those in the top quartile earned $173.31 on average, while those in the bottom quartile earned $6.27 on average. 89% of submitted drug tests were negative for stimulants. Participants felt the “positivity” of CM helped them stay “motivated” and “focused” on recovery instead of being “bored” or stressed in the hospital. 39 (69.6%) patients continued engaging after hospital discharge. Barriers to engagement included physical limitations, feeling overwhelmed, competing priorities, and technological challenges.

Conclusions

A novel hospital-based mobile app CM intervention helped patients with StUD cope with hospitalization and supported recovery goals, although program engagement varied widely.

INTRODUCTION

Drug overdose deaths involving stimulants are increasing rapidly, and co-use of methamphetamine and opioids is associated with a higher risk of overdose.^1,2 Stimulant use disorder (StUD) is associated with increased adverse health consequences, including cardiomyopathy, psychosis, and serious bacterial infections. Consequently, medical hospitalizations related to drug use are increasing across the U.S. with a notable increase in methamphetamine-associated heart failure hospitalizations, particularly on the West Coast.^3,4 In Oregon, hospitalizations for stimulant-related bacterial infections increased 15-fold from 2008 to 2018.⁵ While effective, accessible, evidence-based treatment for opioid use disorder exists, there are no FDA-approved medications for StUD and little is known about managing StUD in the hospital.⁶

Hospital systems struggle to engage patients with StUD and polysubstance use, leading to high rates of re-admission, long lengths of stay, frequent before medically advised (BMA) discharges (also known as against medical advice discharges), limited post-hospital treatment engagement, and increased mortality.^7–11 Moreover, over 30% of people who use drugs consume illicit substances during hospitalization, an event that can lead to patient and staff distress, administrative or BMA discharge, and other harms.^12,13 This heightens the need to develop in-hospital interventions to support people with StUD.

Contingency management (CM) is an evidence-based intervention that utilizes a reward-based system as positive reinforcement and is an effective treatment for many substance use disorders (SUD).^14–16 CM is the most effective intervention for reducing stimulant use and has been shown to increase treatment retention and engagement primarily in outpatient addiction settings.^14–16 Case reports and small case series describing CM implementation in hospital settings demonstrate its potential to improve substance use and health outcomes for hospitalized patients, however larger trials are needed to understand the feasibility and acceptability of implementing CM in this setting.^17,18 To address this gap, we conducted an uncontrolled pilot study of a novel mobile-app based hospital CM intervention for hospitalized patients with StUD.

METHODS

Setting

Oregon Health & Science University (OHSU) is a large quaternary care academic hospital in Portland, Oregon with a robust multidisciplinary addiction consult service, IMPACT (Improving Addiction Care Team). IMPACT includes addiction medicine clinicians, socials workers, peer recovery support specialists with lived experience in addiction and recovery, nurses, and pharmacists who support hospitalized patients with their SUD goals.^19–22 The OHSU institutional review board approved this study (#23484). This study is registered on clinicaltrials.gov (https://clinicaltrials.gov/study/NCT05515757).

Hospital CM intervention

An earlier publication describes a qualitative study that our team conducted with CM experts, hospital staff, and hospitalized patients with SUD to inform adaptation of CM to the hospital setting.²³ We decided to adapt a mobile-app based CM program to improve scalability and decrease implementation barriers, selecting an existing outpatient mobile-app CM program for StUD developed by a digital health company.^24,25 The hospital CM mobile-app intervention uses gift card rewards to large retail stores (e.g. Krogers) to incentivize saliva drug testing, stimulant abstinence, counseling attendance, and daily mobile-app reflection activities (Table 1). We utilized multi-panel saliva tests, which tested for stimulants, opioids, cannabinoids, and benzodiazepines, rather than urine drug tests because they can be administered virtually and may be associated with less stigma than urine drug tests. Based on our findings highlighting challenges of in-hospital substance use,²³ we implemented twice weekly drug testing to maximize efficacy for supporting stimulant abstinence. We offered virtual group counseling at set times throughout the week, with attendance documented by the mobile-app counselor. Mobile-app reflection activities included behavioral education and therapeutic tasks, such as a video on mindfulness, answering questions about substance use triggers, or reading about the benefits of a healthy sleep schedule. Participants could earn up to $330 in gift cards over two months. We chose to have the CM intervention last up to two-months to focus on providing support during hospitalization and discharge transition, while balancing the need to limit costs. In collaboration with the digital health company, we explored changing the incentive amounts and adding hospital-specific target behaviors to the reward schedule, but these changes were not feasible given limited time and lack of dedicated funds for app development.

Table 1.

Hospital CM reward schedule

Hospital CM Incentivized Activity	Amount	Frequency	Maximum reward amount
Saliva drug testing	$3 for taking the test $8 for a stimulant negative test $10 bonus for 4 consecutive negative tests	Twice per week	$216
Group counseling	$5 for attending a meeting	Twice per week	$80
Mobile-app reflection activities	$0.10 per activity	6 per day	$34
Maximum CM reward amount over two months: $330

An in-person CM nurse, a Certified Addictions Registered Nurse with experience caring for patients with SUD, supported implementation by providing education to participants and hospital staff, addressing technological barriers, and distributing saliva drug tests (8 hours/week; 1–3 patient load). The CM nurse provided saliva drug tests weekly during hospitalization, with all remaining tests provided at hospital discharge. The mobile app displayed real-time gift card reward amounts, and the CM nurse delivered or communicated to the participant regarding receipt of weekly gift cards delivered via email. A CM counselor conducted individual sessions over video where participants completed and reviewed results of drug tests and facilitated group counseling. A mobile-app care coordinator supported enrollment, scheduled intake appointments, and coordinated care transitions at program completion to facilitate referrals for continued treatment as needed. Participants without a phone were provided one through IMPACT.

Participants

Participants were hospitalized adults (≥18 years old) with moderate to severe StUD and active stimulant use (methamphetamine or cocaine) within two weeks of hospital admission. Eligibility criteria included an anticipated hospital length of stay (LOS) greater than 2 weeks (as determined by the hospital primary team) or any diagnosis of heart failure (including heart failure with reduced or preserved ejection fraction). We initially only recruited participants with anticipated 2-week or more LOS because we wanted to target the CM intervention to support patients during an extended hospitalization. However, this excluded many patients with StUD and heart failure, a group that hospital cardiologists identified as high-risk and in need of additional treatment options to support disruption of stimulant use. In June 2023, we expanded the inclusion criteria to include this population. Participants were excluded if they were unable to engage due to cognitive impairment or had active mental health or medical problems that precluded their ability to participate in the consent process.

From August 2022 through December 2024, we recruited participants from IMPACT patient lists, and beginning in June 2023, also from inpatient heart failure lists. A research assistant or CM nurse visited the patient in the hospital for screening and consent, then coordinated with the mobile-app care coordinator to schedule an intake appointment where the counselor conducted an SUD assessment for program enrollment.

Measures

Demographics and clinical characteristics

We extracted data from the electronic medical record on SUD diagnoses, hospital admission diagnosis, hospital length of stay, and discharge location including whether the participant was discharged BMA. A research assistant administered self-report surveys to collect demographic information and the Brief Addiction Monitor (BAM) survey, a validated tool that assesses substance use, risk factors, and protective factors.²⁶

Hospital CM engagement data and stimulant use outcomes

We collected CM engagement data via the mobile-app, including appointment attendance of drug tests and group counseling, drug test results, completion of mobile-app reflection activities, and earned incentive amounts.

Participant interviews

We conducted 30- to 60- minute semi-structured interviews to assess participant experience with hospital CM, barriers/facilitators of engagement, participants’ perceptions related to CM’s effect on substance use and health goals, and participants’ experience with the hospital discharge transition (see Supplemental Digital Content 1 for semi-structured interview guide developed by researchers with expertise in qualitative methods (LP, HE)). We conducted interviews at two time points—prior to hospital discharge and at the end of the hospital CM intervention. Researchers (LP, HT, PR, CD) conducted interviews in-person or by phone and audio-recorded all interviews. We collected alternative modes of contact (email, alternative phone numbers) and made at least 3 attempts to contact all participants after hospital discharge. Participants received a $25 gift card for completing an interview. We recruited participants until we had sufficient information power²⁷ based on the specificity of the interview questions and depth of the interview dialogue.

Data analysis

Statistical analysis

We used descriptive statistics to summarize hospital CM engagement metrics, including counseling appointment attendance, saliva drug test results, and mobile app activity completion. We conducted chi-squared tests to compare CM engagement across participant subgroups (e.g., those who completed hospitalization vs. those who discharged BMA.²⁸

Qualitative analysis

We used Dedoose (Sociocultural Research Consultants LLC, 2016) to manage qualitative interview data and analysis. Researchers (LP, PR, HT, CD) generated codes and coded transcripts using a reflexive thematic analysis at a semantic level.²⁹ Researchers (LP, PR, HT, CD, KY) extracted codes and used a matrix-based framework method to summarize coded data.³⁰ The team met regularly to analyze codes, review code summaries, discuss emerging themes, and refine themes using an iterative consensus-based approach.

RESULTS

Feasibility: participant demographics and recruitment rate

From August 2022 through December 2024, we assessed 213 participants for eligibility. 125 participants met the inclusion criteria, and 92 consented and enrolled in the intervention. 56 participants completed intake into the hospital CM intervention. Here, we report the results of these 56 participants. Figure 1 demonstrates the study flow.

Figure 1.

Flow diagram for study participants

Baseline demographics, hospitalization characteristics, SUD diagnoses and BAM scores of participants are shown in Table 2. Participants demonstrated high levels of social and economic vulnerability—33 (58.9%) participants reported unstable housing and 39 (69.6%) reported a yearly income below $20,000. Participants were hospitalized for an average of 33.3 days (SD 30.25), with infection as the most common reason for hospitalization (64.3%), followed by cardiac conditions (17.9%).

Table 2.

Participant demographics, hospitalization characteristics, and substance use disorder diagnoses and severity

Demographics (n = 56)
Age (years), mean (SD)		44.1 (11.3)
Gender	Female	11 (19.6%)
	Male	38 (67.9%)
	Transgender female	1 (1.8%)
	Unknown	6 (10.7%)
Race	American Indian or Alaskan Native	3 (5.4%)
	Asian	1 (1.8%)
	Black or African American	5 (8.9%)
	Native Hawaiian or Other Pacific Islander	2 (3.6%)
	White	39 (69.6%)
	More than one race	2 (3.6%)
	Other	2 (3.6%)
	Unknown	3 (5.4%)
Ethnicity	Hispanic	5 (8.9%)
	Not Hispanic	45 (80.4%)
	Unknown	6 (10.7%)
Housing status	Unstable housing (e.g., outdoors, shelter)	33 (58.9%)
	Stable housing (e.g., own/rent room)	18 (32.1%)
	Unknown	6 (10.7%)
Education	Grades 1 – 11	12 (21.4%)
	Grade 12 or GED	24 (42.9%)
	College 1 – 3 years	14 (25%)
	Unknown	6 (10.7%)
Yearly income	$0 – $20,000	39 (69.6%)
	>$20,000	8 (14.3%)
	Unknown	9 (16.1%)
Hospitalization
Hospital length of stay (days), mean (SD)		33.3 (30.25)
Reason for hospitalization	Infection	36 (64.3%)
	Cardiac	10 (17.9%)
	Trauma	7 (12.5%)
	Renal	1 (1.8%)
	Other	2 (3.6%)
Number of patients that discharged AMA (%)		5 (8.9%)
Stimulant use disorder diagnosis
Stimulant use disorders	Methamphetamine use disorder, severe	35 (62.5%)
	Methamphetamine use disorder, moderate	18 (32.1%)
	Cocaine use disorder, severe	3 (5.4%)
Other concurrent SUDs	Opioid use disorder	32 (57.1%)
	Alcohol use disorder	11 (19.6%)
	Benzodiazepine use disorder	2 (3.6%)
Brief Addiction Monitor (BAM) survey
Number of participants that completed BAM survey (%)		49 (87.5%)
BAM survey scores	Use score (Max score: 12), mean (SD)	4.96 (2.87)
	Risk factor score (Max score: 24), mean (SD)	15.94 (5.02)
	Protective factor score (Max score: 24), mean (SD)	8.52 (3.93)

Most participants (62.5%) had a severe methamphetamine use disorder and over half (57.1%) had a concurrent opioid use disorder. Overall, participants exhibited high addiction severity, as reflected by elevated substance use and risk factor scores that generally exceeded protective factor scores. The mean BAM substance use score was 4.96 (SD = 2.87), the mean risk factor score was 15.94 (SD = 5.02), and the mean protective factor score was 8.52 (SD = 3.93).

Acceptability: hospital CM engagement and patient perspectives

Hospital CM engagement

Engagement in the hospital CM program varied widely. Participants earned a mean of $65.19 (SD = 69.71; range $5.05- $261.87) and remained engaged for a mean of 33.9 days (SD = 21.0). On average, participants attended 5.6 (SD = 5.9) group counseling sessions (offered up to twice weekly), completed 3.34 (SD = 3.58) drug tests (scheduled up to twice weekly), and completed 57.8 (SD = 59.3) mobile app–based reflection activities. Most participants (n = 39; 69.6%) continued the CM program after hospital discharge, with a mean post-discharge engagement duration of 16.4 days (SD = 27.1).

Although engagement varied across participants, those in the top quartile of earned reward amount demonstrated consistent and frequent engagement, while those in the bottom quartile had little engagement beyond completing the initial program intake. On average, the top quartile earned $173.31 (SD = $47.57), attended 6.54 (SD = 2.88) group counseling sessions, and completed 8.62 (SD = 2.40) drug tests, while the bottom quartile earned $6.27 (SD = 1.53), attended 0 (SD = 0) group counseling sessions, and completed 0.13 (SD = 0.35) drug tests. Figure 2 shows CM incentive earning trajectories for each participant over the course of 2 months and average trajectories for each quartile.

Figure 2.

Participant CM earnings trajectories color coded by quartile (Figure 2a) and highlighting mean earnings trajectories (Figure 2b)

Stimulant use outcomes and completion of hospitalization

Participants submitted 187 total drug tests and attended 58% of scheduled drug tests while engaged in the CM program. 52% of scheduled drug tests and 89% of submitted drug tests were negative for stimulants. The proportion of attended drug tests was slightly higher before discharge compared to after discharge (62% vs. 56%), but proportion of negative tests was similar. 51 (91.1%) participants completed hospitalization without discharging BMA. Participants who completed hospitalization had a mean engagement duration of 35 days (SD = 21.0), compared to 18 days (SD = 17.5) among those discharged BMA (p = 0.093). Engagement metrics and stimulant use test results are shown in Table 3.

Table 3.

Hospital CM engagement metrics and stimulant use outcomes

Hospital CM engagement metrics
Mobile-app activities completed per patient, mean (SD)	57.8 (59.3)
Length of CM program engagement, mean (SD)	33.9 days (21.0)
Total CM incentives earned, mean (SD)	$65.19 (69.71)
Hospital CM scheduled appointments
Group counseling sessions, mean (SD)	Overall	Before discharge	After discharge
Group counseling sessions attended per patient, mean (SD)	2.7 (3.3)	1.1 (1.7)	1.6 (2.7)
Proportion of group counseling sessions attended	48%	46%	50%
Saliva drug tests
Total number of saliva drug test samples submitted	187	93	94
Saliva drug test samples submitted per patient, mean (SD)	3.34 (3.58)	1.66	1.68
Proportion of attended scheduled drug tests (attended/scheduled)	58%	62%	56%
Proportion of negative scheduled stimulant tests (negative/scheduled)	52%	50%	54%
Proportion of negative submitted stimulant test (negative/submitted)	89%	88%	90%
Post-discharge CM engagement
Continued CM after hospital discharge (%)
Yes	39 (69.6%)
No	17 (30.4%)
Length of CM engagement after hospital discharge, mean (SD)	16.4 days (27.1)

Participant perspectives

We completed 21 participant interviews prior to hospital discharge and 14 interviews at the end of the intervention (conducted at 3.7 months post-discharge on average), representing a total of 27 unique participants. Participant interviews revealed the following themes (see Supplemental Digital Content 2 for representative quotes).

Theme 1: The structure and accountability provided by hospital CM kept participants focused on their stimulant use goals, while incentives provided additional motivation to engage in recovery-oriented activities.

Participants valued the structure and “responsibility” of hospital CM. They appreciated having scheduled appointments, noting that drug testing held them “accountable” to their own substance use goals and provided additional motivation to maintain abstinence. Participants described the counselor as supportive and caring and expressed appreciation for her lived experience with addiction and recovery, which fostered trust and connection. Here, we define recovery—consistent with how participants described it—as a process through which individuals improve their health, wellness, and lives, which may or may not include substance abstinence.³¹

Participants consistently reported that the incentives supported their substance use and health goals by motivating them to engage in recovery activities. They appreciated the flexibility of the gift cards, which could be used to purchase a wide variety of items (e.g. food and clothing). However, a few participants noted challenges in keeping track of gift cards and expressed a preference for cash or a more universally accepted credit card.

Theme 2: Hospital CM supported patients in tolerating the challenges of hospitalization by increasing empowerment around health, decreasing cravings, and reducing boredom—all common triggers for in-hospital substance use.

Participants described hospital CM as empowering, stating it increased their engagement with healthcare teams and encouraged more active involvement in their care. They felt the program helped them navigate the daily challenges of hospitalization by providing tools to support abstinence from substances during and after their hospital stay. Participants also highlighted the emotional support, describing hospital CM as giving them “something to look forward to” and creating a “comfort zone.” They shared that it kept recovery “front of their mind” and offered a positive distraction during boredom. Several participants acknowledged that substances were available during hospitalization and that they had used substances during prior admissions; however, they felt hospital CM helped them avoid substance use during their current stay.

Most participants found the mobile app convenient and appreciated the flexibility to engage “on your own time, on your own terms,” which they found particularly helpful in the busy hospital environment. They noted that the daily in-app activities helped reduce cravings by introducing coping techniques such as taking walks, talking to others, and reading recovery-related content. However, a few participants expressed a preference for in-person interactions and reported feeling less comfortable with mobile technology, which limited engagement.

Theme 3: hysical limitations, feeling overwhelmed, conflicting hospital schedules, and technology challenges limited CM participation during hospitalization.

Most participants had complex medical conditions that required multiple medications and frequent provider visits, which often left them feeling unwell or too tired to engage in hospital CM. Some participants reported feeling “overwhelmed,” distracted, or having difficulty remembering appointments. Many also identified technical challenges as a barrier, including poor hospital Wi-Fi connectivity, difficulty navigating the app or logging into appointments, and issues with broken or malfunctioning phones. Additionally, some participants were disinterested or not yet ready to fully engage in addiction treatment.

Many participants noted that the CM nurse helped them navigate barriers to participation, particularly technological challenges. They appreciated the support provided in troubleshooting issues with the app, accessing appointments, and staying engaged with the program despite other competing demands.

Theme 4: Hospital CM was a valuable tool for maintaining focus on addiction recovery during the discharge transition; however, continued engagement was limited by the complexities of returning to a chaotic environment with competing priorities.

Participants reported that hospital CM helped them stay focused on recovery, maintain motivation, and engage in constructive activities to manage boredom and downtime after discharge. Many expressed a desire to continue working with the counselor after discharge, emphasizing the importance of the trusting relationship they had already established during hospitalization.

Although most participants expressed a desire to continue CM after hospital discharge, many reported experiencing significant challenges to post-discharge engagement. Participants often returned to “chaotic” environments, including social and living situations that were not supportive of recovery. Participants also reported that shifting priorities—including the need to focus on securing housing, returning to work, and attending other healthcare appointments—created barriers to continued participation. In addition, some participants reported technological limitations, including broken phones or lack of reliable internet access. These barriers were reported more frequently among participants in the lowest engagement quartile compared to those in the highest quartile.

DISCUSSION

This pilot study demonstrates the feasibility and acceptability of a novel mobile-app-based hospital CM intervention for hospitalized adults with StUD. Supported by a part-time CM nurse and virtual care coordinator, we successfully implemented the intervention among a medically complex population with high addiction severity. Engagement varied widely; average engagement was lower than in some CM studies reflecting the challenges of engaging a non-treatment-seeking population with high medical complexity. Participants who were more engaged described the intervention as highly effective and supportive of their recovery and health goals. Most (89%) submitted drug tests were stimulant-negative, and 91% of participants completed hospitalization without BMA. Barriers to engagement included competing priorities (e.g. returning to houselessness, medical issues), feeling overwhelmed, and technological challenges.

To our knowledge, this is the largest study of a hospital-based CM intervention to date and the first to utilize a mobile-app. Our findings align with prior research in ambulatory settings demonstrating that CM supports treatment engagement and stimulant abstinence^16,32–34 and builds on a very limited body of literature suggesting that CM may support antibiotic adherence and reduce in-hospital drug use.^17,18 The hospital setting introduced implementation challenges—39% of enrollees did not participate, primarily due to discharging sooner than anticipated. The CM RN mitigated this by communicating regularly with hospital staff and the mobile-app coordinator but identifying the appropriate timing for enrollment given the unpredictability of hospitalization was an inherent feasibility challenge. Technological challenges were also a major barrier, underscoring the importance of an in-person CM nurse to provide troubleshooting and support implementation. Even so, a mobile-app has feasibility advantages, including flexibility in a busy hospital environment and fewer personnel needs compared to in-person CM programs.

Despite implementation challenges, participants reported that hospital CM supported hospitalization challenges by providing structure, accountability, and motivation, helping them focus on recovery while reducing cravings and boredom—major drivers of in-hospital substance use and BMA discharges.^7,35 Among people who use drugs, BMA discharge rates range from 25% to 30%, leading to increased readmissions, overdose, and mortality.^10,11,36 In our pilot, 5 (9%) participants discharged BMA. Our qualitative findings suggest that hospital CM may facilitate hospitalization completion, but future studies should explore the relationship between CM and BMA hospital discharges.

Furthermore, the hospital discharge transition is a particularly vulnerable time for patients with StUD.³⁷ Participants reported that hospital CM helped them maintain focus on recovery during this transition, valued ongoing engagement with the same counselor, and appreciated the convenience of the mobile app. CM engagement was similar before and after discharge, suggesting that a mobile app-based intervention that can “travel” with the patient from the hospital to the community may support this transition and improve continuity of care,

This study has important limitations. First, we implemented hospital CM at an academic hospital with a robust interprofessional addiction consult service, IMPACT,^19–22 which may limit generalizability to other hospitals. Some observed effects of hospital CM may be partially attributable to IMPACT rather than CM alone. However, it’s also possible that having IMPACT underestimates the potential effect of CM in hospitals that lack as robust resources. Future research should explore CM adaptation to settings with limited addiction-related resources. Second, more engaged participants may have been more likely to participate in interviews, over representing positive experiences. However, we interviewed participants with limited engagement and asked all participants to share critical feedback. Third, drug test results should be interpreted with caution as many scheduled tests were missed, and the true rate of stimulant abstinence remains uncertain. Finally, it is possible hospital CM may have been more effective with higher reward magnitudes.³⁸

Even with limitations, our study has important implications. Our pilot demonstrates that a novel app-based CM intervention in hospitalized adults is feasible and has potential to support patients with StUD during and after hospitalization. These results highlight the potential of leveraging mobile-app technology to expand CM implementation in hospital settings,³⁹ potentially reaching patients who face unique barriers to accessing medical and StUD care. Our findings underscore the need for payers and policy-makers to address regulatory and financial barriers to CM access,⁴⁰ such as by increasing funding (e.g. insurance reimbursement) to support widespread implementation in new settings. Future research should explore factors influencing varying levels of engagement in hospital CM and controlled studies are needed to assess the intervention’s impact on hospitalization and health outcomes.

CONCLUSIONS

This pilot study demonstrates that mobile-app-based CM is feasible and acceptable for hospitalized adults with StUD. Hospital CM helped patients cope with the challenges of hospitalization—such as boredom, cravings, and stress—by providing structure, accountability, and motivation. Despite variable engagement, most participants completed hospitalization and had stimulant-negative tests. Mobile-app CM may be a scalable tool to support this high-risk population, and further research is needed to optimize engagement and assess broader health and StUD outcomes.

Supplementary Material

Supplement 2

Supplemental Digital Content 2. Hospital CM qualitative themes and representative quotes

Supplement 1

Supplemental Digital Content 1. Semi-structured interview guide