Peer support services for individuals with health-related needs reentering the community after incarceration: a scoping review of program elements and outcomes

Abstract

Background

Peer support services (PSS) have become increasingly formalized in many healthcare settings. While use of PSS in the criminal-legal space is expanding, no comprehensive reviews of program designs and outcomes are available to characterize current approaches. This scoping review sought to identify PSS models for individuals with health-related needs transitioning from incarceration to the community and summarize key features and outcomes related to the models.

Results

A search of PubMed, PsycInfo, Web of Science, National Criminal Justice Reference Service, Criminal Justice Abstracts, Criminal Justice Database, Embase, CINAHL, and Social Services Abstracts databases resulted in a total of 66 studies that described 49 unique PSS programs delivered at re-entry. Fifty-six of these studies also reported on implementation factors and program outcomes. Programs varied in terms of target populations, staffing, services offered, setting, and duration. Quantitative outcomes most commonly surrounded linkage to services, substance use, mental health, HIV, and recidivism. Lived experience of peers, extensive engagement with participants, participant-centered support, and collaboration between agencies were highlighted as key factors that supported program implementation, while challenges largely related to staffing and participant outreach.

Conclusions

The heterogeneity in program design and the mixed results in both quantitative and qualitative outcomes likely reflect the need for programs to be responsive to the specific communities served. This review highlights innovative approaches within the growing use of PSS to support the health-related needs of individuals reentering the community after incarceration and may guide future research, design, implementation, and evaluation of such programs in the criminal-legal space.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40352-025-00358-0.

Background

Individuals with health-related needs who are returning to the community after incarceration face many barriers to successful reintegration, including limited access to health care and social services, unstable housing, and onerous legal requirements imposed as a condition of release (Harding et al., 2019). They are often inadequately connected to post-release healthcare services, in part because of insurance termination or suspension, the lack of integration between correctional- and community-based healthcare services, and a high burden of health-related social needs (e.g., housing, transportation) (Russ et al., 2021). Individuals with health-related needs are therefore at high risk for adverse health consequences and recidivism after release (Binswanger et al., 2007; Zgoba et al., 2020). The risk of death in the year after prison release is estimated to be 12.7 times higher for all causes and 8.3% higher for drug overdose compared to the general population (Binswanger et al., 2007).

These challenges highlight the need for interventions that improve access to healthcare and other supports during re-entry. Peer support services (PSS), or services delivered by peer navigators who share lived experiences with those they serve, have emerged as a promising approach for supporting re-entry among individuals with health-related needs, including those with substance use disorders (SUDs), mental health conditions, and HIV (Bassuk et al., 2016; Eddie et al., 2025; Matthews, 2021; Sells et al., 2020; Woznica et al., 2021). Peer navigators are individuals who utilize their own personal experiences to support clients navigating similar issues and systems through a relationship built on both mutual trust and professional support (Davidson et al., 2006). The title of such peer navigators varies depending on the agency, community, and context in which they are employed and include “peer worker,” “peer specialist,” and “peer coach,” among others. In contexts where workers share key lived experiences with their clients (e.g., incarceration history), community health workers (CHWs) may also be considered peer navigators (Daniels et al., 2017). Unlike providers with clinical training (e.g., psychologists, counselors), peer navigators’ expertise derives from their lived experience, which they draw on to establish rapport with clients, serve as role models, and share their extensive knowledge of resources in the community to help people meet their needs (Beales & Wilson, 2015). PSS have become increasingly formalized in recent years, facilitated through the creation of national certification processes (Substance Abuse and Mental Health Services Administration, 2023) as well as reimbursement from major payers including Medicaid (Bao et al., 2024). While PSS have long existed in community-based settings, particularly for mental healthcare (Salzer, 2002), they have only recently been adopted more widely in criminal-legal settings.

Several reviews have examined PSS outside of correctional settings. An umbrella review of PSS for SUD found that peer support is associated with improved substance use outcomes, reductions in relapse and hospitalization, increased engagement with and completion of treatment, linkage to services, and improved social supports (Mahon, 2025). However, the quality of studies included was mixed, and they evaluated heterogeneous interventions, making it difficult to draw conclusions about any one model. The review concluded that there is a need for further research using more-rigorous designs, as well as mixed methods and implementation science research to elucidate more conclusive findings regarding intervention design. In addition to PSS for SUD, an umbrella review of PSS for mental health reported inconclusive results surrounding some clinical outcomes but noted that current evidence suggests PSS reduce the risk of hospitalization, perinatal depression symptoms, suicidal ideation, and stigma, while improving self-efficacy, stigma experiences, and recovery outcomes (e.g., hope, empowerment, goal-attainment, quality of life) (Cooper et al., 2024). However, as with studies of PSS for SUD, most studies were determined to be of low quality, and the authors concluded that further research is needed. A recent narrative review examined linkage facilitation models in criminal-legal settings, identifying barriers, challenges, and opportunities for scaling and integrating these services in justice systems, highlighting the need for synthesis of peer support models specifically targeting re-entry populations (Satcher et al., 2024).

While PSS targeting the re-entry population have expanded in recent years (McCrary et al., 2022), no comprehensive reviews of program designs and evidence currently exist. PSS for individuals undergoing re-entry are theory-supported and hold promise (Salzer, 2002). For example, peer programs draw on ideas from social learning theory (Bandura, 1971), which describes how new behaviors are more likely to be adopted when modeled by peers; social comparison theory (Festinger, 1954), in which clients may use “upward comparisons” to their peer navigators to motivate self-improvement; and the concept of experiential knowledge (Borkman, 1976), which emphasizes learning through lived experience rather than formal instruction. Despite their promise, comprehensive descriptions of re-entry peer program features and their outcomes remain limited. Program models have been described in studies and reports (Commonwealth of Massachusetts, 2025; Swarbrick, 2019; Waddell et al., 2020), but program designs differ considerably across multiple domains including program duration, staffing, and services provided. A scoping review of these models is needed to better understand alternative program models, identify intervention components to target for future research, and begin examining the effectiveness of different models. To address these gaps, this scoping review examines program designs and outcomes of PSS for individuals with health-related needs reentering the community following incarceration.

Study objective

This scoping review examines program elements and outcomes of PSS for individuals with health-related needs reentering the community following incarceration. The objectives of this scoping review include: (1) Describe PSS models for people with health-related needs transitioning from incarceration to the community; (2) examine specific features of PSS models including services provided, staffing, and duration; and (3) summarize outcomes and implementation factors associated with PSS for people reentering the community after incarceration.

Methods

The methods used in this scoping review are outlined in the protocol published to Open Science Framework before starting the review (Treitler, 2024). The actual process and any deviations from the protocol are detailed below.

To avoid duplication, we conducted a preliminary search of multiple databases for existing or planned reviews on this topic in January 2024. The databases searched were: JBI Evidence Synthesis, Cochrane Database of Systematic Reviews, PROSPERO, Database of Promoting Health Effectiveness Reviews, Database of Abstracts of Reviews of Effects, The Campbell Collaboration Online Library, NeuroBITE, Turning Research into Practice, Open Science framework, and Research Registry. The search yielded no results with significant overlap with the proposed scoping review.

Inclusion and exclusion criteria

Sources were included if they described the components of a program that (1) targeted adults aged 18 years and older experiencing re-entry following incarceration, (2) utilized services delivered by peers, and (3) addressed the health-related needs of the participants. Sources were excluded if the interventions did not occur during re-entry, such as prison-based education delivered by peers or diversionary programs in which participants were not incarcerated. Additionally, the source needed to be published between January 1, 2000 and December 4, 2024, when the search for the review concluded. Sources of any study design (e.g., quantitative, qualitative, mixed-methods, evaluation, descriptive) found in peer-reviewed literature or grey literature and originally written in or translated into the English language were included. Website program designs not accompanied by a publication and literature reviews of any type were excluded.

Search strategy

The search strategy was developed in consultation with a professional Boston University librarian. Two sets of search terms were used in each database query, where at least one term from each set must have been present for a source to be retrieved. The first set pertained to the setting, context, and population of the intervention being studied (i.e., individuals incarcerated in a correctional facility). The second set pertained to the type of intervention being studied (i.e., PSS). Exact search formulas were adapted for each database based on the search operators allowed in the database and can be found in Additional file 1. The following example search formula was used for PubMed:

(“prison*” OR “jail*” OR “correctional facil*” OR “correctional institution*” OR “detention center*” OR “incarcerat*” OR “criminal justice” OR “criminal legal”) AND (“peer support” OR (peer AND mentor*) OR (peer AND navigat*) OR “peer counselor” OR (peer AND specialist) OR (peer AND advoca*) OR “peer recovery” OR “recovery specialist” OR “recovery coach*” OR “recovery support” OR “recovery mentor” OR “recovery peer” OR (peer AND coach*) OR “reentry peer” OR “re-entry peer” OR “peer-led” OR “lived experience*”).

Searches for peer-reviewed literature were conducted using the PubMed, PsycInfo, Web of Science, National Criminal Justice Reference Service, Criminal Justice Abstracts, Criminal Justice Database, Embase, CINAHL, and Social Services Abstracts databases. Grey literature searches were performed using Google Scholar; ClinicalTrials.gov; Cochrane Central Register of Controlled Trials; AHRQ research summaries, reviews, reports; OSF preprints; Health Evidence Canada; and PCORI reports databases. The limited success in finding grey literature on the topic led the researchers to refrain from customized Google searches and website reviews, which was a deviation from the published protocol (Treitler, 2024). The initial search was completed in February 2024, and the search was repeated in December 2024 to ensure the most up-to-date publications were included in the review.

Screening and study selection

Search results from each database were imported to the Covidence platform (Covidence Systematic Review Software, n.d.) for deduplication and screening. Two independent reviewers completed preliminary screening of each source’s title and abstract, including screening for the third inclusion criterion which was not reflected in the search formula. The full texts of potentially relevant sources were then screened, and the reference lists of included sources were reviewed with the two phases of screening repeated for any new sources found. In both phases of screening, any discrepancies between the two reviewers were resolved by consensus through discussion or by review of the first author.

Data extraction and synthesis of findings

For each article, data on evidence source, model description, outcomes, and key findings were extracted for charting in Tables 1 and 2 below. The data extraction process consisted of entering information into a spreadsheet that included publication data (year, authors, title); program/intervention description (location, years of study, program name, type of lead organization, staffing, type of lived experience of peers, services offered, target population, setting, duration, funding source); program/intervention evaluation methods (study objective, study design and methodology, sample size, intervention group, comparison group, follow-up period); and program/intervention outcomes (outcomes assessed, key findings). Key findings were determined through review of each study’s abstract and discussion section by two independent reviewers, with specific outcomes data extracted from further review of the study’s results section. These data were extracted from each of the included studies by two reviewers, with one reviewer completing the initial extraction, and the second reviewer verifying each extraction.

Table 1.

Characteristics of programs in included studies (N = 49)

Characteristic		N (%)
Target Population	Age
	Younger adults (18–35 yrs) Older adults (50 + yrs) Unspecified (18+)	3 (6.1) 1 (2.0) 45 (91.8)
	Sex
	Women only Men only Men or transgender women Unspecified	9 (18.4) 8 (16.3) 2 (4.1) 30 (61.2)
	Health conditionsa
	SUD HIV positive or at-risk Mental health condition Co-occurring disorders Unspecified	20 (40.8) 9 (18.4) 4 (8.2) 3 (6.1) 20 (40.8)
Staffinga	Peers Case managers Mental health clinicians/social workers Program/project administrators Medical providers Nurses/nurse case managers Otherb	49 (100.0) 15 (30.6) 9 (18.4) 7 (14.3) 6 (12.2) 4 (8.2) 9 (18.4)
Type of Peer Lived Experiencea	Formerly incarcerated SUD Mental health condition HIV positive Veteran Gender identity	40 (81.6) 22 (44.9) 7 (14.3) 6 (12.2) 2 (4.1) 2 (4.1)
Services Offereda	Service Linkages Planning, Goal Setting, Problem-solving Mentoring/Role Modeling Education & Skill Development Transportation/Accompanying to Appointments Support Groups Advocacy Psychotherapy Transitional Housing Medical Care Naloxone/Harm Reduction Supplies Spirituality Financial Assistance Otherc	40 (81.6) 31 (63.3) 26 (53.1) 21 (42.9) 20 (40.8) 12 (24.5) 10 (20.4) 6 (12.2) 4 (8.1) 4 (8.1) 4 (8.1) 3 (6.1) 3 (6.1) 6 (12.2)
Setting	Community Jail/prison Both community and jail/prison	13 (26.5) 2 (4.1) 34 (69.4)
Duration	< 3 months 3 to < 6 months 6 to < 12 months ≥ 12 months Unspecified	5 (10.2) 6 (12.2) 11 (22.4) 15 (30.6) 12 (24.5)

^a Responses do not sum to 100% because more than one could be selected

^b Other includes responses with N < 4, including corrections staff, drug treatment staff, chaplains, legal staff, family support specialists, and nutritionists

^c Other includes responses with N < 4, including legal services, family reunification, and mobile app-based support

Table 2.

Study design and key findings

Program Name	Reference (Author, Year)	Study Design	Study Objective	Key Findings
Boston Reentry Initiative (BRI)	Braga et al., 2009	Quasi-experimental	Test program effect on recidivism	Lower rates of rearrest among program participants (36.1% at year 1 and 77.8% at year 3) vs. comparison group. (51.1% at year 1 and 87.7% at year 3).
Community Health Workers Eliminating Barriers in Access to Care (COMEBACK)	Khazi-Syed et al., 2024	Mixed methods	Test effect of program on SUD and HIV outcomes	Intervention dose trended with improved HIV and substance use outcomes but also higher recidivism; however, the results were not statistically significant. CHWs provided extensive outreach, non-judgemental support, and improved participant motivation and accountability.
Comprehensive Opioid Stimulant Substance Use Program (COSSUP)	Howard et al., 2024	Cohort	Evaluate effect of program on recovery and recidivism	Baseline social capital predicted rearrest and personal capital at 90-day follow-up. Program model of building social and cultural capital through family support and supporting participant’s beliefs was associated with increased housing stability and reduced recidivism.
DC-Reentering Individual Service Enhancement and Support (DC-RISES)	Portillo et al., 2017	Qualitative	Evaluate program effect on individuals with mental health diagnosis re-entering community	Peer navigators played roles of (1) role model, (2) legitimizer, and (3) resource broker. Peers increased legitimacy and trust of the program.
Female Offender Reentry Movement (FOR-Me)	Mejia et al., 2024	Quasi-experimental	Evaluate program effect on reducing substance use and supporting re-entry	Decreases in drug/alcohol related consequences (22–6%), days of heavy alcohol consumption in the past 30 days (12.7 to 0.12), and psychiatric symptoms (42–23%) from baseline to follow-up. Decreases in substance use (overall and by substance), days with depression/anxiety, and trauma symptoms. Improvements in recovery capital and psychosocial functioning.
Formerly Incarcerated Peer Support (FIPS) Group	Boles et al., 2022	Descriptive	Describe program development and implementation	Collaboration, flexibility, community building, and centering the perspectives of formerly incarcerated people were seen as key factors leading to successful implementation of program. Formal evaluation of program is ongoing.
Girlfriends Connect (GC)	Sevelius et al., 2023	Mixed methods	Adapt current intervention and test feasibility of adapted intervention	Peer support was critical in facilitating high participant acceptability of program. Main needs addressed were housing, benefits, employment, and healthcare. Feasibility challenges included high attrition, difficulty in locating participants in the community, and misclassification of transgender inmates.
Health Justice Network (NYC HJN)	Hood et al., 2024	Qualitative	Evaluate feasibility of implementing a program surrounding re-entry	Facilitators of program implementation included lived experience of CHWs, lack of enrollment restrictions, ease of access to services, buy-in from leadership, use of trauma-informed approach, integration of CHWs with partner sites, and prioritizing participant needs. Challenges included lack of affordable housing, lack of support from parole officers, and absence of an implementation protocol.
Intensive Recovery Treatment Support (IRTS)	Swarbrick et al., 2019	Descriptive	Describe program	Lessons from program implementation included importance of collaboration with project partners, importance of connecting with clients within the first 48 h after release, benefit of providing phones to assist in communication, and need for extensive time to recruit and train staff.
	Enich et al., 2023	Qualitative	Describe participants’ perspectives towards peer supports and unmet needs	Participants found peer services to be helpful in general and critical in navigating SUD treatment in the community. Participants appreciated peers who shared their lived experiences, were open-minded, and were consistent in their support. Housing and employment were the most commonly reported unmet needs.
Justice Community Opioid Innovation Network (JCOIN)	Tillson et al., 2022	Mixed methods	Describe peer re-entry intervention surrounding SUD treatment and lessons from first year of implementation	Majority of participants chose OUD treatment as primary goal, with transportation, employment, and housing following. Peers viewed their work as valuable. Challenges included unpredictability of jail release process, virtual format, MOUD stigma, and lack of resources in rural areas.
	Staton et al., 2024	Mixed methods	Describe perspectives of telehealth intervention surrounding women with SUD	MOUD providers and peer navigators support the use of telehealth for connecting incarcerated women with SUD treatment in the community.
Key Changes: Unlocking Women’s Potential	Hardy, 2018	Mixed methods	Describe participants’ and peers’ perspectives of re-entry program	Peer mentoring encouraged agency, safety, trust, and lack of judgement. Findings indicate the importance of gender-informed practice, individualized support, and strong relationships between peers and participants.
Kingdom Life Ministries (KLM) program	Scarbrough, 2012	Mixed methods	Evaluate program effect on recidivism and participants’ experiences with re-entry	Lower rates of recidivism among KLM program participants compared to other program participants. KLM program helped participants prevent relapse and re-arrest during re-entry by providing hope and housing.
Latino Discharge Planning (LDP)	Motta-Moss et al., 2001	Mixed methods	Describe program implementation	Overall program goals were fulfilled, with staff consistently providing case management services, engaging with and retaining clients. Lived experience of peers, intensive staff training, pre-release outreach, engagement on day of release, involvement of families, and collaboration with other agencies were identified as key factors in successful implementation. Challenges included staff turnover, difficulty and inefficiency of traveling long distances for prison outreach, and emotionally draining work.
Linking Inmates to Care Los Angeles (LINK-LA)	Cunningham et al., 2018	Randomized controlled trial	Test intervention effect on viral HIV suppression	Viral suppression was greater among peer intervention participants (49.6%) compared to control (36%) at follow-up. Peer intervention maintained higher viral suppression between release and follow-up compared to control, with 22% adjusted difference-in-difference. Intervention also improved: self-reported HIV care engagement, retention and adherence knowledge, use of mental healthcare and case management, and reduced ED visits.
	Goodman-Meza et al., 2019	Randomized controlled trial	Test substance use as a moderating variable on viral HIV suppression outcomes from intervention	High-risk drug use was independently correlated with decreased viral suppression among program participants, such that those who used high-risk drugs had 53% lower adjusted odds of maintaining viral suppression compared to non-users.
Maintaining Independence and Sobriety through Systems Integration, Outreach, and Networking - Criminal Justice (MISSION-CJ)	Grohs, 2020	Descriptive	Describe program	Relationship between peer and client is cornerstone of program, and long-term peer engagement is seen as essential for success in re-entry. Reports that trials of MISSION-CJ program have consistently shown that program improves outcomes related to long-term SUD recovery, co-occurring disorders, and employment.
	Hanna et al., 2020	Mixed methods	Evaluate implementation of re-entry program surrounding SUD	42% of participants released to community were enrolled in MAT. Adaptability of clinical model and flexibility of staff were critical to program implementation. Procedural differences across correctional and treatment facilities required frequent and structured forums for communication. Challenges to implementation included recruitment and enrollment, staffing, MAT engagement, and data collection.
Offender Alumni Association (OAA)	Moak et al., 2023	Cross-sectional	Evaluate effect of switching to virtual service delivery on social capital and health during re-entry	Program participants reported stronger social support and less social isolation compared to comparison group and supported the use of technology as means of connection. No differences between groups in emotional loneliness, anxiety, depression, or perceived stigma. Lived experiences of peers was strength of program.
Peer Coaching - Nurse Case Management (PC-NCM)	Nyamathi et al., 2015	Randomized controlled trial	Test effect of intervention on Hepatitis A/B vaccine completion	Vaccine completion rates did not vary by intervention condition (73% across all groups).
	Nyamathi et al., 2016	Randomized controlled trial	Test effect of different levels of intervention on re-entry outcomes	No differences in any study outcomes were observed between the 3 intervention conditions at 12 month follow-up.
	Nyamathi et al., 2017	Randomized controlled trial	Test effect of different levels of intervention on recidivism	No differences in rearrest between the 3 intervention conditions at 6 or 12 months.
Peer Education (PE)	Stephens et al., 2002	Descriptive	Describe program implementation	Peer education model is practical method for supporting re-entry of individuals with HIV risks. Case management services, building capacity of community agencies, cultural competency within prison culture, implementing youth-specific models, and applying a holistic approach were highlighted as key factors to successful implementation.
Peer Engaged Empowered Recovery (PEER) Program	Parekh et al., 2022	Cross-sectional	Evaluate feasibility and potential effectiveness of peer recovery program	Peer recovery specialists successfully connected participants to services, with majority of communication taking place over the phone. Participants with higher health and social needs required greater peer effort to maintain contact. Funding found to be key challenge to program sustainability.
Peers Reach out Supporting Peers to Embrace Recovery (PROSPER)	Andraes et al., 2010	Mixed methods	Describe program and provide evaluation of first 12 months	General self-efficacy, perceived social support, quality of life, and guilt- and shame-based emotions increased while perceived stress decreased among program participants from baseline to 12-month follow-up. Program benefits: socialization, recovery support, use of computers, peer and staff accessibility. Program limitations: unavailable on weekends, limited staff, distance between residences and program.
PeerStar, LLC	Bellamy et al., 2019	Cohort	Evaluate program effect on recidivism	Lower rate of reincarceration among program participants (22%) compared to general US jail/prison population (43%).
Post-Incarceration Engagement (PIE)	Hyde et al., 2022	Quasi-experimental	Develop and pilot test program surrounding veteran re-entry	Significantly higher rates of linkage to SUD treatment (86% vs. 19%), mental healthcare (93% vs. 64%), and other outpatient care (98% vs. 83%) among program participants compared to control at 90-day follow-up. No significant difference in primary care engagement, VA ED or inpatient use. Low recidivism (7%) and majority of participants who had been released over a year were living in permanent housing (84%).
PrEP-Link	Horton et al., 2024	Randomized controlled trial	Report baseline characteristics of pilot program	Baseline results demonstrate PrEP need and acceptance among participants and low healthcare utilization, indicating potential positive results of the completed RCT.
Project START	Koester et al., 2014	Qualitative	Describe peer navigator program surrounding re-entry and HIV	Peers effectively helped those with HIV connect to health and social services upon re-entry. Lived experience of peers and intensive time spent between peers and participants were essential to program success.
Forensic AIDS Project (FAP)	Myers et al., 2018	Randomized controlled trial	Test effect of program on engagement with HIV care upon re-entry	Peer navigation participants were twice as likely to be linked to care within 30 days of release and were almost twice as likely to remain in care compared to control. Peer navigation participants reported less risky sex compared to control (7.5% vs. 17.8%) at 12-month follow-up. No significant differences in alcohol and drug use risk behavior or viral suppression between groups.
Reintegration Centre (at the John Howard Society of Toronto)	McLuhan et al., 2023	Mixed methods	Evaluate process of program	Program improved the service encounter experience and helped address reentry needs. Strengths of the program included provision of intermediate supports, proximity to detention center, and peers’ influence on trust in program and on participants’ hope, autonomy, and self-worth. Key limitation was lack of pre-release engagement.
Smart Reentry Project	Romain Dagenhardt et al., 2024	Qualitative	Evaluate process of program surrounding re-entry for men	Program strengths included trauma-informed training for staff, client-centered approach, family-like atmosphere, and egalitarianism among staff. Limitations included staff authenticity versus professional accountability and resistance from correctional staff.
Substance Use Programming for Person-Oriented Recovery and Treatment (SUPPORT)	Victor et al., 2021	Qualitative	Implement and evaluate effect of program on SUD recovery during re-entry	Peer feedback was essential in shaping program. Inclusion of peer services set program apart from others in the area.
	Ray et al., 2021	Randomized controlled trial	Test effect of program on SUD recovery during re-entry	Substance use decreased among program participants from baseline to 6-month follow-up (30–16%) but increased among control (26–41%) and increased nonsignificantly for both groups between 6-month and 12-month follow-up. Program attrition was high, with less than half of participants completing 6-month and about one-third completing 12-month follow-ups.
The Connection, Inc.	Sells et al., 2020	Randomized controlled trial	Test effect of program on recidivism and influence of criminogenic risk factors	Parole violation rates (used to represent recidivism) were significantly lower among peer navigation participants compared to control.
The Gamble Institute (TGI)	Marlow et al., 2015	Mixed methods	Evaluate feasibility of program and effect of program on re-entry	Program participants reported significant improvement in negative affect and habitual craving subscales of abstinence self-efficacy from baseline to 60-day follow-up. Qualitative findings of program link success based on structural support, emotional/social support, and role modeling, noting that peer mentoring was unavailable elsewhere in the community.
The Well	Best et al., 2022	Mixed methods	Describe program surrounding re-entry and SUD recovery	Program continued to be feasible and expanded during COVID. Peers had high level of satisfaction with work, and program positively affected participant recovery and re-entry outcomes.
Transitional Community Adherence Club	Mabuto et al., 2024	Randomized controlled trial	Test feasibility of program and effect of program on HIV treatment engagement during recovery	Higher HIV treatment enrollment by 6-month follow-up among program participants (61%) compared to control (36%). Program deemed highly feasible, with 80% of participants assigned to intervention group attending 1 + session.
Transitions Clinic Network (TCN)	Wang et al., 2012	Randomized controlled trial	Test effect of program on increasing primary care use and decreasing acute care utilization	Lower ED utilization among program participants (25.5%) compared to control (39.2%) at 12-month follow-up. No significant difference found in primary care utilization, hospitalization, or recidivism rates.
	Wang et al., 2019	Quasi-experimental	Evaluate effect of program on decreasing recidivism	Lower odds of parole/probation technical violations among program participants (17%) compared to control (33%) at 12-month follow-up, but odds of overall reincarceration were similar between groups. Program participants spent fewer days incarcerated compared to control (101 vs. 187).
	Aminawung et al., 2021	Mixed methods	Describe how peers support participants’ health and social needs	High utilization of CHW services, with 79% of participants having 1 + CHW interactions outside of clinic. Housing was the most common issue addressed by CHWs (35%).
Unlocking the Gates Peer Health Mentoring Program	McLeod et al., 2020	Mixed methods	Describe program surrounding brief re-entry support for women	93.3% of program participants reported that peer mentor helped them access community resources, and 89.5% reported mentor helped them achieve their re-entry goals. Most common needs at intake were clothing and social assistance (> 57%), housing (37%), and healthcare (30%).
	McLeod et al., 2021	Qualitative	Describe peers’ perspectives on work during COVID-19 and overdose epidemics	Insufficient housing highlighted as key challenge, and providing phones for connection with peers and social support noted as essential. Coordination between peers, correctional system, and public health system was highlighted as strength of the program.
	Palis et al., 2024	Qualitative	Describe guiding principles of program surrounding re-entry	Peers provided hope, respectful relationships, consistent support, and participant-centered support and relied on shared experiences and connection to services to support participants.
Welcome Home Ministries (WHM)	Miller, 2009	Descriptive	Describe research base and program surrounding re-entry for women	Existing research supports implementation of interventions like WHM.
	Goldstein et al., 2009	Cohort	Describe outcomes of program surrounding re-entry for women with co-occurring disorders	Over 91% of program participants successfully managed medications by 3-month follow-up. Over 80%: received outpatient psychiatric services by 3 months, were medication compliant by 6 months, demonstrated symptom reduction (of depression/bipolar disorder/attention-deficit/ hyperactivity disorder) by 6 months, and were housed by 12 months. Over 70%: maintained sobriety by 6 months, maintained abstinence by 12 months, were employed/enrolled in education by 12 months, were not rearrested by 12 months, and followed treatment plan by 12 months.
	Warner-Robbins & Parsons, 2010	Mixed methods	Describe program surrounding re-entry for women with co-occurring disorders and implementation thus far	74% of individuals identified for program were successfully contacted during 6-month follow-up. Only 1.4% of participants reported using substances, and 3.5% reported any involvement with the criminal justice system at follow-up.
Women’s Initiative Supporting Health Transitions Clinic (WISH-TC)	Morse et al., 2017	Cross-sectional	Describe program surrounding re-entry for women	Program successfully connected participants to SUD treatment, mental health services, and medical care. Suggests primary care settings with specialty programs including CHWs can help to provide needed services to formerly incarcerated women.
	Thomas et al., 2019	Qualitative	Describe participants’ experiences with program surrounding re-entry for women	Participants prioritized accessing program and noted its services were essential to and supported their autonomy and competence in recovery. Participants highlighted relatedness as important component of connecting with staff.
WORTH Transitions: Women on the Road to Health Transitions (WORTH) and Transitions Clinic Network (TCN)	Elumn et al., 2023	Qualitative	Describe program surrounding re-entry for women with HIV and SUD risks from peers’ perspectives	CHWs viewed program as successful in helping participants improve health, connect to needed services, and build community and in helping CHWs develop support skills. Lived experience of peers and flexibility of program were critical to its success.
Not specified	Anderson & Medendorp, 2024	Quasi-experimental	Evaluate effect of program attrition on success/failure of re-entry programs	Increased peer support significantly lowered odds of program attrition. Program attrition was associated with higher rates of recidivism, while program completion did not have a significant impact on recidivism compared to control.
Not specified	Dubose et al., 2023	Mixed methods	Describe development of program to train incarcerated individuals as certified peers	Only 1 of 54 program participants was reincarcerated by 6-month follow-up. Program trained and certified 121 incarcerated people to provide PSS, and 40 of the 121 were employed at the time of article publication. Program benefits: increased self-awareness surrounding recovery, improved recovery, connection to needed services. Program limitations: understaffing.
Not specified	Lowther-Payne et al., 2024	Qualitative	Describe participant and staff perspectives on program surrounding re-entry	Program staff viewed program as promising approach to supporting re-integration in the community. Program strengths included mentoring from peers with lived experience, opportunity for participating in physical activity, holistic approach, and collaboration among service providers.
Not specified	Martin et al., 2021	Qualitative	Describe program development and implementation	Lived experience of peers, regular presence of peers in jails, early and consistent detection of OUD in jails, specialized treatment program in jails, early engagement between peers and clients, and consistent collaboration between correctional and community services providers were highlighted as key factors to successful implementation.
Not specified	Reingle Gonzalez et al., 2019	Qualitative	Describe program implementation and qualitative outcomes.	Peers spent most time helping with housing and treatment needs and securing IDs. Lived experience was essential for rapport building.

For the articles extracted from the initial search (February 2024), extraction by two authors was supplemented by the exploratory use of a large language model (LLM). Our goal was to treat the LLM as an additional reviewer to reduce the likelihood that key information was overlooked. In the absence of specific guidance on the use of LLMs for scoping reviews, we developed an approach in which both reviewers first extracted information from ten articles then imported the completed spreadsheet and ten articles into ChatGPT (ChatGPT, 2025). Next, the lead author prompted the program to train itself on the type of information to extract from each article. We then uploaded the remaining 47 articles from the initial search and prompted the program to extract the relevant information. This process was only done after both human reviewers had already independently completed their extraction, and any new information extracted by the LLM was carefully reviewed for accuracy given their tendency toward hallucination (Huang et al., 2025). The authors found that this approach rarely resulted in new information and thus opted not to use it for articles identified in the second search conducted in December 2024. LLMs were not otherwise used in this work (e.g., writing, editing).

Following initial extraction, data were standardized through categories that encompassed commonalities across studies, such as for staffing, services offered, setting, and target population. Categories for standardization were defined through consensus from two reviewers to maintain objectivity while condensing the data. From the standardized data, Table 1 was then created through calculating frequencies related to program descriptions, and Table 2 was created by compiling study designs, objectives, and key findings.

To incorporate qualitative data derived from the data extraction process, we completed a basic qualitative content analysis using deductive and inductive open coding (Pollock et al., 2023). After familiarizing ourselves with the data, key qualitative findings from the initial data extraction were organized into high-level categories derived by the authors. Program outcomes were deductively coded into predefined outcomes (i.e., linkage to services, substance use and recovery, mental health, HIV, recidivism, and other outcomes). Program implementation successes and challenges were identified using inductive open coding, with themes emerging from the data. These categories were confirmed by consensus from at least two authors and finalized as: lived experience of peers, early and extensive engagement with participants, participant-centered support, collaboration with other agencies, and challenges to implementation.

Results

Three thousand eleven studies were screened for inclusion, and 151 full texts were reviewed. Sixty-six studies were included in the final review, with 56 contributing both intervention descriptions and outcomes data and the remaining 10 studies with intervention descriptions only (see Fig. 1 for flow chart). Included studies were published between January 1, 2000 and December 4, 2024, with over half (59%) of studies published in 2020 or later.

Fig. 1.

Identification, Screening, and Inclusion of Studies

Program characteristics

Characteristics of 49 unique programs described in the 66 included studies are described below and summarized in Table 1. Detailed program characteristics can be found in Additional file 2.

Target population

Consistent with eligibility criteria for the review, the target population of all programs included adult (18+) individuals who were currently or recently incarcerated. A few programs targeted specific age groups, which we collapsed into young adults aged 18 to 35 years (n = 3, 6.1%) and older adults aged 50 years or older (n = 1, 2%). Nine programs (18.4%) included women only and eight (16.3%) included men only. The most common health conditions among targeted participants were SUD (n = 20, 40.8%), HIV (n = 9, 18.4%), and mental health conditions (n = 4, 8.2%).

Staffing

Consistent with the definition of PSS, all programs included peers in staffing. These peers had direct lived experience in that they had first-hand experience of at least one of the identities, issues, or systems that their clients were navigating (Hogue et al., 2024). CHWs were also categorized as peers in cases where they had lived experience of incarceration, reflecting the overlap between CHW and peer roles (Daniels et al., 2017). After peers, the most common additional staffing included case managers (n = 15, 30.6%), mental health clinicians/social workers (n = 9, 18.4%), program administrators (n = 7, 14.3%), medical providers (n = 6, 12.2%), and nurses/nurse case managers (n = 4, 8.2%). Corrections staff, chaplains, nutritionists, family support specialists, and legal staff were also, though less frequently, included in program staffing.

Type of peer lived experience

The majority of programs specified peer staff as being formerly incarcerated (n = 40, 81.6%). Other common types of peer lived experience were SUD (n = 22, 44.9%), mental health diagnosis (n = 7, 14.3%), and HIV positive (n = 6, 12.2%). Veteran status (n = 2, 4.1%) and gender identity (n = 2, 4.1%) were also included in descriptions of peers’ lived experience.

Services offered

The most common services explicitly described as offered by the programs were service linkages (n = 40, 81.6%); planning, goal setting, and problem solving (n = 31, 63.3%); mentoring/role modeling (n = 26, 53.1%); education and skills development (n = 21, 42.9%); and transportation and/or accompanying to appointments (n = 20, 40.8%). Other services offered included support groups, advocacy, psychotherapy, medical care (e.g., MOUD, HIV treatment, and primary care), spirituality, financial assistance, naloxone and harm reduction supplies, transitional housing, legal services, mobile app-based support, and family reunification.

Setting

The majority of programs (n = 34, 69.4%) took place in both jail/prison and community settings. Thirteen (26.5%) programs took place in community settings only, and two (4.1%) programs took place in the jail/prison settings only.

Duration

The duration of programs varied from one month to two years and ongoing. Most of the programs with specified durations lasted over 12 months (n = 15, 30.6%). Eleven had a duration of between 6 and 12 months (n = 11, 22.4%), five (10.2%) had a duration of less than 3 months, and six (12.2%) had a duration of 3–6 months. The remaining studies (n = 12, 24.5%) did not specify the program duration.

Program outcomes

Findings for the 56 studies that went beyond program description to report outcomes or implementation experiences are summarized in Table 2. Of these studies, the most common designs were mixed-methods (n = 16, 28.6%), qualitative (n = 13, 23.2%), and randomized controlled trial (RCT) (n = 11, 19.6%). The remaining studies utilized quasi-experimental, cohort, descriptive, and cross-sectional designs. Study objectives generally included evaluating program effects on participant outcomes and examining implementation processes. Outcomes assessed included recidivism, linkage to services, substance use and recovery, mental health, HIV treatment, and recidivism. Quantitative and qualitative findings for each of these outcomes are summarized below.

Linkage to services

Linkage to external services was the most common service offered by the programs described in included studies and was assessed as an outcome in 10 quantitative studies. Peer support programs linked participants to a wide variety of services in the community, including mental health and SUD treatment, other medical care, legal services, support groups, housing, employment, and social welfare benefits. Eighty-five percent of Unlocking the Gates participants who provided feedback were successfully connected to at least one community resource within three days of their release, and over 90% noted that their peer mentor helped connect them to community resources (McLeod et al., 2020). A mixed methods process evaluation of the Reintegration Centre found that two-thirds of program participants reported their reentry needs had either been met or were in progress of being met through referrals by the time of the study interview (McLuhan et al., 2023). Eighty-two percent of Welcome Home Ministries (WHM) participants were successfully connected to treatment or housing, and 73% were employed, in an educational program, or applying for disability benefits by 12 months after release (Goldstein et al., 2009).

In studies that assessed linkage to healthcare services specifically, an RCT of the Forensic AIDS Project (FAP) found that peer navigation participants were twice as likely to be linked to care within 30 days of release and nearly twice as likely to remain in care for 12 months compared to participants of the control group (Myers et al., 2018). In the Women’s Initiative Supporting Health Transitions Clinic (WISH-TC), 66–69% of Hepatitis A/B/C/HIV testing and pneumococcal vaccinations ordered were completed, along with 87% of STI tests, 29.4% of colonoscopies, 53.6% of mammograms, and 68.4% of pap smears (Morse et al., 2017). Separately, the Transitions Clinic Network (TCN) program found no significant difference in primary care visits among participants who received support from a CHW compared to participants who received expedited referral but no CHW support (Wang et al., 2012).

Nine studies examined linkage to SUD, mental health or HIV treatment. Post-Incarceration Engagement (PIE) participants were more likely to be receiving SUD treatment (86% vs. 19%) and be engaged with mental health services (93% vs. 64%) compared to those in a historical comparison group at 90 days after release and had higher average monthly substance use visits, but no significant difference was found in linkage to primary care (Hyde et al., 2022). Linking Inmates to Care Los Angeles (LINK-LA) participants who received peer support reported a greater increase in medication-assisted treatment (MAT) visits at 6-month follow-up, while the control group had a greater increase in these visits at 12 months (Cunningham et al., 2018). Additionally, LINK-LA participants reported a greater increase in annual mental health visits compared to control participants at both 3- and 6-month follow-ups along with a 12% greater probability of linkage to HIV primary care at 6 months but no significant difference in the probability of having at least one post-release HIV primary care visit between the groups at 12 months (Cunningham et al., 2018). Forty-two percent of participants in the Maintaining Independence and Sobriety through Systems Integration, Outreach, and Networking - Criminal Justice (MISSION-CJ) program were enrolled in MAT once in the community (Hanna et al., 2020). Sixty-four percent of WISH-TC participants with SUD received SUD treatment, 78.9% of those with OUD received methadone or suboxone, and 91.5% who had a mental health diagnosis received mental health treatment (Morse et al., 2017). A cohort study of WHM found that 86% of participants received outpatient psychiatric services at three months post-release. Additionally, an RCT of the Transitional Community Adherence Club found that those receiving peer support were more likely to receive HIV-related care, with 61% of peer support participants enrolled in HIV treatment at 6-month follow-up compared to 36% of the control group (Mabuto et al., 2024).

Findings from qualitative studies also suggested PSS successfully facilitated service linkage. Peers from the WORTH Transitions program observed program participants’ success in obtaining healthcare, employment, housing, and education and that these connections to community resources were maintained throughout the program (Elumn et al., 2023). A qualitative description of guiding principles of the Unlocking the Gates program noted that the peers’ ability to repair trust in and assist with navigation of services within the community was the most consistent positive outcome of the peers’ work (Palis et al., 2024). Lowther-Payne et al. (Lowther-Payne et al., 2024) reported that successful partnerships between peers and community agencies were essential in connecting program participants to resources. Participants of the Intensive Recovery Treatment Support (IRTS) program highlighted peer support as critical in navigating community-based SUD treatment following release (Enich et al., 2023). Peers and providers of the Justice Community Opioid Innovation Network (JCOIN) perceived telehealth as beneficial in increasing access to OUD treatment during re-entry (Staton et al., 2021).

In addition to connection to healthcare, housing was found to be a key need reported by participants and peers (Aminawung et al., 2021; Enich et al., 2023; Hood et al., 2024; Khazi-Syed et al., 2024; Martin et al., 2021; McLeod et al., 2020, 2021; Reingle Gonzalez et al., 2019; Sevelius et al., 2023; Tillson et al., 2022). Four of the programs described in the included studies directly provided transitional housing to participants (Howard et al., 2024; Scarbrough, 2012; Sells et al., 2020; Sneed et al., 2023), and one program provided funding for housing through a voucher (Howard et al., 2024). The rest of the programs that included housing support provided such support indirectly, such as through connection to external agencies or application assistance.

Substance use and recovery

Eight quantitative studies assessed substance use and recovery. By 6-month follow-up, Female Offender Reentry Movement (FOR-Me) participants reported decreased drug or alcohol related health, behavioral, or social consequences (22% to 6%), decreased days of both any (13.0 to 0.1) and heavy alcohol consumption (12.7 to 0.1), decreased days of general illegal drug use (71.8 to 1.4), and decreased days of using both alcohol and drugs (17.1 to 0.0) when compared to baseline (Mejia et al., 2024). At 6-month follow-up, substance use had decreased among Substance Use Programming for Person-Oriented Recovery and Treatment (SUPPORT) program participants compared to baseline (30% to 16%) but increased among those in the control group (26% to 41%) (Ray et al., 2021). In terms of recovery, SUPPORT participants were also found to have increased treatment motivation and self efficacy scores but decreased recognition and ambivalence scores from the Stages of Change Readiness and Treatment Eagerness Scale assessment at the 6-month follow-up. Over 70% of participants in the WHM program maintained sobriety by 6-month follow-up and maintained abstinence from alcohol and other substances by 12 months (Goldstein et al., 2009). Furthermore, in reflecting back on data from three years of WHM, Warner-Robbins et al. (Warner-Robbins & Parsons, 2010) found that only 1.4% of the women served during those years reported using any substances. The Gamble Institute (TGI) participants’ Abstinence Self-Efficacy negative affect and habitual craving scores improved significantly from pretest to posttest, indicating increased confidence in abstinence in those situations, but no significant differences were found between pretest and posttest for total Abstinence Self-Efficacy, self-esteem, social support, and coping measures or for engagement with 12-step programs (Marlow et al., 2015). Although all groups of the Peer Coaching - Nurse Case Management (PC-NCM) program reported decreased substance use, no significant difference was found in substance use between usual care and peer support interventions during a 12-month observation period (Nyamathi et al., 2016). An RCT of FAP found no significant difference in alcohol and substance use risk behavior between peer support and control groups (Myers et al., 2018).

Many studies also reported on qualitative findings related to substance use and recovery. A process evaluation of the WISH-TC found that the participants who were interviewed highlighted that the peers supported their autonomy in their SUD recovery journey and that the program’s services were essential for their recovery (Thomas et al., 2019). Dubose et al. (Dubose et al., 2023) reported that PSS increased participants’ self-awareness around recovery. Kingdom of Life Ministries (KLM) participants reported that the program encouraged motivation for recovery by helping them understand addiction as a disease, and that the provision of transitional housing was key to successful recovery when compared to their experiences with other recovery-oriented programs (Scarbrough, 2012). Peers of TGI supported participants’ recovery through emotional/social support and role modeling (Marlow et al., 2015). Martin et al. (Martin et al., 2021) highlighted that peers with lived experience were essential in maintaining the linkages between the jail and community that were needed for participants’ recovery. Interviews with JCOIN peers found that stigma against the use of medications for opioid use disorder (MOUD) among program participants was a challenge to program implementation and highlighted the importance of peers using a harm reduction perspective to provide ongoing support, even if participants didn’t immediately engage in treatment (Tillson et al., 2022).

Mental health

Five studies reported on quantitative measures of mental health outcomes. A quasi-experimental study of FOR-Me reported a 44.5% decrease in psychiatric symptoms from baseline to 6-month follow-up, including significant decreases in symptoms of depression, anxiety, hallucinations, and trouble with cognitive brain function and a significant decrease in use of psychiatric medications (Mejia et al., 2024). A mixed methods evaluation of the Peers Reach out Supporting Peers to Embrace Recovery (PROSPER) program found that participants reported significantly lower levels of perceived stress from baseline to the 12-month follow-up (Andreas et al., 2010). Participants of the Offender Alumni Association (OAA) peer support group reported significantly higher levels of social support and stronger social networks and, although not statistically significant, lower anxiety, depression, loneliness, and perceived stigma compared to formerly incarcerated individuals who were not members of the support group (Moak et al., 2023). A cohort study of WHM found that the participants of the program reported a reduction in symptoms of depression, bipolar disorder, and/or attention-deficit/hyperactivity disorder at 6-month follow-up, and were following the mental health treatment plan developed by the program at 12-month follow-up (Goldstein et al., 2009). No significant differences were found between pretest and posttest scores of self-esteem for TGI participants (Marlow et al., 2015).

A qualitative evaluation of the DC-Reentering Individual Service Enhancement and Support (DC-RISES) program found that peers with lived experience with the mental health system served as important examples of successful reintegration into the community, even with a mental illness (Portillo et al., 2017). A description of the Formerly Incarcerated Peer Support (FIPS) Group (Boles et al., 2022) noted that the group was unique in that it provided space to discuss and normalize experiences of incarceration and learn adaptive behaviors and coping strategies compared to other re-entry programs that focus more on linking to services like finding employment (Boles et al., 2022).

HIV

Four studies reported on quantitative measures of HIV outcomes surrounding peer re-entry programs. A mixed methods evaluation of the Community Health Workers Eliminating Barriers in Access to Care (COMEBACK) program found that participants who received peer support tended to have better HIV control, decreased positive results in screenings for stimulant use, and increased attendance at clinical appointments when compared to those in the control group (Khazi-Syed et al., 2024). An RCT of LINK-LA found that the group receiving peer support achieved viral suppression at a significantly higher rate compared to the control group at 6-month (53% vs. 37%) and 12-month follow-up (49.6% vs. 36.0%) (Cunningham et al., 2018). Additionally, high-risk drug use was found to be associated with decreased viral suppression among participants in LINK-LA (Goodman-Meza et al., 2019). An RCT of FAP found that those receiving peer support reported less risky sex at 12-month follow-up when compared to the control group (7.5% vs. 17.8%), were more likely to attend a non-urgent HIV-related healthcare visit within 30 days of release (44% vs. 28%), and were more likely to be consistently engaged in HIV care by 12-month follow-up (39% vs. 28%) (Myers et al., 2018).

In terms of qualitative results, COMEBACK program participants reported improved motivation and accountability surrounding HIV treatment when engaging with peers (Khazi-Syed et al., 2024). Additionally, peer navigators of the Project START program helped break through the distrust of the healthcare system felt by participants with HIV to support long-term care in the community (Koester et al., 2014).

Recidivism

Recidivism was examined quantitatively in 15 studies measured through rates of rearrest, reincarceration, and parole/probation violations. Boston Reentry Initiative participants had lower rates of rearrest compared to the control group at both one-year (36.1% vs. 51.1%) and three-year (77.8% vs. 87.7%) follow-ups (Braga et al., 2009). PeerStar program participants had a significantly lower reincarceration rate of 22% compared to the rate of 43% for the general U.S. jail/prison population (Bellamy et al., 2019). At one-year follow-up, TCN program participants had lower odds of parole/probation violations compared to the control group (17% vs. 33%) and spent fewer days incarcerated (101 vs. 183 days), but odds of overall incarceration were similar between the two groups (Wang et al., 2019). The peer mentored group of The Connection, had significantly lower rates of recidivism compared to the control group that didn’t receive mentoring (Sells et al., 2020). The Comprehensive Opioid Stimulant Substance Use Program (COSSUP) reported reduced recidivism, with only 14% of participants rearrested by 90-day follow-up (Howard et al., 2024). Recidivism was low among veterans who participated in the PIE program, with only 7% of participants rearrested during the study (Hyde et al., 2022). Two studies of WHM found low recidivism rates of 3.5% in the 6 months after release from 2004 to 2007 (Warner-Robbins & Parsons, 2010) and 23% in the 12 months after release from 2007 to 2009 (Goldstein et al., 2009). Another program for individuals with OUD found that only 1 of 54 participants were reincarcerated by 6-month follow-up (Dubose et al., 2023). KLM program participants had reduced recidivism rates when compared to recidivism rates from the jail as a whole and to rates from another program within the jail that did not offer support for the reentry transition (Scarbrough, 2012). Additionally, five studies found no significant difference in recidivism rates between program participants and control groups (Anderson & Medendorp, 2024; Khazi-Syed et al., 2024; Nyamathi et al., 2016, 2017; Wang et al., 2012). Of note, Nyamathi et al. (Nyamathi et al., 2017) found that having a parolee substance abuse program contract, spending 6 months or more in SUD treatment, and use of problem-focused planning coping were protective factors against recidivism.

Qualitative results from a cohort study of COSSUP suggest that increasing social and personal capital through a combination of housing stability, peer support, care coordination, and community building may account for reductions in recidivism (Howard et al., 2024). Interviews with participants of KLM highlighted that the program changed participants’ views towards hope for opportunity after incarceration and that participants noted the provision of transitional housing as essential to supporting successful reentry into the community (Scarbrough, 2012).

Other outcomes

A few studies reported on outcomes additional to those mentioned above, including emergency department (ED) and hospital visits, vaccinations, and employment. Two TCN studies had diverging results with respect to ED visits and hospitalization (Wang et al., 2012, 2019). An RCT found that those receiving CHW services from the TCN were less likely to visit the ED compared to those in the control group by 12-month follow-up, with a 51% lower annual rate of visits, but no significant difference was found in hospitalizations between the two groups (Wang et al., 2012). On the other hand, a quasi-experimental study found that among those who were hospitalized, TCN participants had significantly fewer events of preventable hospitalizations and shorter lengths of hospital stays compared to the matched comparison group, but no significant difference was found between the two groups in preventable ED visits (Wang et al., 2019). In the PIE program, no significant difference was found in ED use or hospitalization between peer support participants and a historical comparison group, but 84% of the peer support participants who had been released over a year were living in permanent housing (Hyde et al., 2022). Participants with HIV who received the LINK-LA intervention had fewer ED visits at 3- and 6-month, but not 12-month follow-up, when compared to control participants (Cunningham et al., 2018). Evaluating efforts in Hepatitis A and B prevention, Nyamathi et al. (Nyamathi et al., 2016, 2017) found that there was no significant difference in Hepatitis A and B vaccination rates among parolees who received peer coaching, peer coaching plus nurse case management, or usual care. Further, no significant difference was found between these three groups for employment status, health condition, or having multiple sex partners (Nyamathi et al., 2016). Dubose et al. (Dubose et al., 2023) highlighted that the described re-entry program trained and certified 121 incarcerated people to provide PSS and that 40 of the 121 were employed at the time of article publication.

Program implementation successes and challenges

Forty-seven studies included descriptions of program implementation factors, which we categorized under five themes: lived experience of peers, early and extensive engagement with participants, participant-centered support, collaboration with other agencies, and challenges to implementation.

Lived experience of peers

Lived experience of peers was directly highlighted as a key strength of re-entry programs (Enich et al., 2023; Grohs, 2020; Hardy, 2018; Lowther-Payne et al., 2024; Moak et al., 2023; Palis et al., 2024; Reingle Gonzalez et al., 2019; Thomas et al., 2019) and as crucial to their successful implementation (Elumn et al., 2023; Hood et al., 2024; Koester et al., 2014; Martin et al., 2021; Motta-Moss et al., 2001; Sevelius et al., 2023). Staffing of peers with shared lived experiences was identified as important in building rapport with participants and in building acceptability and legitimacy of the program as a whole (Lowther-Payne et al., 2024; McLuhan et al., 2023; Portillo et al., 2017; Reingle Gonzalez et al., 2019; Warner-Robbins & Parsons, 2010) and was seen as a unique aspect compared to other community programs (Goldstein et al., 2009; Marlow et al., 2015; McLuhan et al., 2023; Victor et al., 2021). Additionally, peers felt that their work was meaningful and helpful for clients’ re-entry and recovery (Best et al., 2022; Elumn et al., 2023; Lowther-Payne et al., 2024; Tillson et al., 2022) and that their lived experience gave them the motivation and skills to provide meaningful support to participants (McLeod et al., 2021; Reingle Gonzalez et al., 2019).

Early and extensive engagement with participants

Four studies (Martin et al., 2021; Miller, 2009; Motta-Moss et al., 2001; Palis et al., 2024) identified pre-release engagement of participants as crucial to program success, one study (Swarbrick et al., 2019) directly highlighted the importance of connecting with participants within the first 48 h after release, and nine studies (Best et al., 2022; Koester et al., 2014; Martin et al., 2021; McLeod et al., 2020, 2021; Miller, 2009; Motta-Moss et al., 2001; Palis et al., 2024; Romain Dagenhardt et al., 2024; Scarbrough, 2012) specified engagement on the day of release as a key component of the program. Furthermore, two studies (Aminawung et al., 2021; McLuhan et al., 2023) identified lack of pre-release engagement of participants as a key limitation of the program. Many studies also pointed to the importance of extensive engagement throughout the program, highlighting the importance of consistency of outreach (Khazi-Syed et al., 2024; Lowther-Payne et al., 2024; Martin et al., 2021; Motta-Moss et al., 2001; Palis et al., 2024) and long-term nature (Grohs, 2020; Palis et al., 2024) of peer support, as well as intensive time peers spent with participants (Koester et al., 2014; Reingle Gonzalez et al., 2019). Furthermore, in examining attrition within a peer re-entry program, Anderson and Medendorp (Anderson & Medendorp, 2024) found that increased support from peers significantly lowered the odds of attrition. Related to the earlier discussion on linkages to services, many programs provided the additional step of peers accompanying participants to appointments in the community to enhance linkage (Cunningham et al., 2018; Edwards et al., 2020; Goodman-Meza et al., 2019; Hailemariam et al., 2020; Koester et al., 2014; Marlow et al., 2015; Martin et al., 2021; McLeod et al., 2020, 2021; Mejia et al., 2024; Miller, 2009; Myers et al., 2018; Parekh et al., 2022; Pho et al., 2021; Waddell et al., 2020; Wang et al., 2012).

Participant-Centered support

Participant-centered support was also highlighted as a key strength of peer re-entry programs. Centering the perspectives of formerly incarcerated individuals (Boles et al., 2022), prioritizing participant needs (Enich et al., 2023; Hood et al., 2024; Palis et al., 2024; Romain Dagenhardt et al., 2024), individualized support (Hardy, 2018), flexibility of the program (Elumn et al., 2023; Hanna et al., 2020; McLeod et al., 2021), supporting participant autonomy (McLuhan et al., 2023; Thomas et al., 2019) and a holistic approach to programming and services (Lowther-Payne et al., 2024; Stephens et al., 2002) were reported as important findings from studies of program implementation and success.

Collaboration with other agencies

Collaboration with other agencies was identified as a key factor in supporting the implementation of peer re-entry programs (Boles et al., 2022; Hanna et al., 2020; Hood et al., 2024; Lowther-Payne et al., 2024; Martin et al., 2021; McLeod et al., 2021; Motta-Moss et al., 2001; Swarbrick et al., 2019). This is also evident in the large number of programs that were led by a collaboration of multiple agency types, including community-based, academic, corrections, government, healthcare centers/clinics, faith-based, drug treatment centers, and behavioral health organizations. Lowther-Payne et al. (Lowther-Payne et al., 2024) noted that their program’s collaboration with a community football trust acted as a ‘hook’ to encourage participants to engage with the program. Martin et al. (Martin et al., 2021) highlighted that over a decade of extensive effort to integrate community-based service providers and the criminal justice system helped to develop a shared vision of coordinated care, which was essential for the successful implementation of a PSS program for individuals with OUD in Maricopa County jails.

Challenges to implementation

Staffing and outreach were highlighted as challenges to PSS implementation. Staff turnover was identified as a key challenge to the Latino Discharge Planning (LDP) program (Motta-Moss et al., 2001), and limited staff or understaffing were noted challenges to three programs (Andreas et al., 2010; Dubose et al., 2023; Hanna et al., 2020). A qualitative study of the Smart Reentry Project described challenges in balancing authenticity versus professional accountability among staff and resistance from correctional staff (Romain Dagenhardt et al., 2024). Challenges related to outreach included locating participants in the community after release, misclassification of transgender inmates (Sevelius et al., 2023), the need for staff to travel long distances to prisons (Andreas et al., 2010; Motta-Moss et al., 2001), lack of pre-release engagement with participants (McLuhan et al., 2023), and difficulties in recruitment and enrollment of participants (Hanna et al., 2020). Additional implementation challenges included funding (Lowther-Payne et al., 2024; Martin et al., 2021; Parekh et al., 2022), high attrition of program participants (Sevelius et al., 2023), emotionally draining work (Motta-Moss et al., 2001), lack of participants’ identification documents (Reingle Gonzalez et al., 2019), MAT engagement (Hanna et al., 2020), data collection (Hanna et al., 2020), unavailability of program on weekends (Andreas et al., 2010), MOUD stigma (Staton et al., 2024), lack of resources in rural areas (Staton et al., 2024), and reduction in available resources and ability to conduct outreach in the jails due to the COVID-19 pandemic (Martin et al., 2021; McLeod et al., 2021).

Discussion

PSS programs for individuals with health-related needs experiencing jail and prison re-entry have proliferated rapidly across the US. This scoping review assessed the key characteristics of such programs and summarized the evidence on their effectiveness and implementation to date. Our assessment of intervention characteristics revealed that programs are highly heterogeneous. While most programs shared certain characteristics, such as employing formerly incarcerated peers and prioritizing linkages to health and social services for their clients, they diverged on many others. For example, programs differed in the specific populations targeted (e.g., individuals with HIV vs. SUD); the duration of services; whether services were provided pre-release, post-release, or both; and the specific types of services that were provided by peers and other staff as part of the program. This heterogeneity likely reflects program designs that are responsive to the needs of the population served, local context, and available resources.

Overall, we found evidence that PSS were associated with improved post-release outcomes, though there was substantial variation by specific outcome and in the quality of evidence across studies. Many studies reported a positive association between PSS and service linkages, which was the most common activity carried out by PSS programs included in this review. Qualitative findings reported in reviewed studies provide some context to these positive findings; for example, peer navigators were reported to have robust relationships with community-based providers as well as deep knowledge of the resources available in their communities and how to access them.

Many of the included programs targeted patients with SUD or mental health conditions, and studies generally found an association of PSS with less substance use and fewer SUD and mental health symptoms. Several studies examining HIV outcomes also had positive findings and generally had more-rigorous designs, with three RCTs finding that PSS improved viral suppression, increased HIV care engagement, and reduced risky sex.

Recidivism was also assessed in many studies, but with varying results. This is consistent with other research on health-related services delivered at re-entry, including those examining service linkage interventions (Grella et al., 2022) and community-based SUD treatment programs (Graves & Fendrich, 2024), which have mixed findings. However, recidivism has been criticized as an outcome measure for re-entry programs, as it likely reflects criminal-legal system characteristics (e.g., enforcement activity) as much or more than individual behavior (Barrenger et al., 2021; Rosenfeld & Grigg, 2022). Furthermore, many of the programs examined were designed specifically to address SUD, mental health, HIV, or other health-related needs, rather than criminal activity. Future development of PSS interventions for justice-involved individuals with SUD might consider approaches that simultaneously address both substance use and criminality, considering that pathways to recovery overlap substantially with those of desistance from crime (Best & Colman, 2019).

While these findings highlight the promise of PSS for improving post-incarceration outcomes, they also demonstrate the need for further research. Few of the included studies used designs that allow for causal inferences, and additional RCTs and quasi-experimental studies in usual care populations are needed. Several such studies, including some whose protocols are included in this review, are currently underway. There is a further need for research that examines the specific aspects of interventions that are associated with better outcomes. In the studies we examined, program characteristics and study designs varied considerably, creating challenges in making comparisons across program features. Studies should also examine the mechanisms of peer programs that account for success, including studies that use real-world health services data from usual care populations (Quiroz Santos et al., 2025). Future research could further extend our findings by applying Implementation Science frameworks to systematically analyze implementation processes in peer re-entry programs, providing deeper insight into the mechanisms underlying program successes and challenges. Finally, future research should consider a broader set of outcomes, particularly those that may be more directly targeted by PSS, such as recovery capital, quality of life, and readiness for change. Barrenger et al. (Barrenger et al., 2021) note that despite its limitations, recidivism is the most common measure of success for re-entry programs for individuals with mental health needs. The authors suggest collection of a broader range of outcomes that may be improved through re-entry interventions such as employment, social relationships, and participation in prosocial activities (Barrenger et al., 2021).

Many of the studies we reviewed examined implementation processes, successes, and challenges, providing valuable information for organizations seeking to implement PSS at the point of re-entry. Challenges related to staffing were common, including confusion regarding the specific role of peers as part of a larger care team, interactions between peers and correctional staff, and burnout due to the emotionally challenging nature of the work. These issues highlight the need for comprehensive training for all personnel involved (including peers, care team members, and correctional staff), as well as ongoing supervision supported by policy and funding, careful management of peer workloads, and prioritization of self-care among staff (Abraham et al., 2022; Bell et al., 2025; Hogue et al., 2024; Satcher et al., 2024; Tate et al., 2022). Another commonly raised issue was the limited and often temporary grant funding available for PSS. Although many state Medicaid programs now cover PSS (Bao et al., 2024), reimbursement rates are low and the Medicaid Inmate Exclusion Policy prohibits Medicaid reimbursement for services delivered in correctional facilities. However, 28 states now have approved or pending 1115 waivers which will allow them to bill Medicaid in the 30–90 days before release (Kaiser Family Foundation, 2025) and could improve the financial sustainability of PSS for re-entry populations (Satcher et al., 2024). Additional outcomes and cost effectiveness research is needed to inform decisions by Medicaid and other payers to implement or enhance coverage for re-entry PSS (Castedo de Martell et al., 2025).

Despite these challenges, many successful aspects of PSS were also highlighted, including the great value of peers’ shared lived experience for building rapport with clients, peers’ ability to serve as role models, and their deep knowledge and connection to community-based recovery supports. Also highlighted as a key ingredient to success was engaging with patients early—preferably before release—to establish strong, trusting relationships that would be more likely to continue in the community. Finally, consistent with research on patient-centered care (Rathert et al., 2013), providing individualized services that center patient priorities and needs was regarded as central to success.

Limitations

Several limitations of this review should be noted. First, although we included 49 unique interventions, our limited inclusion of the grey literature due to the difficulties in conducting systematic searches means that interventions described outside of the included databases (e.g., on websites) were not captured. Second, our review criteria required that programs focused on addressing individuals’ health-related needs and may have excluded literature that did not describe an explicit focus on such needs even if they were ultimately provided as part of the intervention. Third, to limit the scope of the review, we excluded PSS for individuals on probation or drug court, who may or may not have been recently incarcerated. We also excluded individuals under age 18, given the differences in services and legal procedures they experience. Finally, an inherent limitation of scoping reviews is that we did not conduct an assessment of the quality of evidence gathered, precluding our ability to draw definitive conclusions regarding program elements associated with better outcomes. Our ability to draw such conclusions is further limited by the small number of studies using designs that allow for causal inferences.

Conclusion

In this scoping review summarizing program designs and evidence from 49 re-entry PSS programs described in 66 publications, we found evidence that PSS may improve post-release outcomes, including linkage to health services, reduced substance use and mental health symptoms, and greater adherence to HIV treatment. Studies on program implementation identified peer lived experience, extensive participant engagement, person-centered care, and collaboration between agencies as factors that are integral to success, while notable challenges related to staffing and participant outreach. Overall, few of the studies used designs that allow for causal inferences, highlighting the need for additional research to understand the effectiveness of re-entry PSS, as well as specific program elements associated with better participant outcomes.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

VDL and PT contributed to the conceptualization and design of the study. All authors conducted the literature search; data extraction and analysis; and drafting, review, and editing of the manuscript.

Funding

Support for this work was provided by the Boston University School of Social Work Small Grant Award and by the National Institute on Drug Abuse (R01DA058664; PI: Crystal).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Competing interests

The authors declare no competing interests.