Clinical guidelines generally recommend psychotherapy as the first-line treatment for BPD, with Dialectical Behavior Therapy (DBT) often highlighted, despite no consensus regarding the superiority of any psychological intervention (11). However, access to adequate treatment for BPD remains limited in most countries because of significant shortage of qualified professionals, insufficient funding and ongoing stigmatization of this population within the healthcare system (12–14). As a result, many individuals are left without access to the recommended care, as the demand for these services far exceeds the available supply (13). Individuals with BPD frequently report dissatisfaction with the services they receive, citing a significant disparity between their needs and the care provided, while also facing critical stigmatization (15). Although DBT and other psychotherapies are recognized as the most effective treatments, meta-analyses have shown only moderate effect sizes in reducing BPD symptoms with psychotherapy (16). Additionally, a meta-analysis indicates that the dropout rate for outpatient psychotherapies is 28.2% (17), highlighting the challenges of retaining patients in these therapeutic programs.

Given these limitations, it is crucial to explore complementary approaches that could help bridge the gap in BPD care, improving both accessibility and patient engagement in therapeutic programs. Peer support, defined as the provision of emotional, social, and practical assistance by individuals with lived experience of mental health challenges (18), has gained recognition as a valuable alternative to traditional clinical care for people with mental health conditions (19). By engaging with peers who have faced similar challenges, individuals can experience a sense of validation and support, possibly enhancing their commitment into treatment (19, 20). This peer-based approach not only provides practical coping strategies, but also creates a relational dynamic grounded in shared experience, fostering understanding and empathy that may be harder to cultivate in traditional professional settings (21, 22). Indeed, individuals with BPD often struggle with feelings of isolation (23), a lack of understanding from their social circles (24) and tend to have smaller social networks, increased loneliness and lower-quality relationships (25). Support groups and structured social interactions could play a critical role in reducing isolation and enhancing perceived social support among individuals (26, 27). Studies also suggest that peer support programs can improve outcomes such as self-efficacy, empowerment, and hope, all of which are crucial in the recovery process (19, 22). Furthermore, peer support is typically more accessible and cost-effective than traditional therapies (28), making it an invaluable tool for bridging gaps in mental healthcare accessibility and patient engagement. Peer support emerges as a promising intervention for individuals living with BPD. However, despite its potential, its implementation entails specific risks that must be carefully explored. Individuals with BPD may experience significant challenges related to impulsivity (29) and interpersonal functioning (30), which can complicate peer interactions and disrupt group dynamics. These difficulties underscore the importance of identifying and anticipating potential challenges to ensure that peer support remains both safe and therapeutically beneficial in this population.

This study aims to evaluate the potential benefits and challenges of peer support for individuals living with BPD and identify key functional and symptomatic areas that may be impacted by such interventions. Specifically, this research will investigate:

By synthesizing existing evidence and addressing these objectives, this study seeks to provide practical insights for clinicians, researchers, and policymakers, supporting the development of structured, evidence-based peer-support interventions to complement traditional therapeutic approaches and better address the specific needs of individuals with BPD.

A scoping review methodology was selected to address the objectives of this study, as it enables systematic mapping, exploration and synthesis of existing literature, while also identifying knowledge gaps (31). The review was conducted in accordance with the Joanna Briggs Institute (JBI) guidelines for Scoping Reviews (32) and the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for scoping review (PRISMA-ScR) checklist (33, 34). The protocol for this review was not registered; however, it is available in French and English upon request with the corresponding author.

The eligibility criteria were defined according to the Population-Concept-Context (PCC) framework (32). Studies not meeting the following criteria were excluded.

Prior to conducting this scoping review, a preliminary search was done in Medline, the Cochrane Database of Systematic Reviews, Embase, and Google Scholar to verify the absence of any existing or ongoing systematic or scoping reviews on the topic. In August 2024, a librarian specializing in knowledge synthesis in mental health at the Research Center of the University Institute of Mental Health in Montreal conducted a comprehensive literature search using the Medline, PsycINFO, EMBASE, Cochrane Library, Google Scholar, and CINAHL databases to identify peer-reviewed articles. The search was limited to publications from the past 20 years, from 2004 to 2024, to capture recent advancements, emerging trends, and evolving methodologies related peer support for individuals with BPD. Additionally, a grey literature search was performed using the Google search engine with targeted keywords and Boolean operators. The grey literature search aimed to expand the scope of the analyzed documents and include sources not indexed in traditional scientific databases, such as institutional reports, peer-support initiatives, theses, and government publications. To ensure global coverage and mitigate regional biases in search results, a VPN was used to access content from four continents. The full search strategy for each database and for the grey literature search is detailed in Supplementary File 1 . In line with best practices for scoping reviews, a final bibliographic alert was conducted just before submission to capture any newly published relevant studies.

Search results were imported into Covidence systematic review management software, which automatically identified and removed duplicates (Covidence Systematic Review Software, 2021). Based on predetermined eligibility criteria, two reviewers (A.-S.D. and M.A.) independently screened the titles and abstracts of the remaining records. Prior to the screening process, a pilot test was conducted to ensure a minimum inter-rater agreement of 75%. Discrepancies were resolved by a third reviewer (F.T.). Full texts were then independently assessed by the same two reviewers (A.-S. D.), with discrepancies settled by the third (F.T.)

Data to extract from eligible articles was discussed, and consensus was reached through meetings held by the research team (A.-S. D, M.A., L.C., F.T.). An extraction template was created within Covidence, including the following fields: author, year, country, study design, study objective, population characteristics (age, gender, and diagnosis), intervention details, and primary outcomes. A dual extraction was conducted in parallel by two reviewers (A.-S.D. and F.T.), with the two versions consolidated by a third member (M.A).

The literature search identified 2,114 studies, which were imported for screening. One duplicate was detected and removed by Covidence. Following the title and abstract screening, 2,048 articles were deemed irrelevant and subsequently excluded. A total of 65 full-text studies were assessed for eligibility, of which 56 were excluded for the following reasons:

The detailed study selection process is illustrated in the PRISMA-ScR flow diagram ( Figure 1 ), which was automatically generated by Covidence to provide a systematic overview of the inclusion and exclusion criteria applied throughout the screening process. Two relevant articles (35, 36) were identified through a final literature monitoring process conducted immediately prior to submission. As it met all inclusion criteria, it was added to the final set of included studies, resulting in a total of 11 articles (35–45).

The 11 studies included in this scoping review were published between 2019 and 2025. Detailed characteristics of each study are presented in Supplementary File 2 . Australia was the most represented country (n = 5), followed by the United Kingdom (n = 2), with one study each from Mexico, South Africa, Spain, and France. A variety of methodological approaches were employed, most were qualitative studies (n = 5), using interviews and thematic analysis to explore participants’ experiences. One study adopted a mixed-methods design, combining both quantitative and qualitative analyses to provide a more comprehensive understanding of the phenomenon. Another study was a theoretical review (n = 1), synthesizing existing literature to develop conceptual frameworks or theoretical perspectives. One study was a descriptive report (n = 1) on the functioning of a peer support group, offering insights into its structure, processes, and impact. One naturalistic pre-post quantitative study (n = 1) evaluated the feasibility and acceptability of integrating a peer-support worker into an evidence-based group psychoeducation program. A feasibility randomized controlled trial protocol (n = 1) assessed the feasibility and acceptability of an intervention before conducting a larger-scale trial. Finally, one two-arm parallel-group randomized controlled trial compared a peer-clinician co-led intervention with treatment as usual.

Several methodological limitations must be considered when interpreting the findings. One key issue is the predominance of qualitative studies. While qualitative research offers rich, in-depth insight into participants’ experiences, peer-support establishment as an intervention based on evidence would benefit from complementary quantitative studies. Such studies could contribute to measuring clinical outcomes and comprehensively assessing the impact of these interventions. Additionally, most studies included lack robust methodological controls, such as randomized controlled trials or comparator groups. Without appropriate control conditions, it is challenging to distinguish between the specific effects of peer support and other external influences. Moreover, there is no standardized peer support intervention across studies, leading to significant variability in implementation. Differences in training, structure, and delivery methods complicate the comparison of results and their generalization. Only three studies provided detailed information on the selection, training, and supervision of peer-support workers; greater reporting of these elements would not only clarify best practices but also facilitate the development of standardized interventions. Another critical limitation of the included studies is the substantial variability in follow-up durations, ranging from short-term assessments to periods that are insufficient to capture sustained effects. This heterogeneity hinders the ability to draw firm conclusions regarding the long-term efficacy and sustainability of peer support interventions. Furthermore, these interventions are implemented within their specific cultural and healthcare system contexts. Factors such as access to specialized psychotherapy, the structure and availability of mental health services, and differences in healthcare infrastructure, shape both the implementation and its potential effectiveness of peer support (50). Additionally, technological factors, such as internet accessibility and digital literacy, influence the feasibility and engagement in online peer support programs, contributing further to variability in outcomes.

This scoping review presents several limitations that should be considered when interpreting its findings. First, the study is subject to selection and publication bias, as it relies on existing literature, which may disproportionately include studies with positive or significant results while excluding unpublished or inconclusive research (55, 56). Additionally, despite a comprehensive search strategy, relevant studies may have been overlooked due to language restrictions or limitations in database coverage. Another significant limitation is the limited empirical investigation into the mechanisms and effectiveness of peer support interventions for individuals with BPD. While several studies suggest potential benefits, few have systematically examined how and why these interventions might lead to positive outcomes. A notable strength of this review is the inclusion of grey literature, which enabled the identification of alternative forms of peer support, such as online forums. This broadened perspective highlighted that, beyond structured interventions led by professionals, individuals with BPD naturally tend to seek and form peer-based connections. The broad scope of the review also revealed a growing interest in peer support not only within academic research but also in community-based settings, underscoring the need for further empirical investigation. Moreover, the use of PRISMA-ScR guidelines and the JBI methodology for scoping reviews ensured methodological rigor and transparency throughout the selection, data extraction, and synthesis processes.