STUDY PROTOCOL Open Access Assessing the efficacy of a stepped-care group treatment programme for borderline personality disorder: study protocol for a pragmatic trial Judy A. Pickard 1* , Adam Finch 2 , Elizabeth Huxley 1 , Michelle L. Townsend 1 , Stephanie Deuchar 2 , Kate L. Lewis 1 , Jason Pratt 2 and Brin F. S. Grenyer 1 Abstract Background: Borderline personality disorder (BPD) is a high prevalence and serious mental health disorder that has historically challenged the finite resources of health services. Despite empirical evidence supporting structured psychological therapy as the first line of treatment, there remains significant barriers in providing timely access to evidence-based treatment for this population. The primary aim of this study is to evaluate the effectiveness of providing a stepped-care structured psychological group treatment to individuals with BPD within local mental health services. The secondary aims of the study are to identify the variables that predict the need to step up or down in care and the effectiveness of treatment on psychosocial functioning. Methods: Participants seeking treatment at two community mental health services will be invited to participate. Randomised controlled trial assignment will be to either (i) group skills treatment or (ii) treatment as usual. Group treatment will be offered via a stepped-care pathway with participants initially attending a 12-week group with the option of a subsequent 16-week group. The criteria for inclusion in continuing treatment includes meeting > 4 BPD diagnostic criteria or severity on GAF (< 65) at the completion of the 12-week group. Data will be collected at baseline and at five follow-up time points over a 12-month period. Discussion: This pragmatic trial will provide valuable information regarding the effectiveness of a progressive stepped-care group treatment for individuals with BPD in the real-world setting of a community mental health service. It will further the current understanding of variables that predict treatment dose and duration. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12618000477224. Registered on 3 April 2018 Keywords: Borderline personality disorder, Stepped care, Pragmatic trials Background and rationale Borderline personality disorder (BPD) is a high preva- lence, serious mental health disorder that represents sig- nificant personal, social and economic cost [19]. People with BPD present frequently to outpatient mental health facilities and place a significant demand on hospital in- patient and emergency services [16]. Studies have re- ported as many as 20% of psychiatric outpatients, and over 30% of persons treated in an inpatient mental health unit have a diagnosis of BPD [2, 12, 14], with 11% of individuals also presenting with Axis I co-morbidity, © The Author(s). 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. * Correspondence: jpickard@uow.edu.au 1 School of Psychology, University of Wollongong, Wollongong, Australia Full list of author information is available at the end of the article Pickard et al. Trials (2021) 22:383 https://doi.org/10.1186/s13063-021-05327-0