Dear Dr. Michalak,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Nov 15 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Rakesh Karmacharya, MD, PhD

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Thank you for stating the following in the Competing Interests section:

“EM has received honorarium for advising on the development of unrelated educational materials for Neurotorium, an online educational platform supported by the Lundbeck Foundation. AK declared no competing interests with respect to the research, authorship, and/or publication of this article. EEM has received funding to support patient education initiatives from Otsuka-Lundbeck.”

Please confirm that this does not alter your adherence to all PLOS ONE policies on sharing data and materials, by including the following statement: "This does not alter our adherence to PLOS ONE policies on sharing data and materials.” (as detailed online in our guide for authors http://journals.plos.org/plosone/s/competing-interests). If there are restrictions on sharing of data and/or materials, please state these. Please note that we cannot proceed with consideration of your article until this information has been declared.

Please include your updated Competing Interests statement in your cover letter; we will change the online submission form on your behalf.

3. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information.

4. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. 

Additional Editor comments:

Review #3: 

Overall:

Project has strong rationale, and the paper is well written.

Introduction:

Recommend rewording the first sentence to say “BD is a serious, potentially chronic mental health condition” – as symptoms are significant, no matter their duration.

The authors cite a meta-analysis of 17 peer-facilitated self-management groups for those with smi – could they specify how many of those participants across studies these studies had a diagnosis of BD? This would help establish that the uniqueness of the present study.

Methods:

For the qualitative analyses, it is unlikely saturation will be reached if only interviewing four facilitators; consider increasing this sample if possible.

Lots of detail is provided about the quantitative measures that will be given, but the qualitative interview guide is not as specific. Consider including questions that will be asked to parallel the specificity of quantitative measures described.

The authors state that participants will not be able to skip questions in Qualtrics. Typically, participants are given the choice to skip questions or not answer questions (and this is explained to them in the informed consent process). While it does increase missing data, it is important to give participants the option to skip questions they wish to skip so they do not feel coerced into participation, especially when being paid.

The authors should share more about their analysis plan for the qualitative analyses. How will they know when saturation has occurred for given themes? Will one researcher do all of the coding? If multiple coders, what will the consensus process be?

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #1: Yes

Reviewer #2: Partly

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #1: Summary:

The present article reports an original clinical trial protocol to test Thriving with Bipolar Disorder, a peer-led psychoeducational group program developed with a community-based participatory (CBPR) framework. Specifically, the authors describe the planned methods for evaluating the feasibility of this single-arm pilot clinical trial in a series of four groups of approximately 10 participants, while collecting fidelity, acceptability, and outcome data. They also proposed to collect qualitative data from a subset of participants and peer facilitators through feedback interviews. Strengths include focusing on an important topic of developing the peer workforce and enhancing bipolar disorder recovery, previously registering the protocol with clinicaltrials.gov, including a detailed Table 1 description of session topics and objectives, inclusion of the Behavioural Research Ethics board-approved protocol, and partnering with the Hope+Me charity to deliver the intervention. However, the selected SPIRIT checklist version (2013 instead of 2025), minor points about the intervention, and self-rated fidelity assessment temper the enthusiasm for this manuscript, although these points are addressable.

Major:

N/A

Minor:

Abstract

1. N/A

Introduction

1. N/A

Intervention

1. Pages 8-9: Given the high rates of substance use among individuals with bipolar disorder, is substance use discussed in one of the self-management session topics (e.g., physical health)? If not, it might be worth considering adding or assessing in the feedback interview which topics, if any, participants would want to add to the program.

2. Page 10: It may be helpful to update the expected study dates (e.g., recruitment of program participants is described as concluding by August 2025, but as of September 12, 2025, the clinicaltrials.gov listing states that the study is not yet recruiting.

Procedures

1. Pages 14-15: Facilitator-reported fidelity presents challenges in that people tend to rate their own performance more favorably than objective fidelity raters. Although having an external observer is noted as potentially impacting participant willingness to participate in group discussions and activities, the option to unobtrusively record sessions, as is easily facilitated on Zoom, is not discussed and could be a viable option to rate fidelity. Given the pilot nature of this project, this would be a good opportunity to at least ask participants whether they would be open to recording to ensure that the facilitators are conducting the group in the best way possible or similar rationale, which will provide data to inform how fidelity would be monitored in future randomized controlled trials.

Discussion

1. N/A

Supplemental

1. The authors include the 2013 SPIRIT checklist. Given the availability of the 2025 SPIRIT checklist, it seems most appropriate to use the current checklist: https://www.consort-spirit.org/.

Reviewer #2: This manuscript describes the protocol for a single-arm pilot study designed to evaluate the feasibility (main outcome: session attendance), fidelity, acceptability, short-term participant impact and perceptions of a peer-delivered, group psychoeducational program for persons living with bipolar disorder. The manuscript is well written and the methodology detailed in it is generally sound. My main comments/suggestions are related to the data analysis.

Major comments:

- Analysis of the main outcome: Please include a description of the statistical methods that will be used to analyse the main outcome (session attendance). Will any inferential procedures be conducted? As session attendance will be measured only once per participant (i.e., number of sessions attended), repeated measures ANOVA is not appropriate as an analytic method (page 19, lines 425-426). Also, the per-protocol and intention-to-treat analyses are not relevant, as all individuals will have all relevant data for this outcome.

- Analysis of other outcomes: Although repeated measures ANOVA is appropriate for other outcomes that may change over time (and which are, thus, clustered within the subject), it has several problems relative to modern longitudinal methods, most notably (i) restrictive assumptions (sphericity is unlikely when an intervention has an effect) and (ii) inflexibility to handle missing data (see comment below). Moreover, repeated measures ANOVA cannot handle multiple levels of clustering as will occur in the proposed research (clustering of longitudinal measures within subject and also clustering of subjects within facilitator/peer group). Simple alternatives would include either using (a) linear mixed models with REML (due to the small sample size) or (b) repeated measures ANOVA supplemented by (i) tests for sphericity and adjustments, (ii) modern methods for assessing and handing missing data (see comment below) and (iii) adjusting for facilitator/peer group as fixed effects (acknowledging limitations from having a small sample size).

- Assessment of missing data: I would suggest the authors to describe the methods that will be used to examine the mechanisms and correlates of missingness, as well as informing the handling of missing data (see comment below)

- Handling of missing data: The authors propose to handle missing data by using simple imputation (last observation carried forward) in intention-to-treat analyses (page 19, lines 434-435). However, this method is suboptimal relative to more modern alternatives and has a high risk of introducing bias even in the least stringent scenarios. I would suggest the authors to (a) use models that can handle missing data more flexibly under less restrictive scenarios (e.g., linear mixed models) or (b) use modern missing data methods. Optionally, the authors may find it useful to implement sensitivity analyses assuming "worst-case" scenarios for missing data.

Minor comments:

- Qualitative interviews: Please clarify if sampling for the in-depth interviews will be based on any participants' characteristics (and the criteria that will be used).

-- Typographical errors:

- Page 17, lines 364-365: Please correct the phrase “(…) where formal psychiatric evaluation and support is not be available (…)”

- Please add page numbers for reference 4

- Please correct the formatting of page numbers in references 5, 39, 46 and 64

- Please replace the DOI with the volume, issue and page numbers for reference 11

- Please correct the page numbers in reference 19

-Please add the issue number for reference 27

- Please quote the supplement number inside brackets in reference 60

-Please add the volume, issue and page numbers for reference 70

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review?  For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: No

Reviewer #2: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

‘Thriving with bipolar disorder’: The co-design of a peer-delivered group psychoeducation program and single-arm pilot feasibility evaluation protocol.

PONE-D-25-37425R1

Dear Dr. Michalak,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager®  and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support .

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Rakesh Karmacharya, MD, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #2: Yes

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #2: Yes

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #2: Yes

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #2: Yes

**********

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #2: The authors have addressed all of my comments thoroughly and satisfactorily. I have no further concerns about the proposed statistical analysis and the reporting of the study protocol.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #2: No

**********