PONE-D-24-04206Environmental risk factors for self-harm during imprisonment: a prospective cohort studyPLOS ONE

Dear Dr. Stephenson,

Thank you for submitting your manuscript to PLOS ONE. I have now received peer-review reports, and I am pleased to invite you to submit a revised version of the manuscript that addresses the points raised during the review process by Reviewer #1.

Their feedback was mainly provided to improve the rigour and transparency of reporting. Please do take their feedback into account, and if you find you are not able to do so, I would appreciate you detailing the reasons behind the decision, so that they can be considered following the submission of the revised manuscript.

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We look forward to receiving your revised manuscript.

Kind regards,

Dr Nasrul Ismail

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: No

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

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: No

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have written an article regarding self-harm in prisoners. They have investigated environmental in-prison risk factors for self-harm in a prospective study. They initially included 149 prisoners within a remand setting who were assessed on a range of previously identified environmental risk factors for self-harm specific to the prison setting. The study is framed as a pilot study. During follow-up a substantial amount of participants were lost due to prison and sentencing related factors, which resulted in a final sample of 82 or 83 participants. Several of the investigated environmental risk factors were found to be associated with the outcome. The article contributes to the base of academic knowledge and highlights a public health problem within the prison system. The design of the study sound and acceptable in order to reach the authors’ aims. However, this article needs revision before it is ready for publication.

PLOSE ONE’s criteria for publication

1. This article contributes to the base of academic knowledge and presents results of original research by exploring prison environmental factors for self-harm and estimating their effects.

2. I have found no evidence of these findings being reported elsewhere, except in a preprint format, which adheres to PLOS ONE’s criteria for publication: https://www.medrxiv.org/content/10.1101/2024.01.31.24302059v1.

3. The statistical analyses were performed to a good technical standard but could require some improvements and the accompanying text requires improvements. This is elaborated on below.

4. Conclusions are generally presented in an appropriate fashion but due some concerns regarding the validity and robustness of the results, revisions are requested.

5. Generally, the article was written in good English but needs revision to improve clarity and reduce ambiguity.

6. The research appears to adhere to the ethical standards and it received approval from the relevant ethical board as well as the national prison and probation services.

7. The article generally follows appropriate reporting standards but requires some improvements. The data have not been made available to others, a decision that is sound given the design and participants of the study. Data requests are directed to relevant services.

Abstract and introduction

The authors summarize previous research and articulate their research questions. The introduction provides a concise understanding of the field, along with a rationale and aims for their study. It offers sufficient information about self-harm during imprisonment. However,

1. The introduction lacks contextualizing of self-harm during a life-course in antisocial, aggressive and/or offending populations. Self-harm is more likely to have occurred both before and after imprisonment. Furthermore, self-harm is overrepresented in acute phases (e.g., remand), acute psychiatric conditions (e.g., adjustment disorders), and generally enduring psychiatric disorders (e.g., anxiety, personality, and severe mental disorders). Thus, the introduction lacks information regarding self-harm as part of the psychiatric spectrum in prisoners and consequently lacks preceding information about psychiatric morbidity in prison populations. I believe this omission reflects a conscious choice from the authors. However, I would argue that this information is crucial in their introduction, and it seems the authors also consider it important, as evidenced, for example, by the inclusion of such details in their questionnaires.

2. The second sentence of the introduction, which mentions the troublesome doubling of self-harm incidents among prisoners. This substantial increase prompts questions about the report’s methodology and the reasons behind this trend. Furthermore, the citation of a non-academic article as the source raises concerns about the claim’s credibility (I have not reviewed the given reference). It would be beneficial to substantiate this claim with research from academic sources and from various contexts.

3. The final sentence of the first paragraph, which describes self-harm as a resource burden for service providers, lacks citations. Moreover, its relevance to the paper may be questioned. If the authors deem this information important to the introduction, further elaboration and supporting references are needed, but may also be saved for the discussion and clinical implications of the study.

4. The last sentence of the second paragraph requires improvements in language and clarity, along with more precise reporting of the odds ratio, including a confidence interval.

5. In the third paragraph, the authors discuss a wide array of prison environmental factors that might contribute to self-harm, but the direction of these associations should be clarified. Furthermore, while the authors note the current uncertainty around the strength of these effects, it is important to recognize that the strength of associations varies significantly depending on the context and prison population. This aspect warrants some elaboration.

6. The introduction incorporates multiple references to specifically female samples, which is not inherently problematic. However, given that this study focuses on an all-male sample, it is important to clearly highlight when employing such references.

7. The aims appear to be structured as a primary and a secondary aim, suggesting a hierarchy of importance. If my understanding is correct, this distinction should be explicitly stated.

8. The introduction provides minimal context regarding the secondary aim. This aim might be considered for removal. Alternatively, it would be beneficial to elaborate on the design of a wider array of previous studies (including sample size, and statistical approaches), and the insights they have offered for the purpose of this aim.

9. Mentioning that the article was part of a wider project is redundant for the aims paragraph. However, as a reader, I would appreciate a summary description of the SHAPE project (if this is what the authors are referring to here) in the methods section, but I leave this entirely up to the authors to decide.

Methods

1. Please describe the attrition, for example, how many participants were excluded due to their English language skills or decision-making capacity, respectively.

2. Participants lost due to suicide during the follow-up period should be mentioned, even if there were no cases, if this was measured.

3. Category B prisons are contrasted with Categories C and D but should also be contrasted with Category A.

4. A strength of this study is that the sample corresponds to the general prison population on key factors. However, note observed differences between prisoners awaiting trial, those sentenced, and those detained under immigration law in the final sample.

5. It is unclear whether the sample comprises "all male prisoners who had recently arrived" or an all-male sample.

6. Briefly describe the simple random sampling approach used in this study.

7. If I understand Figure 1, the sentence describing eligibility criteria in the sample segment is need of correction. Should it state “aged 18 or older, male, and current prison spell had lasted less than one month”?

8. The average length of follow-up was 73.5 days. Please indicate the standard deviation or other measure of variability.

9. The instruments used such as DUDIT and CTQ, are insufficiently described and not referenced. Furthermore, it is not clear how information from these instruments were utilized in this study and if they were administered alongside the supplemented questionnaires.

10. In the methods section, it is mentioned that this was an exploratory pilot study, a description with which I agree. However, the language in the abstract, aims, and discussion needs revision to consistently reflect this.

11. The three participants who withdrew their consent were not accounted for in the comparison of non-identifiable demographic data, as they seem to be missing from the stated n=126, referencing the last paragraph in the sample segment. This figure should likely be adjusted to 129 and comparative test rerun accordingly.

12. Throughout the document, ensure that statistical notation is used correctly, such as changing ‘mean’ to italicized M, and consistently reporting odds ratios with or without the 95% numeral in accordance to applied reporting standards.

13. The independence of the researchers from the regular prison staff should be clarified in the methods section. If there was no independence, this raises questions for the limitations section, such as the potential impact on informed consent and the data collected. Additionally, the lack of researcher blindness to participants could have influenced the findings. The potential effects of this potential lack of blinding and independence on the study’s reliability and impartiality need to be addressed.

14. SHAPE is used as an abbreviation but not explained.

15. The decision to include vape use as an exposure for self-harm warrants further explanation. Since this variable has been singled out based on the authors’ unpublished results, it is crucial to offer a rationale for its inclusion. Additionally, clarifying why vape use is considered an environmental risk factor, rather than a risk factor related to individual behaviour, is needed.

16. It is unclear whether number of cellmates includes a cumulative number of cellmates the participants have during the follow-up or the number of people the prisoner is sharing their cell with at data collection.

17. I would like confirmation that risk factors were assessed at baseline and not during the three-month follow-up period, as assumed from the prospective design, but this is not entirely clear.

18. The structure of variables such as the number of cell changes, number of cellmates, time to first phone call, time on the phone, emergency bell response rate, prisoner-staff ratio, and prisoner-listener ratio could be reconsidered, for example through standardization or dichotomization.

19. The methods state that TS and IH conducted interviews while the roles of researchers state TS, IH, and CA, correct or clarify this please.

20. Studies in preparation are generally referred to and referenced in the reference list.

21. Describe the methods of the scoping review and briefly describe the preliminary results from the parallel qualitative study you apply in this study.

22. Ethnicity is used both as a categorical variable in describing attrition and as a dichotomized variable in regression analysis. Please choose one approach for consistency.

23. The exit interview timing is unclear, as it is stated to be conducted after the end of the follow-up period, which is hard to conceptualize as to me the exit interview would represent the end of follow-up. This process was said to occur approximately 4 weeks after completion, in parenthesis it mentions 7 days. Please clarify the exact timing of the exit interviews and what actually represents the end of follow-up for consistency and understanding.

24. The authors state that they have included their secondary outcome, NSSI ideation, with a view to improving the statistical power. I disagree with this. Instead, they have studied two quite different outcomes (i.e. NSSI and NSSI ideation). In regards to power, the power would be increased by, for example, adding more participants to the study, the statistical tests employed, or changing the significance level – not by analysing a distinct outcome.

25. A (recent) history of self-harm and/or suicide attempts is captured in the baseline questionnaire and may represent a confounder for several analyses in this study, as mentioned in the limitations in regards to single cell and prisoner-staff ratio. This information could be used in sensitivity analyses.

26. In the light of the aims it is not clear what the 66 participants that dropped out during follow-up adds to the study. This should be clarified or reframe the study as a study of a sample of 83/82 individuals.

27. It is stated that the authors did not analyse solitary confinement as a predictor. However, such results are presented in Table 5.

28. The high levels of missingness in time on phone-variable require methods to deal with this issue or exclude it from analysis.

29. The authors state that they conduct multivariable logistic regression models. However, it seems to me as if the unadjusted models are univariable. This requires clarification.

30. It is confusing that the authors state that they use a set p-value cut-off, yet they consider a positive tendency (CI 0.93 – 7.75, p=0.071) to be associated with the outcome.

Figures and tables

1. Table 2 generally displays that those lost to follow-up differ in few aspects, aspects already mentioned in the results section. Mentioning this in text would suffice. Thus, removing some information from the table. This will improve its readability without losing any relevant information.

2. Tables 3 and 4 should be combined into a single table, with clear indications of the units for each variable (e.g., minutes, days, and percent). The table should, as currently presented, denote missing data. However, the accompanying text can then draw attention to the key findings and significant aspects of the data presented in this consolidated table rather than levels of missingness.

3. For readability, S3 Supplementary table 1 is better summarized in text and not as a supplement.

Results, discussion, and conclusions

1. Key information in regards to the validity of the secondary aim is the correlation or concordance or NSSI and NSSI ideation and could be reported. Auxiliary, the comparison between the 14/82 registered versus the 13/78 self-reported events of NSSI suggests a need to assess their concordance or discordance as suggested by the authors in the methods section. This also have bearing on the third limitation.

2. The baseline questionnaire lacks questions about the incidence of self-harm/suicide attempts during the ongoing legal process, focusing instead solely on occurrences within prison at any given time. Including this information is essential for a prospective study, an issue that is briefly mentioned in the limitations section.

3. I am concerned about the methodology used by the authors in treating the staff-to-prisoner ratio variable, specifically the imputation of numbers based on prison conditions in a new ward. This may have influenced the negative association found for prisoners per staff member. Without direct access to the data, it is impossible to evaluate this issue. Therefore, I recommend the authors to carefully consider this factor and potentially reanalyse their data. This concern is heightened by the observation that a previously significant relationship turned insignificant after the exclusion of just one outlier, casting further doubt on the validity of the results regarding the staff-to-prisoner ratio.

4. Remove the term "unexpected" in relation to the negative association found between staff-prisoner ratio and NSSI, as the article present no hypotheses and is framed as explorative.

5. Given the low number of participants and the relatively few positive primary outcomes, it is advisable to handle outliers through methods other than simple removal. Techniques such as Winsorization could be considered to explore or manage extreme values and its effects on the robustness of the results.

6. My interpretation is that the results does not indicate a major issue of power regarding interpretations of time in activities, working status and social visit status. An issue of power would have been indicative by a tendency in a given direction but with a too wide confidence interval to draw conclusive results. However, conceptually the issue of power is of course relevant here, as in any small sample study, but not based on the presented findings.

7. In the limitations section, you mention that the study size was too small to detect small to moderate effect sizes. Yet, you have identified some small to moderate effect sizes in the current study. This needs clarification.

8. Length of stay up to baseline could have had influence on the risk factors that was not accounted for and is a limitation. Furthermore, it is a limitation that information regarding the length of follow-up was not incorporated in statistical analyses and could be mentioned.

9. Given the authors discussion of aggression and single cell placements, your discussion, for example, in regards to the second limitation, would benefit from considering the context of existing studies on aggression (separate from self-directed aggression) as a factor linked to self-harm.

Thank you for an interesting read and good luck on your future endeavours. With revisions, I am confident that the current study, along with your upcoming larger study, will make significant contributions to the field. This is particularly relevant in a global context where prison populations are expanding, often without adequate consideration of the implications for individual and public health.

Reviewer #2: Thank you for the opportunity to review this paper which examines the relationship between environmental factors and self-harm in prison. More prospective studies of this kind are needed. The manuscript is well written and clear, the methods and variables well explained, and limitations acknowledged.

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Reviewer #1: Yes:  André Tärnhäll

Reviewer #2: No

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PONE-D-24-04206R1Environmental risk factors for self-harm during imprisonment: a prospective cohort studyPLOS ONE

Dear Dr. Stephenson,

Thank you for submitting your manuscript to PLOS ONE. The manuscript reviewer recorded some minor concerns about regressive analyses, as well as a need to provide more context for these analyses. As such, the reviewer recommended further revisions be made.

In my judgment, these revisions are minor, and therefore I would be pleased to offer a minor revision decision. Still, since the timescale is shorter than can be accommodated for the swift turnaround required for publication, please let me know if you would prefer an extended deadline.

On a final note, I suggest that you ignore the advice on APA referencing style, since the journal follows the Vancouver referencing style.

Please submit your revised manuscript by Oct 12 2024 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.

Please include the following items when submitting your revised manuscript:

• 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 you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

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,

Nasrul Ismail

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

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

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: General comments

I would like to express my gratitude to the editor for the opportunity to review this revised article and to the authors for the significant improvements they have made. The authors have effectively addressed most of my previous comments and have provided well-reasoned explanations for the areas where they chose not to make revisions. However, I still hold one major concern (see R1.17) regarding the analytic approach and a few instances where my queries remain unsatisfactorily addressed. I have detailed these below (for reference, "R1.3" pertains to the third specific comment in my previous review, while "R2.1" refers to new specific comments in this review).

Generally, I would like to invite the authors to revise the study to better reflect the APA guidelines (or the chosen guideline to be followed consistently). For example and based on my understanding, “(17/218)” should be written as “17 out of 218” (or simply as a percentage). Additionally, the number of decimal places varies across the manuscript, and the numerical representation of thousands should be consistent (i.e., 1,000 or 1000). Tables should be capitalized in text and numbers that never exceed one should not be written with a zero (i.e., p = .03 is correct, while p = 0.03 is incorrect according to APA). I also noticed a missing “p=” in the first paragraph of the regression analyses. Furthermore, the text could benefit from minor edits to improve clarity and reduce ambiguity. The tables, in particular, require such editing. For example, the sentence regarding the exclusion of participants in the sample section needs revision, and there is a repetition of “due to [with subsequent information]” in the same section.

PLOSE ONE’s criteria for publication

1. This article contributes to the base of academic knowledge and presents results of original research by exploring prison environmental factors for self-harm and estimating their effects.

2. I have found no evidence of these findings being reported elsewhere, except in a preprint format, which adheres to PLOS ONE’s criteria for publication: https://www.medrxiv.org/content/10.1101/2024.01.31.24302059v1.

3. The statistical analyses were performed to a good technical standard but improvements are recommended, as elaborated on below.

4. Conclusions are presented in an appropriate fashion but with remaining concerns regarding the statistical approach and interpretations, revisions are recommended.

5. The article is presented in an intelligible fashion and is written in standard English.

6. The research appears to adhere to the ethical standards and it received approval from the relevant ethical board as well as the national prison and probation services.

7. The article generally follows appropriate reporting standards but requires some improvements. The data have not been made available to others, a decision that is sound given the design and participants of the study. Data requests are directed to relevant services.

Introduction

Comment from the original submission

R1.3.

If available, use an academic or other reference for this intervention.

New comment

R2.1

The fourth sentence in the second paragraph of the introduction, starting with “[t]he authors…”, seems to use reference (4) but this is not clear.

Methods

Comment from the original submission

R1.17

To my understanding, the study collected data on certain risk factors at baseline, but with most risk factor information gathered during the prospective follow-up period. Further, the data for the outcome of self-harming behaviour was also collected during this follow-up period. Logistic regression analyses were conducted, without considering follow-up time or time-to-event in the statistical analyses.

In a prospective cohort study, it is possible to analyse risk factors collected during the same follow-up period as the outcome. However, this approach has notable limitations, such as the risk of reverse causality, as the authors are aware. Understanding cause and effect – or as in here, when estimating effect sizes – requires proper time orientation, i.e., an exposure (risk factor) must occur before the outcome. This also requires having a sufficient level of detail in the data regarding when exposure and outcome occur so that the temporal order can be accurately distinguished (or explored/estimated). Furthermore, it requires an adequate model of analysis. The authors briefly discuss reverse causality as a limitation, but I find this to be insufficient. I recommend that the authors improve their analytic approach pertaining to the regression analyses approach. This could involve using alternative methods or multiple methods that consider the varying characteristics of risk factors, and reanalyse their data. Favourably, with time-to-event and, if appropriate, subsequent censoring taken into account. If my understanding is correct, approximate time-sensitive data is available to the authors through prison medical records. This would significantly improve the article. If the authors decide to revise their analytic approach, I further recommend that the authors reconsider the number of risk factors included in the analysis of the outcome. Given the low number of participants and events, the current number of risk factors may be too extensive, even for an exploratory pilot study.

These revisions are important partly due to the authors’ allusive recommendations on prison services based on interpretations of the data that are currently weakly supported by the data due to mentioned limitations. Furthermore, the authors state and acknowledge that a self-harm event increases the probability of encountering certain risk factors after the event, making the timing of data collection even more crucial when employing risk factors in statistical analyses collected before and after potential events.

New comment

R2.1

In the first paragraph of the sample section, the authors state that previous longitudinal research at the same study site has documented a higher than average prevalence of self-harm, suggesting it is a suitable study location. However, this suitability depends on the context. While it may offer valuable insights, it could also potentially lower the generalizability of the findings, depending on the study’s aims. This increased prevalence might be influenced by systematic biases, such as the characteristics of the sample or the prison environment. Please consider this and revise accordingly.

Additionally, as a reader, I am interested in the previous research mentioned. If the authors deem it appropriate, I would recommend including a reference to this prior research.

Figures and tables

New comment

R2.1

The tables, especially Table 2 and 3 needs improvement, focusing on removing redundant information, minimizing double reporting in text and tables, as well as general readability.

Results, discussion and conclusions

Comments from the original submission

R1.1

The information of discordance is important. However, the paragraph with this information could do with streamlining.

R1.3

Thank you for a good response. However, here I believe that the authors have misunderstood parts of my comment, in part based on my comment’s ambiguity. My stated concern was primarily regarding the methodology used regarding the prison wing that was closed at the start of the study (i.e.: One prison wing was closed at the start of the study but gradually reopened during the second half of the study and reached approximately 50% capacity at end of the follow-up period. The total occupancy for this particular wing was imputed as 25% of capacity throughout the period of reopening based on consultation with prison officials). Please reconsider this comment and my apologies if I am misunderstanding the given response.

New comments

R2.1

As the aim was to “…estimate the effect sizes…”, the discussion lacks discussion regarding the effect sizes in the current study. Please revise the discussion to include this, or alternatively, adjust the aim if this better align with the study’s underlying purpose.

R2.2

The discussion appropriately highlights the novelty of several results, which is commendable. However, it appears to lack adequate contextualization of these findings within the specific setting of the study, such as the remand context, the prison environment with a higher-than-average prevalence of self-harm, the male sample, and the location in England. Providing a more detailed contextualization of the results could enhance their relevance and usefulness, after considering comment R1.17.

R2.3

In the clinical implications section, it is (kind of) mentioned that the authors suggest a reduced use of single-cell placements. This either needs to be explicitly stated as a recommendation from the authors or revised. My interpretation of the results, in combination with the discussion above this section, is that the results are preliminary and in need of replication before making such recommendations, partly as the findings may vary across different subgroups and contexts. Therefore, such a recommendation may currently be most valuable to the specific prison in question and for guiding future studies at this time. Furthermore, this revision should also reflect the R1.17-comment. Nevertheless, I leave the final interpretation and wording up to the authors.

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Environmental risk factors for self-harm during imprisonment: a pilot prospective cohort study

PONE-D-24-04206R2

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