Review Reports - Mental Health in Primary School Children Before and During the COVID-19 Pandemic

Round 1

Reviewer 1 Report

Dear author.

The manuscrit has both strengths and weaknesses.

Strenghts

The manuscript is well written and clearly structured, offering an appropriate and relevant analysis of children's mental health during the COVID-19 pandemic. The study uses a robust methodology and carefully validates the SDQ questionnaire, with well-interpreted and contextualised results, making a valuable contribution to the field.

Weaknesses

British and American English are mixed in the test, for instance, behaviour in British English and analyze in the American English.

References. The Discussion section has mistakes such as " Usall (2021) [30] suggest". Also, it is advisable to review the guidelines for the references section.

Warm regards.

Dear author.

Please refer to my comments in the attached document.

Warm regards.

Comments for author File: Comments.pdf

Author Response

We are confident that the reviewers’ suggestions and recommendations have substantially improved our study. Below, we provide detailed responses to each of the comments made by the reviewers.

REVIEWER 1

Does the introductionprovide a comprehensive yet concise overview about the state of knowledge in the area of research?

The introduction provide a comprehensive yet concise overview, clearly, addressing the context, previous research, and knowledge gaps in a clear manner. However, it could benefit from shorter sentences and a slightly more concise summary of previous studies. It would be preferable for the citations in the introduction to be arranged from oldest to most recent, in order to provide a historical perspective on the knowledge while also making it easier for the reader to see how the background has led to the current state of the subject and highlighting the novelty of the study by placing it at the end.

Several sentences have been rewritten in lengthy paragraphs that could hinder readability. Nevertheless, regarding the chronology of the studies, it is important to note that the central topic of our research concerns a public health issue that developed primarily between 2020 and 2022, is the period in which most of the references are focused. Studies from earlier years are included to contextualize the characteristics of the child population that may explain the impact the COVID-19 pandemic had on minors.

Is the research design appropriate and are the methodsadequately described?

Although the manuscript presents a sound methodology, it is recommended to include more explicit details, such as the type of research (in this case, quantitative). Currently, this can be inferred from the description of the methods and data analysis, but stating it explicitly would enhance the clarity and rigour of the Materials and Methods section.

The quantitative nature of the study has been specified in the Design section, thereby completing the description of the methodological approach employed.

COMMENTS

The manuscrit has both strengths and weaknesses.

Strenghts

Weaknesses

British and American English are mixed in the test, for instance, behaviour in British English and analyze in the American English.

References. The Discussion section has mistakes such as " Usall (2021) [30] suggest". Also, it is advisable to review the guidelines for the references section.

Some citation errors in the Discussion section have been corrected.

In addition to what has been discussed above, it is also advisable to review the guidelines for improve the citation style in the References section.

Done

Reviewer 2 Report

Dear Authors,

Thank you for the opportunity to read your manuscript, “Mental Health in Primary School Children Before and During the COVID-19 Pandemic.” The topic is very relevant, and I appreciate the large sample size and the use of a validated instrument (SDQ). However, the manuscript requires substantial revision to improve clarity, transparency, and the strength of the conclusions. Below I outline my main observations, with specific line references where issues need to be addressed.

Major Comments

Abstract clarity (Lines 12–24): Sentences are overly long and results are vague. Please break down the findings clearly, specifying which domains worsened and which improved. Add effect sizes or odds ratios if possible.
Introduction (Lines 47–52): The placeholder “(………..)” must be removed and replaced with appropriate data or a reference. This gap undermines credibility.
Methods – Study design (Lines 110–119): Please clarify whether the “before pandemic” and “during pandemic” groups are independent samples (they are not the same students). This limitation should also be acknowledged later in Discussion (Lines 280–289).
Participants (Lines 123–131): More detail on the socio-economic background of the sample is needed. Mental health is strongly influenced by context, and without this, generalizability is limited.
Instruments (Lines 132–144): You mention AVE, ω, and α values, but Table 1 is incomplete. Please provide the full reliability and validity indices for all SDQ subscales.
Procedure (Lines 153–162): The approval date (2024) seems inconsistent with data collection in 2018 and 2021. Please clarify chronology.
Results – Tables (Lines 179–183): Table 2 appears duplicated, with repeated data. This should be cleaned to avoid confusion.
Results – Odds ratios (Lines 213–229): The presentation of Table 3 is confusing. Some rows repeat values, and alignment of percentages is inconsistent. Please revise table formatting and ensure consistency.
Discussion (Lines 230–246): The discussion restates results but lacks more in-depth analysis of why hyperactivity and conduct problems decreased during the pandemic. Please expand with possible contextual explanations.
Limitations (Lines 280–289): Expand limitations to include (a) self-report bias, (b) non-longitudinal comparison (different students), and (c) limited generalizability outside Spain.
Figures/Tables clarity: Figures are missing, and tables are difficult to interpret. Add graphs (e.g., bar plots of scores before/during) to visually support findings.

Minor Comments
1. Line 25–26 (Keywords): Please alphabetize keywords and remove redundancy (“students” and “primary education” could be merged into “primary school students”).
2. Line 53–55: The sentence on long-term consequences is speculative. Please rephrase more cautiously.
3. Line 87–98: The UNICEF citation [22] and others are mixed with NGO data; please ensure proper referencing style and update access dates.
4. Line 186–190: Report effect sizes consistently (e.g., η² values). Some is missing.
5. Line 231–239: Avoid repetition of what was already presented in results. Focus instead on interpretation and implications.

This manuscript addresses a timely and relevant issue: the impact of the COVID-19 pandemic on the mental health of primary school children. The large sample size and the use of the SDQ are strengths. However, I have serious concerns regarding the clarity of the methodology, the presentation of the results, and the quality of the tables. It requires a major revision with clearer methodological reporting, corrected tables, and a more critical discussion.

Best regards

Comments for author File: Comments.pdf

Author Response

We are confident that the reviewers’ suggestions and recommendations have substantially improved our study. Below, we provide detailed responses to each of the comments made by the reviewers.

REVIEWER 2

Is the research design appropriate and are the methodsadequately described?

Although the study is described as an ex post facto, cross-sectional design, the description is not sufficiently clear. In lines 110–119 the text refers to comparisons “before” and “during” the pandemic, but it is not explicitly stated that these were two independent cohorts, not the same students followed over time. This distinction is essential, as it fundamentally affects how the results can be interpreted. In addition, the section on participants (lines 123–131) lacks contextual socio-economic information, which is a key determinant of children’s mental health. In the section on instruments (lines 132–144), some subscales show low reliability values, but this is not acknowledged as a limitation. Finally, the ethics approval is dated 2024, while data were collected in 2018 and 2021, which appears inconsistent and needs clarification. Altogether, these issues weaken the methodological section.

The participation of two independent cohorts has been clarified in the Design section, and information on the students’ socioeconomic context has been included. Likewise, the low reliability of two SDQ subscales has been added among the study’s limitations. We also thank the reviewer for noting the inconsistency between the date of approval from the ethics committee and the study’s implementation. This discrepancy was indeed an oversight by the authors, as the study was extended over time and led to a second project proposal with new objectives, for which a new ethical approval was obtained—the latter being mistakenly attached to this study. The correct approval date for the first phase of the study has now been amended in the Procedure section, and we sincerely apologize for the confusion.

Are the resultspresented clearly and in sufficient detail, are the conclusionssupported by the results and are they put into context within the existing literature?

The results section needs more structure and clarity. For instance, Table 2 is almost duplicated (lines 179–183), which creates confusion, and Table 3 is poorly formatted, with repeated rows and percentages that are difficult to follow. Not all univariate contrasts report effect sizes (η²), which makes it difficult to assess the actual magnitude of the differences. In the discussion (lines 230–246), the findings are largely repeated but not critically explored. The fact that hyperactivity and conduct problems decreased during the pandemic is striking, but this is only briefly mentioned, without deeper interpretation. More engagement with existing literature would help contextualize these results. The limitations section (lines 280–289) is too brief and does not address key issues such as self-report bias, the use of different cohorts, and the constraints of a cross-sectional design. As a result, the conclusions are not fully supported by the presented evidence.

Regarding Table 2, it has been carefully reviewed, and no duplication was found. To clarify its interpretation, we have specified the number of participants who took part in the study before and after the COVID-19 pandemic, as well as the total number of participants in the last column. The table presents a descriptive analysis of the participants’ mental health symptoms before and during the pandemic.

With respect to Table 3, separating lines have been added in accordance with APA formatting guidelines to improve readability, as the previous version was slightly misaligned and hindered interpretation.

Following Table 2, the univariate contrasts are now presented in the text, and effect sizes are reported for each of them. The remaining reviewer comments have been addressed in the Discussion section, and the Limitations section has also been expanded accordingly.

Are all figuresand tablesclear and well-presented?

As they stand, the tables do not sufficiently help the reader. Table 1 reports reliability values, but two subscales fall below acceptable thresholds, and this is not discussed. Table 2 is redundant due to duplication. Table 3 has serious formatting problems, with repeated numbers and misaligned percentages, which makes it very difficult to interpret. Moreover, there are no figures (e.g., bar charts or plots) to visually illustrate the differences between pre- and during-pandemic samples. Given the topic, such graphical representation would add clarity and strengthen the article.

We have included in the Limitations section the lower reliability values observed in some of the mental health subscales, although it should be noted that these values remain within acceptable ranges. The rest of the reviewer’s observations have been addressed in the previous point. Regarding the inclusion of figures, we have not considered it necessary to add them, since the results are already clearly presented through the tables and their accompanying explanations in the text. We believe that including graphs would be redundant in this case.

COMMENTS

Dear Authors,

Thank you for the opportunity to read your manuscript, “Mental Health in Primary School Children Before and During the COVID-19 Pandemic.” The topic is very relevant, and I appreciate the large sample size and the use of a validated instrument (SDQ). However, the manuscript requires substantial revision to improve clarity, transparency, and the strength of the conclusions. Below I outline my main observations, with specific line references where issues need to be addressed.

Major Comments

Abstract clarity (Lines 12–24):Sentences are overly long and results are vague. Please break down the findings clearly, specifying which domains worsened and which improved. Add effect sizes or odds ratios if possible.

Sentences have been shortened. Findings have been broken down by worsening and improving areas.

Introduction (Lines 47–52):The placeholder “(………..)” must be removed and replaced with appropriate data or a reference. This gap undermines credibility.

A reference has been included.

Methods – Study design (Lines 110–119):Please clarify whether the “before pandemic” and “during pandemic” groups are independent samples (they are not the same students). This limitation should also be acknowledged later in Discussion (Lines 280–289).

They are two independent samples, and it is now clarified. It was already reflected in the Limitations section (line 297).

Participants (Lines 123–131):More detail on the socio-economic background of the sample is needed. Mental health is strongly influenced by context, and without this, generalizability is limited.

The sample’s socio-economic background has been detailed.

Instruments (Lines 132–144):You mention AVE, ω, and α values, but Table 1 is incomplete. Please provide the full reliability and validity indices for all SDQ subscales.

The reliability indices are presented in the table, and a note regarding lower reliability in some subscales is included in the Limitations section. Regarding validity, the SDQ is a widely used instrument across numerous studies, and its validity has been consistently demonstrated. Therefore, we did not consider it necessary to conduct a confirmatory analysis in our study.

Procedure (Lines 153–162):The approval date (2024) seems inconsistent with data collection in 2018 and 2021. Please clarify chronology.

Chronology has been clarified and discussed.

Results – Tables (Lines 179–183):Table 2 appears duplicated, with repeated data. This should be cleaned to avoid confusion.

Ns for boys, girls, and totals are specified in Table 2.

Results – Odds ratios (Lines 213–229):The presentation of Table 3 is confusing. Some rows repeat values, and alignment of percentages is inconsistent. Please revise table formatting and ensure consistency.

The type of statistical test has been clarified, specifying that it corresponds to a Chi-square test.

Discussion (Lines 230–246):The discussion restates results but lacks more in-depth analysis of why hyperactivity and conduct problems decreased during the pandemic. Please expand with possible contextual explanations.

Further on in the Discussion section—from lines 258 to 267— we provide an argument supported by other studies explaining why hyperactivity and conduct problems decreased during the pandemic. Subsequently, additional contextual explanations are included, based on findings from other studies similar to ours.

Limitations (Lines 280–289):Expand limitations to include (a) self-report bias, (b) non-longitudinal comparison (different students), and (c) limited generalizability outside Spain.

Limitations has been expanded.

Figures/Tables clarity:Figures are missing, and tables are difficult to interpret. Add graphs (e.g., bar plots of scores before/during) to visually support findings.

By clarifying the tables we consider that it is not necessary to include any graphs.

Minor Comments

Line 25–26 (Keywords):Please alphabetize keywords and remove redundancy (“students” and “primary education” could be merged into “primary school students”). Modified and ordered after the reviewer’s suggestions.
Line 53–55:The sentence on long-term consequences is speculative. Please rephrase more cautiously.

Rephrased.

Line 87–98:The UNICEF citation [22] and others are mixed with NGO data; please ensure proper referencing style and update access dates.

Reviewed and modified.

Line 186–190:Report effect sizes consistently (e.g., η² values). Some is missing.

In Table 2, the descriptive statistics of the study variables are presented to facilitate the interpretation of the results obtained from the MANOVA test. These results are described in the text, including the corresponding effect sizes.

Table 3, prepared in accordance with APA guidelines, presents the results of the Chi-square test, used to examine the association between two dichotomous variables, as well as the Odds Ratio values, which themselves serve as a measure of effect size in a contingency table.

Line 231–239:Avoid repetition of what was already presented in results. Focus instead on interpretation and implications.

A thorough revision has been carried out, providing methodological clarifications, corrected tables, and a more critical analysis.

Author Response File: Author Response.pdf

Reviewer 3 Report

Thank you for the opportunity to review your manuscript. The authors provide a brief and concise introduction about the COVID-19 pandemic and impact on the mental health of children and adolescents with connections to relevant literature. The aim of the study is clearly stated. The tables are clear and align with the results described. The topic is still timely and one that has the potential to provide information to inform how schools, educational policy, and communities prepare for supporting the mental health of children and adolescents during a future pandemic or large-scale event. Some areas of growth would be expanding upon the participants and procedures sections, as well as adding specific recommendations for future research. Please see more detailed comments and suggestions below.

Recommendations for authors:

Consider capitalizing the acronym COVID instead of “Covid” to be consistent throughout your manuscript. The World Health Organization and the Centers for Disease Control both use COVID.
1. For example, you use “Covid” in your abstract.
Page 2, line 45
1. Consider rephrasing “under 16s” for clarity.
Page 2, line 50
1. Appears you forgot to include the end reference/s for this sentence.
Page 2, lines 51-52
1. You mention several studies in your sentence but only cite one reference.
Page 2, line 53 and page 2, line 66
1. Review journal formatting guides to see if the year should be removed from this sentence and others throughout your manuscript.
Page 2, lines 66-71
1. Consider separating this sentence into multiple sentences.
Participants
1. Do you have any additional information about participants, such as race/ethnicity, sociodemographic standing, parent educational level, etc.?
2. If not, this should be added to your limitations section.
Page 3, line 133
1. Be mindful of spacing.
Page 3, lines 139-140
1. Have end parentheses but no beginning.
Procedures
1. Please provide more explicit detail about this process. How did parents provide consent for their child to participate? Did you send home a paper consent form or email a digital form?
2. Was the procedure different during COVID? Did participants that participated during COVID complete the procedure digitally at home? If not, I would add in when the “during” participants completed the survey and add that they were able to return to in-person schooling at this time.
3. Did you assent the participants since they were of age to understand the research they were being asked to participate in?
4. Was the questionnaire paper or digital?
Page 6, line 216 – Table 3
1. I would add a space for the heading of your third column
  1. “%Experiencing” = “% Experiencing”
2. Discussion
  1. Does the study by Bar-On (2006) refer to adults or adolescents and children when making their claims? I would make sure to clarify this statement to better contextualize it with your target age range.
  2. Page 6, lines 243-245
    1. I would also consider rephrasing this statement to better align with the target age range you are focused on for your research.
  3. Page 7, lines 252-254
    1. Please add citations to back up this claim.
  4. Page 6, line 243
    1. Be mindful of spacing
  5. Study Limitations and Future Directions
    1. You note limitations in this section, but do not expand upon future directions. I would recommend adding an additional paragraph to this section to outline specific recommendations based on this research.
  6. Page 8, line 296
    1. Be mindful of spacing
  7. Conclusion
    1. Consider adding an additional sentence or two to explicitly state how this research contributes to the field and why it matters. You begin to do this in your last sentence, but a stronger conclusion would strengthen this article and how it is situated within existing literature.

Author Response

We are confident that the reviewers’ suggestions and recommendations have substantially improved our study. Below, we provide detailed responses to each of the comments made by the reviewers.

REVIEWER 3

Is the research design appropriate and are the methodsadequately described?

Participants a. Do you have any additional information about participants, such as race/ethnicity, sociodemographic standing, parent educational level, etc.? b. If not, this should be added to your limitations section. 10. Procedures a. Please provide more explicit detail about this process. How did parents provide consent for their child to participate? Did you send home a paper consent form or email a digital form? b. Was the procedure different during COVID? Did participants that participated during COVID complete the procedure digitally at home? If not, I would add in when the “during” participants completed the survey and add that they were able to return to in-person schooling at this time. c. Did you assent the participants since they were of age to understand the research they were being asked to participate in? d. Was the questionnaire paper or digital?

It has been clarified that all participants belong to the middle socioeconomic class, and some considerations for future studies—such as parental education level or race—are addressed in the limitations, explaining why these factors were not analyzed in this study.

Additionally, we believe the reviewer may be conflating the pandemic with confinement. All students completed the questionnaires in person, in the classroom. Specifically, the second cohort, as clarified in the corresponding section, participated once in-person classes resumed, following the same procedure as the first cohort.

Once the school administration was informed of the study’s objectives, parents were provided with printed consent forms to authorize their children’s participation, as all participants were minors. Students were also informed about the voluntary nature of their participation, as well as the confidentiality and anonymity of their responses. This information is detailed in the Participants and Procedure sections.

Are the resultspresented clearly and in sufficient detail, are the conclusionssupported by the results and are they put into context within the existing literature?

Discussion a. Does the study by Bar-On (2006) refer to adults or adolescents and children when making their claims? I would make sure to clarify this statement to better contextualize it with your target age range. b. Page 6, lines 243-245 i. I would also consider rephrasing this statement to better align with the target age range you are focused on for your research. c. Page 7, lines 252-254 i. Please add citations to back up this claim. 13. Page 6, line 243 a. Be mindful of spacing 14. Study Limitations and Future Directions a. You note limitations in this section, but do not expand upon future directions. I would recommend adding an additional paragraph to this section to outline specific recommendations based on this research.

Amended. Suggestions have been incorporated throughout the article.

COMMENTS

Recommendations for authors:

Consider capitalizing the acronym COVID instead of “Covid” to be consistent throughout your manuscript. The World Health Organization and the Centers for Disease Control both use COVID. For example, you use “Covid” in your abstract

Unified as COVID for consistency.

Page 2, line 45

Consider rephrasing “under 16s” for clarity.

Removed and replaced by “minors”.

Page 2, line 50

Appears you forgot to include the end reference/s for this sentence.

A reference has been included.

Page 2, lines 51-52

You mention several studies in your sentence but only cite one reference.

The sentence and the reference have been included (it was translation error).

Page 2, line 53 and page 2, line 66

Review journal formatting guides to see if the year should be removed from this sentence and others throughout your manuscript.

Year has been removed according to the journal formatting guides.

Page 2, lines 66-71

Consider separating this sentence into multiple sentences.

It has been divided into two sentences.

Participants

Do you have any additional information about participants, such as race/ethnicity, sociodemographic standing, parent educational level, etc.?

Those data were not requested as they were not within the scope of the study.

If not, this should be added to your limitations section.

Added to the Limitations section.

Page 3, line 133

Be mindful of spacing.

Done

Page 3, lines 139-140

Have end parentheses but no beginning.

Colon has been removed and parentheses have been added at the beginning.

Procedures

Please provide more explicit detail about this process. How did parents provide consent for their child to participate? Did you send home a paper consent form or email a digital form?

Procedure has been explained. The informed consent from parents has been presented.

Was the procedure different during COVID?

It was not different.

Did participants that participated during COVID complete the procedure digitally at home? If not, I would add in when the “during” participants completed the survey and add that they were able to return to in-person schooling at this time.

It has been clarified that the second administration of the questionnaire took place in September 2020, after the students returned to the classrooms.

Did you assent the participants since they were of age to understand the research they were being asked to participate in?

The informed consent was provided to the parents through the classroom teacher.

Was the questionnaire paper or digital?

Paper, since it was filled in in the classroom, as indicated in the study.

Page 6, line 216 – Table 3

I would add a space for the heading of your third columna “%Experiencing” = “% Experiencing”

Space added.

Discussion

Does the study by Bar-On (2006) refer to adults or adolescents and children when making their claims? I would make sure to clarify this statement to better contextualize it with your target age range.

It has been replaced by boys and girls since Bar-On refers to different ages, boys/girls and adults before social challenges.

Page 6, lines 243-245

I would also consider rephrasing this statement to better align with the target age range you are focused on for your research.

It has been replaced by boys and girls since we want to highlight the difference by gender in the age range of minors.

Page 7, lines 252-254

Please add citations to back up this claim.

This claim refers to Bar-On’s citation.

Page 6, line 243

Be mindful of spacing,

Space has been added.

Study Limitations and Future Directions

You note limitations in this section, but do not expand upon future directions. I would recommend adding an additional paragraph to this section to outline specific recommendations based on this research.

Future Directions have been added.

Page 8, line 296

Be mindful of spacing

Done

Conclusion

Consider adding an additional sentence or two to explicitly state how this research contributes to the field and why it matters. You begin to do this in your last sentence, but a stronger conclusion would strengthen this article and how it is situated within existing literature.

Sentences have been added to explicitly explain how this research contributes to the field.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear authors.

The manuscript is clearly structured, offering an appropriate and relevant analysis of children's mental health during the COVID-19 pandemic. The study uses a robust methodology with well-interpreted and contextualised results, making a valuable contribution to the field.

The topic of this research is relevant to this field because it focuses on primary school pupils, a group that has been less studied than others. As this study deals with the mental health of children during and after the COVID-19 pandemic, it was a priority issue globally due to the psychological impact of lockdown and the challenge that school closures posed for education.

However, it is recommended that the organisation of the references cited in the introduction be reviewed, as they are not presented in strict chronological order (from oldest to most recent). Although it is evident that the references are grouped thematically, which can be a valid approach, a more systematic structure, such as following a chronological order within each thematic block, could improve coherence and make it easier to follow the development of scientific knowledge regarding the impact of the pandemic. You explain in your response that there are a lot of references in the years between 2020 and 2022 but the references [8] and [13] are of 2018 and 2002 , they are in the middle of the introduction and in my view do not begin a new topic.

Although you stated the following objectives "This cross-sectional study aims to analyse the mental health of students in the final years of primary education, both before the pandemic and during periods when some restrictive measures were still in place, but normal life and school routines were gradually resuming. It also seeks to examine how a stressful event of this kind and associated restrictions on social activity can lead to a rise in emotional, social and behavioural problems among school children." Adding an explicit research question would help to better focus the study, guide the methodology, and enable readers to clearly understand the main objective of the research.

Your manuscript compared with other published studies, which often rely solely on surveys conducted during the pandemic, this study provides a pre-pandemic baseline, improving understanding of the true effect of the pandemic on children's mental health and serving as a basis for potential interventions in future crises.

The methodology is sound and well written.

The Discussion section is solid in its interpretation of results and connection with previous studies, but it contains some citation errors such as " Usall (2021) [30] suggest". Also, it is advisable to review the guidelines.

The conclusions are good and consistent with the evidence and arguments presented.
This study aimed to analyse changes in mental health before and during the pandemic and differences by gender. The conclusions cover both aspects: they compare the periods and point out gender differences, thus fulfilling the objectives.

The tables are clear and easy to understand. There are no figures, although this is not strictly necessary, it would improve the clarity and understanding of the results.

The references are appropriate because they come from reliable scientific sources, including peer-reviewed journals, reports from official organisations, and significant literature on child and adolescent mental health during the pandemic. However, criteria must be standardised, as there are various formats in the DOI ( some https: doi.org and others https:doi alone, the correct way is with org) ; It is also advisable to review the guidelines for improve the citation style in the References section.

Warm regards.

Dear authors.

The manuscript is well written, but there are some errors, such as inmediate, which is not a real word; the correct spelling is immediate. Also, Psychiatry2004 needs a space between the words. These are just a few examples. It is recommended to carefully reread the entire manuscript.

Warm regards

Author Response

It is recommended that the organisation of the references cited in the introduction be reviewed, as they are not in chronological order (from lowest to highest year of publication). Although it is clear that they are grouped thematically which may be a valid strategy)a more systematic presentation, for instance, following a chronological order within each thematic block, could improve coherence and facilitate understanding of the development of scientific knowledge regarding the impact of the pandemic. There are two references of 2002 and 2018 in the middle of the text.

Major comments

Dear authors.

The methodology is sound and well written.

The tables are clear and easy to understand. There are no figures, although this is not strictly necessary, it would improve the clarity and understanding of the results.

Detailed comments

Dear authors.

The manuscript is well written, but there are some errors, such as inmediate, which is not a real word; the correct spelling is immediate. Also, Psychiatry2004 needs a space between the words. These are just a few examples. It is recommended to carefully reread the entire manuscript.

RESPONSE

We thank the reviewer for his comments, which help us improve our study.

The references cited in the introduction have been reorganized, also beginning with an introductory paragraph on mental health in childhood and adolescence. Two old references from 2002 and 2013 have been removed from the introduction and some errors in some bibliographic citations of the discussion, and some grammatical errors noted by the reviewer have also been corrected. Regarding the doi, it's true that in some cases it appears alone, while in other cases it is accompanied by org. However, this doi was taken from the same journal that publishes the article, and we have found that when adding the org, the link sometimes fails and doesn't lead to the article itself. Therefore, for greater security, we prefer to leave it as is.

On the other hand, in relation to the research question, and in accordance with the suggestions of another of the reviewers, we have chosen to specify the variables under study within an additional explanation of the statistical tests used.

Reviewer 2 Report

The revised manuscript shows substantial improvement in methodological clarity, structure, and interpretative depth. The authors have adequately addressed nearly all previous reviewer comments, including clarifications regarding the independent cohorts, ethical approval, reliability of the SDQ subscales, and contextual details about participants.

The results are now clearly presented, with consistent reporting of effect sizes and corrected table formatting. The discussion section has been expanded and includes relevant contextual interpretation. The limitations section now properly acknowledges self-report bias, non-longitudinal design, and generalizability issues.

A few minor aspects remain:

The Methods section could briefly specify the exact statistical tests used and how missing data were handled.

A slightly deeper reflection on implications for educational or public health policy would strengthen the conclusion.

These are minor adjustments that do not affect the overall validity of the study.

Author Response

Major comments

The results are now clearly presented, with consistent reporting of effect sizes and corrected table formatting. The discussion section has been expanded and includes relevant contextual interpretation. The limitations section now properly acknowledges self-report bias, non-longitudinal design, and generalizability issues.

A few minor aspects remain:

Detailed comments

The Methods section could briefly specify the exact statistical tests used and how missing data were handled.

A slightly deeper reflection on implications for educational or public health policy would strengthen the conclusion.

These are minor adjustments that do not affect the overall validity of the study.

RESPONSE

We thank the reviewer for his comments, which help us improve our study.

A more detailed explanation of the statistical tests has been provided in the data analysis section.

Likewise, the conclusion has been enriched with the reviewer's suggestions.

Reviewer 3 Report

Thank you for the opportuntiy to review your revised manuscript. Thank you for your description of how you addressed reviewer comments. Your revisions have provided greater clarity about the methodology, as well as your discussion and inclusion. This manuscript will provide valuable information about mental health implications and for school children before and during COVID, as well as implicaitons for stratategies that can be designed within educational spaces to support mental health for children.

Page 3, line 111 - Review spelling in added sentence in red.

Author Response

Major comments

Detailed comments

Page 3, line 111 - Review spelling in added sentence in red.

RESPONSE

We thank the reviewer for his comments, which help us improve our study.

The spelling in the sentence has been checked