PONE-D-24-42587Revisiting the Cognitive and Behavioral Aspects of Loneliness: Insights from Different Measurement ApproachesPLOS ONE

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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

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: Partly

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

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: 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: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: Yes

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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: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: 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: I would like to compliment the authors on a really well written and clear paper. It doesn't promise anything it can't deliver, and I recognize that the authors explicitly point out its exploratory nature. I would encourage the authors to also upload their analysis scripts to OSF and not just the raw data - I would have liked to have had a look at the code. I think the paper will be a great contribution to the literature, and I have only relatively minor suggestions before I can recommend acceptance of the paper.

Abstract

1. This is just my personal opinion, but “ancova” as a keyword seems strange to me. It's not a specific modeling approach that people might be looking for, nor is it a content-related keyword.

Introduction

2. In the research I was involved in, we looked at the fact that loneliness should be differentiated at the state and trait level. This aspect could fit well in the introduction (only if the authors consider it relevant).

Gründahl, M., Weiß, M., Maier, L., Hewig, J., Deckert, J., & Hein, G. (2022). Construction and validation of a scale to measure loneliness and isolation during social distancing and its effect on mental health. Frontiers Psychiatry, 13, 798596.

3. Overall, I really liked the introduction very much. If the authors could think about how to tighten it up a bit, I think a lot of people might enjoy reading it. The rationale for the approach is well explained. It's a bit sad that the authors did not pre-register their study.

Methods

4. Please provide further information on the survey: How many participants dropped out of the study? Was there a data-related quality/exclusion criterion (e.g., straightlining)? Were the questionnaires presented in random order or always in the same order (which order?)?

Results

5. As the authors state in their introduction, loneliness can also maintain or further reinforce maladaptive cognitive and behavioral patterns. Since this study is cross-sectional, the direction is not clear. I wondered if adding three logistic regressions (one for each division method) using all the outcomes from the ancovas as predictors could also account for this aspect? This is by no means mandatory, it was just an idea that could also be argued against.

Limitations

6. I don't want to start an unrelated Covid debate here. But the question about the last 24 months in 2021/2022 could have led to a distorted self-assessment of chronic loneliness, as many people may have thought about lockdowns etc. This could also (partly) explain the relatively high prevalence of chronic loneliness.

Reviewer #2: I would like to express my sincere gratitude for the opportunity to review your manuscript titled "Revisiting the Cognitive and Behavioral Aspects of Loneliness: Insights from Different Measurement Approaches." I deeply appreciate the meticulous and rigorous work you have conducted, and the significant contribution it makes to understanding the cognitive and behavioral models related to loneliness.

Your study highlights the complexity of loneliness and explores its various dimensions, providing a more nuanced and detailed view of this phenomenon, thanks to the use of distinct measures that account for frequency, duration, and distress. The results, which show significant differences in all the cognitive and behavioral components analyzed, form a solid basis for targeted interventions that can more precisely address different forms of loneliness.

After careful review, I would like to offer the following suggestions to further improve the manuscript:

Lines 30-32: The statement on the division of the sample into "lonely and not lonely" individuals could be clarified. I suggest adding a more detailed description of the methodology used to distinguish between the different groups, specifying the criteria for each measure more clearly.

Lines 49-51: The control of depressive and social anxiety symptoms is mentioned. It would be helpful to expand this section by providing more details on the methods and tools used to control for these factors.

Lines 121-125: The definition of "chronic loneliness" could benefit from further elaboration, explaining the choice of the 24-month period as a threshold for chronicity, perhaps integrating additional studies that support this choice.

Lines 206-210: The results regarding the agreement between the three loneliness measures (frequency, distress, chronicity) could be supported by explanatory graphs that visually illustrate the percentage of agreement and disagreement between the different measures.

Lines 255-265: The interpretation of the correlation between loneliness and social avoidance behavior could be enriched by discussing possible psychological mechanisms that might explain this link.

Lines 350-355: I suggest a broader discussion of the study's limitations. Although depressive and social anxiety symptoms were included, there may be other confounding factors, such as social networks or the quality of interpersonal relationships, that deserve to be mentioned as potential influences not accounted for.

Lines 400-405: It would be helpful to include a dedicated section on the study’s limitations. For example, the cross-sectional nature of the study design might limit causal conclusions. Additionally, the influence of potential self-selection bias in the sample collection should be considered, given that most participants were women and the average age was relatively young.

Lines 425-430: Lastly, I recommend expanding the clinical implications section by providing more concrete examples of how interventions can be adapted to the different dimensions of loneliness identified.

Regarding the data analysis and results, the statistical methods used are appropriate and rigorous, with suitable controls for depressive and social anxiety symptoms. However, I would recommend providing more details on the adjusted p values using the Benjamini-Hochberg method and on interaction effects between the cognitive and behavioral variables. No specific sections need to be eliminated, but I suggest streamlining some parts of the discussion to reduce repetition and make the text more fluid.

In conclusion, the work presented is of great scientific value and significantly contributes to the existing literature. I hope these suggestions will help further refine the manuscript. Once again, thank you for entrusting me with the review of this important contribution.

I would kindly suggest that you include a reference to the following article in your manuscript:

Diotaiuti, P., Valente, G., Mancone, S., Grambone, A., & Chirico, A. (2021). Metric goodness and measurement invariance of the Italian brief version of Interpersonal Reactivity Index: A study with young adults. Frontiers in Psychology, 12, Article 773363. https://doi.org/10.3389/fpsyg.2021.773363.

This article is highly relevant for your discussion on measurement tools, particularly when addressing the methodological aspects related to the validation and reliability of psychological scales. I recommend citing this work in the section where you discuss the psychometric properties of the tools used to measure loneliness, specifically around Lines 150-160, where you explore the reliability and validity of different scales. The reference could enrich your discussion on the robustness of measurement instruments across different cultural and demographic groups.

Reviewer #3: The study "Revisiting the Cognitive and Behavioral Aspects of Loneliness: Insights from Different Measurement Approaches" conducted a comprehensive examination of the cognitive and behavioral differences associated with various facets of loneliness in a sample of 790 German-speaking adults. The researchers employed three distinct measures of loneliness—frequency, distress, and chronicity—to categorize participants as lonely or not lonely. They then analyzed group differences in cognitive and behavioral aspects such as interpretation bias, social avoidance, self-esteem, and rejection sensitivity, while controlling for depressive and social anxiety symptoms. The findings revealed fair to substantial agreement between the three loneliness measures and significant group differences in all cognitive and behavioral components for each loneliness measure. This highlights the multifaceted nature of loneliness and the importance of using diverse measures to capture its complexity. The study contributes to a more nuanced understanding of loneliness and suggests that interventions should consider specific dimensions of loneliness to effectively address its cognitive and behavioral implications. I suggest the authors to directly indicate the three definitions of loneliness and the study participants in the title, to be strict. In the introduction, when describing the negative mental and physical health outcomes of enduring loneliness, the authors must be aware of the limited availability of evidence on some consequences of persistent loneliness (PMID: 24550354, PMID: 26905049). I suggest the authors to revise the sentence “While nearly everyone experiences loneliness at some point in their life, for some, it can become an enduring condition with significant negative implications for mental and physical health and even increased mortality, elevating loneliness as a global health priority”. In the part of assessing loneliness, please consider to review the De Jong-Gierveld Loneliness Scale and explain why the authors did not use it. In the methodology, please consider the poor representativeness of the study sample. The authors need to be aware of the different constructs of loneliness in adolescents, adults, and older adults. The online survey was conducted during the COVID-19 pandemic but the authors did not have comments on this special social context (PMID: 37562972). My concern the generalizability of the current findings.

Reviewer #4: General Assessment:

The manuscript presents a well-designed and timely study exploring the multifaceted nature of loneliness, using three distinct measures: loneliness frequency, distress, and chronicity. The study's emphasis on understanding the cognitive and behavioral aspects of loneliness through diverse measurement approaches is commendable and contributes to the ongoing discourse on the complexity of loneliness. I do have some comments which I hope will help to authors to further strengthen the manuscript:

1. While the authors acknowledge the cross-sectional nature of the study, additional discussion on how self-selection bias might have impacted the findings (given that participants self-identified for a loneliness study) would be beneficial. More emphasis on potential biases due to the high proportion of female participants (81%) and the relatively young sample would also strengthen the paper.

2. The use of a self-reported measure of chronicity (24 months) could be refined further. While grounded in previous literature, it may not fully capture the nuanced experiences of chronic loneliness, and a more detailed discussion of why this specific threshold was used and its potential limitations would add clarity.

3. Although the manuscript provides a solid analysis of the cognitive and behavioral components of loneliness, the reliance on self-report questionnaires introduces possible response biases (e.g., social desirability or recall biases). Addressing the potential limitations of self-reported data and suggesting alternative or supplementary measures (such as behavioral data) would provide more balance.

4. The implications for interventions could be expanded. While the discussion touches on how different facets of loneliness could guide targeted interventions, more specific examples or suggestions (e.g., interventions tailored to chronic vs. distress-related loneliness) would enhance the practical applicability of the findings.

Specific Comments:

Abstract: The abstract is succinct and informative but could benefit from specifying the sample characteristics (age range, gender distribution) to provide context for the generalizability of the findings.

Introduction: The introduction could briefly address the global health implications of loneliness, especially its rising importance during post-pandemic times, which would make the study even more relevant.

Results: The presentation of statistical results is thorough. However, some readers might benefit from a more intuitive explanation of Cohen's κ and rϕ values, particularly in the context of agreement between the loneliness measures.

Tables: The tables are well-organized and provide essential data. Adding brief interpretative captions below some of the more complex tables (e.g., explaining what constitutes a “strong positive association” in lay terms) could make the findings more accessible to a broader readership.

Reviewer #5: This study presents valuable insights into the cognitive and behavioral aspects of loneliness. The topic of loneliness is highly relevant, particularly in the context of contemporary societal issues related to mental health, the authors provide a comprehensive review of existing literature, framing their research within established theoretical frameworks, and the study employs a multi-dimensional approach to assess loneliness through frequency, distress, and chronicity, which is commendable. However, it requires a more critical approach to theoretical frameworks, measurement choices, and the interpretation of results. Addressing these issues would enhance the overall rigor and impact of the research. The specific issues are as follows.

1. Clarification of theoretical frameworks: the manuscript heavily leans on established theoretical frameworks. However, it lacks a critical assessment of these frameworks. For instance, while the text acknowledges the adaptive aspects of loneliness, it does not thoroughly explore how this adaptive nature contrasts with the maladaptive outcomes. furthermore, a more nuanced discussion regarding the interplay between adaptive and maladaptive loneliness would enhance the theoretical grounding of the study.

2. Measurement choices: the authors critique the use of the UCLA Loneliness Scale and other measurement tools for their limitations, such as not capturing the intensity or duration of loneliness adequately. However, the manuscript does not provide a clear rationale for the selected measures or how they were specifically adapted for this study. In addition, the choice of cut-off points for categorizing loneliness is somewhat arbitrary and lacks a robust justification.

3. Sample limitation: the sample is predominantly female (81%) and relatively young (mean age of 31.86 years). While the authors note the limitations of generalizability, they do not adequately explore how these demographic factors might influence the findings. For example, the experiences and expressions of loneliness may differ significantly across genders and age groups.

4. While the statistical analyses employed, such as ANCOVA and χ2 tests, are appropriate, the manuscript could benefit from a more detailed explanation of why these specific methods were chosen over others. Additionally, the analyses focus on group differences, but they lack a discussion on the potential for mediating or moderating variables that could provide deeper insights into the relationships being examined.

5. The results section presents significant differences across groups; however, the discussion lacks a critical interpretation of these findings. For instance, the authors assert that increased loneliness correlates with higher rejection sensitivity and avoidance behaviors, yet they do not address the implications of these relationships adequately. How might these cognitive and behavioral tendencies manifest in real-life social contexts? A more profound exploration of the practical implications of the findings would enhance the relevance of the research.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

Reviewer #4: No

Reviewer #5: Yes:  Chia-Ling Hsu

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Revisiting the Cognitive and Behavioral Aspects of Loneliness: Insights from Different Measurement Approaches

PONE-D-24-42587R1

Dear Dr. Skoko,

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.

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Kind regards,

Bao-Liang Zhong

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

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

Reviewer #2: All comments have been addressed

Reviewer #5: 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: Yes

Reviewer #2: Yes

Reviewer #5: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #5: 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: Yes

Reviewer #2: Yes

Reviewer #5: Yes

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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

Reviewer #2: Yes

Reviewer #5: 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: The authors have responded to all comments thoroughly. Congratulations on this nice contribution to the literature.

Reviewer #2: We are therefore pleased to inform you that the manuscript, in its final version, is now ready to be accepted and published. We believe that this article represents a significant contribution to the field and will be of great interest to the readers.

Thank you for your commitment and collaboration during this revision process. Should there be any further steps required before official publication, we remain at your disposal for any final clarifications or adjustments.

Reviewer #5: Thank you for thoroughly addressing my previous questions, I generally agree with your responses. I have no more question.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean? ). If published, this will include your full peer review and any attached files.

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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: Yes:  Pierluigi Diotaiuti

Reviewer #5: No

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