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Instructions to authors

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General Information

Chronobiology in Medicine (official abbreviation: Chronobiol Med; CIM) is the official journal of the Korean Academy of Sleep Medicine (KASMED). CIM is peer-reviewed journal published in English on the last day of March, June, September, and December (eISSN: 2635-9162). CIM publishes research articles dealing with the circadian rhythms in various medical fields and clinical sleep medicine. CIM covers various biological rhythm studies, including sleep and wakefulness, in various medical areas, basic sciences, and social sciences. Topics on the clinical sleep disorders such as sleep disordered breathing and insomnia influencing on the circadian rhythm disturbances will be considered for publication. CIM is primarily for physicians, psychiatrists, neurologists, sleep medicine specialists, basic scientists, and social scientists.

Research and Publication Ethics

CIM aims to ensure that all articles published in the journal report on work that is morally acceptable, and expects authors to follow the World Medical Association’s Declaration of Helsinki ( All of the manuscripts should be prepared in strict observation of research and publication ethics guidelines recommended by the Council of Science Editors (CSE,, International Committee of Medical Journal Editors (ICMJE,, World Association of Medical Editors (WAME,, and the Korean Association of Medical Journal Editors (KAMJE, Any study including human data must be reviewed and approved by a responsible Institutional Review Board (IRB). Animal experiments also should be reviewed by an appropriate committee (IACUC) for the care and use of animals. Also studies with pathogens requiring a high degree of biosafety should pass review of a relevant committee (IBC). The editor may request submission of copies of informed consents from human subjects in clinical studies or IRB approval documents. CIM will follow the guidelines by the Committee on Publication Ethics (COPE, for settlement of any misconduct.

Informed Consent and Confidentiality
A statement of informed consent for human investigation should be made in the text, along with the name of the institutional review board that approved the study protocol. Authors must ensure that patient confidentiality is in no way breached. Do not use real names, initials, or disclose information that might identify a particular person without informed consent for publication.

Disclosure of Conflict of Interest and Funding Statement
The corresponding author(s) of an article is asked to inform the Editor of the authors’ potential conflicts of interest possibly influencing the research or interpretation of data. Such conflicts may include financial support or private connections to pharmaceutical companies, political pressure from interest groups, or academic problems. A potential conflict of interest should be disclosed in the cover letter even when the authors are confident that their judgments have not been influenced in preparing the manuscript. In particular, all sources of funding for a study should be explicitly stated.

All persons designated as authors should qualify for authorship. Each author should have participated sufficiently in the work to take public responsibility for the content. According to criteria formulated by the International Committee of Medical Journal Editors (ICMJE), authorship credit should be based on the following 4 criteria: 1) substantial contributions to conception and design or analysis and interpretation of data, AND 2) drafting the article or revising it critically for important intellectual content, AND 3) final approval of the version to be published; AND 4) agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All these 4 conditions must be met. Participation solely in the acquisition of funding or the collection of data does not justify authorship. All other contributors who do not meet these criteria for authorship should be noted in the Acknowledgments section. CIM does not consider people thanked in the Acknowledgements or listed as members of a study group on whose behalf a paper is submitted to be authors. CIM does accept notice of equal contribution for the first author when the study was clearly performed by co-first authors. After the initial submission of a manuscript, any changes whatsoever in authorship (adding author(s), deleting author(s), or re-arranging the order of authors) must be explained by a letter to the editor from the authors concerned. This letter must be signed by all authors of the paper. But after publication, CIM does not correct authorship unless a mistake has been made by the editorial staff. Copyright assignment must also be completed by every author.

Corresponding author(s): One of the authors should be designated to receive correspondence and proofs, and the appropriate address indicated. This author(s) must take primary responsibility for communication with the journal during the manuscript submission, peer-review, and publication process. The corresponding author typically ensures that all the journal’s administrative requirements, such as providing details of authorship, ethics committee approval, clinical trial registration documentation, and disclosures of relationships and activities are properly completed and reported, although these duties may be delegated to one or more co-authors. The corresponding author should be available throughout the submission and peer-review process to respond to editorial queries in a timely way, and should be available after publication to respond to critiques of the work and cooperate with any requests from the journal for data or additional information should questions about the paper arise after publication [].

Overlapping Publication
Duplicate Submission: All submitted manuscripts should be original and should not be considered by other scientific journals for publication at the same time. There should be no plagiarism or duplicate publication in the submitted manuscript. The fraudulent data should not be added to the manuscript. Any part of the accepted manuscript should not be duplicated in any other scientific journal without the permission of the Editorial Board.
Secondary Publication: Secondary publication of material published in other journals or online may be justifiable and beneficial, especially when intended to disseminate important information to the widest possible audience (e.g., guidelines produced by government agencies and professional organizations in the same or a different language). Secondary publication for various other reasons may also be justifiable provided conditions of the International Committee of Medical Journal Editors (ICMJE) Recommendations are met (

Copyright and Licensing

Copyright: The copyright of the whole content of papers published in the Journal belongs to the Korean Academy of Sleep Medicine (KASMED) and all authors should sign the copyright transfer form after when their manuscript is submitted.

Licensing: CIM is an open access journal distributed under the terms of the Creative Commons Attribution Non-Commercial License (, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. For any commercial use of materials in CIM, permission must be obtained from the Korean Academy of Sleep Medicine (

Preprints and Self-Archiving

Authors are permitted to self-archive the submitted version (preprint), accepted version (peer-reviewed), and and publisher’s version/PDF of the article at any time in their institutional repository or any non-profit repositories.
CIM accepts submission of manuscripts that have previously been posted on any recognized, not-for-profit, preprint server. CIM does not consider the deposition of preprints in the repositories at the same time as, or before, submission to a journal to be prior publication. Authors disclose the existence of the preprint at submission (e.g., in the cover letter). Note that preprints operate independently of the journal and posting a preprint does not affect the peer review process.

Preparation of Manuscripts

The manuscript must be written in English. The manuscript (including references, legends, and tables) must be typed double-spaced. Start each of these sections on a new page, numbered consecutively, beginning with the title page. Use only 10- or 12-point font size. Manuscripts should be concisely written in a readily understandable style. Standard nomenclature should be used throughout; unfamiliar or new terms and arbitrary abbreviations should be defined when first used.

Reporting guidelines for specific study designs
It is recommended for authors to follow the established reporting guidelines ( for the specific study design, such as randomized control study (i.e., CONSORT), study of diagnostic accuracy (i.e., STARD), meta-analyses and systematic reviews of randomized controlled trials (i.e., PRISMA), meta-analysis of observational studies in epidemiology (i.e., MOOSE), strengthening the reporting of observational studies in epidemiology (i.e., STROBE), and Case Reports (CARE). The details are available on the website at (IV.A.2).

Type of manuscript

Original articles: Original articles should include structured Abstracts (Objective, Methods, Results, and Conclusion) and main text (Introduction, Methods, Results, and Discussion). The original articles should not exceed 5,000 words (excluding references, tables and figure legends).

Review Article: Review article must have an Abstract, but the structured format is not necessary. Word count, number of references, and number of figures and tables in the main body are not limited in these types of article.

Mini Review: Mini Review should not exceed 1,500 words (excluding references, tables and figure legends) and contain no more than three figures or tables.

Brief Report: Brief Report should not exceed 1,500 words (excluding references, tables and figure legends) and contain no more than one figure or table.

Editorial: Editorial is written in-house by the Editor-in-Chief, a member of the Editorial Board or a Guest Editor. A brief text should be prepared with less than 5 references. Maximum word count of the text is 1,000.

Perspective: Perspective describes the practice of psychiatry and social, historical, cultural, economic, or even political issues. It should not exceed 1,000 words (excluding references, tables and figure legends) and contain no more than 10 references and contain no more than one figure or table.

Correspondence: A brief text should be prepared with less than 5 references. Maximum word count of the text is 1,000. If an individual patient is described, his or her consent should be obtained and submitted with the manuscript.

Title page
Each manuscript must have a separate title page which includes the title; authors’ full names and academic or professional affiliations; complete addresses, as well as the name, e-mail, telephone, fax numbers of the author to whom proofs and correspondence should be addressed; ORCID iDs for all authors (Please refer to; author contributions; conflict of interests; and funding statement. If an author’s affiliation has changed since the work was done, list the new affiliation as well. The title should be short, clear and concise and should indicate the major point of the paper. They should not exceed 150 characters including spaces, if possible. Do not use abbreviations in the title. The running title should consist of no more than 8 words.

Original Articles should include structured abstracts with the following information, under the headings indicated: Objective - the primary purpose of the article; Methods - data sources, subjects, design, measurements, data analysis; Results - key findings; and Conclusion - implications, future directions. The abstract of Original articles should be no longer than 250 words. Review article, Mini review, and Brief reports require an unstructured abstract of one paragraph, not exceeding 200 words. A list of keywords, with a maximum of six items, should be included at the end of the abstract. The selection of keywords should be based on Medical Subject Heading (MeSH, An abstract is not required for Editorial, Perspective, and Correspondences.

Main text
The text of the Original Article and Brief Reports should include four major sections: Introduction, Methods, Results, and Discussion. The Introduction should give the reasons for undertaking the study and a summary of the experimental plan. Exhaustive reviews of literature should be avoided. The Methods should be described in sufficient detail so that the work can be duplicated, or by reference to previous descriptions if they are readily available. Commonly used methods require only a citation of the original source unless they have been substantially modified. Ensure correct use of the terms “sex” (biological factors) and “gender” (identity, psychosocial, or cultural factors). Also, unless inappropriate, report the sex or gender of study participants, the sex of animals or cells, and describe the methods used to determine sex or gender. If the study involved an exclusive population (in only one sex, for example), authors should justify why, except in obvious cases (e.g., prostate cancer). Authors should also define how they determined race or ethnicity, and justify their relevance. Statistical tests used for evaluation of data should be briefly explained. Special chemicals and drugs with their sources should be grouped under a separate sub-heading (“material” or “drugs”). For drugs, generic names should be used; trade names may be given in brackets where the drug is first mentioned. In case of new drugs, a detailed chemical description (formula) should be given. The Results should be described clearly, concisely, and in logical order without extended discussions of their significance. Only in case of Brief Report, the results and discussion sections may be combined. Results should usually be presented in graphic or tabular form, rather than discursively. There should be no duplication in text, tables, and figures. The Discussion should be as concise as possible. In this section, conclusions should be drawn from the results accompanied by an assessment of their significance in relation to previous works. The structured format of main text for Review article, Mini review, Editorial, Perspective, and Correspondences is not required.

Funding statement
Grant support should be acknowledged in a separate paragraph under a separate heading at the end of the discussion section. The full name of the granting agency and grant number should be included.

Conflict of interest
Any potential conflicts of interest must be disclosed in this section. These also should list employment by, consultancy for, shared ownership in, or any close relationship with, an organization whose interests, financial or otherwise, may be affected by the publication of the paper. This pertains to all the authors of the study. If there are no potential conflicts of interest, the following statement should be added: “The authors have no potential conflicts of interest to disclose.”

Availability of data and material
Authors are required to provide a Data Availability Statement that details where data are available, and how the data can be accessed and reused (listing specific restrictions, if any).

ORCID (Open Researcher and Contributor ID) iDs of all authors should be described.

Author contributions
What authors have done for the study should be described in this section. To qualify for authorship, all contributors must meet at least one of the seven core contributions by CRediT (conceptualization, methodology, software, validation, formal analysis, investigation, data curation), as well as at least one of the writing contributions (original draft preparation, review and editing).

Acknowledgments (optional)
Any individual and/or organization that contributed to the study or the manuscript, but not meeting the requirements of an authorship could be mentioned here. For mentioning any individuals or organizations in this section, there should be a written permission from them.

There should be carefully selected to acknowledge previous work or to document a specific point. Referencing follows the Vancouver method of reference citation. In this system, references are numbered consecutively in the order in which they are first mentioned in the text. Identify each reference in text, tables, and legends by Arabic numbers [1], [2], or [5,8-10]. All references cited should be listed numerically at the end of the paper. Personal communications, unpublished data, or manuscripts either “in preparation” or “submitted for publication” are unacceptable. If essential, such material may be incorporated at the appropriate place in the text. The abbreviated journal title should be used according to the list of Journals Indexed for NLM Catalog ( When there are less than seven authors, each must be listed in the citation. When seven or more authors, list the first six followed by "et al." after the name of the sixth author. The endnote reference style for CIM is specified on the journal homepage. Representative examples are as follows:

Journal Article
1. Kwon JS, Shin YW, Kim CW, Kim YI, Youn T, Han MH, et al. Similarity and disparity of obsessive-compulsive disorder and schizophrenia in MR volumetric abnormalities of the hippocampus-amygdala complex. J Neurol Neurosurg Psychiatry 2003;74:962-964.

Book Chapter
2. Fairburn CG, Cooper Z. The eating disorders examination (12th ed). In: Fairburn CG, Wilson GT, editors. Binge eating: nature, assessment, and treatment. New York: The Guilford Press, 1993, p. 317-331.

3. Tudor I. Learner-centeredness as language education. Cambridge: Cambridge University Press; 1996.

4. Nation Center for Injury Prevention and Control. Traumatic brain injury & concussion [Internet]. Available at: Accessed February 22, 2022.

Web References
Please keep a print copy of any reference to Web only information. If the URL changes or disappears, interested readers may contact the corresponding author for a copy of the information.

Each table and its title and legend should appear on a separate page. Title each one and number them in the order of their citation in the text. If a table must be continued, repeat the title on a second sheet, followed by “(continued).” Tables should contain sample sizes and units of measurement, when appropriate. Any explanatory notes to be printed with the table must be typed single-spaced beneath the table, the following symbols should be superscripted and used in the indicated sequence: *, †, ‡, §, ∥, ¶, **, ††, and ‡‡. Each abbreviation and significance of observations, as determined by appropriate statistical analyses should be defined in the legend of the table. The desired position of the table in the main text should be indicated. Authors must obtain permission from the original publisher if they intend to use tables from other sources, and due acknowledgment should be made in a footnote to the table.

Figures must also be cited in numerical order in the main text. Figure legends must appear on a separate page at the end of the manuscript file. To ensure the highest quality print production, your figures must be submitted in TIFF or JPEG format according to the following minimum resolutions:

  • • 1,200 dpi (dots per inch) for black and white line art (simple bar graphs, charts, etc.)
  • • 300 dpi for halftones (black and white photographs)
  • • 600 dpi for combination halftones (photographs that also contain line art such as labeling or thin lines) Vector-based figures (usually created in Adobe Illustrator) should be submitted as EPS. Do not submit figures in the following formats: GIF, Word, Excel, PowerPoint, PDF.
Graphs must show an appropriate grid scale. Each axis must be labeled with both the quantity measured and the unit of measurement. Color figures must be submitted in a CMYK color space. Do not submit files as RGB. Authors are encouraged to submit color illustrations that highlight the text and convey essential scientific information. For best reproduction, bright and clear colors should be used. All figures should be mentioned in the text and the desired position of the figure in the manuscript should be indicated. Authors must obtain permission from the original publisher if they intend to use figures from other sources, and due acknowledgment should be made in the legend. All color figures will be reproduced in full color in the online edition of the journal at no cost to authors.

Methods of statistical analysis should be described in language that is comprehensible to the numerate psychiatrist as well as the medical statistician. Particular attention should be paid to clear description of study designs and objectives, and evidence that the statistical procedures used were both appropriate for the hypotheses tested and correctly interpreted. The statistical analyses should be planned before data are collected and full explanations given for any post hoc analyses carried out. The value of test statistics used (e.g. t, F-ratio) should be given as well as their significance levels so that their derivation can be understood. Trends should not be reported unless they have been supported by appropriate statistical analyses for trends. The use of percentages to report results from small samples is discouraged, other than where this facilitates comparisons. The number of decimal places to which numbers are given should reflect the accuracy of the determination, and estimates of error should be given for statistics. A brief and useful introduction to the place of confidence intervals is given by Gardner & Altman (Br J Psychiatry 1990;156:472-474). Use of these is encouraged but not mandatory. Authors are encouraged to include estimates of statistical power where appropriate. To report a difference as being statistically significant is generally insufficient, and comment should be made about the magnitude and direction of change.

General Text Style

Abbreviations: Use only standard abbreviations; use of nonstandard abbreviations can be confusing to readers. Avoid abbreviations in the title of the manuscript. The spelled-out abbreviation followed by the abbreviation in parenthesis should be used on first mention unless the abbreviation is a standard unit of measurement.
Units of measurement Measurements of length, height, weight, and volume should be reported in metric units (meter, kilogram, or liter) or their decimal multiples. Temperatures should be in degrees Celsius. Blood pressures should be in millimeters of mercury, unless other units are specifically required. Authors should report laboratory information in International System of Units (SI).
Editors may request that authors add alternative or non-SI units, since SI units are not universally used. Drug concentrations may be reported in either SI or mass units, but the alternative should be provided in parentheses where appropriate. Generally, SI units should be used; where they are not, the SI equivalent should be included in parentheses. Units should not use indices: i.e., report g/mL, not g·mL-1. Footnotes: The use of notes separate to the text should generally be avoided, whether they be footnotes or a separate section at the end of a paper. A footnote to the first page may, however, be included to give some general information concerning the paper.

Materials, Equipment, and Software
The source of any compounds not yet available on general prescription should be indicated. The version number (or release date) and manufacturer of software used, and the platform on which it is operated (PC, Mac, UNIX etc.), should be stated. The manufacturer, manufacturer’s location and product identification should be included when describing equipment central to a study (e.g., scanning equipment used in an imaging study).

Data Sharing and Data Deposit

Data Sharing Policy
CIM follows the ICMJE Recommendations for data sharing statement policy ( As of July 1, 2018, manuscripts submitted to ICMJE journals that report the results of clinical trials must contain a data sharing statement. Authors are required to provide a data sharing statement indicating the following: whether individual deidentified participant data (including data dictionaries) will be shared (“undecided” is not an acceptable answer); what data in particular will be shared; whether additional, related documents will be available (e.g., study protocol, statistical analysis plan, etc.); when the data will become available and for how long; by what access criteria data will be shared (including with whom, for what types of analyses, and by what mechanism).

Registration of Clinical Trial Research
Clinical trials are recommended to register with public repositories such as WHO International Clinical Trials Portal (, NIH (, ISRCTN Resister (, or Clinical Research Information Service (CRIS, If applicable, trial registration numbers should be included in the methods section. The registry should be publicly accessible (at no charge), open to all prospective registrants, and managed by a not-for-profit organization. For a list of registries that meet these requirements, please refer to the WHO International Clinical Trials Registry Platform (ICTRP). Registration of all clinical trials facilitates information sharing among clinicians, researchers and patients, increases public confidence in research, and is consistent with ICMJE guidelines.

Access to Data
If the study includes original data, at least one author must confirm that he or she had full access to all the data in the study, and takes responsibility for the integrity of the data and the accuracy of the data analysis. Authors are encouraged to share or make open the data supporting the results or analyses presented in their paper where this does not violate the protection of human subjects or other valid privacy or security concerns. Authors wishing to do so may deposit their data in a publicly accessible repository and include a link to the DOI within the text of the manuscript. Authors are further encouraged to cite any data sets referenced in the article and provide a Data Availability Statement.

Open Access and Article Processing Charge

Open Access
Articles are published open access under the terms of the Creative Commons Attribution Non-Commercial License (, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article Processing Charge
There is no author-side submission fee or article processing charge. All publishing cost are supported by KASMED.

Submission of Manuscripts

Manuscripts should be submitted online at: Follow all instructions. All submitted papers are peer-reviewed before it is decided whether they should be accepted, minor revision, major revision, or rejected. Authors must suggest 5 preferred reviewers. The journal reserves the right to edit the language of papers accepted for publication for clarity and grammatical correctness, and to make formal changes to ensure compliance with this Journal. Proofs will be sent to the corresponding author for final approval. Upon acceptance of a manuscript for publication, the corresponding author will be required to sign an agreement transferring copyright to the publisher. The completed copyright transfer form should be scanned and uploaded online through the website (

Review Process

All papers, including those invited by the Editor, are subject to peer review. If a manuscript does not fit the aims and scope of the Journal or does not adhere to the Instructions for Authors, it may be returned to the author immediately after receipt and without a review. A submitted manuscript will be acknowledged and assigned a manuscript number, which is to be used in all further correspondence. Before reviewing, all submitted manuscripts are inspected by Similarity Check powered by iThenticate (, a plagiarism-screening tool. Manuscripts are reviewed and given a priority based on their originality, importance of the findings, scientific merit and significance for the field, interest to readers, lucidity, and suitability for publication. Manuscripts with insufficient priority for publication are rejected promptly. Other manuscripts are sent to expert consultants for peer review. The journal uses a double-blind peer-review process such that the identities of both the reviewers and authors are kept confidential. The existence of a manuscript under review is not revealed to anyone other than peer reviewers and editorial staff. Peer reviewers are expected to maintain strict confidentiality. Reviewers are also expected to inform the Editor of any conflicts of interest, including any financial arrangements involving companies whose products (or competing products) are featured in the manuscripts they agree to review. Statistical editing may be done if the data needs professional statistical review by a statistician. After review, the editorial board determines whether or not the manuscript is accepted for publication. Once rejected, the manuscript is not subject to further review. Once the manuscript is received by the editorial board, an e-mail confirmation will be sent to the author within seven days. The author will be notified of any delays due to evaluation difficulties. Authors may contact the editorial committee for the current review phase of the manuscript. The board will inform the author of the status of the review process.

Proofs and Post-publication Discussion

Authors should keep a copy of their manuscripts as proofs will be sent to them without manuscript. Only printer’s errors may be corrected; no change in, or addition to, the edited manuscript will be allowed at this stage. Authors will receive proofs by e-mail. The corrected proofs must be returned within 72 hours after receipt by email or FAX. If the Publisher receives no reply, the assumption will be made that there are no errors to correct and the article will be published after in-house correction.

Post-publication Discussion
The post-publication discussion is available through the Correspondence. If any readers have a concern on any articles published, they can submit a Correspondence on the articles. If there founds any errors or mistakes in the article, it can be corrected through errata, corrigenda, or retraction. Corrections are reviewed by editors and authors, published promptly, and linked online to the original article.

Contact for inquiry
Regarding your accepted manuscript or post-publication discussion, please phone, fax, or email us at the following numbers.
Tel: +82-2-445-1611, Fax: +82-2-445-1633
Editorial Office, Choronobiology in Medicine, RN1611, 725, Suseo-Dong, Gangnam-Gu, Seoul 06367, Republic of Korea.


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Editorial Office
RN1611, 725, Suseo-Dong, Gangnam-Gu, Seoul 06367, Republic of Korea
Tel: +82-2-445-1611    Fax: +82-2-445-1633    E-mail:                

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