Title: Biological rhythms in premenstrual syndrome and premenstrual dysphoric disorder: A
systematic review
Version: 4 Date: 31 May 2024
Reviewer's report:
Biological rhythms in premenstrual syndrome and premenstrual dysphoric disorder: A
systematic review
BMC Women’s Health
Review completed on 05/30/2024
Overview
Thank you for the opportunity to review the manuscript “Biological rhythms in premenstrual
syndrome and premenstrual dysphoric disorder: A systematic review.” This manuscript is
a systematic review that reports differences between individuals with PMS or PMDD and
controls on measures of biological rhythms, mainly focusing on sleep-related metrics. Major
strengths of the manuscript include comprehensive search strategy, transparency of methods, and
quality assessment. Major weaknesses include a lack operationalized definition of PMS, unclear
reasoning for the inclusion of non-sleep related biological rhythms, and drawing conclusions
that are not supported by their systematic review. This manuscript has potential to be a strong
addition to the literature if those concerns are addressed.
Major Comments
Introduction
- The description of PMDD (Introduction, paragraphs 2 and 3) is strong and clear. However,
there is no equivalent description provided for PMS, which is a major omission, given that many
of the included studies use “PMS” as their clinical group (not PMDD). While I understand that
PMS has many definitions that have varied over time and still vary greatly, please provide the
working definition used in this manuscript. If the omission of a PMS description is because
there is no clear definition, then please describe how you determined that an article included a
clinically significant “PMS” group (and not a variant of PMS that would fall under the 30-40%
of the population described in the first sentence).
- The final two paragraphs in the introduction are somewhat confusing and do not set up an
argument for why non-sleep related biological rhythms are of interest in PMDD. As written,
paragraph 4 seems to suggest that only women experience infradian rhythms, and the only non-
circadian rhythm is that of reproductive hormones. However, then paragraph 5 mentions several
non-sleep related rhythms, with no explanation for why these rhythms were selected, how they
fluctuate, or most crucially, how they may help us better understand PMS/PMDD.
- Please provide a relevant description of cortisol, prolactin, and TSH.
Methods
- Please include a description of your inclusion criteria for “women with PMS/PMDD” and
“healthy controls”
Results
- There are three studies that do not use prospective diagnosis for PMS/PMDD. These studies
should not be included in this systematic review, as PMDD cannot be diagnosed reliably from
retrospective report.
- In the paragraph, “Characteristics of Included Studies,” the authors describe that most included
studies diagnosed PMDD with “DSM-III-R (n=9) and DSM-IV (n=10), all prospectively-
assessed.” The DSM is a single timepoint interview that does not prospectively assess PMDD;
diagnoses are provisional and require two months of daily ratings for confirmatory diagnosis.
Please clarify this statement to correctly state what methods were used to prospectively assess
PMDD in the included studies.
- In the section, “Sleep,” subsection “Self-report assessments,” there is a sentence that begins
“In the sample of 19 women, whose diagnosis of PMDD was confirmed with two months of
prospective charting…”. This statement is not used to describe any other sample, which raises
concern that the other samples were not confirmed with two months of prospective charting.
If other samples were not confirmed with two months of prospective charting, it must be
clearly stated that these are provisional PMDD diagnoses that are not accurately assessed. If
this phrasing is extraneous (i.e., all other included studies do use prospective charting), please
remove to avoid confusion.
Discussion
- There are several statements that draw conclusions unsupported by the data presented. For
example, the first sentence states “This systematic review showed that women with PMS/PMDD
experience abnormal profiles of certain parameters that typically display rhythmic circadian
patterns.” However, at least half of the studies on melatonin, body temperature, cortisol, and
wrist actimetry do not show differences between PMS/PMDD and controls. It appears that only
two of the topics studied (subjective sleep, polysomnography) have a majority of studies within
that category showing differences between PMS/PMDD and controls. This sort of language
implying “abnormal biological rhythms” between PMS/PMDD is carried on throughout the
discussion and conclusions, despite the systematic review not showing a clear majority or
consensus. If there are reason the authors believe that the studies that do show significant
differences are more reliable than those that do not, that needs to be clearly described. As is,
the conclusions in this systematic review seem to be that some, specific metrics of biological
rhythms may differ between PMS/PMDD and controls – not that biological rhythms are broadly
abnormal in PMS/PMDD.
- On a similar note, it is unclear why the authors stress body temperature as a topic with consistent
findings of abnormal rhythms in PMS/PMDD.
- Unless there are structural requirements by the journal to have the section headings in the
current order, it would be more logical to the reader to explain specific limitations of included
studies when you are summarizing that topic.
- In the limitations of included studies section, is there concern that 12 of the included studies
use the same single sample? Or that there are multiple pairs of studies that each use data from
the same samples, adding up to 12 studies with at overlap with at least 1 other same? If it is
the former (12 studies using one sample), that is a major limitation that drastically impacts the
present findings.
Tables and Figures:
- The tables are very clear and add great value to the manuscript.
Minor Comments
Introduction
- It appears there is a sentence missing a citation, where the authors describe that PMDD is
associated with 7x and 4x greater risk of suicide attempts and ideation, respectively (unless this
sentence goes with the citation for the following sentence).
Results
- Define acrophase
Discussion
- If there is space available, a more in-depth description of proposed serotonergic dysfunction
in PMDD may be warranted
- The authors argue that the importance of sleep in PMDD is due to PMDD’s overlap with MDD,
which also has altered sleep and activity. Changes in sleep (hypersomnia/insomnia) is one of the
DSM-5 symptoms of PMDD. Not discussing sleep as a direct symptom of PMDD seems like a
notable omission in understanding the clinical relevance.
- The “clinical implications” paragraph seems beyond the scope of the main points of the review.
It is not clear why the authors focus here on specific treatments for sleep quality and insomnia,
when the rest of the paper compared observational group-level differences in sleep metrics
between PMS/PMDD and controls. The content in Table 3 provides better examples of clinical
implications and future directions.