Depression is one of the commonest mental illnesses and a significant cause for morbidity and mortality worldwide. This article looks at a novel treatment for depression-viz onabotulinumtoxin A. OnambotulinumtoxinA injection into the procerus and corrugator muscles for frown correction may serve as a modality for treatment-resistant depression in future, based on the Facial Feedback Hypothesis.

Title: The title of the article is concise and effectively outlines the aims and the study characteristics

Abstract: The abstract is a single paragraph and unstructured and follows the guidelines of the journal. The need for the study could have been better highlighted. The other parts of the study are well described.

Introduction: The introduction describes the need for the study considering the methodological limitations and lack of generalizability in the previous studies. The need for the study can however be justified more clearly. The references for the STAR-D trial and the approval status of onambulotoxainA for frown lines are missing.

Methods: The methodology has been clearly described for most parts and includes the relevant details of sample recruitment, outcome measures and how data was collected. Details of trial design, allocation and masking are required.

Results: The results of the study and their statistical analysis are appropriately described and are suited to deriving the necessary conclusions. Flow diagram can be added to improve reader understanding. Paired t-test can be used to compare pre- and post-test scores. The table does not report Mean +/-SD which needs changing. The figure depicts the measured improvement in depression over time in sufficient detail. A table to highlight the frowning response is required.

Discussion and Conclusions: The authors have adequately described and summarized the important findings with whatever literature on the aspect is available so far. Relevant past studies have been quoted to signify the importance of the findings obtained. In conclusion, highlighting the potential implications of the study and its tension in future research can enhance the value of the article.

The study loses significant value due to funding and conflict of interest aspects-with the study being funded by the cosmetic centre owned by the primary author.

References: The references do not follow the guidelines of the journal and need amendment(I think the journal reference guidelines changed after the article came out).The references for the STAR-D trial and the approval status of onambulotoxainA for frown lines are missing.

General: The study has significant novelty, though it is based on an older theory of emotion. Language and proofreading aspects need more attention-'homicide' instead of 'suicide' on page 2 line 5(right block)need correction. The scale MINI used in the article needs to be expanded the first time it is mentioned. Trial registration details need to be provided. Concise language and writing style are also recommended to make the article more enjoyable to the reader.