Thanks for the opportunity to review this very interesting paper that deals with an important public health issue. The manuscript is well written and the comparison between methods of suicide across the three disorders of severe mental illness and between individuals with versus without such diagnoses is of high clinical relevance. However, I have some concerns to address in relation to this manuscript.
1. Most of the studies investigating suicide methods reported the presence of specific socio- economic, religious, and cultural factors. In the current study, these factors are not well addressed except for the accessibility of firearms in US. Putting in consideration that the current systematic review includes 12 studies from 3 different continents with large geographic area (Asia, Europe, and North America), It could be beneficial to the reader to know more about these important contributing factors. I suggest addressing these factors in the introduction and/or discussion.

1. Furthermore, the age and gender are very important factors that affect the choice of suicide methods across different diagnoses. In USA, the most prevalent method among males was firearm while among females the most common was self-poisoning (Schmutte et al., 2021).
   If it is feasible with this small number of studies reporting such data, I suggest conducting additional analysis, investigating the suicide methods in relation to age or age groups and gender.

2. Although there are few studies reporting suicide method in the literature, The authors did not clearly consider the small number of articles included in the analysis as limitation. Kindly add this important point to the limitation section.

no further comments. Thank you