To add to the sibling comments, Japan has very restrictive gun laws [1], but a suicide rate (12.2) similar to the US (14.5) [2]. Let me add that I find the instinct to restrict personal freedom as the very first measure very disturbing. As if the loss of freedom is not a harm in itself. More pragmatically, how many people will admit to being suicidal, if the immediate consequence is being locked in a padded room without so much as a shoelace?

[1] https://en.wikipedia.org/wiki/Overview_of_gun_laws_by_nation...

[2] https://en.wikipedia.org/wiki/List_of_countries_by_suicide_r...