Granted, I'm not calling for a ban, but I'm more worried about someone with depression having a gun. My rationale is simply that there are a lot of depressed people, and the impairment lasts longer, thus the risk exposure is higher.
If I'm ever asked in an attempt to limit my rights, I'll say that I never have and I'll be convincing. The only proper way to implement this kind of policy is by using police reports based on credible threats towards others.
Self-harm isn't something that needs more policing; let's stick to better treatment there.
[1] https://news.gallup.com/poll/505745/depression-rates-reach-n...
[2] https://www.nimh.nih.gov/health/statistics/major-depression