29% of people report having been diagnosed with depression in their lifetimes [1]. Major depression seems to be more like 8.3% [2], but once you start restricting someone's freedoms based on their state of minds, the treatment itself becomes stigmatized.
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