I actioned this policy (see photo) almost 3 years ago in Feb 2017. I am happy to report that the policy worked brilliantly. I did not get depressed from the news any more even though I have a faint inkling that there might be things happening in the world.
The funny thing is that I didn't get depressed even during the last months of 2019 when I completely uprooted my life and moved across the country, and was stone-cold broke for a few months (still stoney broke but not cold).
That brings me to the conclusion that we (editorial 'we') get more depressed by the general news even more so than by the things that happen directly to us.
For those who may be interested I use a Chrome add-on called F.B. Purity to suppress the news, ads and other junk that Facebook itself pushes to the page alongside your news feed. For the actual posts shared by people in my friends list I simply unfollow the person if their posts contain news of the world.