That it should in some way affect my mental health has never once occurred to me. If anything, i assume that living on one's body's own natural schedule would be optimal in terms of related effects on mental health.

> How do you deal with times day and night are flipped?

When there's not something pressing me into a schedule, e.g. a job, i kind of "circle around" to a conventional schedule every few weeks. All things considered, i prefer the "swapped" times because it's quieter at night. e.g. less traffic driving by, fewer neighbors making various noises, and no DHL/UPS/DPD deliveries for the neighbors being dropped off here because the neighbors aren't home (whereas i am almost always at home and both the neighbors and the local delivery folks know it).

i'm a retiree so, with the exception of shopping and rare appointments, the night/day or weekend/weekend[^1] are not generally distinctions which affect me, and it's never bothered me in the slightest to not have a fixed schedule. On the contrary, a fixed schedule somewhat bums me out long-term, presumably because it does not match my biological clock.

> How does it affect your social life?

My social life is (by preference and choice) comprised solely of (A) my FOSS work, and there's no clock associated with any of that, and (B) my wife. Both my and my wife's biological families are all on another continent, so we've no family obligations which require physical presence. When i'm not FOSS'ing, we play a lot of board games.

[^1]: stores are closed on Sundays and all public holidays in Germany. More than once i've gone to the store, only to discover it's closed due to a holiday i've overlooked (like, most recently, May 1st).