if someone is stressed or sleep-deprived because of work, then surely taking vacations will have positive effects.
If someone’s mental health problems are caused only by insufficient free time/energy/sleep, then yes. I’d wager the majority of depression cases are caused by work-independent internal factors, and either would resolve on their own (even while working) or would not resolve even when taking three months off.
Interesting to contrast with Leave a Line of Retreat:
There, you leave a line of retreat for yourself; here, for your conversation partner.