Little data exists on how meditators feel that meditation and mindfulness influences well-being. I am running a short academic survey that asks meditators about their meditation experience. Anyone over the age of 18 that meditates is welcome to complete the survey, it encompasses all forms of health based and spiritual meditation practice.
filling in interesting years ago, when suffering with depression (wasn't taking any meds) meditation made it much worse. I then didn't read anything to that effect until quite recently. I think it's because I had a silence in my head already so meditation was a stupid thing to try but I was in denial a bit.
now I need to slow down a very full brain, I don't find meditation helpful either. I do find a good brainless bit of cardio at the gym - total zone out with correct music, equipment rather than outdoors so no need to watch out for hazards - very helpful.
I imagine lane swimming would be similar but I cba with all the faff of changing rooms etc.
Although I'm a meditator myself I know it doesn't work for everyone in all situations and I have encountered people for whom meditation and mindfulness weren't useful at all. Understanding exactly what it does and how is I think central to being able to understand its therapeutic value. Even within spiritual traditions not all newcomers will necessarily be given the same meditation practice and some may be asked to wait a while before they begin.