Yes I do, less now. I started about 4 years ago. For people who suffer with mental health I can imagine it works as whenever I write things down it helps me not to keep dwelling on my thoughts or feelings.
I've been keeping a journal since elementary. I've lost a lot but still have some from 2010. It's very therapeutic. I can say everything I feel no filter and it makes me feel heard. Also helps me understand what I'm feeling and why. If a situation that upsets me happens it's definitely going into my journal, I also write poetry as well in them.
I started in 99 by tracking my bicycle rides; distance, time, weather and temperature. Then I started adding daily events of significance followed that up with mood feelings etc. It came in handy when trying to put a medical history together and helped with my PTSD diagnosis. So I can vouch for the mental health aspect.
I would start on the first day of the year but totally forget until it's my birthday on the last quarter and would like to write something about my special day....old age beckons! 🙃
in general it's a good thing, as long as the act of self talk doesn't become an crutch and echo chamber. I know someone who has fallen into the latter, it's meant to be an exercise in reflection, not walling off from reality