Just wanted to give hope to anybody who is currently struggling with either of the above issues. I suffered with both for the last couple of years until I discovered this subreddit. I went straight in with hard mode for 23 days and I am so grateful that it has resolved the problems for me. Big thanks to the founders for creating this forum!
Now obviously both these disorders can be caused by underlying medical conditions, so I suggest visiting your GP to rule other things out, but for me temporary abstinence seems to have done the trick.
On separate point, I consider myself a scientist and I wish there were more studies done on this subject. But, for what its worth, I can also say that my energy levels and confidence have increased noticeably. The depth and projection of my voice seems to have changed as well which was unexpected. I found an old recording of my voice from January this year, and I recorded my current voice with the same script (obviously a sample size of N=1 is pretty irrelevant in the grand scheme of things so make your own mind up!):
I am 25 years old if that matters.
Best of luck!