I think the causes of anxiety are complicated, it can be anything from how we programme our brains to chemical imbalances in the mind, body, spirit, right down to our diet or environmental factors, so I don't think there's just a one size fits all solution.
I now meditate to relax, but this would not have worked at a time when I was chemically overloaded with stress, nothing short of prozac would have calmed my racing mind, palpitations, hyper energetic frenzy, and catastrophic thinking, exacerbated by sleeplessness and attracting worse and worse things into my life through stress.
Violence and trauma kick started it, but I perpetuated it by keeping the anger and anxiety alive for decades, this keeps a viscious cycle in place and gets worse and worse, I finally threw in the towel and handed my life over to God, this acceptance and surrender changed my life, but the habit of anxiety was hard to break till I discovered something that worked for ME.
My anxiety turned into O C D negative thinking, so I decided to become O C D with the Bible! Knowing it would be unlikely to induce more anxiety, obsession over this book slowly calmed me down and replaced my catastrophic thinking with intrigue and questioning, the neaurological highway compelling my negative thinking is now dead, I can look at a flower and just enjoy the flower without any intrusive thoughts, it has also given me the unexpected gift of praying and lead me to meditative prayer, it am now weaning myself off sleeping tablets and alcohol, and the need to understand my life story has diminished to virtually nothing, although in reading the bible, I felt as though it was giving me all the answers I needed, in short, it started using it to brainwash myself, but I have been given SO much more.
I hope you find a solution to your particular kind of anxiety.