As someone who struggles mightily with anxiety and a mood disorder, breathing does help and I practice it regularly. However, CBT and mindfulness have provided

As someone who struggles mightily with anxiety and a mood disorder, breathing does help and I practice it regularly. However, CBT and mindfulness have provided so much more in terms of calming and reducing anxious thoughts. Yes, it takes a long time to internalize the thought patterns necessary, but once you do, nothing can rattle you unless you allow it. It provides a level of self control that no breathing technique I've ever tried can match. Do the work, meditate, and self assess as much as you can and you will see the benefits.