Clients of state that they have "tried relaxation training" such as deep breathing and it has not worked. I find the timing of when I introduce relaxation training to be critical. When clients first come in and are at a "I can't function until I eradicate anxiety from my life" stage, I often use a lot more education, mindfulness, acceptance, exposure, etc. Once my clients get that anxiety is not the enemy and that the more they fight it, the worse their anxiety will be and that in fact they can live with their anxiety and engage in any form of valued living that they choose, even if anxiety comes along for the ride, it is at this point that I find introducing and working with relaxation training, such as diaphragmatic breathing, to be the most helpful ( and least harmful ). As with anything else, it is not the tool that is dangerous but how and when one chooses to use it. Is one holding the tool lightly and using when appropriate or clinging to it desperately, as though their life depends on it?