The Ashton Manual is a part of the National Health System in the United Kingdom, and not something normally listed in the USA as something to be followed. We have many people on here who are from other English speaking countries of the world. Each country has there own idea of what is right. The guidelines in the USA are now benzos are supposed to be used only 2 weeks. Many drugs have changed in what is expected of the prescription as doctor's find out things themselves. The FDA requires testing of new drugs for short periods, but in reality they may end up being used very long term. An example are antidepressants that were tested for 6 months. I have been taking them for decades. Without them I would probably be dead from suicide. With them I can live a fairly normal life.
It is too bad that there are not enough np/psychiatric to be able to give you decent service. The shortage is nationwide and even in other countries. Psychiatrists used to do it all, but then insurance companies said no a np should do it. In many states the np must get the approval of a psychiatrist to change or add medications, thus adding to the time to get a service in psychiatry. Many psychiatrists are not interested in being an overseer, but want to deal with the actual patient. Thus many have retired and not many new people want to start. The states have been quick to approve these changes. I really do not understand that. Usually these changes go through without much publicity so the average person never even knew they occurred. You are right in stating that plain Medicare allows you to have any doctor that is accepting Medicare. However because Medicare reimburses doctors at much lower rates than the general public, some doctors do not accept Medicare. Medicare advantage and supplement plans are different. They usually require you to see doctors within their plan.