The blending of east and west is a significant topic which I can only address from my own experience, my personal biases, and my hopes. This blending is happening around the world and for some countries it is quite standard. There are many positives and negatives to this blending which ultimately come down to what you are blending - the practitioners or the techniques. As it stands currently we see questionable laws being passed in the US allowing the practice of acupuncture in many states by MD's, DC's, and others - with or without the specialized training to properly understand and utilize Chinese Medicine. This is a blending of the techniques, but without qualified practitioners the techniques will only go so far.
The best path, in my opinion, would be that MD's stick to western medicine but understand more about alternatives and when to use them, DC's stick to chiropractic but understand better their own limitations and have better cross referral networks, and Doctors of Chinese Medicine stick to what they know and also have better referral networks. This would be best for the patient, ensuring they are getting the appropriate information and treatment at the appropriate time - rather than the time consuming trial and error path, or the simply wandering path, that many patients are on.
As with many practitioners, Chinese Medicine is often a last stop for many folks as it is furthest down the line in many countries from being well understood by both the general public and the western medical community. Even as it has made many headways into the western medical community it is still poorly understood and under utilized. Certainly it is under utilized at appropriate times which are often before more invasive western medical procedures have already taken place and/or stronger western medications have already been administered. In simple terms, most people would benefit more from seeing an acupuncturist before they go too far down the western medical route.
There are, of course, times where they work well together, but western treatments are arguable harsh at times and often meant primarily for the "management" of conditions, not their complete treatment as is more often the case with Chinese Medicine. This is particularly true in conditions like asthma, allergies, chronic immune issues, pain, psychological conditions, etc. These are conditions where the west attempts to manage them, and the east gets to the root and treats them.
Western medicine does have a stronghold in areas of acute medical issues and does extremely well there and when surgery is called for what can be done is absolutely amazing. I don't think, however, that one medical system can rule all which is what has been happening here in the US and elsewhere for the last 40 years or so. It's just not practical that one system can heal all conditions, nor can individual practitioners be expected to know everything about everything.
That said, even where western medical excels you still see a place for acupuncture with acupuncture anasthesia and the like used in many countries to lower the amount of medications needed during surgeries, for example.
To continue on the topic of integration, in the US you see the emergence of a field called "Medical Acupuncture" which is a term that has many meanings. At it's core, however, is the use of acupuncture by western trained physicians for conditions that can be helped with standard protocols, instead of more complex - but infinitely more useful - Chinese Medicine patterns. In some ways this is good. I, for example, didn't go into Chinese Medicine to do acupuncture anasthesia (nearly always identical points on nearly everyone) - that would be somewhat boring for me personally and more appropriate for a tech (i.e. a good place for integration). You see this in states that license detox specialists to perform the NADA auricular acupuncture drug detox protocol (they are not allowed to needle any other points or do any form of Chinese Medicine diagnosis). This protocol is akin to a "medical acupuncture" protocol where no diagnosis is necessary, the points do not change, and anyone with very limited training can replicate the results.
As you juxtapose "Medical Acupuncture" with "Chinese Medicine" there are two critical points that must be understood. First, Chinese Medicine does not treat conditions, per se, it treats patterns (there is a bit about this in my recent article, uses of Chinese Medicine in the prevention of disease). Suffice it to say that pattern differentiation in Chinese Medicine takes years to understand and even more time to utilize. This is where Chinese Medicine begins to take on aspects of both an art form and a science and your ability to balance both sides will lead to improved results for any type of case. This type of understanding is hard enough for people with 4 years in graduate school for acupuncture - all of which are nearly completely devoted to Chinese Medicine history, theory, and treatment. So you can begin to imagine what a western trained doctor might miss with a 100 hour course in Chinese Medicine.
The other aspect to be concerned with is that Chinese Medicine is not just "acupuncture". It involves the use of herbs, massage, cupping, moxibustion, energy healing, dietary habits, lifestyle habits, and more - in short it is a complete medical system and using only one part will often lead to inferior results as well.
So to answer your question in short (something difficult with a topic like this). Whether or not a person has a western medical diagnosis has little or no bearing on how you will treat them with Chinese Medicine. Again, Chinese Medicine is pattern based, not condition based so an official western diagnosis is just another piece of information that will be used to varying degrees depending on each individual case. However, as most people try acupuncture after western options - you most often have a western diagnosis for many conditions.
For differentiating anxiety and fear, for example, that comes along with many conditions you need to look at the root. An important aspect of Chinese Medicine pattern differentiation (and that which is most difficult for beginning students and practitioners early in their training) is coming up with a root pattern. In short, you do this by first taking all of the signs and symptoms you use in Chinese Medicine and looking at which patterns they fall into. If you are lucky, this exercise will offer you a very clear pattern. More often than not, however, you will have a mix where you will need to prioritize or signs and symptoms to come to a clearer pattern. In some cases, anxiety/fear will be a big part of the overall pattern and in others it will be secondary and either not treated directly (assuming the treatment of the pattern will remedy it) or treated as a local condition (see my article on general acupuncture point selection guidelines for an idea of how this works).
As far as referrals go, this will be up to each individual practitioner. Certainly it is out of the scope of acupuncturists to recommend specific western drugs - so if you feel western drugs should be used they will need to be referred to a western medical doctor. In all other cases, it is good for practitioners to have a referral network setup of some kind. Acupuncturists, again as they are often last on the line, may not need many specific western referrals as most people are already coming from the western route. But knowing other acupuncturists, healers, bodyworkers, etc. and knowing when to use them is good. The main aspect of referrals is to learn when a patient (not due to anything you are doing in particular) is not going to get better (or any better) with you. The same exact set of points from one acupuncturist vs. another will elicit different reactions - this has to do with qi, but also just the practitioner demeanor, the types of questions they ask, and the relationship between the two people. Knowing that you cannot help everyone at all times is an important part of being a healer and an important part of being in the field of medicine.
What the future holds for the integration/collaboration of these various fields of medicine and techniques no one knows. And, ultimately, it seems to have less to do with what might be right for patients and more to do with laws, regulations, insurance, and - money. As people learn more, however, we shape our own uses - we create our own personal medical system. As we are finding with western drugs and treatments, you still need to be a well informed patient. You need to trust your doctors and other health care providers, but you need to also search out what may be best for you. As enough people do this (and they are doing it in very large numbers) the system will begin to reflect that. In might be minor things like health savings accounts to help you pay for non-insured services, or a complete integration of other systems of medicine into our current system. Only the future knows, so the important part for practitioners is to begin to get clear what you would like to see and also to make clear what you do and what you provide both to yourself, your patients, and the general public.