An excellent summary from
The so simple body - The physical therapy Forum
Guest, the thread was started by a PT who lives in Denmark. His interest is to expose quackery, not to have people stop manipulating. (I personally don't think manipulation is safe for the high neck, but that's my own opinion which is not shared by all.. ).
The point is, manipulation is a tool, and should never have given rise to an entire profession in and of itself. The problem is with the deeply different training of traditional chiropractic:
1. Belief based rather than science based: the chiropractic manipulation system is not about detecting a physical problem, assessing it, and deciding whether to manipulate it or use some other strategy (i.e.: manipulation as one tool out of many..); It's about learning to believe in invisible subluxations, or blocks in nervous system flow, by impingments in the spinal column, and manipulate to remove them.
2. Competition with ordinary medical practice: The belief is instilled that manipulation will cure whatever ails you, there is a strong bias in many schools that regular medicine is evil and that recieving chiropractic treatment is the only way to be healthy. The trend among chiros is to advise against vaccinations etc. Chiropractors are not taught standard differential diagnosis, indeed they don't "believe" in illness. Everything is fine as long as you can be adjusted regularly. They sell 'adjustment' as prevention or insurance against illness. They believe in subluxation, not in "disease".
3. Comptetition with other practitioners of manipulation: In many states in the US chiropractors have successfully lobbied to have manipulation be illegal if used by all other professions, e.g.: physical therapy. In other words, if a PT performs manipulation a chiro can arrange to have their liscence revoked. This is way too much power in the hands of one group that is quack-based to begin with, but legislators in the US have been slow to rectify the problem.
4. Intense self-promotion: Values are instilled into students that are considered to be unethical by other healthcare practitioners. For example, much time is spent in school and in continuing ed. to learn how to build patient volume and a flourishing business. These are tactics generally taught in sales promotion schools, not health professions. Students are taught to memorize scripts that have been carefully worded to prey on patients' dark imaginings, and persuade them to place their entire health future in the hands of the chiro. Patients are encouraged to bring in their friends and families, and kickback systems are in place where the patient (who is called a "practice member" in chiro circles) will recieve special deals, a free treatment every ten treatments or similar sales incentives. Patients are groomed to become lifelong patients, attending for chiropractic "adjustments" for the rest of their lives, to free up their "innate intelligence", prevent the awful "subluxations"(which only a chiro can see) from impairing their health.
5. Opportunity for quackery to flourish: Once launched out into the world with this dubious set of values, no critical thinking skills, poor appreciation for science, and having access to the vulnerability of patients, the chiro mentality is to sell sell sell, anything and everything, whatever they can dream up, with elaborately devised claims of worth and efficacy but no proof. Q-ray bracelets are one such scam. The forum linked to for chiro assistants has a whole section devoted to such scams.
I think there are individual chiropractors out there and maybe the odd school that is better than the norm, who try to employ actual judgement in their patient care, and don't try to take advantage of people. But this situation is where chiropractic comes from. Has nothing to do, really, with whether manipulation is a valid tool or not.