Studies show that increased neck pain, headache, and dizziness are common after manipulation. Patients treated by a physical therapist can have these symptoms but they occur much less often (6.8 percent).
Patients under the care of a medical doctor are affected about 5 percent of the time. Often these symptoms are drug-related. Patients who aren't taking any pills also report similar symptoms.
It seems that some patients have worse symptoms after treatment no matter what kind of treatment they get. This may be more common in patients with neck trauma. High levels of pain, severe headaches, and nausea are also linked with poor response to chiropractic care.
In some cases, a lack of confidence or a lack of expected benefits may lead to an adverse response to treatment. For other patients it's possible that short-term side effects are the price to pay to get better in the end.