Chronic widespread pain and fibromyalgia: what we know, and what we need to know.

Fibromyalgia (FM) is currently defined as the presence of both chronic widespread pain (CWP) and the finding of 11/18 tender points on examination. Only about 20% of individuals in the population with CWP also have 11/18 tender points; these individuals are considerably more likely to be female, and have higher levels of psychological distress. There is no clear clinical diagnosis for the other 80% of individuals with less than 11/18 tender points, but it is likely that these persons, like FM patients, also have pain that is 'central' (i.e. not due to inflammation or damage of structures) rather than peripheral in nature. Research into FM has taught us a great deal about the confluence of neurobiological, psychological and behavioural factors that can cause chronic central pain. These conditions respond best to a combination of symptom-based pharmacological therapies, and non-pharmacological therapies such as exercise and cognitive behavioural therapy. In contrast to drugs that work for peripheral pain due to damage or inflammation (e.g. NSAIDs, corticosteroids), neuroactive compounds [especially those that raise central levels of noradrenaline (norepinephrine) or serotonin] are most effective for treating central pain.