The etiopathogeny of fibromyalgia syndrome (FMS) remains unknown, although current hypotheses centre on anomalous peripheral nociception caused by wind-up, central sensitivization, high levels of substance P and neurotrophins, and alterations to the hypothalamus-hypophysis-adrenal axis [1, 2].
It is a multidimensional disorder, with currently poor therapeutic results. Despite the considerable increase in the number of studies published from 2000 to 2010, current treatment protocols are still unable to resolve the persistent symptoms experienced or improve the functional limitations and quality of life of these patients .
The prevalence of FMS among the Spanish population has been estimated at 2.7%, but at 4.2% for women and 0.2% for men . Factors that may raise the risk of FMS include middle age, early school leaving and low family income.
Levels of anxiety and depression among patients with musculoskeletal pain are known to be related to FMS ; thus, the prevalence of patients with FMS and severe depression varies from 20-80% .
Pharmacological treatment continues to be the chief treatment option; in this respect, an important role is played by tricyclic antidepressants, which have a direct effect on the reuptake of serotonin and norepinephrine, thus improving sleep patterns and alleviating depression, stress and anxiety, as well as inhibiting pain pathways and recognition , although they have only been proved to be moderately effective [8, 9]. Studies with new dual serotonin-norepinephrine reuptake inhibitors have produced promising preliminary results [10–12]. In addition, pregabalin has produced improvements, in comparison to a placebo, with respect to the treatment of pain, asthenia and sleep disorders among patients with FMS , and the combination of paracetamol and tramadol has also been found to be beneficial [14, 15]. These approaches, thus, are opening up new possibilities in the pharmacological treatment of FMS syndrome. New contributions to our understanding of the etiopathogenic mechanism of FMS are orienting treatment toward improving central sensitivization, for example via antagonists of N-Methyl-D-aspartate (NMDA) receptors .
Non-pharmacological options include aerobic exercise, and muscle toning and stretching [3, 17], which activate anti-nociceptive mechanisms and achieve pain reduction. There is moderate evidence that aerobic exercise is more beneficial than flexibilization, but no evidence that any one type of exercise is superior to another . Cognitive-behavioural therapy has proved to be effective for alleviating symptoms and pain-related behavioural disorders, by improving central sensitization and activating anti-nociceptive mechanisms [19, 20].
Acupuncture has been used as a treatment option in China for over 2000 years  and is increasingly accepted in the West, where its use has become considerably more common in recent decades, especially for pathologies producing high levels of pain [22, 23], and thus it has been suggested as a remedy for FMS [23, 24].
According to traditional Chinese medicine, FMS results from an imbalance that blocks or exhausts a person's internal energy (Qi) and the flow of blood, giving rise to the appearance of the symptoms that are characteristic of this syndrome [25, 26].
Despite the broad acceptance of acupuncture among patients and healthcare staff, the studies conducted to date have not produced sufficient evidence of its effectiveness in treating FMS , although the latest systematic reviews have shown these studies to be of low quality [17, 28, 29]. Since the last of these published reviews, in June 2004 , various other studies, of higher quality, have been conducted, but the results they report are uneven, and thus little light is shed upon the role of acupuncture in treating FMS. One well-designed study  randomised 100 FMS patients into among four groups (one given true acupuncture, and the other three, sham acupuncture), with two sessions per week being given for 12 weeks. No differences were found among any of the outcome measures, but this is not surprising, as the authors used a standard prescription of acupuncture points, which is not the correct procedure . Similar results have been found in another study, also well designed, which concluded that the level of analgesia attained is independent of the location of the acupuncture needles . On the contrary, another well-designed study  obtained positive results on comparing real acupuncture with a placebo in terms of relieving pain, asthenia and anxiety, with a reduction of 7 points on the scale of the Fibromyalgia Impact Questionnaire. Another study, carried out in 2008, also reported a reduction in pain intensity and an improvement in quality of life, three months after acupuncture treatment was applied to a group of FMS patients, in comparison with tricyclic antidepressant treatment and exercise . Acupuncture appears to be both safe and effective in treating depression, and is comparable with antidepressant treatment .
In view of these data, we designed this randomized controlled multicentre study of FMS patients, with the aim of determining the effectiveness of traditional acupuncture, using a point-selection algorithm established on the basis of the particular characteristics of each patient (seeking to reproduce standard clinical practice), and evaluating the progression of the illness using a specific measurement system, following OMERACT recommendations , and evaluating levels of depression, clinical and subjective pain intensity, the family life cycle, psychological aspects, quality of life, the duration of short-term disability, the consumption of anti-depressant, analgesic and anti-inflammatory medication, and the potential effect of factors considered to be predictors of a poor prognosis .