Fibromyalgia in patients with non-psychotic mental disorders: Prevalence, associated factors and validation of a brief screening instrument.

It is the first study to determine the prevalence of FM in people with non-psychotic spectrum mental disorders. The study design included a consecutive sample in a real-life setting to avoid bias. In addition, we evaluated the psychometric properties of the FM screening instrument in a population of people with mental disorders and established the cut-off. The specificity of this subpopulation is explained by both the high prevalence of pain symptoms and the overlap of some psychiatric and FM symptoms.