1. Research Unit; Galdakao-Usansolo Hospital; Galdakao Bizkaia Spain
2. Pain Management Unit; Galdakao-Usansolo Hospital; Galdakao Bizkaia Spain
3. Department of Psychiatry; Galdakao-Usansolo Hospital; Galdakao Bizkaia Spain
4. Health Services Research on Chronic Patients Network (REDISSEC); Galdakao Bizkaia Spain
5. Department of Psychology; Universidad Deusto; Bilbao Bizkaia Spain