POMC and major depressive disorder: Also to be included in the study are the possible changes in the secondary efficacy variables from baseline as assessed by the Short Form 36 version 2 health survey (patient-perceived quality of life), patient plasma cortisol and beta-endorphin levels at the different treatment stages, the Goldberg Anxiety and Depression Scale, pain medication use, functional capacity and stiffness (WOMAC subscales), and a VAS.