Depression and chronic pain

Chronic pain and depression are highly prevalent pathologies. The publications that account for the relationship between chronic pain and mood alterations date back to the 1940s. In the years that followed, and with the advances in psychopharmacology, the first stepswereta ken totrytounderstand the neurophysiological relationship between depression and pain. Epidemiological data demonstrate this relationship in symptomatology, diagnosis, prognosis and targets for treatment. The presence of both pathologies has serious repercussions for the patient, such as reduced functionality, higher severity indices, a worsening in the perception of health, higher use of opiods, among others. A hypothesis that integrates current knowledge of the physiopathology of chronic depression and pain has been put forward. A stress factor, persisting over time would alter the hypothalamic-pituitary-adrenal axis (HPA), thus increasing the release of cortisol, which causes maladaptive changes and results in deregulation of inflammatory markers, and decreases neurogenesis and monoaminergic transmission, these latter two involved in depression as well as descending modulation of pain. Some other studies have focused on certain mutations, which could be responsible for the presence of this comorbidity. The objective of this study is to review the bibliography of the relationship between chronic pain and depression in order to assess the current knowledge status on the subject, and the questions that need to be addressed in the future.