Pain and depression have a high impact on caring for the people who need palliative care, but both of these are neglected compared with the approach for other symptoms encountered by these patients.
Areas of Uncertainty:
There are few studies in humans that support the existence of common neural circuits between depression and pain that also explore the use of drugs with effects in both conditions. More knowledge is needed about the relationship of these clinical entities that will lead to the optimization of the treatment and improvement of quality of life.
We conducted a search in PubMed to identify relevant articles and reviews that have been published in the last 5 years, concerning the topic of common pathways between depression and pain (2014–April 2019).
The connections between the 2 clinical entities start at the level of the cortical regions. The hippocampus is the main site of neural changes, modification of the immune system, neuromodulators, neurotransmitters, and signaling pathways implicated in both conditions. Increased levels of peripheral proinflammatory cytokines and neuroinflammatory changes are related to the physiopathology of these entities. Inflammation links depression and pain by altering neural circuits and changes in their common cortical regions. Antidepressants are used to treat depression and chronic, pain but more experimental studies are needed to determine which antidepressant drugs are the most effective in treating the 2 entities.
Pharmacological and nonpharmacological interventions targeting cortical changes in pain and depression are promising, but more clinical studies are needed to validate their usefulness.