Common mechanisms of pain and depression: are antidepressants also analgesics?
Neither pain, nor depression exist as independent phenomena per se, they are highly subjective inner states, formed by our brain and built on the bases of our experiences, cognition and emotions. Chronic pain is associated with changes in brain physiology and anatomy. It has been suggested that the neuronal activity underlying subjective perception of chronic pain may be divergent from the activity associated with acute pain. We will discuss the possible common pathophysiological mechanism of chronic pain and depression with respect to the default mode network of the brain, neuroplasticity and the effect of antidepressants on these two pathological conditions. The default mode network of the brain has an important role in the representation of introspective mental activities and therefore can be considered as a nodal point, common for both chronic pain and depression. Neuroplasticity which involves molecular, cellular and synaptic processes modifying connectivity between neurons and neuronal circuits can also be affected by pathological states such as chronic pain or depression. We suppose that pathogenesis of depression and chronic pain shares common negative neuroplastic changes in the central nervous system (CNS). The positive impact of antidepressants would result in a reduction of these pathological cellular/molecular processes and in the amelioration of symptoms, but it may also increase survival times and quality of life of patients with chronic cancer pain.
Institute of Physiology, Academy of Sciences of the Czech Republic Prague, Czech Republic ; Department of Zoology, Ecology and Ethology Research Group, Faculty of Natural Science, Charles University in Prague Prague, Czech Republic.
Tereza
T
Nekovarova
Department of Normal, Pathological and Clinical Physiology, Third Faculty of Medicine, Charles University in Prague Prague, Czech Republic.
Anna
A
Yamamotova
Institute of Physiology, Academy of Sciences of the Czech Republic Prague, Czech Republic.
Karel
K
Vales
Institute of Physiology, Academy of Sciences of the Czech Republic Prague, Czech Republic.
Ales
A
Stuchlik
Department of Anesthesiology and Intensive Care Medicine, Pain Management Center, First Faculty of Medicine and General University Hospital, Charles University in Prague Prague, Czech Republic.
Jitka
J
Fricova
Department of Normal, Pathological and Clinical Physiology, Third Faculty of Medicine, Charles University in Prague Prague, Czech Republic.
Richard
R
Rokyta
antidepressants; chronic pain; cytokines; default mode network; depression; neuroplasticity; stress