Chronic pain and comorbid conditions

The great social and economic significance of chronic pain is widely recognized. The financial costs of treating back pain alone are three times greater than the costs of treating cancer patients. There is a well-founded opinion that the development of chronic pain depends to a greater extent on psychological factors than on the intensity of peripheral nociceptive effects.

It has been established that the prevalence of major depression among all persons seeking primary health care is 5-10%, and the prevalence of depressive disorders that do not meet the criteria for major depression is 2-3 times higher. Worldwide, depression ranks 4th among causes of disability, and by 2020 it is expected to take 2nd place on this list, second only to cancer. Depression (Latin depressio - suppression, oppression) is a mental disorder characterized by a pathologically depressed mood (hypothymia) with a negative, pessimistic assessment of oneself, one's position in the surrounding reality and one's future. Depressive mood changes along with distortion of cognitive processes are accompanied by ideational and motor inhibition, decreased motivation for activity, somatovegetative dysfunctions.

Depressive symptoms negatively affect the social adaptation and quality of life of the patient.

A study of depression in somatic patients (in therapeutic, cardiological and neurological practice) conducted in 2002 showed that 45.9% of patients had symptoms of depression; 22.1% of patients had mild depressive spectrum disorders, and 23.8% required mandatory prescription of antidepressants. At the same time, no reliable differences in the prevalence of depression at the reception of therapists, cardiologists or neurologists were noted. Correct diagnosis of depression is carried out only in 10-55% of patients in the general medical network, and only 13% of them receive adequate therapy with antidepressants.

The most widely recognized relationship (comorbidity) is that between chronic pain and depression. Depression of varying severity is observed in approximately 50% of patients with chronic pain, and more than 20% of patients meet the criteria for a major depressive episode. J.B. Murray (1997) believes that depression should be sought first in chronic pain, citing the existing opinion that any chronic pain is caused by severe depression. According to other authors, the incidence of depression in chronic pain varies from 10% to 100%. Depression among patients with chronic pain is more common in women. The greatest controversy is caused not by the fact of comorbidity of chronic pain and depression, but by the cause-and-effect relationships between them. Three possible options are considered: chronic pain is the cause of depression, depression increases susceptibility to pain, chronic pain and depression are associated with common pathogenetic mechanisms. It has been established that the presence of depression reduces pain thresholds, and the presence of anxiety and depression is associated, in particular, with tension headaches with the presence of trigger zones of the pericranial and cervical muscles. In addition to depression, anxiety disorders in the form of generalized disorder, panic disorder and post-traumatic disorder are often encountered in chronic pain. A combination of depression and anxiety is characteristic of chronic pain syndromes. In 40-90% of patients with anxiety, depression was present in the past or is currently present. Comorbidity of anxiety and depression is a clinical reality, characterized by high prevalence and cannot be reduced to random coincidences or methodological errors. In many patients, psychological disorders are combined with physical symptoms of fevoga: muscle tension, hyperhidrosis, nausea, dizziness, tachycardia, hyperventilation, increased urination and diarrhea.

Recently, an increasing number of works have appeared. indicating the commonality of the biochemical defect in the central nervous system in chronic pain and depression, in which the leading role is played by the insufficiency of the monoaminergic systems of the brain, which is confirmed by the high efficiency of antidepressants in chronic pain syndromes and the detection of intensive production of autoantibodies to serotonin, dopamine, norepinephrine in experimental animals with neuropathic syndrome. Experimental studies have shown that the pain syndrome is more severe when its development is preceded by the development of depressive syndrome, and not by its reversal.

Chronic pain also depends on the characteristics of personal development, the presence of similar problems in close relatives, and the factor of "beaten paths" after injury, surgery, somatic diseases.

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