Depression, pain, and somatoform disorders

PURPOSE OF REVIEW: The frequent co-occurrence of depression and somatic symptoms poses a continuing challenge to clinicians, researchers and experts involved in drawing up classifications. In this review we present recently published literature on aspects of epidemiology, classification and treatment in this important overlap area. RECENT FINDINGS: From the multitude of papers published annually on the co-occurrence of different pain conditions and depression, temporomandibular dysfunction stands out this year by sheer quantity; it can be seen as a model case of the necessity for differentiated high-quality assessments on the biological as well as the psychosocial level. There is a general move to separate utility of diagnostic classifications from their validity, and this strengthens classificatory approaches that help to view the regular overlap of depression, pain and other somatic symptoms as the rule rather than the exception. The incorporation of cognitive variables like causal attributions should help to distinguish clinically relevant subtypes among overlap cases. The classificatory future of the category of 'somatoform disorders' is somewhat in doubt, but reforms seem to be more productive than abolishment. Psychopharmacology provides rather intense recent coverage of the overlap field, with newer dual serotonergic-noradrenergic reuptake inhibitors offering some promise. SUMMARY: Treating the overlap of depression, pain and other somatic symptoms as the rule rather than the exception is necessary for adequate aetiological research as well as for diagnosis and treatment, with one-dimensional classificatory and treatment approaches almost certainly being insufficient.     

Acute injury, inflammation, and pain

Post-traumatic analgesia may depend on presynaptic inhibition, by a restriction of the input from damaged tissues into the central nervous system. With the development of inflammation, primary afferent depolarization decreases. Persistent irritation of nociceptors evoked by tissue inflammation can lower the pain threshold and cause hyperalgesia.     

Depression, pain, and hemispheric activation

The present study attempts to delineate the role of hemispheric activation in depression and pain. It was hypothesized that the right hemisphere is specialized to become activated by and to process negative affective stimuli, and that this specialization may play a role in the co-occurrence of depression and pain. The relationship between depression, experimental pain, and cerebral laterality was investigated in 16 depressed and 16 nondepressed, right-handed, female students. Cerebral laterality was measured via tasks assessing visual and auditory biases, and pain was assessed via a cold pressor task. The proposition that the right hemisphere mediates the co-occurrence of pain and depression was not supported, but specific findings did suggest that the right hemisphere may play a unique role in pain perception. Data from the visual task indicated that prior exposure to pain results in increased right hemisphere activation as indicated by a left visual field bias. Pain perception was a complex function of mood, preceding tasks, and the hand tested, and it was suggested that exposure to a typical right-hemisphere task increased the left side lateralization of pain in nondepressed subjects. Implications of these findings are discussed for coexisting problems of pain and depression and for the lateralization of pain in disorders judged to involve a significant psychogenic component.     

Facial pain, distress, and immune function

Chronic facial pain syndromes are associated with high levels of distress and depression. Immune system measures were investigated in otherwise healthy patients suffering from chronic temporomandibular pain and dysfunction syndrome (TMPDS) and in matched controls. No mean differences were found between TMPDS patients and the controls on any of the immune measures; however, both ConA and PWM responses in TMPDS patients were decreased in relation to the level of demoralization (P less than 0.05). Cognitive symptoms such as low self-esteem and perceptions of helplessness/hopelessness were implicated in these effects. In addition, among patients pain severity was independently associated with decreased ConA response (P less than 0.05). The data suggest possible correlates of stress-induced changes in the immune system.     

The role of spouse reinforcement, perceived pain, and activity levels of chronic pain patients

Levels of pain, activity, marital satisfaction, and contingent reinforcement for expressions of pain and suffering were assessed in chronic pain patients. In addition, spouses' marital satisfaction, mood, life control, and self-reported responses to the patient's pain were examined. Multiple regression analyses revealed that spouse reinforcement of overt expressions of pain was significantly related to both perceived pain and activity levels of chronic pain patients. The best predictor of patients' pain and activity levels was patients' perception of spouse reinforcement, followed by spouses' self-reported responses to the patients' pain. Spouse reinforcement of pain was not associated with spouses' marital satisfaction or perception of patients' pain levels. Rather, spouse reinforcement was associated with high interference of patients' pain with spouses' lives, spouses' positive mood, spouses' perception of more life control, as well as longer duration of the pain problem. The data support the importance of the spouse as a potential source of reinforcement of pain behavior.     

Phantom-limb pain: characteristics,causes, and treatment

Phantom-limb pain is a common sequela of amputation, occurring in up to 80% of people who undergo the procedure. It must be differentiated from non-painful phantom phenomena, residual-limb pain, and non-painful residual-limb phenomena. Central changes seem to be a major determinant of phantom-limb pain; however, peripheral and psychological factors may contribute to it. A comprehensive model of phantom-limb pain is presented that assigns major roles to pain occurring before the amputation and to central as well as peripheral changes related to it. So far, few mechanism-based treatments for phantom-limb pain have been proposed. Most published reports are based on anecdotal evidence. Interventions targeting central changes seem promising. The prevention of phantom-limb pain by peripheral analgesia has not yielded consistent results. Additional measures that reverse or prevent the formation of central memory processes might be more effective.     

Neck pain and associated head pain: persistent neck complaint with subsequent, transient, posterior headache

Background – During the Vågå headache epidemiology study, there were indications that various types of work, such as carpentry and hairdressing, frequently seemed to be linked to a combination of neckache and headache. Objectives – A post hoc study was conducted among 1838, 18‐ to 65‐year‐old Vågå citizens, looking for patients with combined neck/headache. Design – Face‐to‐face interview was conducted. Results – Combined neckache and headache were detected in 121 (6.6%) individuals. The bilateral headache originated in the neck; it was mild/moderate, symptom‐poor, and frequently provoked by awkward neck positions. No such headache occurred without a neckache. Headache in this group of patients resembles tractor drivers’ headache, except for the provoking factor itself. Conclusions – This headache is not listed in headache classification systems/textbooks on headache. This headache must be distinguished from the unilateral cervicogenic headache proper because of the different treatment perspectives.     

Adjustment to chronic pain: The role of pain acceptance,coping strategies,and pain-related cognitions

Background: Previous research has found that acceptance of pain is more successful than coping variables in predicting adjustment to pain.Purpose: To compare the influence of acceptance, pain-related cognitions and coping in adjustment to chronic pain.Methods: One hundred seventeen chronic pain patients attending the Clinical Pain Unit were administered a battery of questionnaires assessing pain acceptance, active and passive coping, pain-related cognitions, and adjustment.Results: The influence of acceptance, coping, and cognition on all the adjustment variables was considered simultaneously via Structural Equation Modeling using LISREL 8.30 software. A multigroup analysis showed that the male and female samples did not significantly differ regarding path coefficients. The final model showed that acceptance of pain determined functional status and functional impairment. However, coping measures had a significant influence on measures of emotional distress. Catastrophizing self-statements significantly influenced reported pain intensity and anxiety; resourcefulness beliefs had a negative and significant influence on depression.Conclusions: These findings suggest that acceptance may play a critical role in the maintenance of functioning and, with this aim, acceptance-based treatments are promising to avoid the development of disability. They also lend support to the role of control beliefs and of active coping to maintain a positive mood. Acceptance and coping are presented as complementary approaches.     

Social cognitions,personality and chronic pain

The assumptions of cognitive social psychology provide a suitable analysis for the understanding of how chronic pain sufferers interpret information and make decisions about attendance for treatment. This approach pays particular attention to the social context in which the pain behaviour occurs. Studies of socio-cognitive aspects of pain are reviewed and the implications for future research are outlined.