Negative affect and pain in arthritis

Optimism and Psychological Resilience are Beneficially Associated With Measures of Clinical and Experimental Pain in Adults With or at Risk for Knee Osteoarthritis

OBJECTIVES

This cross-sectional study examined the associations among optimism, psychological resilience, endogenous pain inhibition, and clinical knee pain severity. Two hypotheses were tested. First, we hypothesized that experimentally tested endogenous pain inhibition would mediate the relationship between optimism and clinical knee pain severity. Second, it was also hypothesized that optimism would moderate the relationships of psychological resilience with endogenous pain inhibition and clinical knee pain severity, particularly for individuals with high optimism.

METHODS

A total of 150 individuals with or at risk for symptomatic knee osteoarthritis completed the Life Orientation Test-Revised, the Brief Resilience Scale, and the revised Short-Form McGill Pain Questionnaire-2 to assess optimism, psychological resilience, and clinical knee pain severity, respectively. Endogenous pain inhibition was examined experimentally using a conditioned pain modulation (CPM) protocol with algometry (test stimulus) and a cold pressor task (conditioning stimulus).

RESULTS

As hypothesized, results showed that increased CPM significantly mediated the association between higher optimism and lower clinical knee pain severity. Further, optimism moderated the association between psychological resilience and CPM. However, contrary to our hypothesis, greater psychological resilience was associated with enhanced CPM in individuals with low optimism only.

DISCUSSION

This study suggests that an optimistic outlook may beneficially impact clinical pain severity by altering endogenous pain modulatory capacity. Furthermore, individuals with low optimism (ie, pessimists) may be more adept at engaging resources that promote psychological resilience, which in turn, enhances endogenous pain modulatory capacity. Therefore, this study supports consideration of psychological resilience factors when evaluating experimental and clinical pain outcomes.

Affect and Incident Participation Restriction in Adults With Knee Osteoarthritis

OBJECTIVE

Participation restriction, common among people with knee osteoarthritis (OA), may be influenced by affect. We examined the risk of incident participation restriction over 84 months conferred by positive and negative affect among people with knee OA.

METHODS

Participants were from the Multicenter Osteoarthritis Study and had or were at high risk of knee OA. Participation restriction was measured using the Instrumental Role Limitation subscale of the Late-Life Disability Index, and affect was measured using the positive affect and depressed mood subscales of the Center for Epidemiologic Studies Depression Scale. Robust Poisson regression was used to calculate the risk of incident participation restriction over 84 months conferred by combinations of low and high positive and negative affect, adjusting for covariates.

RESULTS

Of 1,810 baseline participants (mean age 62.1 years, 56% female), 470 (26%) had incident participation restriction over 84 months. Participants with low positive affect had 20% greater risk of incident participation restriction than those with high positive affect; participants with high negative affect had 50% greater risk of incident participation restriction compared to those with low negative affect. Participants with both low positive and high negative affect had 80% greater risk of incident participation restriction compared to other combinations of positive and negative affect.

CONCLUSION

Low positive and high negative affect, both alone and in combination, increase the risk of participation restriction among adults with knee OA. Efforts aimed at preventing participation restriction in this population should consider these mood states.

Depressive Symptoms and Momentary Mood Predict Momentary Pain Among Rheumatoid Arthritis Patients

BACKGROUND

Although a relationship between mood and pain has been established cross-sectionally, little research has examined this relationship using momentary within-person data.

PURPOSE

We examined whether baseline depressive symptoms and within-person levels of negative and positive mood predicted momentary pain among 31 individuals with rheumatoid arthritis (RA).

METHODS

Depressive symptomatology was measured at baseline. Mood and RA symptoms were self-reported via ecological momentary assessment five times a day for seven consecutive days. Analyses controlled for gender, age, weekend day, time of day, and experiences of stress.

RESULTS

Greater momentary positive mood was associated with less momentary pain and fewer arthritis-related restrictions; negative mood was associated with more restrictions. Greater depressive symptomatology also predicted more pain and restrictions, an effect which was not accounted for by mood.

CONCLUSIONS

Results suggest that both depression and mood are uniquely associated with momentary pain; as such, multi-component interventions may provide optimal disease management.

Pain Disability Among Older Adults With Arthritis

Objective: The principal objective was to examine pain disability (the degree to which chronic pain interferes with daily activities) among older adults with arthritis. Specifically, answers to two research questions were sought: (a) Does psychological distress reliably predict pain disability; and (b) do certain theoretically important host, sociodemographic, and health-related factors reliably predict pain disability? Method: Descriptive, univariate, and multivariate regression analyses were employed to assess key psychosocial, disease, and host factors among the sample ( N =141) of adults with arthritis, aged [UNKNOWN] 50 years old. Results: The resultant regression model accounted for 63.7% (60.0% adjusted) of the variance and was significant at p < .01. Psychological distress, overall health, disease activity, and disease self-efficacy were found to predict pain disability. Discussion: Sample members with greater pain disability experienced heightened psychological distress, poorer perceptions of their overall health, more surgeries, higher unemployment, more intense disease activity, longer disease duration, and lower disease self-efficacy.

Relationship between fear avoidance beliefs and burnout syndrome in patients with lumbar disc herniation

OBJECTIVES

Lumbar disc herniation leads to disability by restricting of patients' lives and reducing their quality of life. This situation causes a decrease in motivation of patients by triggering depressive mood. Therefore, the aim of the study was investigation of correlation between fear avoidance beliefs and burnout syndrome in patients with lumbar disc herniation.

METHODS

Totally forty-seven patients (24 male and 23 female patients) diagnosed lumbar disc herniation was included in this study. Maslach II Burnout Inventory (MBI) and Fear Avoidance Beliefs Questionnaire (FABQ) for determining of levels of burnout and fear avoidance level were used, respectively.

RESULTS

It was observed that MBI and FABQ scores of the patients were 50.78 ± 10.07 and 36.61 ± 13.91, respectively. Moderate level correlation was found between FABQ and MBI total scores (r= 0.49, p= 0.00).

CONCLUSIONS

Fear avoidance beliefs of patients with chronic back pain can affect level of burnout syndrome. Therefore, symptoms of burnout syndrome and fear avoidance beliefs of patients should be considered in evaluation and treatment process.

Persistent pain facilitates response to morphine reward by downregulation of central amygdala GABAergic function

Opioid-based analgesics are widely used for treating chronic pain, but opioids are highly addictive when repeatedly used because of their strong rewarding effects. In recent years, abuse of prescription opioids has dramatically increased, including incidences of misuse of opioid drugs prescribed for pain control. Despite this issue in current clinical pain management, it remains unknown how pain influences the abuse liability of prescription opioids. Pain as aversive experience may affect opioid reward of positive emotion through common brain sites involved in emotion processing. In this study, on a rat model of chronic pain, we determined how persistent pain altered behavioral responses to morphine reward measured by the paradigm of unbiased conditioned place preference (CPP), focusing on GABAergic synaptic activity in neurons of the central nucleus of the amygdala (CeA), an important brain region for emotional processing of both pain and reward. We found that pain reduced the minimum number of morphine-conditioning sessions required for inducing CPP behavior. Both pain and morphine conditioning that elicited CPP inhibited GABA synaptic transmission in CeA neurons. Pharmacological activation of CeA GABAA receptors reduced the pain and inhibited CPP induced both by an effective dose of morphine and by a sub-threshold dose of morphine under pain condition. Furthermore, inhibition of CeA GABAA receptors mimicked the pain effect, rendering the sub-threshold dose of morphine effective in CPP induction. These findings suggest that pain facilitates behavioral responses to morphine reward by predisposing the inhibitory GABA function in the CeA circuitry involved in the behavior of opioid reward.

The relationship between pain and eating among overweight and obese individuals with osteoarthritis: an ecological momentary study

The relationship between pain and overweight/obesity is bidirectional – excess weight can cause pain, yet eating food high in calories, fat and sugar has been shown to alleviate pain. It appears likely that overweight/obese individuals may turn to these types of foods when they experience pain, leading to weight gain; however, this phenomenon has not been examined to date. The authors of this study set out to elucidate the relationship between pain and food intake in obese and overweight patients with osteoarthritis.

BACKGROUND:

Osteoarthritis (OA) patients who are overweight or obese report higher levels of pain compared with their normal-weight OA counterparts. Evidence suggests that overweight or obese OA patients also experience pain relief from eating foods high in calories, fat or sugar. Eating to alleviate pain may be problematic because it can lead to additional weight gain, which may contribute to heightened pain.

OBJECTIVES:

To investigate the relationship between pain and food intake using ecological momentary assessments in a sample of 71 over-weight and obese OA patients.

METHODS:

Participants completed two consecutive days of diary entries in which they recorded their levels of pain, mood and food intake throughout the day. Data were analyzed using generalized estimating equations that modelled pain as a predictor of calorie, fat and sugar intake. All models were adjusted for sex, body mass index, negative mood, time and treatment history.

RESULTS:

Pain significantly predicted calorie (Z=2.57; P=0.01) and fat intake (Z=1.99; P=0.05).

CONCLUSIONS:

Using ecological momentary assessments as a novel approach, the present study provides preliminary data supporting a relationship between pain and food intake among overweight and obese OA patients. Continued advances in our understanding of the relationship between pain and eating behaviour may help to optimize intervention strategies for these patients.

Relationship between psychological factors and arthralgia in patients with rheumatoid arthritis

Abstract Various factors were assessed in terms of their contribution to arthralgia in a rheumatoid arthritis patient. Eighty-two outpatients (62 women and 20 men) with rheumatoid arthritis (RA) were examined with respect to the subjective degree of arthralgia, age, disease duration, dysfunction, steroid dose, steroid period, depression, anxiety, extroversion, neurotic disorder, and number of caretakers. The results were explained on the basis of stepwise regression analysis and psychological and clinical data. We analyzed results of a correlation coefficient test on the mutual relationship between variables. Stepwise regression analysis was performed to assess factors of arthralgia in terms of "depression," "mean activity," "morning stiffness," and "steroid dose." Depression is a factor of arthralgia as shown in this study, but it is clear that other factors are also involved. Anxiety was a factor distinct from the activity of RA. The factor contributing most to arthralgia was found to be depression, whereas anxiety had no effect.

A prospective study of mental health care for comorbid depressed mood in older adults with painful osteoarthritis

BACKGROUND

Comorbid depression is common among adults with painful osteoarthritis (OA). We evaluated the relationship between depressed mood and receipt of mental health (MH) care services.

METHODS

In a cohort with OA, annual interviews assessed comorbidity, arthritis severity, and MH (SF-36 mental health score). Surveys were linked to administrative health databases to identify mental health-related visits to physicians in the two years following the baseline interview (1996-98). Prescriptions for anti-depressants were ascertained for participants aged 65+ years (eligible for drug benefits). The relationship between MH scores and MH-related physician visits was assessed using zero-inflated negative binomial regression, adjusting for confounders. For those aged 65+ years, logistic regression examined the probability of receiving any MH-related care (physician visit or anti-depressant prescription).

RESULTS

Analyses were based on 2,005 (90.1%) individuals (mean age 70.8 years). Of 576 (28.7%) with probable depression (MH score < 60/100), 42.5% experienced one or more MH-related physician visits during follow-up. The likelihood of a physician visit was associated with sex (adjusted OR women vs. men = 5.87, p = 0.005) and MH score (adjusted OR per 10-point decrease in MH score = 1.63, p = 0.003). Among those aged 65+, 56.7% with probable depression received any MH care. The likelihood of receiving any MH care exhibited a significant interaction between MH score and self-reported health status (p = 0.0009); with good general health, worsening MH was associated with increased likelihood of MH care; as general health declined, this effect was attenuated.

CONCLUSIONS

Among older adults with painful OA, more than one-quarter had depressed mood, but almost half received no mental health care, suggesting a care gap.

Cognitive-affective assets and vulnerabilities: two factors influencing adaptation to fibromyalgia

This study set to explore whether variables related to cognitive-affective assets would complement measures of psychological vulnerability for the prediction of physical functioning and pain tolerance in 138 women with Fibromyalgia Syndrome (FMS). Depression, anxiety, stress response and negative affect were defined a priori as measures of vulnerability, while pain self-efficacy, internality and positive affect were identified as assets. Confirmatory factor analyses supported the validity of the hypothesised two-factor structure in FMS. A structural equation model (SEM) revealed that the two factors were associated with different outcomes in FMS as predictors. Pain and associated symptoms appeared related to psychological vulnerabilities in FMS patients, whereas physical functioning and tolerance for pain were better predicted by assets. These results are discussed with reference to current theoretical models concerning the role of psychological factors in FMS, and intervention methods designed to improve quality of life and reduce pain in FMS patients.

Facilitation of synaptic transmission and pain responses by CGRP in the amygdala of normal rats

Calcitonin gene-related peptide (CGRP) plays an important role in peripheral and central sensitization. CGRP also is a key molecule in the spino-parabrachial-amygdaloid pain pathway. Blockade of CGRP1 receptors in the spinal cord or in the amygdala has antinociceptive effects in different pain models. Here we studied the electrophysiological mechanisms of behavioral effects of CGRP in the amygdala in normal animals without tissue injury.Whole-cell patch-clamp recordings of neurons in the latero-capsular division of the central nucleus of the amygdala (CeLC) in rat brain slices showed that CGRP (100 nM) increased excitatory postsynaptic currents (EPSCs) at the parabrachio-amygdaloid (PB-CeLC) synapse, the exclusive source of CGRP in the amygdala. Consistent with a postsynaptic mechanism of action, CGRP increased amplitude, but not frequency, of miniature EPSCs and did not affect paired-pulse facilitation. CGRP also increased neuronal excitability. CGRP-induced synaptic facilitation was reversed by an NMDA receptor antagonist (AP5, 50 microM) or a PKA inhibitor (KT5720, 1 microM), but not by a PKC inhibitor (GF109203X, 1 microM). Stereotaxic administration of CGRP (10 microM, concentration in microdialysis probe) into the CeLC by microdialysis in awake rats increased audible and ultrasonic vocalizations and decreased hindlimb withdrawal thresholds. Behavioral effects of CGRP were largely blocked by KT5720 (100 microM) but not by GF109203X (100 microM).The results show that CGRP in the amygdala exacerbates nocifensive and affective behavioral responses in normal animals through PKA- and NMDA receptor-dependent postsynaptic facilitation. Thus, increased CGRP levels in the amygdala might trigger pain in the absence of tissue injury.

Anxiolytic-like effects of morphine and buprenorphine in the rat model of fear-potentiated startle: tolerance, cross-tolerance, and blockade by naloxone

RATIONALE

Morphine and buprenorphine have analgesic and anxiolytic-like properties. While their analgesic effects have been well characterized, their anxiolytic-like properties have not.

OBJECTIVES

Effects of acute morphine and buprenorphine on the expression of acoustic fear-potentiated startle (FPS) and naloxone pretreatment were assessed. Effects of chronic morphine and buprenorphine on tolerance, cross-tolerance, and withdrawal were also examined.

MATERIALS AND METHODS

Fear-conditioned rats were given subcutaneous drug treatment immediately before testing for FPS. Experiment 1, rats were administered morphine (0.03, 0.25, 0.63, 2.5, or 10 mg/kg) or buprenorphine (0.004, 0.0075, 0.015, 0.03, or 0.25 mg/kg). Experiment 2, rats were given saline or naloxone (0.5 mg/kg) and 5 min later given saline, morphine (2.5 mg/kg), or buprenorphine (0.03 mg/kg). Experiment 3, rats received once-daily injections of saline, morphine (10 mg/kg), or buprenorphine (0.25 mg/kg) for 7 days. Immediately before testing, saline-treated rats were given saline, morphine (2.5 mg/kg), or buprenorphine (0.03 mg/kg), morphine-treated rats were given morphine (2.5 mg/kg) or buprenorphine (0.03 mg/kg), and buprenorphine-treated rats were given buprenorphine (0.03 mg/kg) or morphine (2.5 mg/kg). Tolerance and cross-tolerance in analgesia were assessed via the tail-flick test, as were naloxone-precipitated withdrawal.

RESULTS

Morphine and buprenorphine had parallel dose-response curves in blocking FPS, with buprenorphine 40 times more potent than morphine. Naloxone reversed these effects. Morphine and buprenorphine showed tolerance and cross-tolerance in their anxiolytic-like and analgesic effects. Chronic buprenorphine produced less withdrawal than chronic morphine.

CONCLUSIONS

Cross-tolerance between morphine and buprenorphine suggests a common receptor mediating their anxiolytic-like and analgesic effects.

Understanding the pain experience in hip and knee osteoarthritis--an OARSI/OMERACT initiative

OBJECTIVE

To examine the pain experience of people with hip or knee osteoarthritis (OA), particularly changes over time and most distressing features.

METHOD

Focus groups in individuals aged 40+ years with painful hip or knee OA obtained detailed descriptions of OA pain from early to late disease. A modified Patient Generated Index (PGI) was used to assess the features of OA pain that participants found most distressing. Content analysis was performed to examine response patterns; descriptive statistics were used to summarize PGI responses.

RESULTS

Mean age of the 143 participants (52 hip OA; 91 knee OA) was 69.5 years (47-92 years); 60.8% were female and 93.7% Caucasian. Participants described two distinct types of pain - a dull, aching pain, which became more constant over time, punctuated increasingly with short episodes of a more intense, often unpredictable, emotionally draining pain. The latter, but not the former, resulted in significant avoidance of social and recreational activities. From PGI responses, distressing pain features were: the pain itself (particularly intense and unpredictable pain) and the pain's impact on mobility, mood and sleep.

CONCLUSIONS

Two distinct pain types were identified. Intermittent intense pain, particularly when unpredictable, had the greatest impact on quality of life.

Arthritis and pain. Neurogenic origin of joint pain

Arthritis pain affects millions of people worldwide yet we still have only a limited understanding of what makes our joints ache. This review examines the sensory innervation of diarthroidal joints and discusses the neurophysiological processes that lead to the generation of painful sensation. During inflammation, joint nerves become sensitized to mechanical stimuli through the actions of neuropeptides, eicosanoids, proteinase-activated receptors and ion channel ligands. The contribution of immunocytes to arthritis pain is also reviewed. Finally, the existence of an endogenous analgesic system in joints is considered and the reasons for its inability to control pain are postulated.

Relation Between Mood and Self-Reported Dry Eye in Contact Lens Wearers

PURPOSE

The etiology of dry eye disease is poorly understood, and a significant percentage of the population reports experiencing frequent and burdensome symptoms. Recent evidence from other disciplines has shown a relation between self-rated mood and symptom reporting, and the purpose of this work was to explore the relation between self-rated mood and dry eye symptoms.

METHODS

A cross-sectional/nested case-control study was used to examine factors associated with self-reported dry eye disease. Logistic and linear regression analyses were used to examine the relation between self-reported dry eye and positive and negative affect. All models included age, sex, education, income, race, and marital status, when appropriate.

RESULTS

Four hundred fifteen individuals were enrolled in the study. Two thirds were women, and the average age was 30.6 +/- 11.2 (SD) years. Two hundred fifteen (51.8%) self-reported dry eye. The average positive-affect scores were 34.6 +/- 5.9 and 34.9 +/- 6.0 (t = 0.58, P = 0.56) for those self-reporting dry eye and not reporting dry eye, respectively. The average negative-affect scores were 19.4 +/- 6.0 and 18.6 +/- 5.7 (t = -1.38, P = 0.17) for the dry eye and non-dry eye groups, respectively. After controlling for age, neither logistic regression nor linear regression showed a relation between positive or negative affect and self-reported dry eye.

CONCLUSION

Preliminary analyses suggest that self-reported mood is not related to dry eye status in contact lens wearers. Although symptoms are a hallmark of dry eye disease, they may not be significant enough such that they relate to affective states in the way they do for other symptomatic diseases with more associated pain (eg, arthritis).

Dynamic neuronal responses in cortical and thalamic areas during different phases of formalin test in rats

Although formalin-induced activity in primary afferent fibers and spinal dorsal horn is well described, the forebrain neural basis underlying each phase of behavior in formalin test has not yet been clarified. The present study was designed to investigate the cortical and thalamic neuronal responses and interactions among forebrain areas during different phases after subcutaneous injection of formalin. Formalin-induced neuronal activities were simultaneously recorded from primary somatosensory cortex (SI), anterior cingulate cortex (ACC) and medial dorsal (MD) and ventral posterior (VP) thalamus during different phases (i.e., first phase, interphase, second phase and third recovery phase starting from 70 min after injection) of formalin test, using a multi-channel, single-unit recording technique. Our results showed that, (i) unlike the responses in primary afferent fibers and spinal dorsal horn, many forebrain neurons displayed monophasic excitatory responses in the first hour after formalin injection, except a small portion of neurons which exhibited biphasic responses; (ii) the response patterns of many cortical and thalamic neurons changed from excitatory to inhibitory at the end of the second phase; (iii) the direction of information flow also changed dramatically, i.e., from cortex to thalamus and from the medial to the lateral pathway in the first hour, but reversed in phase 3. These results indicate that the changes of activity pattern in forebrain networks may underlie the emerging and subsiding of central sensitization-induced pain behavior in the second phase of formalin test.

Depression in rheumatoid arthritis patients: demographic, clinical, and psychological predictors

OBJECTIVE

To confirm the prevalence of depression in a sample of rheumatoid arthritis (RA) patients; to identify the most significant predictors of depression in RA and to explore patients attitudes to medication in relation to depression.

METHODS

A cross-sectional survey was used to collect data from 134 RA patients (77% female, 23% male). Participants were divided into depressed and nondepressed groups based on their scores on the Center for Epidemiological Studies-Depression (CES-D) scale. Discriminant analysis was conducted to identify the predictors that would best categorise patients into those two groups.

RESULTS

Twelve predictors correctly classified 80% of patients into depressed or nondepressed groups. The strongest predictors of depression were high tension and low self-esteem followed by the perceived impact of RA, fatigue, passive coping, pain, and physical disability. Other predictors included medication effectiveness and importance as well as perceived lack of control over pain.

CONCLUSION

Both physical and psychological factors have an impact on depression in RA. The key predictors identified in this study need to be considered within the regular RA management as possible cues to depression development.

Pain-related emotions modulate experimental pain perception and autonomic responses

The effect of emotions on pain perception is generally recognized but the underlying mechanisms remain unclear. Here, emotions related to pain were induced in healthy volunteers using hypnosis, during 1-min immersions of the hand in painfully hot water. In Experiment 1, hypnotic suggestions were designed to induce various positive or negative emotions. Compared to a control condition with hypnotic-relaxation, negative emotions produced robust increases in pain. In Experiment 2, induction of pain-related anger and sadness were found to increase pain. Pain increases were associated with increases in self-rated desire for relief and decreases in expectation of relief, and with increases in arousal, negative affective valence and decreases in perceived control. In Experiment 3, hypnotic suggestions specifically designed to increase and decrease the desire for relief produced increases and decreases in pain, respectively. In all three experiments, emotion-induced changes in pain were most consistently found on ratings of pain unpleasantness compared to pain intensity. Changes in pain-evoked cardiac responses (R-R interval decrease), measured in experiments 2 and 3, were consistent with changes in pain unpleasantness. Correlation and multiple regression analyses suggest that negative emotions and desire for relief influence primarily pain affect and that pain-evoked autonomic responses are strongly associated with pain affect. These results confirm the hypothesized influence of the desire for relief on pain perception, and particularly on pain affect, and support the functional relation between pain affect and autonomic nociceptive responses. This study provides further experimental confirmation that pain-related emotions influence pain perception and pain-related physiological responses.

Depression, anxiety and pain in children with juvenile idiopathic arthritis (JIA)

The aim of this study was to assess relations among depression, anxiety and pain in children with juvenile idiopathic arthritis (JIA). Pain was measured with the visual analogue scale (VAS), and depression and anxiety with depression and anxiety subscales from the Trauma Symptom Checklist for Children (TSC-C). Pain perception was significantly correlated with depression scores.

The impact of pain on psychological well-being in rheumatoid arthritis: the mediating effects of self-esteem and adjustment to disease

The aim of this study was to determine whether self-esteem and adjustment to disease can mediate the association between pain and psychological well-being in patients with Rheumatoid Arthritis (RA). Coefficients of correlation, multiple linear regressions and Structural Equation Model (SEM) were employed in order to examine the direct and indirect relationships between pain, self-esteem, adjustment to disease and psychological well-being in a sample of 160 recently-diagnosed RA-patients. The outcomes of the analyses indicate that self-esteem and adjustment to disease are important links between pain and psychological well-being. Moreover, the results suggest the increasing importance of personality variables in mediating the relationship between pain and psychological well-being as the disease advances. The findings provide evidence for considerations that psychosocial interventions, focused on increasing the self-esteem and improving the adjustment to disease, may reduce the impact of pain on patients' psychological well-being and quality of life in general.

Computerized analysis of audible and ultrasonic vocalizations of rats as a standardized measure of pain-related behavior

The behavioral assessment of experimental pain is essential for the analysis of pain mechanisms and the validation of therapeutic targets. Arthritic pain, in particular, is significantly associated with negative affective states and disorders. Here we present a standardized method for the quantitative analysis of audible and ultrasonic (25 +/- 4 kHz) vocalizations in awake rats as a measure of higher integrated behavior in a model of arthritic pain. A bat detector and a condenser microphone were used to record ultrasonic and audible vocalizations, respectively, in response to innocuous and noxious mechanical stimulation of the knee before and after induction of acute arthritis in one knee. A computerized system was used to analyze number and duration of the filtered signals. For the behavioral tests, the animal was placed in a customized recording chamber to ensure consistent stimulus application and stable recordings and to eliminate any movement-induced noise. Noxious stimuli produced stronger vocalizations than innocuous stimuli. Both audible and ultrasonic vocalizations to innocuous (allodynia) and noxious (hyperalgesia) stimuli increased after the induction of acute arthritis. These changes were accompanied by increased knee joint circumference, lowered hind limb withdrawal thresholds and reduced exploratory behavior in the same animals. The computerized analysis of audible and ultrasonic vocalizations is a valid, quantitative, reliable and convenient method to measure pain-related behavior.

Block of NMDA and non-NMDA receptor activation results in reduced background and evoked activity of central amygdala neurons in a model of arthritic pain

The latero-capsular division of the central nucleus of the amygdala (CeA) is now defined as the 'nociceptive amygdala' because of its high content of neurons activated exclusively or preferentially by noxious stimuli. Multireceptive (MR) neurons that respond to innocuous and, more strongly, to noxious stimuli become sensitized in arthritis pain. This form of nociceptive plasticity involves presynaptic group I metabotropic glutamate receptors, which increase glutamate release. Here we address the role of N-methyl-D-aspartate (NMDA) and non-NMDA receptors. Extracellular single-unit recordings were made from 25 CeA neurons in anesthetized rats. The neurons' responses to graded brief (15 s) mechanical stimuli, background activity, receptive field size and threshold were measured before and after the induction of kaolin/carrageenan arthritis in one knee and before and during drug applications into the CeA by microdialysis. All neurons examined received excitatory input from the knee(s) and were MR neurons. A selective NMDA receptor antagonist (AP5) inhibited responses to noxious stimuli more potently in the arthritic pain state (n = 6) than under control conditions before arthritis (n = 8) AP5 also inhibited the enhanced background activity and increased responses to normally innocuous stimuli in arthritis, but had no significant effects on these parameters under control conditions. A selective non-NMDA receptor antagonist (NBQX) inhibited background activity and evoked responses under normal control conditions (n = 6) and in arthritis (n = 8) These data suggest that activation of both NMDA and non-NMDA receptors contributes to pain-related sensitization of amygdala neurons.

Perceived importance of activities of daily living and arthritis helplessness in rheumatoid arthritis; a prospective investigation

OBJECTIVE

To examine the contribution of perceived importance of activities of daily living (ADL) to arthritis-specific helplessness in a sample of rheumatoid arthritis (RA) patients over a 1-year period.

METHOD

Forty-two individuals from an outpatient rheumatology clinic completed measures of ADL importance, helplessness, depression, pain, and disability; the physician's assistant provided objective ratings of disability.

RESULTS

Time 1 importance of ADL predicted a significant amount of variance in Time 2 arthritis helplessness after statistically controlling disease and psychological covariates. Moreover, increased perceived ADL importance predicted decreased arthritis helplessness over the 1-year period.

CONCLUSIONS

Results indicate that RA patients' experience of arthritis-specific helplessness may be minimized over time when performing ADL is perceived as important. Furthermore, these findings provide preliminary evidence for one possible antecedent to increased perceptions of arthritis helplessness in individuals with RA.

The amygdala and persistent pain

A reciprocal relationship exists between persistent pain and negative affective states such as fear, anxiety, and depression. Accumulating evidence points to the amygdala as an important site of such interaction. Whereas a key role of the amygdala in the neuronal mechanisms of emotionality and affective disorders has been well established, the concept of the amygdala as an important contributor to pain and its emotional component is still emerging. This article will review and discuss evidence from anatomical, neuroimaging, behavioral, electrophysiological, pharmacological, and biochemical data that implicate the amygdala in pain modulation and emotional responses to pain. The latero-capsular division of the central nucleus of the amygdala is now defined as the "nociceptive amygdala" and integrates nociceptive information with poly-modal information about the internal and external bodily environment. Dependent on environmental conditions and affective states, the amygdala appears to play a dual facilitatory and inhibitory role in the modulation of pain behavior and nociceptive processing at different levels of the pain neuraxis. Only recently, electrophysiological, pharmacological, and biochemical neuroplastic changes were shown in the nociceptive amygdala in persistent pain. It is conceivable, however, that amygdala plasticity plays an important role in emotional pain behavior and its modulation by affective state.

Enhanced group III mGluR-mediated inhibition of pain-related synaptic plasticity in the amygdala

Pain has a strong emotional component. A key player in emotionality, the amygdala is also involved in pain processing. Our previous studies showed synaptic plasticity in the central nucleus of the amygdala (CeA) in a model of arthritic pain. Here, we address the role of group III metabotropic glutamate receptors (mGluRs) in the regulation of synaptic transmission in CeA neurons. Whole-cell current- and voltage-clamp recordings were made from neurons in the latero-capsular part of the CeA in brain slices from control rats and arthritic rats (>6 h postinduction). The latero-capsular part of the CeA is the target of the spino-parabrachio-amygdaloid pain pathway and is now designated as the "nociceptive amygdala". Monosynaptic excitatory postsynaptic currents (EPSCs) were evoked by electrical stimulation of afferents from the pontine parabrachial (PB) area. LAP4 decreased the amplitude of EPSCs more potently in CeA neurons from arthritic rats (EC(50)=1.2 nM) than in control animals (EC(50)=11.5 nM). The inhibitory effect of LAP4 was reversed by a selective group III mGluR antagonist (UBP1112). During the application of LAP4, paired-pulse facilitation was increased, while no significant changes in slope conductance and action potential firing rate of CeA neurons were observed. These data suggest that presynaptic group III mGluRs are involved in the regulation of synaptic plasticity in the amygdala in an arthritis pain model.

Depressive Symptoms as a Risk Factor for Disabling Back Pain in Community-Dwelling Older Persons

OBJECTIVES

To determine whether the presence of depressive symptoms is an independent risk factor for disabling back pain in community-dwelling older persons.

DESIGN

Prospective cohort study with a 12-month follow-up period.

SETTING

General community.

PARTICIPANTS

Seven hundred forty-four members of a large health plan who were aged 70 and older and independent in bathing, walking, dressing, and transferring at baseline.

MEASUREMENTS

The presence of depressive symptoms, defined as a score of 16 or greater on the Center for Epidemiologic Studies-Depression Scale, was documented during a comprehensive baseline assessment that also included information regarding participants' demographic, medical, and physical/cognitive status. The occurrence of disabling back pain was ascertained during monthly telephone interviews.

RESULTS

Depressive symptoms were present in 153 (20.6%) participants at baseline. Over the 12-month follow-up period, 186 participants (25.0%) reported disabling back pain during 1 to 2 months and 91 (12.2%) during 3 or more months. After adjustment for potential confounders, the presence of depressive symptoms was independently associated with the occurrence of disabling back pain (adjusted odds ratio (AOR)=2.3 (95% confidence interval (CI)=1.2-4.4) for 1 to 2 months with disabling back pain; AOR=7.8 (95% CI=3.7-16.4) for 3 or more months with disabling back pain).

CONCLUSION

The presence of depressive symptoms is a strong, independent, and highly prevalent risk factor for the occurrence of disabling back pain in community-dwelling older persons.

Differential roles of mGluR1 and mGluR5 in brief and prolonged nociceptive processing in central amygdala neurons

The laterocapsular division of the central nucleus of the amygdala (CeA) is now defined as the "nociceptive amygdala" because of its high content of neurons that respond to painful stimuli. The majority of these neurons become sensitized in a model of arthritis pain. Here we address the role of G protein-coupled group I metabotropic glutamate receptor subtypes mGluR1 and mGluR5 in nociceptive processing under normal conditions and in pain-related sensitization. Extracellular single-unit recordings were made from 65 CeA neurons in anesthetized rats. Each neuron's responses to brief mechanical stimuli, background activity, receptive field size, and threshold were measured before and after induction of the kaolin/carrageenan mono-arthritis in one knee and before and during applications of agonists and antagonists into the CeA by microdialysis. All neurons received excitatory input from the knee(s) and responded most strongly to noxious stimuli. Before arthritis, a group I mGluR1 and mGluR5 agonist (DHPG, n = 10) potentiated the responses to innocuous and noxious stimuli. This effect was mimicked by an mGluR5 agonist (CHPG, n = 15). In the arthritis pain state (>6 h after induction), the facilitatory effects of DHPG (n = 9), but not CHPG (n = 7), increased. An mGluR1 antagonist (CPCCOEt) had no effect before arthritis (n = 12) but inhibited the responses of sensitized neurons in the arthritis pain state (n = 8). An mGluR5 antagonist (MPEP) inhibited brief nociceptive responses under normal conditions (n = 19) and prolonged nociception in arthritis (n = 8). These data suggest a change of mGluR1 function and activation in the amygdala in pain-related sensitization, whereas mGluR5 is involved in brief as well as prolonged nociception.

Differential sensitization of amygdala neurons to afferent inputs in a model of arthritic pain

Pain is associated with negative affect such as anxiety and depression. The amygdala plays a key role in emotionality and has been shown to undergo neuroplastic changes in models of affective disorders. Many neurons in the central nucleus of the amygdala (CeA) are driven by nociceptive inputs, but the role of the amygdala in persistent pain states is not known. This study is the first to address nociceptive processing by CeA neurons in a model of prolonged pain. Extracellular single-unit recordings were made from 41 CeA neurons in anesthetized rats. Each neuron's responses to brief mechanical stimulation of joints, muscles, and skin and to cutaneous thermal stimuli were recorded. Background activity, receptive field size, and threshold were mapped, and stimulus-response functions were constructed. These parameters were measured repeatedly before and after induction of arthritis in one knee by intraarticular injections of kaolin and carrageenan. Multireceptive (MR) amygdala neurons (n = 20) with excitatory input from the knee joint responded more strongly to noxious than to innocuous mechanical stimuli of deep tissue (n = 20) and skin (n = 11). After induction of arthritis, 18 of 20 MR neurons developed enhanced responses to mechanical stimuli and expansion of receptive field size. These changes occurred with a biphasic time course (early peak: 1-1.5 h; persistent plateau phase: after 3-4 h). Responses to thermal stimuli did not change (7 of 7 neurons), but background activity (16 of 18 neurons) and electrically evoked orthodromic activity (11 of 12 neurons) increased in the arthritic state. Nociceptive-specific (NS) neurons (n = 13) showed no changes of their responses to mechanical, thermal, and electrical stimulation after induction of arthritis. A third group of neurons did not respond to somesthetic stimuli under control conditions (noSOM neurons; n = 8) but developed prolonged responses to mechanical, but not thermal, stimuli in arthritis (5 of 8 neurons). These data suggest that prolonged pain is accompanied by enhanced responsiveness of a subset of CeA neurons. Their sensitization to mechanical, but not thermal, stimuli argues against a nonspecific state of hyperexcitability. MR neurons could serve to integrate and evaluate information in the context of prolonged pain. Recruitment of noSOM neurons increases the gain of amygdala processing. NS neurons preserve the distinction between nociceptive and nonnociceptive inputs.

Depression and health-related quality of life

Chronic medical conditions drastically affect the lives of those afflicted, leading to pain, disability, and disruption. Comorbid depression can exacerbate the effects of medical illness and may be an independent source of suffering and disability. Data from the Epidemiological Follow-Up Study (NHEFS) of the first National Health and Nutrition Examination Survey (NHANES I) are used to examine the manner in which depression and comorbid medical conditions interact to affect health-related quality of life (HRQOL). The findings suggest a) that the effects of depression are comparable with those of arthritis, diabetes, and hypertension; and b) that depression and chronic medical illnesses interact to amplify the effects of the medical illness. The data also support the merit of adopting a multidimensional approach to HRQOL rather than treating it unidimensionally.

Recent advances and future directions in the biopsychosocial assessment and treatment of arthritis

This article provides an overview of the emerging literature on biopsychosocial assessment and treatment for two of the most common forms of arthritis: osteoarthritis and rheumatoid arthritis. The article is divided into 3 parts. In the 1st part, the basic elements of the biopsychosocial approach to assessing and treating persons having arthritis is described. In the 2nd part, the authors evaluate studies of biopsychosocial approaches to the assessment of arthritis pain and disability. Six research areas are reviewed: learned helplessness, depression, stress, pain coping, self-efficacy, and the social context of arthritis. The 3rd part of the article reviews studies that testing the efficacy of biopsychosocial treatment approaches for persons having osteoarthritis and rheumatoid arthritis.

Clinical outcomes following a trial of sertraline in rheumatoid arthritis

We report an open-label trial of sertraline in the treatment of major depression in 54 consecutive rheumatoid arthritis (RA) patients meeting DSM-IV criteria for major depressive disorder. We initially surveyed 628 RA outpatients with the Center for Epidemiologic Studies Depression Scale (CES-D) and invited those with depression to be evaluated further and treated. Eighty-four RA patients reporting depressive symptoms agreed to participate in person, and 56 met the criteria for major depressive disorder. Of these 56 patients, 54 agreed to medication treatment and were enrolled in the study. Patients were also randomized to one of three psychological treatment conditions, but for this study, conditions were collapsed because previous research on this sample indicated no significant between-group differences in depression after treatment. Patients were assessed with the CES-D and the Hamilton Rating Scale for Depression after the intervention, at 6-month follow-up, and at 15-month follow-up. At the last follow-up, 41 patients remained for assessment. In this study, sertraline was found to be a safe and efficacious treatment of depression complicating RA.

Chronic pain, chronic stress and depression: coincidence or consequence?

Chronic pain and depressive illness are debilitating disease states that are variably resistant to currently available therapeutic agents. Animal models of chronic pain are associated with activation of the hypothalamo-pituitary-adrenal (HPA) axis, upon which chronic pain acts as an inescapable stressor. Inescapable stress is also associated with 'depressive-like' symptoms in experimental animals. Based on reports of the comorbidity between chronic pain and depressive illness in human patients, it is possible that these disease states are linked, via chronic stress-induced HPA dysfunction. Here, we discuss the possible involvement of the HPA axis in the aetiology of both chronic pain and clinical depression, and suggest a strategy for the development of novel pharmacotherapies.