Specific and general therapeutic mechanisms in cognitive behavioral treatment of chronic pain

OBJECTIVE

Many studies document efficacy of cognitive behavioral therapy (CBT) for chronic pain, but few studies have examined potential treatment mechanisms. In analyses of data from a controlled trial, we examined whether changes in attitudes toward adopting a pain self-management approach-CBT-specific mechanisms-and quality of working alliance and patient expectations-general mechanisms-early in treatment were related to later-treatment changes in outcomes.

METHOD

Our sample was composed of 94 adults (primarily White; mean age: 55.3 years, SD = 11.7; 23% female) who participated in enhanced or standard CBT, and completed measures of attitudes toward self-management (mechanisms), pain intensity, pain interference, depressive symptoms and goal accomplishment (outcomes) at pretreatment, 4- and 8-week assessments, and posttreatment. Working alliance was measured at 4 and 8 weeks, and patient expectations at 3 weeks.

RESULTS

Because the CBT conditions produced comparable improvements, we combined them. Precontemplation and action attitudes toward pain self-management showed significant quadratic trends over assessments such that 67% and 94.1% (respectively) of total pre-post changes occurred in the first 4 weeks. Outcomes showed only significant linear trends. Cross-lagged regressions revealed that pretreatment-to-4-week changes in action attitudes and 4-week levels of working alliance were related significantly with 4-week-to-posttreatment changes in pain intensity and interference but not vice versa and that 3-week patient expectations were related to 4-week-to-posttreatment changes in interference. Analyses in which mechanism factors were entered simultaneously revealed nonsignificant unique effects on outcomes.

CONCLUSIONS

Adopting an action attitude early in treatment may represent a specific CBT mechanism but with effects held largely in common with 2 general mechanisms.

Mindfulness-Based Stress Reduction for Posttraumatic Stress Symptoms

Mindfulness-based psychotherapies are associated with reductions in depression and anxiety. However, few studies address whether mindfulness-based approaches may benefit individuals with posttraumatic stress symptoms. The current pilot study explored whether group mindfulness-based stress reduction therapy reduced posttraumatic stress symptoms, depression, and negative trauma-related appraisals in 9 adult participants who reported trauma exposure and posttraumatic stress or depression. Participants completed 8 sessions of mindfulness-based stress reduction treatment, as well as pretreatment, midtreatment, and posttreatment assessments of psychological symptoms, acceptance of emotional experiences, and trauma appraisals. Posttraumatic stress symptoms, depression, and shame-based trauma appraisals were reduced over the 8-week period, whereas acceptance of emotional experiences increased. Participants’ self-reported amount of weekly mindfulness practice was related to increased acceptance of emotional experiences from pretreatment to posttreatment. Results support the utility of mindfulness-based therapies for posttraumatic stress symptoms and reinforce studies that highlight reducing shame and increasing acceptance as important elements of recovery from trauma.

Can we improve cognitive-behavioral therapy for chronic back pain treatment engagement and adherence? A controlled trial of tailored versus standard therapy

OBJECTIVE

This study evaluated whether tailored cognitive-behavioral therapy (TCBT) that incorporated preferences for learning specific cognitive and/or behavioral skills and used motivational enhancement strategies would improve treatment engagement and participation compared with standard CBT (SCBT). We hypothesized that participants receiving TCBT would show a lower dropout rate, attend more sessions, and report more frequent intersession pain coping skill practice than those receiving SCBT. We also hypothesized that indices of engagement and adherence would correlate with pre- to posttreatment changes in outcome factors.

METHOD

One hundred twenty-eight of 161 consenting persons with chronic back pain who completed baseline measures were allocated to either TCBT or SCBT using a modified randomization procedure. Participants completed daily ratings of pain coping skill practice and goal accomplishment during treatment, as well as measures of pain severity, disability, and other key outcomes at the end of treatment.

RESULTS

No significant differences between treatment groups were noted on measures of treatment engagement or adherence. However, these factors were significantly related to some pre- to posttreatment improvements in outcomes, regardless of treatment condition.

CONCLUSIONS

Participants in this study evidenced a high degree of participation and adherence, but treatment tailored to take into account participant preferences, and that employed motivational enhancement strategies, failed to increase treatment participation over and above SCBT for chronic back pain. Evidence that participation and adherence were associated with positive outcomes supports continued clinical and research efforts focusing on these therapeutic processes.

Temporal associations between spouse criticism/hostility and pain among patients with chronic pain: a within-couple daily diary study

Chronic musculoskeletal pain can strain marriages, perhaps even to the point of engendering spouse criticism and hostility directed toward patients. Such negative spouse responses may have detrimental effects on patient well-being. While results of cross-sectional studies support this notion, we extended these efforts by introducing expressed emotion (EE) and interpersonal theoretical perspectives, and by using electronic diary methods to capture both patient and spouse reports in a prospective design. Patients with chronic low back pain (CLBP) and their spouses (N = 105 couples) reported on perceived spouse behavior and patient pain 5 times/day for 14 days using Personal Data Assistants (PDAs). Concurrent and lagged within-couple associations between patient's perceptions of spouse criticism/hostility and patient self-reported pain and spouses' observations of patient pain behaviors revealed that (1) patient perceived spouse criticism and hostility were correlated significantly with pain intensity, and spouse observed patient pain behavior was related significantly with patient perceived hostility at the same time point; (2) patient perceived spouse hostility significantly predicted patient pain intensity 3 hours later, and spouse observed pain behaviors significantly predicted patient perceived spouse hostility 3 hours later. Results support both EE and interpersonal models, and imply that a comprehensive model would combine these conceptualizations to fully illustrate how spouse criticism/hostility and patient pain interact to produce a negative spiral. Given that marital interactions are amenable to clinical intervention, improved insight into how spouse behavior and patient pain are tightly linked will encourage productive translational efforts to target this neglected area.

Sleep duration and weight change in midlife women: the SWAN sleep study

OBJECTIVE

Short sleep duration has been associated with higher current BMI and subsequent weight gain. However, most prior longitudinal studies are limited by reliance on self-reported sleep duration, and none accounted for the potential confounding effect of sleep-disordered breathing. The associations of sleep duration with current BMI and BMI change were examined among 310 midlife women in the Study of Women's Health Across the Nation (SWAN) Sleep Study (2003-2005).

METHODS

Sleep duration was assessed for approximately one month with concurrent wrist actigraphy and sleep diaries. The presence and severity of sleep-disordered breathing was quantified using the apnea-hypopnea index (AHI) based on in-home polysomnography. BMI was assessed annually through core SWAN visit 10 (2006 and 2008).

RESULTS

Mean BMI increased from 29.6 (SD = 7.8) kg/m(2) to 30.0 (SD = 8.0) kg/m(2) over an average of 4.6 years (SD = 1.0) of follow-up. In cross-sectional analyses controlling for AHI, demographic variables, and several potential confounding variables, actigraphy (estimate = -1.22, 95% confidence interval (CI): -2.03, -0.42) and diary (estimate = -0.86, 95% CI -1.62, -0.09) measures of sleep duration were inversely associated with BMI. Each hour of less sleep was associated with 1.22 kg/m(2) greater BMI for actigraphy sleep duration, and a 0.86 kg/m(2) greater BMI for diary sleep duration. Longitudinal associations between sleep duration and annual BMI change were nonsignificant in unadjusted and fully adjusted models.

CONCLUSION

In this cohort of midlife women, cross-sectional associations between sleep duration and current BMI were independent of sleep-disordered breathing, but sleep duration was not prospectively associated with weight change.

How well does the body adiposity index capture adiposity change in midlife women?: The SWAN fat patterning study

OBJECTIVES

The body adiposity index (BAI) is a proposed alternative to the body mass index (BMI) that has shown good cross-sectional agreement with percent body fat (%BF) in validation studies. The objective of this study was to examine the ability of BAI to track adiposity change over time in a biracial sample of midlife women.

METHODS

African-American (n = 159) and Caucasian (n = 206) women, aged 42-60 years, at the Chicago site of the Study of Women's Health Across the Nation were followed from 2002 to 2008. BAI and BMI were calculated from measurements taken at annual assessments. %BF was quantified using whole-body dual-energy X-ray absorptiometry. Difference scores (BAI(Δ) , BMI(Δ) , and %BF(Δ) ) quantified adiposity change over a mean of 1.6 (SD = 0.7) years. Lin's concordance correlation (ρ(c) ) and Bland-Altman limits-of-agreement assessed agreement between BAI and %BF.

RESULTS

In examining adiposity change, BAI(Δ) showed poor agreement with %BF(Δ) in the overall sample (ρ(c) = 0.41), African-American women (ρ(c) = 0.36), and Caucasian women (ρ(c) = 0.43). BAI(Δ) estimated %BF(Δ) with minimal bias (+0.4%) but low precision (±6.3%BF limits-of-agreement). %BF(Δ) had weaker correlations with BAI(Δ) (rs = 0.38-0.48) than with BMI(Δ) (rs = 0.48-0.59). BAI and BMI showed similar cross-sectional associations with %BF in the overall sample and within each race (rs > 0.74).

CONCLUSIONS

We conclude that BAI is less accurate than BMI in tracking adiposity change in midlife women, and would not be a suitable replacement for BMI in most research applications involving adiposity change.

Screening of potential small volume resuscitation products using a severe hemorrhage sedated swine model

BACKGROUND

Small volumes of resuscitation products to sustain survival until definitive care are desired in extreme environments due to limited resources. A severe controlled hemorrhage model in sedated, sexually mature miniature swine has been developed to evaluate these products. Valproic Acid (VPA) and Pentoxifylline (PTX) have been suggested as potential products for small volume resuscitation following hemorrhage predominately in anesthetized small animal models. We evaluated the survival time of VPA and PTX in the swine model.

METHODS

Fifteen male miniature swine weighing 41.1 ± 2.9 kg were sedated and hemorrhaged 60% of estimated blood volume over 1 hr and treated with one of the following: 1) VPA at 400 mg/kg in a volume of 1.33 ml/kg over 2 min (n=4); 2) VPA at 300 mg/kg in a volume of 2 ml/kg over 30 min (n=3); 3) PTX at 50 mg/kg in a volume of 2 ml/kg over 2 min (n=4); 4) saline vehicle at 2 ml/kg over 2 min (n=4). Survival times were compared to non-resuscitated historic controls (n=16). Survival was determined from the end of hemorrhage/initiation of treatment.

RESULTS

Median (95% CI) survival times were: Control 55.7 (17.5 - 86) min; VPA (400 mg/kg) 6 (4 - 8) min; VPA (300 mg/kg) 17.5 (12 - 24.5) min; PTX 60.8 (21 - 75) min; and vehicle 92 (15 - 180) min. No treatment increased survival time compared to controls and there were no significant differences in percent survival among groups.

CONCLUSION

In this sedated severe hemorrhage model VPA and PTX were unacceptable as small volume resuscitation products at the concentrations and delivery rates used because of early deaths. Considering that these drugs are FDA approved for other indications at lower doses the present data suggest that further investigation of mechanisms involved are warranted.

Is reduction in pain catastrophizing a therapeutic mechanism specific to cognitive-behavioral therapy for chronic pain?

Mechanisms underlying favorable outcomes of psychosocial interventions for chronic pain are unclear. Theory suggests changes in maladaptive cognitions represent therapeutic mechanisms specific to cognitive-behavioral therapy (CBT). We illustrate the importance of examining whether treatments work either uniquely via mechanisms specified by theory or via mechanisms common to different treatments. Secondary data analysis was conducted to examine the effects of reduction in pain catastrophizing on outcomes following CBT and Pain Education. Generally, reductions in pain catastrophizing were significantly related to outcome improvements irrespective of CBT or Pain Education condition. Results underscore the need to assess whether mechanisms presumed to operate specifically in one treatment do indeed predict outcomes and illustrate the importance of broadening the assessment of mechanisms beyond those specified by theory. Theory-specific, competing, and common mechanisms must all be assessed to determine why our treatments work.

Suppression of anger and subsequent pain intensity and behavior among chronic low back pain patients: the role of symptom-specific physiological reactivity

Suppression of anger may be linked to heightened pain report and pain behavior during a subsequent painful event among chronic low back patients, but it is not clear whether these effects are partly accounted for by increased physiological reactivity during suppression. Chronic low back pain patients (N = 58) were assigned to Suppression or No Suppression conditions for a "cooperative" computer maze task during which a confederate harassed them. During baseline and maze task, patients' lower paraspinal and trapezius muscle tension, blood pressure and heart rate were recorded. After the maze task, patients underwent a structured pain behavior task (behaviors were videotaped and coded). Results showed that: (a) Suppression condition patients revealed greater lower paraspinal muscle tension and systolic blood pressure (SBP) increases during maze task than No Suppression patients (previously published results showed that Suppression condition patients exhibited more pain behaviors than No Suppression patients); (b) residualized lower paraspinal and SBP change scores were related significantly to pain behaviors; (c) both lower paraspinal and SBP reactivity significantly mediated the relationship between Condition and frequency of pain behaviors. Results suggest that suppression-induced lower paraspinal muscle tension and SBP increases may link the actual suppression of anger during provocation to signs of clinically relevant pain among chronic low back pain patients.

The Continuing Evolution of Biopsychosocial Interventions for Chronic Pain

In the last several decades, great strides have been made in the treatment of persistent painful conditions. The scope of treatment has shifted from purely biomedical, including approaches built upon cognitive, behavioral, and social psychological principles. This article reports and discusses several key paradigm shifts that fueled this revolutionary change in the management of chronic pain. The progressive development of theoretical metamodels and treatment conceptualizations is presented. Cognitive behavioral therapy (CBT) is the most widely accepted biopsychosocial treatment for chronic pain and is founded upon a rich theoretical tradition. The CBT rationale, and empirical evidence to support its efficacy, is presented. The emergence and promise of mindfulness-based and acceptance-based interventions is also discussed. The article concludes with the assertion that future treatment outcome research should focus on understanding the treatment-specific and common factors associated with efficacy.

What do plasma beta-endorphin levels reveal about endogenous opioid analgesic function?

Plasma levels of beta-endorphin (BE), an endogenous opioid analgesic, are often reported as they relate to acute and chronic pain outcomes. However, little is known about what resting plasma BE levels might reveal about functioning of the endogenous opioid antinociceptive system. This study directly examined associations between resting plasma BE and subsequent endogenous opioid analgesic responses to acute pain in 39 healthy controls and 37 individuals with chronic low back pain (LBP). Resting baseline levels of plasma BE were assessed. Next, participants received opioid blockade (8 mg naloxone i.v.) or placebo in a double-blind, randomized, crossover design. Participants then underwent two acute pain stimuli: finger pressure (FP) pain and ischaemic (ISC) forearm pain. Blockade effects (naloxone minus placebo pain ratings) were derived to index endogenous opioid analgesic function. In placebo condition analyses for both pain stimuli, higher resting BE levels were associated with subsequently greater reported pain intensity (p's < 0.05), with this effect occurring primarily in healthy controls (BE × Participant Type interactions, p's < 0.05). In blockade effect analyses across both pain tasks, higher resting plasma BE predicted less subsequent endogenous opioid analgesia (smaller blockade effects; p's < 0.05). For the ISC task, these links were significantly more prominent in LBP participants (BE × Participant Type Interactions, p's < 0.05). Results suggest that elevated resting plasma BE may be a potential biomarker for reduced endogenous opioid analgesic capacity, particularly among individuals with chronic pain. Potential clinical implications are discussed.

Anger suppression and subsequent pain behaviors among chronic low back pain patients: moderating effects of anger regulation style

BACKGROUND

Suppression of anger is linked to subsequent pain intensity among chronic low back patients, but it is not clear whether anger regulation style (trait anger-out, anger-in) moderates these effects or if aroused anger accounts for links between anger regulation style and pain.

METHOD

Chronic low back pain patients (N=58) were assigned to Suppression or No Suppression conditions for a task with harassing confederate and then underwent structured pain behavior procedures. Spielberger Anger Expression Inventory tapped trait anger-out (AOS) and anger-in (AIS).

RESULTS

Regressions tested Emotion Regulation condition × AOS and AIS effects on outcomes. AOS was related to grimacing and sighing for Suppression condition patients. AIS was related negatively to guarding and bracing for Suppression condition patients. Anger report partly mediated effects for AOS and AIS.

CONCLUSIONS

Anger regulation style moderated effects of state anger suppression on subsequent pain behaviors, effects that were partly explained by aroused anger.

Suppression of pain-related thoughts and feelings during pain-induction: sex differences in delayed pain responses

Women tend to report greater acute and chronic pain intensity than men, and various mechanisms have been proposed to account for these sex differences. Suppression has been related to amplified pain intensity, and thus we examined whether sex differences in the use of suppression partly explained the discrepancy between men and women on pain report. Participants (N = 222; women: 55%) underwent a cold pressor, during which half the sample was randomly assigned to suppress pain-related thoughts and feelings and the other half was not. A 2-min recovery period followed the cold pressor. Ten min later, all participants were exposed to another physical stimulus (a massage device). Significant condition x Sex interactions were found for pain intensity, sensory ratings from the McGill Pain Questionnaire and unpleasantness ratings for the massage device, such that: (a) men in the No Suppression condition reported lower pain and unpleasantness than women in the same condition; (b) men in Suppression condition reported greater pain and unpleasantness then men in No Suppression condition, but equivalent pain and unpleasantness to women in No Suppression condition; (c) differences between men and women on pain in No Suppression condition were partly mediated by women's report of greater spontaneous use of avoidance/suppression during the cold pressor. Results using an "addition" paradigm (i.e., manipulating use of suppression) and a "take away" (i.e., mediation) paradigm converge to suggest that women spontaneously use suppression to regulate pain more than men, and that the differential use of suppression partly explains the tendency for women to report greater pain intensity than men.

Interactive effects of catastrophizing and suppression on responses to acute pain: a test of an appraisal x emotion regulation model

We examined whether people who tend to catastrophize about pain and who also attempt to regulate negative thoughts and feelings through suppression may represent a distinct subgroup of individuals highly susceptible to pain and distress. Ninety-seven healthy normal participants underwent a 4-min ischemic pain task followed by a 2-min recovery period. Self-reported pain and distress was recorded during the task and every 20 s during recovery. Participants completed the Pain Catastrophizing Scale and the White Bear Suppression Inventory. Repeated measures multiple regression analysis (using General Linear Model procedures) revealed significant 3-way interactions such that participants scoring high on the rumination and/or helplessness subscales of the Pain Catastrophizing Scale and who scored high on the predisposition to suppress unwanted thoughts and feelings reported the greatest pain and distress during recovery. Results suggest that pain catastrophizers who attempt to regulate their substantial pain intensity and distress with maladaptive emotion regulation strategies, such as suppression, may be especially prone to experience prolonged recovery from episodes of acute pain. Thus, emotion regulation factors may represent critical variables needed to understand the full impact of catastrophic appraisals on long-term adjustment to pain.

Influence of asymptomatic pneumonia on the response to hemorrhage and resuscitation in swine

INTRODUCTION

Investigation of resuscitation fluids in our swine hemorrhage model revealed moderate to severe chronic pneumonia in five swine at necropsy. Our veterinary staff suggested that we perform a retrospective analysis of prospectively collected data from these animals. We compared the data to that of ten healthy swine to determine the physiologic consequences of the added stress on our hemorrhage/resuscitation model.

METHODS

Anesthetized, immature female swine (40 ± 5 kg) were instrumented for determining arterial and venous pressures, cardiac output and urine production. A controlled hemorrhage of 20 ml/kg over 4 min 40 sec was followed at 30 min by a second hemorrhage of 8 ml/kg and resuscitation with 1.5 ml/kg/min of LR solutions to achieve and maintain systolic blood pressure at 80 ± 5 mmHg for 3.5 hrs. Chemistries and arterial and venous blood gasses were determined from periodic blood samples along with hemodynamic variables.

RESULTS

There were significant decreases in survival, urine output, cardiac output and oxygen delivery at 60 min and O2 consumption at 120 min in the pneumonia group compared to the non-pneumonia group. There were no differences in other metabolic or hemodynamic data between the groups.

CONCLUSION

Although pneumonia had little influence on pulmonary gas exchange, it influenced cardiac output, urine output and survival compared to healthy swine, suggesting a decrease in the physiologic reserve. These data may be relevant to patients with subclinical infection who are stressed by hemorrhage and may explain in part why some similarly injured patients require more resuscitation efforts than others.

Hypoalgesia associated with elevated resting blood pressure: evidence for endogenous opioid involvement

This study used a placebo-controlled, between-subjects opioid blockade design to evaluate endogenous opioid involvement in the hypoalgesia associated with elevated resting blood pressure (BP) in 163 healthy individuals. Participants were randomly assigned to Drug condition (placebo, naltrexone) and Task Order (computerized maze task with harassment followed by an ischemic pain task or vice versa). Resting BP was assessed, followed by drug administration, and then the pain and maze tasks. A significant Drug x Systolic BP (SBP) interaction was observed on McGill Pain Questionnaire-Affective pain ratings (P < .01), indicating that BP-related hypoalgesia observed under placebo was absent under opioid blockade. A significant Gender x Drug x SBP x Task Order interaction was observed for VAS pain intensity (P < .02). Examination of simple effects comprising this interaction suggested that BP-related hypoalgesia occurred only in male participants who experienced the pain task in the absence of emotional arousal, and indicated that this hypoalgesia occurred under placebo but not under opioid-blockade. Results suggest that under some circumstance, BP-related hypoalgesia may have an endogenous opioid-mediated component in healthy individuals, particularly men.

Endogenous opioids may buffer effects of anger arousal on sensitivity to subsequent pain

Evidence suggests that anger and pain are related, yet it is not clear by what mechanisms anger may influence pain. We have proposed that effects of anger states and traits on pain sensitivity are partly opioid mediated. In this study, we test the extent to which analgesic effects of acute anger arousal on subsequent pain sensitivity are opioid mediated by subjecting healthy participants to anger-induction and pain either under opioid blockade (oral naltrexone) or placebo. Participants were 160 healthy individuals. A double-blind, placebo-controlled, between-subjects opioid blockade design is used, with participants assigned randomly to one of two drug conditions (placebo or naltrexone), and to one of two Task Orders (anger-induction followed by pain or vice versa). Results of ANOVAs show significant Drug Condition x Task Order interactions for sensory pain ratings (MPQ-Sensory) and angry and nervous affect during pain-induction, such that participants who underwent anger-induction prior to pain while under opioid blockade (naltrexone) reported more pain, and anger and nervousness than those who underwent the tasks in the same order, but did so on placebo. Results suggest that for people with intact opioid systems, acute anger arousal may trigger endogenous opioid release that reduces subsequent responsiveness to pain. Conversely, impaired endogenous opioid function, such as that found among some chronic pain patients, may leave certain people without optimal buffering from the otherwise hyperalgesic affects of anger arousal, and so may lead to greater pain and suffering following upsetting or angry events.

Effects of anger suppression on pain severity and pain behaviors among chronic pain patients: evaluation of an ironic process model

OBJECTIVE

Evidence for links between anger inhibition or suppression and chronic pain severity is based mostly on studies with correlation designs. Following from ironic process theory, we proposed that attempts to suppress angry thoughts during provocation would increase subsequent pain intensity among chronic low back pain (CLBP) patients, and do so through paradoxically enhanced accessibility of anger.

DESIGN

CLBP patients (N = 58) were assigned to suppression and nonsuppression conditions while performing a computer maze task with a harassing confederate. A structured pain behavior task (SPBT) followed.

MAIN OUTCOME MEASURES

Self-reported anger, anxiety, and sadness following maze task. Self-reported pain severity and number of observed pain behaviors during SPBT.

RESULTS

Patients told to suppress during provocation: (a) reported greater anger following the maze task, reported greater pain intensity during the SPBT, and exhibited more pain behaviors than patients not suppressing; (b) postmaze anger levels significantly mediated group differences on pain behaviors.

CONCLUSION

Attempts by CLBP patients to suppress anger may aggravate pain related to their clinical condition through ironically increased feelings of anger.