Xavier F. Jimenez and Sara Davin
Pain is an experience that is perceived by the brain and is indisputably modifiable by psychological components, including but not limited to emotions and beliefs. Actual physical tissue or nerve damage is neither necessary nor sufficient for the perception of pain. Anger, depression, anxiety, fear and other psychological variables can all increase the perception of both acute and chronic pain, as can believing that the sensation is an indicator of a destructive process.
Chronic Low Back Pain (CLBP) is an enormous problem with wide scale ramifications for patients, health care providers, families, employers and society.1 Interestingly, most spine pain is self-limiting,2 which means almost anything done will lead to the patient reporting a decrease in symptomatology in a matter of days or weeks. One important exception is bed rest, which has been shown to do more harm than good.3 Most patients with back pain do not need to see a spine specialist; rather, they are seen by their primary care physicians or other generalists. Even persistent CLBP is commonly not attributable to any specific pathology or disease process.4 Despite the fact that this has been well documented for many years, the notion that non-specific CLBP must result from objective tissue or bone lesions lives on in the mind of patients and families and is often reinforced by providers. This belief, in and of itself, may lead to the worsening of the pain due to hypervigilance of perceived deficits or pathology. Patients who do go on to see a specialist often do so because the pain has persisted beyond the time of expected spontaneous resolution. This lack of resolution results in a natural degree of worry, yet once again this worry may worsen the pain sensation itself. Some patients will thus develop chronic pain, a situation defined more of a protracted pain sensation with accompanying psychological features than a worsening of physical deficits. The societal and individual costs of this form of chronic debilitating pain are staggering. The economic burden of CLBP specifically has been estimated to range from US$84 billion to US$625 billion, with indirect costs attributable to lost work hours and productivity.5 It is likely that early recognition and intervention in cases with developing chronicity can lead to improved outcomes with less need for extensive interventions.
This chapter will explore both psychosocial factors involved in transformation of back pain into a disabling condition and the psychosocial management approaches to consider.
PSYCHOSOCIAL MECHANISMS OF CHRONIC LOW BACK PAIN
Pain and the Psyche
Psychosocial vulnerabilities may precede or follow the development of CLBP, both proving to substantially contribute to downstream outcomes. Carragee et al. followed 100 patients with mild CLBP and no prior spine related disability for 5 years. Moderate or severe Modic changes (degenerative changes noted on spine MRI) of the vertebral end plate were the only structural variable that weakly predicted adverse outcome. Provocative discography and baseline MRI predicted no outcome variables but were weakly associated with pain episodes. Alternatively, psychosocial variables strongly predicted long and short-term disability and health-care utilization for patients with CLBP. A model based on scores on the Modified Zung Depression Test, Modified Somatic Pain Questionnaire, Fear Avoidance Beliefs Questionnaire (physical activity subscale) and smoking status identified 100% of long-term disability subjects, 88% of all disability subjects and 75% of subjects having a remission.6 This important study thus emonstrates the high predictive power of psychosocial variables in predicting chronicity and associated problematic outcomes in CLBP.
A stress-diathesis model in which the degree of disability from a given degree of organic pathology will vary with the psychological reserves of the individual, the stresses of the workplace and incentives/disincentives for recovery is warranted. These biopsychosocial variables clearly overlap; a patient lacking coping skills and education, unfortunately, is unlikely to obtain the most desirable work situation, elevating the risk for minimal incentive to return to that line of work. This lack of incentive to return to work may overtly or covertly contribute to an alternative incentive: prolonged disability and illness.
The most common psychiatric illnesses in pain center patients (excluding somatic symptom disorders) are anxiety, depression and substance use disorders. In 200 CLBP patients entering a functional restoration program, Polatin et al. found that 77% of patients met lifetime diagnostic criteria, and 59% demonstrated current symptoms for at least one of the psychiatric diagnoses listed above.7 Fifty-one percent also met criteria for a personality disorder. While major depression could either precede or follow CLBP, substance use and anxiety disorders were noted to precede the development of the condition.
The prevalence of depression specifically in chronic pain patients ranges from 10-83%. This high variance reflects different settings, pain syndrome populations and diagnostic criteria. In a survey of 118,533 people, CLBP was present in 9%. Major depression was present in 5.9% of those without pain whereas in 19.8% of those with CLBP. The rate of major depression increased in a linear fashion with pain severity.8 It is likely that causality can point in either direction, as there is supporting evidence that pain predicts depression, and depression predicts pain.9 In a probability sample of 5692 adults, 35% of those with CLBP had accompanying mental disorders with the following incidences: major depressive disorder was present in 12.6%, dysthymia disorder in 5.6%, any anxiety disorder in 26.5% and any substance use disorder in 4.8%.10
There seems to be a vicious cycle in which pain behavior, loneliness, inactivity, helplessness, depression, withdrawal, loss of reinforcers and distractions, inactivity and pain are all mutually reinforcing. Alleviating one aspect of these often benefits others, resulting in improved outcomes. However, most are not addressed by surgical or pharmacological interventions and instead respond to successful rehabilitation (see later section).
Other Psychological Contributors to Chronic Pain
Anxiety worsens the pain experience via a number of mechanisms. It can also interfere with positive outcomes from rehabilitation attempts to treat CLBP. Phobic or avoidant tendencies can result n a cycle of maladaptive self-protection and hesitance to move or rehabilitate. This results in deconditioning in those with chronic pain. Such fear of movement (kinesiophobia) is usually unwarranted and results from anticipatory anxiety or fear of pain experience, not the pain itself. Anxiety often also leads to muscle guarding and tension resulting in muscle shortening and other physical responses serving to worsen pain. It is often overlooked that the diagnostic criteria for generalized anxiety disorder – often thought of as a “psychological worry” condition – requires such “somatic” features as physical pain, tension and insomnia, This illustrates the bodily impact of anxiety disorders on patients, which may be under-recognized in routine pain focused care. Physiologically, it is known that nociceptors that are normally unaffected by norepinephrine become sensitive to it following injury so that neuropathic and other pains are often exacerbated by anxiety, as well as fear, anger or excitement.
Pain catastrophizing is a related cognitive response to anticipated or actual pain, comprised of 3 domains (helplessness, magnification and rumination).11 It has been shown to markedly increase pain sensation and is associated with poorer clinical outcomes, heightened pain sensitivity and impaired functioning.12-13
Anger is also associated with worsening of both acute and chronic pain. A number of authors have found associations between anger regulation, both expression and suppression, and severity of chronic pain.14-15 In a study examining the effects of anger suppression in pain severity, Burns, el al.16 found that patients with CLBP who were told to suppress their anger towards a study coordinator exhibited more pain behaviors and reported more pain than those who did not suppress their anger.
Recent research has looked at other psychological contributors to pain such as guilt and various aspects of mood, including reactivity and positive affect, among those with CLBP. Serbic et al. explored the relations between pain related guilt, lack of diagnostic certainty and disability through structural equation modeling in CLBP patients. They found that pain related guilt (especially social guilt) and diagnostic uncertainty contributed substantially to disability and mood.17 While this study does not attribute causality to the associations, it does underscore the potential importance of addressing guilt through psychosocial treatment strategies. Acceptance may be one such strategy that mediates the impact of social guilt on pain and disability. Furthermore, low levels of positive affect combined with high negative affect among individuals with CLBP may increase the odds of accompanying fibromyalgia and worse functioning overall. Individuals with high levels of reactivity (high negative affect + high positive affect) have shown similar levels of pain, mood and disability as those who are considered having a “healthy” balance of affect (high positive affect, low positive affect).18
Psychosocial Pain Amplifiers
The perception of pain and ability to cope with it are affected by multiple psychological factors. Chronic stress increases both the perception of pain and disability related to it. Distraction reduces pain awareness, while isolation and inactivity increases it and fosters self-preoccupation.
Cognitive theories of depression, anxiety and pain hold that thoughts and beliefs are major determinant of emotions, i.e., how a person feels is less determined by events than by his/her cognitive interpretation of the events. Maladaptive cognitions tend to be automatic and habitual after having been reinforced for years, so they are rarely examined for validity by the patient. Instead, they are simply accepted and unchallenged, and thus feelings follow in a rapid and poorly-understood manner.
Pain is affected by cognitive factors in several ways. First, the adverse quality of pain is modified by its interpretation. Experiencing “catastrophic” perceptions of pain, such as “the nerves are being crushed” or “the exercises feel like they’re tearing something loose,” generally interfere with rehabilitation and coping. This may be worsened by practitioners who attribute pain to incidental findings on imaging that may bear only a modest relationship to the pain. CLBP is often strongly driven by such psychosocial factors as fear of pain/reinjury, “catastrophizing,” depression and anxiety. Failure to address these issues in treatment of CLBP often leads to continued disability. Pain tolerance is reduced by thoughts emphasizing the averseness of the situation, the inadequacy of the person to bear it or the physical harm that could occur. Such beliefs as “I will have a life again only after I am cured,” “I can’t go out to dinner if I am in pain” and “I shouldn’t exercise if it hurts” have obvious impacts upon the patient’s ability to adapt.
Self-appraisal may be as important as appraisal of the pain itself. Those who feel unable to influence events eventually give up. Belief in personal helplessness fosters pain and disability; alternatively, a sense of self-efficacy promotes efforts to cope. Thus, perceptions of helplessness lead to depression, resignation and passivity, which in turn increase disability and pain. Self-efficacy, the opposite of helplessness, has been repeatedly correlated with pain outcomes among a variety of chronic pain conditions, including CLBP.19 “Locus of control” is a psychological construct that refers to one’s sense of the determinants of future events and control. The perception that events are a consequence of the individual’s own behavior (internal locus of control) is associated with better mood and function. Those with external locus of control tend to see future events as contingent on other people, the external environment or “fate.” People with chronic pain who have an external locus of control report depression and anxiety, feel helpless to deal with their pain and often rely on external and maladaptive coping strategies, such as excessive rest, medications, substances to cope and other people’s assistance. Ultimately, decreased perception of self-control (or high “external locus of control”) may explain much of the relationship between depression and pain.
Clues to the presence of addiction in pain patients include frequent intoxication, mood changes, poor hygiene, inappropriate behaviors, and impaired coordination and cognition. Another indicator is provided when, despite generous analgesia, sick role behavior continues to a degree disproportionate to pathology. Those who use analgesics in a non-addictive fashion, in contrast, are likely to have improved function. Combining other intoxicants with prescription drugs is another important and obvious clue. Urine toxicology facilitates the diagnosis of substance use disorders; however, it must be remembered that typical urine toxicology (immunoassay) technology may not identify synthetic or semi-synthetic opioids and that gas chromatography/mass spectroscopy may be needed. In the U.S., many states have enacted electronic prescription monitoring programs that can help identify aberrant use as well.
Loss of control may be shown when patients who are incapable of rationing themselves use a month’s supply in a few days, despite knowing they will have increased pain and withdrawal symptoms when their supply is gone. Additional signs include multi-sourcing and family and/or physician concern about their medication consumption. Usually a patient who has no history of alcohol or drug abuse who becomes physically dependent on benzodiazepines or analgesics in the course of pain treatment, who obtains the drugs legitimately and who has not been behaviorally or cognitively impaired is not addicted. In other words, the fact that chronic high-dose opioids are ineffective in many patients does not alone confirm an addictive disorder; other consequences and behaviors as noted above are critical for the diagnosis.
Conceptually, there are two interrelated issues to consider – the treatment of addiction in pain patients and the treatment of pain in people with the disease of addiction. There seem to be no data as to which treatment should be first, though experience suggests that the pain patient who has an addiction to cocaine, marijuana or alcohol often responds to traditional addiction care in a setting appropriate to the severity of the disease. In contrast, the person who has become iatrogenically addicted seems to respond better if treatment is initiated in a pain-specific treatment program. Acceptance of the diagnosis is facilitated when patients can interact with other chronic pain peers who have also developed addiction “through no fault of their own” and without engaging in illegal behaviors.
PSYCHOSOCIAL TREATMENTS FOR CHRONIC LOW BACK PAIN
Numerous psychosocial strategies exist for the patient with chronic pain and specifically with CLBP. Table 2-1 summarizes these and the following sections discuss each in detail.
|Psychological Treatment Modality||Summary of Empirical Findings||Clinical Recommendations|
|Cognitive Behavioral Therapy (CBT)||
|Mindfulness and Acceptance Based Therapies||
|Psychophysiological and Relaxation Training||
|Family Education and Therapy||
|Interdisciplinary Pain Rehabilitation Programs (IPRPs)||
Cognitive Behavioral Therapies
Cognitive Behavioral Therapy for pain (CBT-P) is predicated on the premise that pain-related beliefs and effectiveness of coping strategies impact the severity of emotional distress and physical disability. CBT-P has been shown to be effective in the treatment of chronic pain. Mirza and Deyo, in a review of randomized trials of fusion vs. non-operative care of CLBP, compared surgery, traditional non-operative care and CBT, finding that both surgery and CBT were better than unstructured, ill-defined non-surgical care.20 They concluded that CBT outcomes were comparable to surgical outcomes at one year and without the obvious risks associated with surgery. A consistent finding across systematic reviews of psychological approaches for chronic pain is that the effectiveness of CBT is best demonstrated for pain-related mood and function, with somewhat less of an effect on pain severity itself.21 Techniques used in CBT include identifying self-talk (both motivational and self-defeating), relaxation techniques, distraction and positive coping strategies. Often patients come to the experience of pain with few coping mechanisms and yet major life stressors. Group, individual and family therapy can help address stresses and teach new ways of managing pain and stress.
Mindfulness and Acceptance Based Therapies
Mindfulness and acceptance based therapies emphasize adaptation and reduced resistance to the pain experience. Rooted in several philosophies, including Buddhism and theoretical models such as “The Ironic Processes Model,” these therapies teach individuals to adapt a non-judgmental and even curious awareness to thoughts, feelings and body sensations (including pain). These therapies are supported by evidence that suppression of negative emotions increases self-reported pain and pain behaviors,22 as well as efforts to control or avoid unwanted experiences may actually increase suffering.23 Techniques utilized in mindfulness and acceptance based therapies, such as Acceptance and Commitment Therapy (ACT), include formal and informal meditation practice, experiential exercises modeling psychological “flexibility,” as well as some of the central tenets of CBT.
The evidence for the efficacy of mindfulness-based treatments is still preliminary, due to small to modest treatment effects and methodological limitations of studies (no control group, evidence of confounders, etc). One systematic review and meta-analysis of meditation programs that included only randomized controlled trials and accounted for placebo effects found moderate evidence for its effects on mood and pain but no evidence that such benefits exceed those obtained from other psychological and medical treatments.24 Another review of mindfulness based therapies across 10 studies specifically for chronic pain reported small non-specific improvements in pain and depression; however, significant and sustained improvements were demonstrated in pain acceptance, quality of life, and stress.25 In a meta-analysis of 22 acceptance-based studies, significant improvements were found for pain, depression, anxiety, physical wellbeing and quality of life.26 Only few studies have specifically examined the use of mindfulness based therapies in CLBP. In one randomized control trial comparing mindfulness-based stress reduction to CBT and usual care among individuals with CLBP, Cherkin et al. found that MBSR and CBT showed equal benefits in terms of pain and function at 26 and 52 weeks, exceeding benefits found in the usual care control arm.27 These relatively new approaches appear to be viable, complementary treatment options offering patients an alternative way to conceptualize, understand and cope with their pain experience.
Psychodynamic and Interpersonal Therapies
Psychodynamic and interpersonal-oriented therapies emphasize relationships and attachment patterns. Psychodynamic therapy focuses heavily on early childhood experiences. While psychodynamic approaches produce improvements in psychiatric and somatic symptoms, as well as reduce healthcare utilization among patients with a variety of somatic medical conditions, there is limited empirical support of its efficacy in chronic pain.28 However, given the high rates of previous trauma and childhood stress in chronic pain, a psychodynamic approach may warrant consideration as a treatment approach in many with chronic pain, including those with CLBP.29
One of the most critical of the psychosocial “therapies” provided is education. It is often crucial because a patient’s behavior and their families’ reaction to disease may be based on faulty information or misconceptions. Education can clarify the problem and indicate the best response. It can be useful to interpret chronic pain as “real” but a “false alarm” that needn’t dictate activity or behavioral response. In particular, education based on the neuroscience of pain has been shown to favorably impact knowledge, catastrophizing, fear of activity and improving participation in rehabilitation.30
Involving family in the education process is essential. Family members often feel confused and helpless in response to a loved one’s pain. In turn, they may respond in ways that unintentionally reinforce the sick role, such as being overly protective or enabling. This dynamic reinforces dependency, overall reliance upon others and an external locus of control in the person with pain. Furthermore, criticism by family members for lack of positive health behaviors or for engaging in pain behaviors is related to greater physical dysfunction in the person with pain. Similarly, solicitous partner responses to pain behaviors are associated with overall poorer functioning in the patient. These findings are not isolated to clinical observations but also supported by research.31
Psychophysiological and Relaxation Training
Chronic uncontrolled stress amplifies pain. Thus, the direct target of these techniques is to teach individuals to self-regulate the stress response and the associated physiological indicators. Relaxation techniques vary in nature, but include deep breathing, progressive muscle relaxation, guided imagery, and visualization. All of these techniques can be used with or without psychophysiological monitoring, such as in biofeedback. Biofeedback involves the use of machinery (computer screen, thermometers, galvanic skin response machines, etc.) to first learn about one’s physiologic changes under stress and then develop mechanisms to master such responses and reduce their impact. The benefits of relaxation training across a variety of health-related conditions are well-established. In fact, the benefits of these techniques have been shown to go beyond a subjective sense of relaxation, including demonstrated reductions in cortisol, ACTH and norepinephrine in individuals who practice these techniques regularly.32
Relaxation techniques can have a direct effect on tense muscles and heightened arousal that is accompanied by the stress of pain. There is empirical evidence that relaxation training, self-hypnosis and progressive muscle relaxation with or without biofeedback assistance offer favorable benefits in the treatment of pain.33 However, systematic reviews evaluating the quality of the evidence for use of relaxation training and biofeedback therapy for pain generally exert caution in providing a “strong” recommendation for these therapies due to consistent methodological flaws across studies.34 In spite of the lack of gold standard studies, these therapies clearly offer a low risk, simple and drug-free method for slowing the cascade of stress hormones that often accompanies chronic pain.
The Role of Exercise
Psychological status and physical fitness have a reciprocal relationship with each affecting the other. Fears of movement and exercise, may present just as other phobias, and when they persist lead to a vicious cycle of activity avoidance. A number of studies have addressed fear of movement in chronic pain, showing that those with kinesiophobia report more pain, disability and self-protective behaviors.35 Conversely, even short bouts of exercise (10 minutes) have demonstrated immediate benefits on depression and anxiety in chronic pain patients.36 Adding to this, graded exercise programs gradually reduce fears of harm from exercise and promote increased function.37 A new movement among physical therapists emphasizes the use of psychological strategies as a critical skill set to optimize treatment, in combination with traditional activity based interventions. Psychologically informed physical therapy (PIPT) trainings and certification programs teach PTs to conceptualize persons with pain from a biopsychosocial framework, with consideration of the psychological and contextual factors that may impact the experience of pain. PIPT teaches psychological techniques primarily based in CBT and operant/classical conditioning. The evidence for the use of such approaches is accumulating and is being increasingly used among physical therapists.38 PIPT has been shown to be effective for the management of patients with CLBP. In particular, outcomes are enhanced when PIPT is utilized with individuals with greater psychosocial risk factors.39
Interdisciplinary Pain Rehabilitation Programs
Interdisciplinary chronic pain rehabilitation programs are designed to help patients with disabling chronic pain restore function and quality of life. Interdisciplinary care is a team approach in which all the members of the team, including the patient, work together towards common goals. These programs have been shown to be more effective than non-interdisciplinary rehabilitation for both CLBP and sub-acute low back pain.40-42 Disciplines commonly involved in these programs include physical and occupational therapy, nursing, psychology, medicine, vocational rehabilitation and chemical dependency counseling when needed. Some programs are intensive, 3-4 weeks long and include: active physical therapy and reconditioning, occupational therapy with an emphasis on body mechanics, group and individual psychotherapy and medication management, while others are of variable duration and intensity. Some programs include weaning off of all habituating substances. When vocational and addiction needs are identified, these services can also be offered as part of the holistic approach to rehabilitation.
Psychosocial variables have been shown to have a significant impact on pain perception, and in turn disability due to pain. Pain intensity, the degree to which it interferes with activities and the extent to which it disrupts mood, all predict chronicity of back pain. Early identification of psychological vulnerabilities is essential to the overall outcome of patients with CLBP. Furthermore, psychosocial treatments offer a “low-risk” treatment option, with evidence of benefits that equal surgical interventions or exceed usual care. These therapies may be particularly important to utilize in the refractory patient or those with enhanced psychosocial vulnerabilities.
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- Pengel LHM, Herbert RD, Maher CG, Refshauge KM. Acute low back pain; systematic review of its prognosis. BMJ 2003;327(7410):323.
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- van Tulder MW, Assendelft WJ, Koes BW, Bouter LM. Spinal radiographic findings and nonspecific low back pain. A systematic review of observational studies. Spine (Phila Pa 1976). 1997;22(4):427-434.
- Gore M, Sadosky A, Stacey BR, Tai KS, Leslie D. The burden of chronic low back pain: clinical comorbidities, treatment patterns, and health care costs in usual care settings. Spine (Phila Pa 1976). 2012;37(11):E668-677.
- Carragee EJ, Alamin TF, Miller JL, Carragee JM. Discographic, MRI and psychosocial determinants of low back pain disability and remission: a prospective study in subjects with benign persistent back pain. Spine J. 2005;5(1):24-35.
- Polatin PB, Kinney RK, Gatchel RJ, Lillo E, Mayer TG. Psychiatric illness and chronic low-back pain. The mind and the spine--which goes first? Spine (Phila Pa 1976). 1993;18(1):66-71.
- Von Korff M, Crane P, Lane M, et al. Chronic spinal pain and physical-mental comorbidity in the United States: results from the national comorbidity survey replication. Pain. 2005;113(3):331-339.
- Rudy TE, Kerns RD, Turk DC. Chronic pain and depression: toward a cognitive-behavioral mediation model. Pain 1988;35(2):129-140.
- DeGood DE, Kiernan B. Perception of fault in patients with chronic pain. Pain. 1996;64(1):153-159.
- Osman A, Barrios FX, Kopper BA, Hauptmann W, Jones J, O'Neill E. Factor structure, reliability, and validity of the Pain Catastrophizing Scale. J Behav Med. 1997;20(6):589-605.
- Quartana PJ, Campbell CM, Edwards RR. Pain catastrophizing: a critical review. Expert Rev Neurother. 2009;9(5):745-758.
- Weissman-Fogel I, Sprecher E, Pud D. Effects of catastrophizing on pain perception and pain modulation. Exp Brain Res. 2008; 186(1):79-85.
- Burns JW, Johnson BJ, Mahoney N, Devine J, Pawl R. Anger management style, hostility and spouse responses: gender differences in predictors of adjustment among chronic pain patients. Pain. 1996;64(3):445-453.
- Bruehl S, Burns JW, Chung OY, Ward B, Johnson B. Anger and pain severity in chronic low back pain patients and pain free controls: the role of endogenous opioid blockade. Pain. 2002;99(1-2):923-933.
- Burns JW, Quartana P, Gilliam W, et al. Effects of anger suppression on pain severity and pain behaviors among chronic pain patients: evaluation of and ironic process model. Health Psychol. 2008;27(5):645-652.
- Serbic D, Pincus T, Fife-Schaw C, Dawson H. Diagnostic uncertainty, guilt, mood, and disability in back pain. Health Psychol. 2016;35(1):50-9.
- Hassett AL, Goesling J, Mathur SN, Moser SE, Brummett CM, Sibille KT. Affect and low back pain: more to consider than the influence of negative affect alone. Clin J Pain. 2016;32(10):907-914.
- Woby S, Watson P, Roach N, Urmston M. Coping strategy use: does it predict adjustment to chronic back pain after controlling for catastrophic thinking and self-efficacy for pain control? J Rehabil Med. 2005;37(2):100-107.
- Mirza S, Deyo RA. Systematic review of randomized trials comparing lumbar fusion surgery to nonoperative care for treatment of chronic back pain. Spine (Phila Pa 1976). 2007;32(7):816-823.
- Eccleston C, Morley SJ, Williams AC. Psychological approaches to chronic pain management: evidence and challenges. Br J Anaesth. 2013;111(1):59-63.
- Burns JW, Quartana P, Gilliam W, et al. Effects of anger suppression on pain severity and pain behaviors among chronic pain patients: evaluation of an ironic process model. Health Psychol. 2008;27(5):645-52.
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- Goyal M, Singh S, Sibinga EM, et al. Meditation programs for psychological stress and well-being: a systematic review and meta-analysis. JAMA Intern Med. 2014;174(3):357-368.
- Chiesa A, Serretti A. Mindfulness-based interventions for chronic pain: a systematic review of the evidence. J Altern Complement Med. 2011;17(1):83-93.
- Veehof MM, Oskam MJ, Schreurs KM, Bohlmeijer ET. Acceptance-based interventions for the treatment of chronic pain: a systematic review and meta-analysis. Pain. 2011;152:533-542.
- Cherkin DC, Sherman KJ, Balderson BH, et al. Effects of mindfulness-based stress reduction vs cognitive-behavioral therapy and usual care on back pain and functional limitations among adults with chronic low back pain: a randomized clinical trial.
- Shedler J. The efficacy of psychodynamic psychotherapy. Am Psychol. 2010;65(2):98-109.
- Turk DC, Swanson KS, Tunks ER. Psychological approaches in the treatment of chronic pain patients--when pills, scalpels, and needles are not enough. Can J Psychiatry. 2008:53(4):213-223.
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- Turk DC, Swanson KS, Tunks ER. Psychological approaches in the treatment of chronic pain patients--when pills, scalpels, and needles are not enough. Can J Psychiatry. 2008;53(4):213-223.
- Chou R, Loser JD, Owens, DK, et al. Interventional therapies, surgery, and interdisciplinary rehabilitation for low back pain: an evidence-based clinical practice guideline from the American Pain Society. Spine (Phila Pa 1976). 2009;34(10):1066-1077.