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Psychological interventions for chronic pediatric pain: state of the art, current developments and open questions

Practice Points

Christiane Hermann† „„

Children and adolescents who report recurrent pain episodes are not necessarily severely disabled. The level of functional disability should be carefully assessed prior to planning an intervention.

„„

If a child suffers from headache or recurrent abdominal pain, several effective psychological interventions (relaxation, biofeedback and cognitive–behavioral treatment) are available. At this point, little is known about which intervention will be most efficacious. Relaxation training is rather easily provided and cost effective and, therefore, may be considered as the initial treatment of choice.

„„

If the child is not severely affected by the pain problem, internet-based self-help programs can be considered as a means of secondary prevention. They are effective, inexpensive for the user and are highly attractive for youths. Yet, outside of a research context, none of these internet-based self-help programs is currently offered on a regular basis.

„„

Parents should be involved in the treatment of chronic pediatric pain. Since parents serve as pain models, it is important to determine parents’ own pain-coping behavior and their proneness to engage in catastrophizing about the child’s pain. Similarly, parental responses to the child’s pain should be assessed systematically. Parents should be educated and alternative responses (e.g., promote active coping in the child) should be practiced, especially when solicitous responses occur frequently.

SUMMARY

Chronic pain, especially headache and recurrent abdominal pain, affects a sizable number of children and adolescents. In this selective overview, the need and rationale for psychological approaches to the treatment of chronic pediatric pain will be explored, and current developments and open questions will be addressed. Thus far, research has mostly focused on the efficacy of various psychological interventions such as relaxation, biofeedback and cognitive–behavioral interventions, specifically for headaches and recurrent abdominal pain. Yet, the differential efficacy of the various psychological interventions still awaits empirical evaluation. In fact, in the past decade, the focus of research has shifted more towards developing and evaluating treatment formats that target specific subgroups of patients, such as multimodal inpatient treatment programs for severely affected youth. On the other hand, much research has been devoted to self-help treatment formats such as internet-based intervention programs. Rather surprisingly, the Department of Clinical Psychology & Psychotherapy, Justus-Liebig-University Giessen, Otto-Behaghel-Str. 10F, D-35394 Giessen, Germany; Tel.: +49 641 992 6081; Fax: +49 641 992 6099; [email protected] †

10.2217/PMT.11.48 © 2011 Future Medicine Ltd

Pain Manage. (2011) 1(5), 473–483

ISSN 1758-1869

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Review  Hermann role of parents in the treatment of chronic pediatric pain is far from being understood, which may be best accounted for by the fact that psychological interventions were mostly adapted from treatment programs in adults rather than being specifically developed for children and adolescents. Conclusions for clinical practice and research are outlined. Since the early 1980s, psychological interventions for chronic pediatric pain are available and have undergone empirical evaluation. Their efficacy has been summarized in several reviews and meta-analyses. It is the aim of this overview to address a number of issues and open questions that should be considered in clinical practice and research. First, the need for such interventions will be discussed based on what we know about the prevalence of chronic pediatric pain. This has important implications for the type and format of treatments that should be available. Second, the development of psychological interventions and their efficacy is briefly summarized in order to outline current trends and to pinpoint open questions with a strong focus on the role of parents. Is there a need for psychological interventions for chronic pain in children? Children and adolescents experience pain from a number of different sources. Aside from acute pain, pain without an underlying disease is the most common type of pain condition during childhood and adolescence. According to a rather recent population-based study in 7–14‑year-old children and adolescents, headaches (HAs) have a 6‑month prevalence of 53.2% with a strong age-related increase [1] . Sundblad reported a 50% 3‑month prevalence of HAs, abdominal and musculoskeletal pain [2] . Hence, many children and adolescents experience pain, yet not necessarily chronic pain. Although no consensus definition exists, chronic pain in children is most often defined as pain that persists for at least 3 months or beyond the expected time for healing [3] . The most common chronic pain problems, aside from HAs, are recurrent abdominal pain (RAP) and musculoskeletal pain. Chronic pain can occur continuously or on a recurrent basis. Across studies, the pain frequency that is required for being considered as recurrent varies considerably from about once a month (e.g., [4,5]) up to at least once a week [1] . The prevalence estimates for chronic pain strongly depend on pain frequency. Chronic pain occurring at least once a month may affect between 25 and 35% of children and adolescents with a pronounced increase during adolescence [6,7] . Chronic pain (HAs, RAP,

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musculoskeletal pain) with a pain frequency of ≥1 per week is reported by approximately 6–12% of youth between 8 and 18 years [1,2] . Chronic pain is associated with reduced quality of life, greater school absenteeism and school frustration, higher use of medication, and more physician visits [8,9] . However, not all affected children necessarily seek treatment. Similar to adults, it is likely to be those who experience high levels of pain intensity and/or pain-related disability. Yet, few epidemiological data exist on the prevalence of disabling chronic pain. Perquin et al. reported that 4–7% of boys and 13–16% of girls (8–18 years) suffer from weekly severe chronic pain (pain intensity >50 on a 100‑mm visual analog scale [VAS]) [7] . Applying a well-validated chronic pain grading scale for adults that takes into consideration pain intensity and disability [10] , Huguet and Miro [6] determined that only about 5% of school children suffer from moderately to severely disabling pain (Figure 1) . While this is still a sizable number, such figures suggest that many children who experience recurrent pain cope rather well with it and do not necessarily require treatment. Relatively little is known about the prognosis of chronic pain in children. Few prospective studies exist. Childhood HA and nonspecific musculoskeletal pain have been found to persist in approximately 40–80% of the children with follow-up periods ranging from 1 to 20 or even 40  years (e.g., [5,11–17]). Aside from persisting throughout childhood [18,19] , pediatric RAP may be a precursor of chronic pain or other health and emotional problems in adulthood (e.g., [18–23]). Taken together, these studies suggest that recurrent pain may persist in a substantial number of children and adolescents well into early adulthood. In children with HA, RAP or musculoskeletal pain, anxiety, depression and psychosomatic complaints predict further ongoing pain [24,25] . Thus, recurrent pain during childhood may increase the risk of a lifetime of chronic pain, at least in a subgroup of children. From this perspective, the treatment of recurrent pain in children and adolescents is not only important as a primary intervention (at least for some of the children), but may also constitute an important measure of secondary prevention. The

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Psychological interventions for chronic pediatric pain  prevalence data also suggest that children with chronic pain differ substantially with regard to disability and, hence, may require psychological interventions that are more specifically tailored to their needs. This conclusion matches well with the observation that children and adolescents undergoing multimodal treatment can be classified into subgroups along a continuum of increasing pain severity and disability [26] . Which psychological interventions for chronic pediatric pain are available & are they efficacious? Virtually all psychological interventions for chronic pediatric pain have been adapted from interventions for pain management in adults. Most of what we know about the efficacy comes from treatment studies in childhood HA, which probably reflects its high prevalence in youth. Furthermore, psychological treatments in all of the available randomized controlled studies have been provided on an outpatient basis (e.g., [27]). Psychological intervention programs typically address children and adolescents between the ages of 8 and 16 years with very few attempts to treat children younger than 6–7 years of age. Consistent with treatment approaches in adults, all available psychological treatments for chronic pediatric pain encourage the child to engage in active coping and self-initiate coping attempts. This requires an understanding of how one’s own thinking and doing influences the experience of pain and well-being. Below the age of about 7–8 years most children have limited capability for this owing to their cognitive development. Interestingly, while a number of interventions for procedural pain are available for these younger children [28] , interventions specifically targeting recurrent pain in this young age group have not been systematically evaluated. However, rather little is known about the need for such interventions. Based on a population survey, Perquin et al. [7] reported that about 12% of children between 0 and 3 years and about 19% of children between 4 and 7 years were suffering from chronic pain defined as any recurrent pain with a duration of 3 months, but without a predefined minimum frequency. For example, chronic pain could occur with a frequency of less than once a month. In addition, the list of possible pain locations in this study included ear and throat, hence chronic pain may also have entailed pains associated with recurrent infections. In this study, severe chronic pain (intensity of >50 on a 0–100  mm VAS)

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Grade 1: low disability, low pain intensity 20%

Grade 0: no chronic pain problem 63.2%

Grade 2: low disability, high pain intensity 11.7%

Grade 4: high disability 1.1%

Grade 3: moderate disability 4.1%

Regardless of pain intensity

Figure 1. Severity of recurrent pain problems in school children (8–16 years) as assessed in an epidemiological survey in schools in Catalonia, Spain. Chronic pain was defined as continuous or recurrent (≥1 per month) pain lasting ≥3 months. Severity of chronic pain was graded using pain intensity and functional disability as assessed by the Functional Disability Inventory [73]. Adapted with permission from [6].

affected about 2–3% of the 0–7 year olds. In a large population-based cohort study, RAP defined as at least five episodes of abdominal pain within a 12 month period was endorsed by the parents of approximately 4% of 2 year olds, 7% of 3 year olds and about 12% of 6 year olds [29] . Overall, chronic pain seems to be less prevalent in children below the age of 8 years. The percentage of children with disabling pain is likely to be even lower. Psychological treatments for chronic pediatric pain were first developed in the late 1980s. Initially, such treatments consisted of single interventions such as relaxation or biofeedback (BFB). Today, most programs entail behavioral and cognitive interventions. Progressive muscle relaxation is one of the most frequently used interventions either as a single intervention or as part of a comprehensive cognitive–behavioral treatment (CBT) program. Relaxation can be taught individually or in groups and even in a self-help format. Such self-help relaxation is efficacious; however, when headaches are frequent, therapist-guided relaxation training was superior to self-help relaxation [30] . Similar to relaxation, BFB has been studied almost exclusively as a treatment for recurrent HA. Electromyogram-BFB is usually taught as BFB-assisted relaxation. Electromyogram-BFB

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Review  Hermann is often combined with progressive muscle relaxation in order to facilitate the transfer of the relaxation response acquired in the session into the child’s daily life. For migraine, various BFB modalities such as thermal BFB (‘hand warming’) or vasoconstriction training are available, which were all designed to modify the presumed underlying pathophysiological processes. Based on the notion that migraine is associated with cortical hyperexcitability, a specific form of electroencephalography-BFB [31] has also been developed and evaluated against a wait list control. The effectiveness of thermal BFB in the treatment of pediatric migraine has been demonstrated in several studies [27] . There is initial evidence from a randomized controlled trials (RCT) for its efficacy when combined with a fiber diet in the treatment of RAP [32] . Since vasoconstriction training for migraine has only been offered in combination with CBT, its specific efficacy is yet to be demonstrated. Different BFB modalities have not been evaluated against each other. In the past few years, surprisingly few studies on BFB have been published despite its well-documented efficacy. Cognitive–behavioral treatments have increasingly become the treatment of choice for chronic pediatric pain. CBT treatment packages for chronic pediatric pain are highly similar to adult programs. They typically comprise four major components: ƒƒ Education about the pain (e.g., migraine); ƒƒ Learning of cognitive and behavioral pain

coping skills, such as imagery, stopping and modifying pain-related negative thoughts (specifically pain-related catastrophizing), distraction away from pain, focused attention (e.g., on sensory information rather than pain), and relaxation; ƒƒ Stress management skills: identifying and

coping with everyday stressful situations using strategies such as thought stopping, cognitive re st r uc t u ring ( ‘ helpf u l t hou g ht s’ ), assertiveness (e.g., increasing self-confidence) and problem solving; ƒƒ Maintenance of learned skills and relapse

prevention. Both pain and stress management rely on similar behavioral and cognitive techniques. These are applied to the coping with and prevention of pain as well as to stressful situations with the aim of reducing the stress-induced occurrence and aggravation of pain episodes.

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More recently, a CBT program specifically tailored for adolescents with pain and depressive symptoms was presented with the specific aim to improve school functioning [33] . In adults, CBT approaches to the treatment of chronic pain in adults increasingly take into account recent CBT developments, in particular acceptance and commitment therapy (ACT) [34] . According to ACT, experiential avoidance is a core problem in emotional disorders (and chronic pain) leading to disability and reduced quality of life. This experiential avoidance is a result of maladaptive cognitions and feelings being treated as reality and acted upon (denoted as cognitive fusion). Exposure to avoided situations and activities is a core intervention with the focus lying on acceptance of negative responses (thoughts, emotions and body sensations – e.g., pain) rather than changing or controlling them. In addition, engagement in personally meaningful activities is promoted (i.e., it is a goal to increase patients’ flexibility such that they pursue personally meaningful values despite interfering cognitions, feelings and body symptoms). A recent RCT by Wicksell and colleagues [35] in 16 children and adolescents between the ages of 10 and 18 years suffering from various chronic pain conditions demonstrated that approximately ten ACT sessions were superior to a multidisciplinary pain management program combined with antidepressant medication (n = 16 patients) with regard to improvements in functional disability, pain intensity, pain-related distress, fear of (re)injury, pain-related interference and quality of life at post-treatment and at follow-up. The patients in the Wicksell et al. study were suffering from different chronic pain syndromes, varied greatly with regard to age and were severely impaired [35] . Moreover, the multidisciplinary pain management program was not standardized. Whether ACT may indeed have additional benefits above and beyond CBT, remains to be demonstrated. „„ Efficacy of psychological interventions for

pediatric pain

Several meta-analyses of available RCT and systematic reviews have repeatedly shown that relaxation, BFB and CBT are efficacious, at least for the treatment of recurrent HA, recurrent abdominal pain and fibromyalgia, although for the two latter pain problems very few studies are available [27,36–39] . In Table 1 the main results of a recent meta-ana­lysis [27] are summarized. It is noteworthy that, overall, relatively few RCTs are

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Psychological interventions for chronic pediatric pain  available and, even more important, that the vast majority of these studies have been conducted prior to the year 2000. With regard to treatment efficacy, there are several open questions. The differential efficacy of the various psychological interventions when compared with each other or even pharmacological interventions remains to be determined. Thus far, direct comparisons between treatments are scarce. In their meta-ana­lysis, Palermo et al. computed separate effect sizes for studies entailing CBT, relaxation and BFB [27] . The obtained results seem to suggest that BFB is most efficacious, followed by relaxation and CBT (Table 2) . Yet, such a conclusion is rather questionable given that there are large differences in the number of available studies and treated patients, and that only children with HAs, but not other pain problems had been treated with relaxation and BFB. Moreover, the effect sizes for the BFB studies were very heterogeneous, suggesting that the obtained average effect size is likely not to be a good estimate of BFB’s general efficacy across studies. The long-term outcome (>6 months) of such psychological pain management has only been evaluated in very few studies. If psychological interventions for pediatric pain do have longterm effectiveness, they may indeed hold promise as a measure of secondary prevention. Traditionally, pain management programs have aimed at reducing pain activity (i.e., frequency and/or intensity and/or duration). Accordingly,

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it is mostly the change in pain activity that has been used as the primary and only outcome measure with little attention to disability, other somatic complaints, coping efforts, and emotional and social adjustment. Consistent with previous recommendations of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) [40] for clinical trials for chronic pain in adults, the Pediatric IMMPACT recommendations have recently proposed pain intensity, physical functioning, emotional functioning, role functioning, sleep, global judgment of satisfaction with treatment, symptoms and adverse events, and economic factors as core domains of treatment outcome [3] . The meta-analysis by Palermo et  al. revealed that psychological interventions led to large improvement in pain activity, whereas disability and emotional functioning showed little change (when they were assessed in the respective studies) (Tables 1 & 2) [27] . To some extent, this may reflect that these outcome measures were only assessed in a few studies. It may also reflect that children and adolescents participating in RCTs evaluating outpatient pain management trainings may experience low-to-moderate levels of disability and emotional distress, which may not greatly change due to treatment. Indirect support for this assumption comes from treatment studies in adolescents with longstanding chronic pain and high levels of disability. In these patients, interdisciplinary pain management programs that include physical, occupational and cognitive

Table 1. Average effect sizes for the comparison between treatment and control groups with regard to different outcome variables. Studies (n) Total (n)

OR† SMD‡

95% CI

Z§ (p-value)

Clinically significant improvement in pain (≥50% pain reduction) Post-treatment Follow-up

18 7

714 239

5.92† 9.88†

4.97, 8.61 5.25, 18.58

9.31 (p < 0.001) 7.11 (p < 0.001)

7 3 6 6

276 137 220 204

-0.37‡ -0.43‡ -0.24‡ -0.12‡

-0.82, 0.09 -1.04, 0.17 -0.51, 0.03 -0.40, 0.17

1.59 1.41 1.73 0.80

Pain intensity Post-treatment Follow-up Disability at post-treatment Emotional functioning at post-treatment

OR refers to the between-group comparison with regard to the proportion of patients with a clinically significant pain reduction (50% or greater) and those without a clinically significant pain reduction. OR >1 indicates that, in the treatment group, the proportion of clinically significant improved patients is higher than in the control group. ‡ SMD refers to the difference between the means for the treatment and the control group at post-treatment or follow-up divided by the pooled standard deviation. Cohen suggested SMD effect sizes of 0.2, 0.5 and 0.8 as representing a small, medium and large effect size, respectively [74]. Here, a negative SMD reflects greater improvement in the treatment group. § The significance of the obtained effect sizes (OR or SMD) was determined by performing a Z-test. OR: Odds ratio; SMD: Standard mean difference. Data taken from [27]. †

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Review  Hermann Table 2. Effectiveness of different psychological interventions: average effect sizes for the comparison between treatment and control group. At post-treatment

Studies (n)

Total (n)

OR† SMD‡

95% CI

Z§ (p‑value)

Clinically significant pain reduction (≥50% pain reduction) Cognitive–behavior therapy Relaxation Biofeedback (EMG, thermal)

9 6 3

406 225 82

4.13† 9.93† 23.34†

2.61, 6.54 4.38, 22.54 5.87, 92.72

6.05 (p < 0.001) 5.49 (p < 0.001) 4.48 (p < 0.001)

6 0 0

220 0 0

-0.24‡ – –

-0.51, 0.00 – –

1.73 (p ≤ 0.1) – –

5 0 1

174 0 30

-0.09‡ – -0.15‡

-0.40, 0.21 – -0.91, 0.61

0.59 – 0.40

Pain-related disability Cognitive–behavior therapy Relaxation Biofeedback (EMG, thermal) Emotional functioning Cognitive–behavior therapy Relaxation Biofeedback (EMG, thermal)

OR refers to the between-group comparison with regard to the proportion of patients with a clinically significant pain reduction (50% or greater) and those without a clinically significant. ORs >1 indicate that, in the treatment group, the proportion of clinically significant improved patients is higher than in the control group. ‡ SMD refers to the difference between the means for the treatment and the control group at post-treatment or follow-up divided by the pooled standard deviation. Cohen suggested SMD effect sizes of 0.2, 0.5 and 0.8 as representing a small, medium and large effect size, respectively [74]. Here, a negative SMD reflects greater improvement in the treatment group. § The significance of the obtained effect sizes (OR or SMD) was determined by performing a Z-test. EMG: Electromyogram; OR: Odds ratio; SMD: Standard mean difference. Modified from [27]. †

therapy as well as pain education, have resulted in a pronounced decrease in functional disability, less school absenteeism, reduced anxiety and somatic awareness, and better physical functioning [41,42] . What are current developments in the psychological treatment of chronic pediatric pain? As stated earlier, most children with chronic pain are not severely disabled and seem to cope rather well. A smaller number of children are severely affected. In line with this observation, there are two trends in the development of psychological treatments for chronic pain. On the one hand, for severely disabled youth, multimodal treatment programs including psychological treatments are offered. On the other hand, increasing efforts have been made to provide (online-based) self‑help programs.

For example, there are programs for children suffering from complex regional pain syndrome in Philadelphia [43] and Boston [44] with a heavy focus on physiotherapy that have reported excellent outcomes. Inpatient interdisciplinary pediatric pain management programs are also established in Germany (Vodafone Stiftungsinstitut für Kinderschmerztherapie und Palliativmedizin, Datteln [42]) and the UK (Bath Pain Management Program [30]). Both of these programs offer treatment for children with chronic HAs, musculoskeletal pain, fibromyalgia, complex regional pain syndrome, and rheumatologic diseases. Both programs are effective in reducing pain activity, functional disability, affective distress and parental distress, and yield impressive return to school rates both in children and adolescents [41,42,45] . „„ Self-help & internet-based treatments

„„ Multimodal treatments

Multimodal and multidisciplinary inpatient and outpatient treatment programs are increasingly available for children and adolescents. In most programs, participants receive medical treatment, psychological interventions and physical therapy. Some programs entail additional services such as occupational therapy, consultations by social workers and schooling by teachers in the clinic.

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Early on, there have been efforts to develop treatment formats with minimal therapist contact (‘home-based treatment’) or selfhelp programs. For example, McGrath and colleagues published a self-help booklet for pediatric migraine in 1990, it proved to be equally successful as the therapist-administered treatment [46,47] . Similarly, home-based thermal BFB have proven to be effective [48,49] .

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Psychological interventions for chronic pediatric pain  Today, self-help programs are increasingly offered as internet-based CBT programs. Although there are now at least three programs that have been evaluated, to the best of our knowledge, each of these programs has been offered only as part of a study protocol and is not available on an ongoing basis either for free or with a certain charge for registration and participation. Hicks et  al. were the first to report that about 70% of the children (9–16  years) suffering from recurrent pain (mostly HA and abdominal pain) showed at least a 50% reduction of pain after completing the program [50] . This self-help program comprises a total of 7 weekly modules that are equivalent to McGrath and colleagues’ self-help booklet. Similarly, an internet-delivered family CBT (i.e., CBT including a parent training) led to a significant reduction in pain activity and painrelated disability in adolescents suffering from various recurrent pains (e.g., HA, abdominal pain, leg pain) [51] . Children and their parents accessed two separate websites and were required to complete one module and one assignment per week (duration: 30 min) for 8 weeks. Assignments were handed in and were commented on by a therapist. The children’s modules were: ƒƒ Education ƒƒ Recognizing stress ƒƒ Deep breathing, relaxation ƒƒ Distraction ƒƒ Cognitions ƒƒ Sleep ƒƒ Activities ƒƒ Relapse prevention

The parents’ modules were: ƒƒ Education ƒƒ Recognizing stress and negative emotions ƒƒ Operant strategies ƒƒ Modeling ƒƒ Sleep hygiene ƒƒ Communication ƒƒ Relapse prevention

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Interestingly, parental solicitousness diminished from pre- to post-treatment in both groups (i.e., treatment did not specifically affect parental behavior). Since little is known about the stability of parent behavior, this finding is difficult to interpret. Both the Hicks et al.  [50] and the Palermo et  al.  [51] studies compared internet-based CBT to a wait list control, hence these findings essentially replicate the efficacy of self-help CBT. As stated earlier, there is a dearth of studies comparing efficacious psychological interventions with each other. Trautmann and Kröner-Herwig conducted a RCT comparing internet-based CBT (with weekly email support by a therapist), self-help applied relaxation and an attention placebo (pain education and regular email contacts with therapist) in children and adolescents with recurrent HA [52] . CBT was superior to applied relaxation and attention placebo at post-treatment. However, at the 6‑month follow-up, responder rates were not significantly different (CBT: 63%, relaxation: 56%, placebo: 55%). These findings highlight that it is far from clear whether there is indeed differential efficacy of psychological interventions. The study also underlines the need for long-term follow-up. The observed success rate in the attention placebo group may be due to an actual placebo effect, it possibly may also reflect the natural course of recurrent HAs in youth. Unlike in adult chronic pain patients, recurrent pain in children does not necessarily persist over a longer period of time even when untreated. Specific questions in the psychological treatment of chronic pediatric pain: what is the role of parents? Similar to other chronic medical conditions such as diabetes, many parents of children suffering from chronic pain report emotional distress and heightened levels of parenting stress [53,54] . In turn, parents themselves also influence their child’s pain and the adjustment to it. Children can learn about pain from their parents via social modeling [55,56] . For example, significant correlations between the child’s coping and parental pain coping have been reported [57] and parental pain problems promote pain catastrophizing in the child  [58] . There is some experimental evidence that social learning modulates the pain response in children. Goodman and McGrath trained mothers to either exaggerate or minimize their pain expression or they received no specific instructions when undergoing a cold pressor

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Review  Hermann task while their children were watching [59] . In a subsequent cold pressor task, children in the ‘exaggerate’ condition had significantly lower pain thresholds than the controls. Children in the ‘minimize’ conditions showed significantly less facial pain expression than the controls. However, perceived pain intensity did not significantly differ between conditions. The operant model of chronic pain postulates that chronic pain is maintained by operant reinforcement of pain behaviors such as verbal and nonverbal expressions of pain, guarding, limping, resting, and reduced activity. Experimentally, it has been demonstrated in healthy children [60] and children with RAP [61] that parental responses can indeed influence the child’s pain behavior and, thus, may contribute to the maintenance of pain. Walker et al. [61] trained mothers either to attend to signs of discomfort in their child when he/ she was undergoing a gastrointestinal symptom provocation test or to distract the child. In the ‘attention’ condition, children with RAP endorsed significantly more gastrointestinal symptoms compared with the controls (Figure  2) . In the distraction and control condition, no betweengroup differences were observed. Hence, children with RAP may benefit if parents are trained not to engage in pain-promoting responses. In children, interventions to modify (pain) behavior are typically based on the operant model. Such parent trainings have mostly been used as an additive to CBT [62] or BFB protocols. Operant treatment is typically provided as brief parent training (1–3 sessions). Parents are taught principles of contingency management with the aim to minimize positively (e.g., paying attention) or negatively reinforcing (e.g., excuse from daily chores) parental responses to the child’s pain behaviors. Moreover, parents learn to support and encourage their child to practice and use pain coping skills and maintain normal daily activities during pain episodes. Overall, surprisingly little is known about the differential contribution of parent training. For example, parent training as an adjunct to BFB has been found to enhance treatment success in some [63] , but not other studies [64] . While there is consensus that a child’s experience of pain is modulated by the social context, it is less clear which pain-related parental behaviors are adaptive and which are not. Indeed, parents are also sources of social support. In adults, the presence of significant others is known to reduce experimental pain [65] . In one of our own

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studies, healthy children were also less sensitive to experimental pain when tested in the presence of their mothers [66] . Intriguingly, in school-aged children with repeated pain experiences during the neonatal period, maternal presence did not attenuate pain sensitivity, while mothers reported significantly higher levels of solicitous responses to their child’s pain. Possibly, heightened solicitousness may interfere with the alleviating influence of social support. One obstacle for determining the differential impact of parent behavior has been the lack of assessment tools for parental behaviors. Only recently, questionnaires to assess pain-related parent behavior have been developed, all based on the assumptions of the operant model of chronic pain [67–69] . Thus far, the findings of studies evaluating the impact of parent training are difficult to interpret because, owing to the lack of available instruments, it was not systematically assessed which parental behaviors were related to the child’s pain activity prior to treatment, which behaviors were changed by treatment and how altered parent behavior may have mediated the child’s clinical improvement. Also, little is known about the factors that determine parental behavior and its stability. Parental catastrophizing may be crucial. As Goubert and colleagues have shown in several studies [70] , parental pain catastrophizing influences how much pain parents perceive their child is having, which eventually will determine parents’ response to the pain [71] and may teach the children how to cope with pain. Consistent with this notion, parental catastrophizing emerged as a significant predictor for mothers’ and fathers’ solicitous responses to their child’s pain above and beyond the child’s age and pain activity [72] . Palermo et  al. observed that solicitous and protective parent behaviors were equally reduced at post treatment in the treatment and the wait list control group [51] . This pattern of change may reflect fluctuations in parental responses or lack of retest reliability of the questionnaire that was used. However, mere participation in a treatment study may already reduce parental catastrophizing and, as a consequence, parents’ solicitousness. Finally, it is an open question whether modifying parental behavior is equally important for different types of chronic pain. Taken together, there are good reasons to involve parents in their child’s treatment even though the specific merits of a parent training require further empirical investigations.

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Psychological interventions for chronic pediatric pain 

Conclusion & future perspective A sizable number of children and adolescents are affected by recurrent pains, mostly HA, abdominal pain and musculoskeletal pain. Fortunately, in most of these children pain and pain-related interference is not severe. Nonetheless, recurrent pain in childhood bears substantial risk for persistence into adulthood. Several psychological interventions for chronic pediatric pain are available that are efficacious, although the available empirical evidence is mostly limited to pain conditions such as HA and abdominal pain. Aside from determining what works best for which type of pediatric pain problem, at what age and for whom, it will be the greatest challenge to make such treatments available for those who need them. Given that the greatest barrier for psychological interventions for pediatric pain is their availability in a given healthcare system, internet-based programs may be particularly promising. It will also be important to know more about the efficacy of psychological interventions in severely affected children with chronic pain other than HA, even though such pain conditions are far less prevalent. Finally, the role of the parent in the treatment of pediatric pain needs to be investigated in more detail. Clearly, this will have important treatment implications. Bibliography

3

Papers of special note have been highlighted as: of interest of considerable interest n

n n

1

2

Kröner-Herwig B, Heinrich M, Morris L. Headache in German children and adolescents: a population-based epidemiological study. Cephalalgia 27(6), 519–527 (2007). Sundblad GMB, Saartok T, Engstrom LMT. Prevalence and co-occurrence of self-rated pain and perceived health in school-children: age and gender differences. Eur. J. Pain 11(2), 171–180 (2007).

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n n

25 Number of child’s verbal symptom complaints

Parents should be educated about their child’s pain, which will help them not to engage in excessive catastrophizing. Furthermore, based on developmental considerations, especially in younger children, parents should learn about what the child is taught in order to be able to encourage and prompt the child to use the coping strategies, given that in younger children self-regulatory skills are still developing.

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* Pain patients 20

Well children

15

10

5

0

Distraction

No instruction

Attention

Figure 2. Number of verbal symptom complaints of children with recurrent abdominal pain (pain children) and healthy controls (well children) when undergoing the water load symptom provocation task. Children drank water until they were full and then interacted with their mothers. Mothers were trained to interact with their child. In the condition ‘attention’ mothers reassured the child and kept the child’s attention focused on body symptoms. In the condition ‘distraction’ the mothers kept the child’s attentional focus away from somatic sensation. *p < 0.05. Reproduced with permission from [61]. Financial & competing interests disclosure The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert t­e stimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript. McGrath PJ, Walco GA, Turk DC et al. Core outcome domains and measures for pediatric acute and chronic/recurrent pain clinical trials: PedIMMPACT recommendations. J. Pain 9(9), 771–783 (2008).

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