Every child experiences acute pain from time to time, especially as a result of an injury.

Although chronic and recurrent pains are considered to be common among elderly people, children and adolescents suffer from such pains quite often. For example, the results of the Dutch study (1) show that 53.7% of children aged 0-18 reported pain in the previous three months including 25% reporting chronic pain. One-third of the chronic pain sufferers have experienced frequent and severe pains. The occurrence of chronic pain increased with age and girls aged 4-18 reported chronic pain significantly more often than boys. Moreover, girls reported multiple and severe pains more often. Limb pain, headache and abdominal pain were the most common types of pain in children. In a German study (2), 83% of the children aged 6-18 have experienced pain during the preceding three months. Thirty point nine percent of pain sufferers reported pain present for more than six months and 35.2% reported pain occurring at least once a week. The mean pain intensity in children and adolescents was 5.7 (max. value = 10). The most prevalent pain types were: headache (60.5%), abdominal pain (43.3%), sore throat (35%), limb pain (33.6%) and back pain (30.2%). In a longitudinal survey conducted in Canada (3), children were examined every other year from the age of 10-11 years till the age of 18-19 years. It was found that headache occurred once a week or more often in 26.2%-31.8% of the studied sample, stomachache in 13.5-22.2% and backache in 17.6-25.8%. Girls had higher rates of pain than boys in respect of all the types of pain, at all time points.

Summing up, pain seems to be a very common phenomenon among children and adolescents, as they often suffer from severe chronic and recurrent pains. However, a recent review (4) of the studies on the epidemiology of chronic pain in children and adolescents revealed a high variability of the results. The prevalence rates were as follows: headache – 8-82.9%; abdominal pain – 3.8-53.4%; back pain – 13.5-24%; musculoskeletal/limb pain – 3.9-40%; multiple pains – 3.6-48.8%; other/general pain – 5-88%. Two general conclusions can be drawn from the results of the previous studies: prevalence rates for most pain types were higher in girls and they increased with age.

Chronic and recurrent pain can have a negative impact on the function, quality of life and psychological well-being of children and adolescents. Children with pain show a substantial impairment within many domains of daily life. For example, 72% of children with chronic pain of unknown origin suffered impairment in sports activities, 51% reported absence from school, 40% experienced limitations in social functioning, and 34% had problems with sleeping. Generally, the number of somatic symptoms was higher in girls than in boys (5). In the German study cited above (2), children with pain reported pain causing: sleep problems (53.6%), inability to pursue hobbies (53.3%), eating problems (51.1%), school absence (48.8%), and inability to meet friends (46.7%). The prevalence of limitations in daily life caused by pain increased with age. In a recent study (6), a significantly higher rate of overweight and obesity was observed among youth with chronic pain in comparison with a normative sample.

Two recent systematic reviews (7, 8) were aimed at assessing problems in the functioning of children and adolescents with chronic pain. It was found that chronic pain negatively affected cognitive and school functioning, however, children’s cognitive and academic disruption was not related to general intellectual deficits. Children with chronic pain function either at or above age expectations according to standardized psychological measures of general intelligence (7).

Chronic pain causes also deficiencies in social functioning and peer relationships in children and adolescents. Reports show that children with chronic pain have fewer friends, are subjected to more peer victimization, and are viewed as more isolated and less likeable than healthy peers (8). Children with pain report having higher levels of distress, anxiety and depression. For example, adolescents aged 13-19 years with frequent headaches had higher levels of anxiety or depressive symptoms (9). Generally, depression is strongly associated with functional disability caused by pain (10). The Canadian longitudinal survey cited above (3) demonstrated that anxiety and depression at the age of 10-11 years had been predictive of the trajectories of pain, which indicated high levels of pain during the observation period and trajectories of pain that increased over time. Moreover, 21-28% of children and adolescents with unexplained chronic pain had clinically relevant psychiatric disorders i.e. anxiety, affective and disruptive disorders (11).

There is a growing evidence that children and adolescents with pain report a worse quality of life (12, 13). For example, it was found that the higher the intensity and frequency of the pain, the lower the quality of life in the youngsters aged 12-18, especially regarding the psychological functioning (e.g. feeling less at ease), physical status (a greater incidence of other somatic complaints) and functional status (more impediments to leisure and daily activities) (14). Chronic pain had also a negative impact on family life, mainly because of the worse child’s physical and psychological functioning. A recent review (15) of studies on family functioning in families of children and adolescents with chronic pain confirmed that in general families of children with chronic pain had poorer family functioning than healthy populations. However, pain-related disability rather than pain intensity was found to be related to family functioning.

Most importantly, children and adolescents with pain are at a risk for continuing into adulthood with chronic pain, physical symptoms, and psychological problems. For example, it was found that children with frequent headaches had an increased risk of headaches, multiple physical symptoms and psychiatric morbidity during adulthood (16). Last but not least, the economic impact of chronic pain in childhood and adolescence is very high. For example, in the United Kingdom the mean cost per adolescent experiencing chronic pain was estimated at £8000 per year. Taking into account the prevalence data of adolescent chronic pain in UK, the cost-of-illness to UK society is approximately £3840 million yearly (17).

Summing up, the impact of chronic pain on children is pervasive. Chronic and recurrent pains in children and adolescents affect nearly every domain of functioning, including physical, cognitive, psychological, social and family functioning. Moreover, chronic pain in childhood and adolescence may increase the risk of chronic pain and other symptoms in adulthood and has a very high economic impact. That is why effective management of pain in childhood is a matter of key.

The operant behavioral therapy was probably the first psychological intervention that gained wide acceptance for treating chronic pain problems not only in childhood but also in adulthood. According to the theory of operant conditioning, all overt behaviors are significantly influenced by their consequences and the surrounding context in which they occur. It means that reinforced behaviors tend to an increase in frequency and last over time, while behaviors that are punished or that are not reinforced are likely to be extinguished or decrease in frequency (18). Reinforcement can include things a person enjoys or derives pleasure from (positive reinforcement) as well as a removal of negative experiences (negative reinforcement). On the other hand, punishment involves unpleasant experiences or aversive situations (19).

Fordyce (20) was the first who systematically extended and described the application of operant conditioning to chronic pain. He proposed that observable pain behaviors (such as medication consumption, guarding, rubbing, limping, grimacing, resting) and more adaptive overt well behaviors (such as smiling, working, walking, standing, engaging in social-recreational activities), although probably initially triggered by antecedent events (e.g. injury, disease), are governed by their contingent consequences (21). Fordyce (20) theorized that pain behaviors are natural responses to acute pain that can persist after healing if they are reinforced and competing well behaviors are not sufficiently reinforced. This may lead to overt pain behaviors occurring not only in response to nociception but also in response to environmental contingency and discriminative stimuli (18). Various stimuli in one’s environment acquire discriminative or cue-like properties. Based on association with the target behavior and contingent consequence, these stimuli acquire the ability to signal the person that emission of a given overt behavior is likely to result in a certain consequence (19). Many overt pain behaviors are controlled by discriminative stimuli (22, 23).

The objective of an operant conditioning treatment of pain is not a reduction of an individual’s subjective experience of pain but a restoration of functioning by changing overt pain behaviors that can interfere with functioning. Some conditions, which have to be fulfilled, determine the effectiveness of operant conditioning methods. Firstly, there should be identified specific overt behaviors and effective positive and negative consequences for those behaviors. It is also important to apply consequences consistently and contingently upon the occurrence of target overt behaviors. Although the shortest time between the application of consequences and the target behavior is the most preferable, it is worth to mention that as long as the patient is aware of the administration being contingent upon emission of the behavior, this time rule is not crucial (19). However, spontaneous occurrence of a given overt behavior is sometimes impossible without an application of some additional shaping procedure, which involves systematically reinforcing consecutive approximations of a given overt behavior until the complete response is obtained (24). Another condition for obtaining an increase in effectiveness of operant conditioning for chronic pain management is the use of other learning-based and behavioral techniques, such as relaxation training, modeling, and desensitization procedures for escape-avoidances and fear responses (25).

One of the most important components of a behavioral treatment based on the operant conditioning model for chronic pain is the identification of (1) target pain behaviors or the lack of well behaviors, (2) discriminative stimuli that precede and influence these behaviors, and (3) reinforcers and punishers for these behaviors (26). Information about these factors is obtained by a direct observation of patients, behavioral assessment questionnaires and a self-monitoring by the patient. Direct observation techniques play a crucial role in the assessment of children who are too young for self-monitoring.

The effectiveness of operant conditioning for pain management is contingent upon the following conditions that should be met: (1) overt pain behaviors are present; (2) salient positive and negative reinforcers or punishers can be identified; (3) there is sufficient environmental control to contingently apply antecedent and consequent stimulus conditions; (4) the patient is not experiencing any major non-drug-related cognitive-learning impairment; and (5) the patient is willing to participate actively (19, p.131). One should point out that operant conditioning may be useful even if none of the indicators are present. In such situations more adaptive well behaviors (like smiling, exercising or walking without cane) can be increased. On the other hand, the presence of all basic indicators does not exclude concurrent presence of ongoing nociception from annoyance or some other factor (19).

There are only few recommendations on the application of operant conditioning in chronic pain patients (20, 27). The first step is an assessment of patients using functional behavioral analysis methods. It enables therapists to identify relevant overt pains and well behaviors, the controlling of antecedent and consequent stimuli and the level of patient and family cooperation. It is also important to identify the extent of physical pathology, which should be included in the process of preparing realistic goals for behavioral interventions. The monitoring of the amount of behavioral change during treatment is crucial for making meaningful decisions about effects of intervention.

The treatment recommendations, used by Sanders (19), are general and can be applied in a wide range of painful conditions. The first suggestion is to reduce overt pain behaviors by using extinction and to increase well behaviors by applying positive and negative reinforcements. The second suggestion is to reduce medication-taking behavior by using time-contingent delivery. This procedure reduces the amount of medication taken per dose or day. It is recommended to use initial baseline levels and gradually increase them at present amounts (determined with patient cooperation) with abundant reinforcement in order to increase the general activity level, uptime and physical exercise. There are also suggestions to use the method of shaping or gradual change for well behaviors, whenever possible. When target behavior occurs consistently it is recommended to reduce the frequency of the application of positive and/or negative reinforcement. To maximize generalization and discriminative stimulus efforts, it is important to apply operant methods to every overt pain and well behavior across as many different environmental conditions and people as possible. In addition, the elimination or reduction of most external controlling stimulus conditions maintaining overt pain behaviors outside the treatment environment is also of importance.

One of the treatment stages often consists in educating patients and important people in their lives in pain behaviors and in asking these people to ignore pain behaviors and reinforce opposing well behaviors (18). The treatment effectiveness usually increases when family members are included, because these individuals often provide various forms of reinforcement for patient’s pain and well behaviors. Moreover, family members spend more time with the patient so they can apply operant conditioning methods in a more regular way. Some authors are of the opinion that behavioral methods need time to work. Therapists should be sure to follow patients for at least three to six months after active treatment in order to facilitate maintenance of change. According to the last recommendation, operant conditioning methods should be used in combination with other psychological and physical treatments (e.g. relaxation, physical therapy, antidepressant and anti-inflammatory medications) within an interdisciplinary treatment approach (19).

The respondent therapy constitutes the other type of behavioral therapy applied for pain management, especially in those pain responses, which are based on unconditioned reflexes, escape/avoidant behavior and/or generalized emotional responses. The fundamentals of respondent therapy are based on the Pavlov’s respondent conditioning model, with special attention given to a conditioning involving the use of aversive unconditioned stimuli such as tissue damage or irritation (28). The respondent therapy includes two techniques commonly used for treatment of chronic pain: (1) progressive muscle relaxation and (2) biofeedback.

Progressive muscle relaxation (PMR) is based on an assumption that pain evokes a response in the form of increased muscle tensions which produce more pain and cause additional problems such as sleep disturbances, immobilization, and depression (29). Thus, the objective of a treatment is a reduction of muscle tension. The first step of a therapy consists in educating patients in the identification of the association between their pain and muscle tension. The second and more important stage of a therapy includes a process of learning to replace this tension with a contrary response, namely the relaxation (30). An eliciting of changes in muscle tension and pain response is achieved by the use of muscular reflex reactions and central nervous system unconditioned and conditioned stimuli (28). However, relaxation is not only a reducer of muscle tension and, as a result of this, of the pain. It also plays a role in the anxiety and sleep disturbance reduction as well as in the increase of well-being and improvement of sense of control (21).

A biofeedback also involves muscle relaxation, but it is achieved in different way. Typically, bodily responses are being monitored by a computer or special apparatus and patients get visual or auditory feedback about their physiological responding. The aim of the biofeedback is to instruct how to control physiological responses related to pain (31). Electromyographic (EMG) feedback, aimed at reducing muscle tension, is the most popular form of biofeedback applied for chronic pain management. This strategy is also used to reduce headaches, low back pain and temporomandibular joint pain (32). In some situations biofeedback and relaxation are used independently and separately, but more often those strategies are used in cooperation or in combination with other treatment approaches (21).