Antonia Barke

A classification of chronic pain for ICD-11

Chronic pain has been recognized as pain that persists past normal healing time5 and hence lacks the acute warning function of physiological nociception.35 Usually pain is regarded as chronic when it lasts or recurs for more than 3 to 6 months.29 Chronic pain is a frequent condition, affecting an estimated 20% of people worldwide6,13,14,18 and accounting for 15% to 20% of physician visits.25,28 Chronic pain should receive greater attention as a global health priority because adequate pain treatment is a human right, and it is the duty of any health care system to provide it.4,13 The current version of the International Classification of Diseases (ICD) of the World Health Organization (WHO) includes some diagnostic codes for chronic pain conditions, but these diagnoses do not reflect the actual epidemiology of chronic pain, nor are they categorized in a systematic manner. The ICD is the preeminent tool for coding diagnoses and documenting investigations or therapeutic measures within the health care systems of many countries. In addition, ICD codes are commonly used to report target diseases and comorbidities of participants in clinical research. Consequently, the current lack of adequate coding in the ICD makes the acquisition of accurate epidemiological data related to chronic pain difficult, prevents adequate billing for health care expenses related to pain treatment, and hinders the development and implementation of new therapies.10,11,16,23,27,31,37 Responding to these shortcomings, the International Association for the Study of Pain (IASP) contacted the WHO and established a Task Force for the Classification of Chronic Pain. The IASP Task Force, which comprises pain experts from across the globe,19 has developed a new and pragmatic classification of chronic pain for the upcoming 11th revision of the ICD. The goal is to create a classification system that is applicable in primary care and in clinical settings for specialized pain management. A major challenge in this process was finding a rational principle of classification that suits the different types of chronic pain and fits into the general ICD-11 framework. Pain categories are variably defined based on the perceived location (headache), etiology (cancer pain), or the primarily affected anatomical system (neuropathic pain). Some diagnoses of pain defy these classification principles (fibromyalgia). This problem is not unique to the classification of pain, but exists throughout the ICD. The IASP Task Force decided to give first priority to pain etiology, followed by underlying pathophysiological mechanisms, and finally the body site. Developing this multilayered classification was greatly facilitated by a novel principle of assigning diagnostic codes in ICD-11, termed “multiple parenting.” Multiple parenting allows the same diagnosis to be subsumed under more than 1 category (for a glossary of ICD terms refer to Table ​Table1).1). Each diagnosis retains 1 category as primary parent, but is cross-referenced to other categories that function as secondary parents. Table 1 Glossary of ICD-11 terms. The new ICD category for “Chronic Pain” comprises the most common clinically relevant disorders. These disorders were divided into 7 groups (Fig. ​(Fig.1):1): (1) chronic primary pain, (2) chronic cancer pain, (3) chronic posttraumatic and postsurgical pain, (4) chronic neuropathic pain, (5) chronic headache and orofacial pain, (6) chronic visceral pain, and (7) chronic musculoskeletal pain. Experts assigned to each group are responsible for the definition of diagnostic criteria and the selection of the diagnoses to be included under these subcategories of chronic pain. Thanks to Bedirhan Ustun and Robert Jakob of the WHO, these pain diagnoses are now integrated in the beta version of ICD-11 (http://id.who.int/icd/entity/1581976053). The Task Force is generating content models for single entities to describe their clinical characteristics. After peer review overseen by the WHO Steering Committee,39 the classification of chronic pain will be voted into action by the World Health Assembly in 2017. Figure 1 Organizational chart of Task Force, IASP, and WHO interactions. The IASP Task Force was created by the IASP council and its scope defined in direct consultation of the chairs (R.D.T. and W.R.) with WHO representatives in 2012. The Task Force reports to ... 2. Classification of chronic pain Chronic pain was defined as persistent or recurrent pain lasting longer than 3 months. This definition according to pain duration has the advantage that it is clear and operationalized. Optional specifiers for each diagnosis record evidence of psychosocial factors and the severity of the pain. Pain severity can be graded based on pain intensity, pain-related distress, and functional impairment. 2.1. Chronic primary pain Chronic primary pain is pain in 1 or more anatomic regions that persists or recurs for longer than 3 months and is associated with significant emotional distress or significant functional disability (interference with activities of daily life and participation in social roles) and that cannot be better explained by another chronic pain condition. This is a new phenomenological definition, created because the etiology is unknown for many forms of chronic pain. Common conditions such as, eg, back pain that is neither identified as musculoskeletal or neuropathic pain, chronic widespread pain, fibromyalgia, and irritable bowel syndrome will be found in this section and biological findings contributing to the pain problem may or may not be present. The term “primary pain” was chosen in close liaison with the ICD-11 revision committee, who felt this was the most widely acceptable term, in particular, from a nonspecialist perspective.

Nocebo hyperalgesia induced by social observational learning

&NA; A nocebo response on pressure pain was induced by social observational learning but not by verbal suggestion. The nocebo response correlated with pain catastrophizing, especially the subscale “Helplessness”. &NA; Nocebo effects can be acquired by verbal suggestion, but it is unknown whether they can be induced through observational learning and whether they are influenced by factors known to influence pain perception, such as pain anxiety or pain catastrophizing. Eighty‐five female students (aged 22.5 ± 4.4 years) were randomly assigned to one of three conditions. Participants in the control condition (CC) received information that an ointment had no effect on pain perception. Participants in the verbal suggestion condition (VSC) received information that it increased pain sensitivity. Participants in the social observational learning condition (OLC) watched a video in which a model displayed more pain when ointment was applied. Subsequently, all participants received three pressure pain stimuli (60 seconds) on each hand. On one hand, the ointment was applied prior to the stimulation. Numerical pain ratings were collected at 20‐second intervals during pain stimulation. The participants filled in questionnaires regarding pain‐related attitudes (Pain Anxiety Symptoms Scale, Pain Catastrophizing Scale, and Somatosensory Amplification Scale). Participants in the OLC showed higher pain ratings with than without ointment. Pain ratings within the CC and the VSC were at the same level with and without ointment. In the VSC, the pain ratings were higher than in the CC with and without ointment. The nocebo response correlated with pain catastrophizing but not with pain anxiety or somatosensory amplification. A nocebo response to pressure pain was induced by observational learning but not by verbal suggestion. This finding highlights the importance of investigating the influence of observational learning on nocebo hyperalgesia.

The German Version of the Internet Addiction Test: A Validation Study

Reports about excessive Internet use, possibly amounting to an addiction, have increased. Progress with research and treatment of this phenomenon requires valid standardized assessment instruments. A frequently used questionnaire is the Internet Addiction Test (IAT) by Kimberly Young. The 20-item questionnaire is well established in a number of languages, but a German validation was lacking so far. An online (ON) sample (n=1,041, age 24.2±7.2 years, 46.7 percent men) completed an Internet version of the IAT and a student sample (offline [OF] sample, n=841, age: 23.5±3.0 years, 46.8 percent men) filled in a paper/pencil version. The participants also answered questions regarding their Internet use habits. A further sample of 108 students (21.5±2.0 years, 25.7 percent men) completed the questionnaire twice to determine the 14-day retest reliability. The internal consistencies were α=0.91 (ON) and α=0.89 (OF). Item-whole correlations ranged from r=0.23 to r=0.65 (ON) and from r=0.30 to r=0.64 (OF). Two-week retest reliability was r(tt)=0.83. Factor analyses with Varimax rotation yielded the same two factors in both samples, which explained 46.7 percent (ON) and 42.0 percent (OF) of the variance. The IAT score correlated with the time spent in the Internet in a typical week (ON: r=0.44; OF: r=0.38). The German version of the IAT was shown to have good psychometric properties and a stable two-factorial structure. Correlations with online time were in line with those reported for the IAT in other languages.

Neural correlates of fear of movement in high and low fear-avoidant chronic low back pain patients: an event-related fMRI study.

Summary High and low fear‐avoidant chronic low back pain patients did not differ with regard to brain activation when they viewed photographs of aversive movements. Abstract The fear‐avoidance model postulates that in chronic low back pain (CLBP) a fear of movement is acquired in the acute phase, which leads to subsequent avoidance of physical activity and contributes to the pain syndrome’s becoming chronic. In the present event‐related functional magnetic resonance imaging (fMRI) study of the neural correlates of the fear of movement, 60 women (30 CLBP patients, 15 healthy controls, and 15 women with spider phobia; mean age 46.8 ± 9.8 years) participated. The CLBP patients were divided into a high and low fear‐avoidant group on the basis of the Tampa Scale of Kinesiophobia. The participants viewed photographs depicting neutral and aversive (back‐stressing) movements, generally fear‐inducing and neutral pictures from the International Affective Picture System, and pictures of spiders while fMRI data were acquired. It was hypothesized that the high fear‐avoidant CLBP patients would show fear‐related activations when viewing the aversive movements and that they would differ from CLBP patients with low fear‐avoidance and controls in this regard. No such activations were found for high or low fear‐avoidant CLBP patients. The random‐effects analysis showed no differences between high and low fear‐avoidant CLBP patients or high fear‐avoidant CLBP patients and controls. Normal fear‐related activations were present in the high fear‐avoidant CLBP patients for the generally fear‐inducing pictures, demonstrating the validity of the stimulation paradigm and a generally unimpaired fear processing of the high fear‐avoidant CLBP patients. Our findings do not support the fear component of the fear avoidance model.

Identifying a subset of fear-evoking pictures from the IAPS on the basis of dimensional and categorical ratings for a German sample

BACKGROUND AND OBJECTIVES The International Affective Picture System (IAPS) is a set of colour photographs depicting a wide range of subject matters. The pictures, which are widely used in research on emotions, are commonly described in terms of the dimensions of valence, arousal and dominance. Little is known, however, about discrete emotions that the pictures evoke. Our aim was to collect dimensional and categorical ratings from a German sample for a subset of IAPS pictures and to identify a set of fear-evoking pictures. METHODS 191 participants (95 female, 96 male, mean age 23.6 years) rated 298 IAPS pictures regarding valence, arousal and the evoked emotion. RESULTS 64 fear-evoking pictures were identified. Sex differences for categorical and dimensional ratings were found for a considerable number of pictures, as well as differences from the US norms. CONCLUSIONS These differences underscore the necessity of using country-specific and sex-specific norms when selecting stimuli. A detailed table with categorical and dimensional ratings for each picture is provided.

Parietal abnormalities are related to avoidance in social anxiety disorder: A study using voxel-based morphometry and manual volumetry

Evidence is accumulating that various mental disorders are related to neural abnormalities in the parietal cortices that are associated with the default mode network (DMN). Participants comprised 67 persons with social anxiety disorder (SAD) and 64 matched healthy controls who underwent structural magnetic resonance imaging (MRI) and a comprehensive clinical assessment. Voxel-based morphometry (VBM) across the entire brain and manual volumetry of the parietal cortices were performed. The results indicate abnormal manually segmented volumes or gray matter (GM) volumes within the precuneus, postcentral gyrus and inferior parietal cortex, as well as in the premotor cortices including the supplementary motor cortex. Significant negative correlations were obtained between parietal, especially precuneus, abnormalities and social avoidance severity, indicating stronger avoidance in SAD participants with smaller volumes or less GM. We conclude that pathological avoidance behaviors in SAD are associated with structural deficits of parietal regions that are associated with the DMN, which has been shown to mediate introspection and reflection upon ones own mental state in healthy humans.

The German Version of the Generalized Pathological Internet Use Scale 2: A Validation Study

The Generalized Pathological Internet Use Scale (GPIUS2) assesses cognitive behavioral aspects of problematic Internet use. To date, the 15-item scale has only been available in English, and the aim of this study was to translate and validate a German version. An online sample (ON, n=1,041, age 24.2±7.2 years, 46.7% men) completed an Internet version of the translated GPIUS2, and a student sample (OF, n=841, age 23.5±3.0 years, 46.8% men) filled in a pencil and paper version. A third sample of 108 students (21.5±2.0 years, 25.7% men) completed the questionnaire twice to determine the 14-day retest reliability. Participants also answered questions regarding their Internet use habits (OF, ON) and depression, loneliness, and social anxiety (ON). The internal consistencies were α=0.91 (ON) and α=0.86 (OF). Item-whole correlations ranged from r=0.53 to r=0.69 (ON) and from r=0.39 to r=0.63 (OF). The 2 week retest reliability was rtt=0.85. Confirmatory factor analyses found a satisfactory fit for the factorial model proposed by Caplan for the original version. The GPIUS2 score correlated moderately with time spent on the Internet for private purposes in a typical week (ON: r=0.40; OF: r=0.36). Loneliness, depression, and social anxiety explained 46% of the variance in GPIUS2 scores. The German version of the GPIUS2 has good psychometric properties in a pencil and paper version as well as in a web-based format, and the observations regarding loneliness, depression, and social anxiety support the underlying model.

Sex-specific predictor analyses for the incidence of recurrent headaches in German schoolchildren.

Objective: The aim of the present study was to identify psychosocial risk factors for the incidence of recurrent headache (HA) in children/adolescents (8–15 years). Method: In 2003 (Wave 1) a representative, population-based sample of 8800 parents was mailed a questionnaire. Those who took part were asked to participate again one year later (Wave 2). Of the parents originally contacted, 47.3% participated in both surveys. Potential risk factors concerning the areas ‘school’ and ‘emotional and behavioural problems’ were collected in Wave 1. Binary logistic regression analyses were performed to assess their predictive value for HA in Wave 2. Results: Univariable regression analyses showed that for boys and girls most of the predictor variables influenced the incidence of recurrent HA, but only to a very low extent. When all variables were assessed jointly in a multivariable model, these factors lost their predictive power for boys. For girls, ‘academic problems’ and ‘dysfunctional stress coping’ were shown to increase the chance for the incidence of recurrent HA. Discussion: In contrast to previous findings, school-related factors and emotional and behavioural problems failed to predict HA in boys, and only two factors appeared relevant with regard to girls. This might be due to the strict unidirectional design, which focussed exclusively on the incidence of HA.

Cognitive processing styles of children and adolescents with headache and back pain: a longitudinal epidemiological study

Background Previous research has shown positive relationships between dysfunctional cognitive styles and different aspects of pain (eg, pain frequency). One goal of our longitudinal study was to investigate potential risk factors for the incidence of headache (HA) and back pain (BP). Methods In the first wave (2003), questionnaires were sent to 6,400 children between the ages of 9 and 14 years. Those who answered in wave 1 were contacted again every year (four survey waves in total: 2003–2006). The data presented are based on the children’s self-reports in the second wave (2004) and third wave (2005). Potential risk factors (dysfunctional stress coping, pain catastrophizing, anxiety sensitivity, and somatosensory amplification) were collected in wave 2. Binary logistic regression analyses – for boys and girls – were performed to assess the predictive value of the risk factors for HA and BP in wave 3. Results In the comprehensive model, none of the examined variables predicted the incidence of HA. Anxiety sensitivity increased the risk that boys would report BP after 1 year by 50% and dysfunctional stress coping increased the risk by 40%. For girls, somatosensory amplification increased the risk of the incidence of BP 1 year later by 80%, whereas pain catastrophizing reduced the risk by 50%. Conclusion In this incidence sample, the amount of variance explained by the psychological variables investigated was very small. Integrating this result with existing findings from cross-sectional studies suggests that dysfunctional cognitive processing styles may develop more as a consequence or a concomitant feature of BP or HA, but play a less important role in its initial development.

Attentional bias in excessive Internet gamers: Experimental investigations using an addiction Stroop and a visual probe

Background and aims Internet Gaming Disorder is included in the Diagnostic and statistical manual of mental disorders (5th edition) as a disorder that merits further research. The diagnostic criteria are based on those for Substance Use Disorder and Gambling Disorder. Excessive gamblers and persons with Substance Use Disorder show attentional biases towards stimuli related to their addictions. We investigated whether excessive Internet gamers show a similar attentional bias, by using two established experimental paradigms. Methods We measured reaction times of excessive Internet gamers and non-gamers (N = 51, 23.7 ± 2.7 years) by using an addiction Stroop with computer-related and neutral words, as well as a visual probe with computer-related and neutral pictures. Mixed design analyses of variance with the between-subjects factor group (gamer/non-gamer) and the within-subjects factor stimulus type (computer-related/neutral) were calculated for the reaction times as well as for valence and familiarity ratings of the stimulus material. Results In the addiction Stroop, an interaction for group × word type was found: Only gamers showed longer reaction times to computer-related words compared to neutral words, thus exhibiting an attentional bias. In the visual probe, no differences in reaction time between computer-related and neutral pictures were found in either group, but the gamers were faster overall. Conclusions An attentional bias towards computer-related stimuli was found in excessive Internet gamers, by using an addiction Stroop but not by using a visual probe. A possible explanation for the discrepancy could lie in the fact that the visual probe may have been too easy for the gamers.