Children and adolescents with chronic pain: parental factors, functioning, and neurodevelopmental comorbidity

Sammanfattning: Background: Pediatric chronic pain affects between 11 and 38% of all children. Although pain may result from injury or disease, the cause of chronic pain is commonly unclear. The interaction between biological, psychological, and social aspects has been emphasized as key to the understanding of the chronic pain experience, as well as risk and resilience factors. Pediatric chronic pain may result in significant impairment affecting both child and family functioning, and addressing family factors such as parental distress and protective behaviors, are generally considered important to pediatric chronic pain management. However, there is still a need to identify resilience factors that can be targeted in parental support programs, and to develop and evaluate effective parent support interventions. The complexity of the pain experience in pediatric chronic pain is well known with a large number of patients suffering from co-occurring disorders such as depression or insomnia. However, despite a considerable number of clinical observations suggesting an elevated prevalence of attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) among children with chronic pain, and similarities in terms of clinical correlates, the empirical support has been scarce. More research on the co-occurrence of pediatric chronic pain, ADHD, and ASD, including relationships with functioning, is therefore warranted. Purpose and aims: The purpose of the present research project was to identify and assess parental and child factors of importance for functioning and treatment effects in pediatric chronic pain. More specifically, the aims of the project were to: validate an instrument for parental psychological flexibility (Study I); evaluate the effects of a brief parental ACTintervention on parent outcomes (Study II); assess the prevalence of clinically significant traits and symptoms of ASD and ADHD in children, and relations to pain- and demographic variables (Study III); and, to explore the relationships between traits and symptoms of ASD and ADHD, functioning, and health-related quality of life (HRQoL) (Study IV). Methods: In Study 1, utilizing a cross-sectional design, the Parent Psychological Flexibility Questionnaire (PPFQ) was translated and psychometrically evaluated in a sample of parents (n=263) of children with chronic pain using principal component analysis (PCA), correlation and regression analyses, and analysis of internal consistency. In Study II, the effects of individual and group ACT-interventions for adolescents (n=48) with chronic pain, and a brief support program for their parents (n=28), were evaluated using a randomized (group/individual) uncontrolled pilot design and non-parametric analyses of differences between groups and over time. In Study III, the prevalence of clinically significant ASD-traits and ADHD-symptoms was evaluated in a descriptive cross-sectional study on children with chronic pain (n=146) and their parents (n=146). Differences in painand demographic variables between children below and above cutoff for clinically significant traits and symptoms of ADHD or ASD were also assessed. Study IV, using the same sample as Study III, examined the relationships between ASD-traits and ADHDsymptoms, functioning (depression and pain interference), and HRQoL in correlation- and regression analyses and with independent t-tests, and assessed the indirect effects of insomnia and psychological inflexibility on the relationships between ASD-traits or ADHD-symptoms as predictors and functioning and HRQoL as dependents. Results: In Study 1, results supported a three-factor solution for the PPFQ with 10 items (PPFQ-10), showing good internal consistency and explaining a significant amount of variance in the criteria variables anxiety (29%) and depression (35.6%). In Study II, significant improvements in parental pain reactivity and psychological flexibility were found with clinically significant changes in the direction of better functioning for 54-76% of parents, with no differences between individual and group formats. In Study III, 13.7% of the sample presented with clinically significant ASD-traits and 19.9% of the sample presented with clinically significant ADHD-symptoms. The combined prevalence of clinically significant ASD/ADHD-traits and symptoms was 26%. Children with clinically significant ASD-traits were more likely to be girls and clinically significant ADHDsymptoms showed no gender differences. In Study IV, children with clinically significant ASD-traits and ADHD-symptoms presented with significantly higher levels of depressive symptoms and pain interference, and significantly lower HRQoL, compared to the rest of the sample. ASD-traits and ADHD-symptoms explained a significant amount of variance in pain interference and depressive symptoms, as well as in HRQoL. Psychological inflexibility was shown to mediate the influence of both ADHD-symptoms and ASD-traits, and insomnia the effect of ADHD-symptoms, on depression, pain interference, and HRQoL. Conclusions: Although tentative, the results suggests the utility of addressing parental psychological flexibility in relation to pediatric chronic pain. However, more research is warranted and future studies should e.g. evaluate the predictive utility of the PPFQ for child treatment outcomes, and evaluate if parental support programs that increase parental psychological flexibility also have positive effects on the children. Also, the results provide empirical support regarding elevated levels of clinically significant ADHD-symptoms and ASD-traits in pediatric chronic pain, and illustrate significant relationships between such traits and symptoms and functioning in children. Children with debilitating chronic pain, particularly girls, may be at risk for having a comorbid, and possibly undetected highfunctioning neurodevelopmental disorder. Results thus suggest the utility of screening for neurodevelopmental disorders in children with chronic pain, and may indicate insomnia, and psychological flexibility as potential treatment targets to improve functioning and HRQoL. The results also warrant further research to e.g. validate these findings in larger studies, evaluate the utility of tailored interventions, and examine the shared neuropathophysiology of chronic pain and neurodevelopmental disorders, including dopamine function and sensory abnormalities.