The occurrence of internalizing problems and chronic pain symptoms in early childhood: what comes first?

Chronic pain and internalizing problems are characterized by concurrent associations but the directionality of this relationship in early childhood remains unclear. This prospective study aimed to investigate the bidirectional effect of chronic pain and internalizing problems and test the persistence of pain over time in a population-based sample of preschoolers. The study was embedded in Generation R, a large population-based cohort. Mothers of 3,996 children assessed their child's experienced pain and internalizing problems at 3 and 6 years. At 3 years, paternal reports were available too. Reports of family functioning, discipline practices and parental psychopathology were also collected. The prevalence of chronic pain was 2.7% (106) and 8.0% (294) at baseline and follow-up, respectively. The presence of internalizing problems at child age 3 years predicted chronic pain at 6 years, for both maternal (OR 1.05, 95% CI 1.02,1.07, p < 0.001) and paternal (OR 1.03, 95%CI 1.00, 1.06, p < 0.05) internalizing problem reports, when adjusted for potential confounding factors. In contrast, chronic pain did not increase the likelihood of internalizing problems. The temporal relationship between chronic pain and internalizing problems appears to follow a largely unidirectional trend in early childhood, with internalizing problems increasing the likelihood of concurrent physical symptoms. Current understanding of the directionality of this relationship, highlights the importance for comprehensive assessment of psychiatric problems contributing to the manifestation of chronic pain.