Co-occurring pediatric chronic pain and mental health: A genetically informed study.

Objective: Pediatric chronic pain is pervasive and associated with myriad adverse consequences, yet due consideration has not been given to the mental health disturbances that often present alongside chronic pain and the etiological mechanisms that potentially underlie both. The current study examined the genetic and environmental etiology underlying chronic pain and internalizing symptomology in middle childhood, considering both independent and co-occurring symptom presentations.

Method: The sample comprised 795 children (399 families; M_age = 9.7 years; SD = 0.92) drawn from the Arizona Twin Project. The sample was 51.2% female and was racially/ethnically diverse (59.8% non-Hispanic White, 28.0% Hispanic/Latinx, 3.4% Asian, 3.9% Black, and 4.9% mixed race/other); 31% of twins were monozygotic, 35% same-sex dizygotic, and 34% other-sex dizygotic. Families were socioeconomically diverse based on income to needs ratios (7.3% below the poverty line, 22.9% at or near the poverty line, 15.9% in lower middle class, and 53.9% in middle to upper class).

Results: The results indicated that chronic pain was highly heritable (78%). Internalizing symptomology was modestly heritable (32%) and further subject to moderate shared environmental influence (50%). Moreover, 9% of the variance in chronic pain was explained by additive genetic factors shared with internalizing symptomology.

Conclusions: In middle childhood, chronic pain and internalizing symptoms are largely distinct, with shared genetic influences accounting for their co-occurrence, supporting the idea that comorbidity increases with age via transactional influences. Results provide novel insight into common liabilities underlying pediatric chronic pain and internalizing symptoms. (PsycInfo Database Record (c) 2025 APA, all rights reserved).