Functional disability and depression symptoms in a paediatric persistent pain sample

Background and aims: Clinicians treating paediatric chronic pain conditions understand that persistent pain, functional ability, and symptoms of depression often co-exist, yet these relationships have only been described to a limited extent by research. This paper more closely examines the relationship between symptoms of depression and subtypes of functional disability.

Methods: Participants included a clinical sample of children and adolescents (N=239) referred to a paediatric multidisciplinary pain clinic for treatment of persistent or recurrent (chronic) pain in Australia. The majority of participants were female, (76.6%), and were aged 7-17 years (mean age at the time of presentation was 13.8 years). Data from standardized instruments and interview data were collected from a clinical file audit. The Pediatric Outcomes Data Collection Instrument (PODCI) was used as a measure of functional difficulties performing activities of daily living, and the Children's Depression Inventory (CDI) was used to measure depressive symptoms.

Results: High rates of depression and functional disability were observed, but were not associated with one another beyond relatively weak associations. Contrary to prior studies using different measures of physical functioning, depression symptoms were not associated with PODCI functional disability beyond a minor association with anhedonia symptoms (primarily driven by the pain/comfort subscale of the PODCI).

Conclusions and implications: We argue that prior research has measured physical functional limitations in paediatric pain sufferers in a way that is heavily influenced by psychosocial factors, in particular by the symptoms of clinical depression. In contrast, using a measure of physical functioning (PODCI) less influenced by psychosocial factors suggests that the relationship between physical functioning during activities of daily living (e.g., use of upper limbs, basic gross and fine motor skills, basic mobility) and depression is weaker, despite both being heightened in this sample. Unlike other functional disability measures, the Pediatric Outcomes Data Collection Instrument (PODCI) may allow researchers to assess functional limitations somewhat independently of depression symptoms. This conclusion requires replication in further studies, but if confirmed, then the PODCI could be advocated as a useful measure to obtain a more 'pure' measure of functional difficulties due to pain, relatively independent of depression.