Researchers have found a significant link between childhood behavioral problems and chronic pain in adulthood. Dr. Dong Pang of Aberdeen University, UK, and colleagues explain that chronic widespread pain affects about 12 percent of adults and can cause disability. It has previously been linked to major events in childhood such as hospitalization after a road accident and separation from mothers.
The team used a group of 19,478 participants who were born in a single week in 1958, and followed them through childhood and adulthood. Childhood behavior was recorded by parents and teachers at ages 7, 11, and 16, based on aspects such as restlessness, worrying, solitariness, ability to make friends, obedience, stealing, sucking thumbs and biting nails, lying, bullying, or displaying truant behavior. Pain in adulthood was measured at 45 years.
Children whose teachers reported “severe persistent behavior problems” at all ages had more than double the risk of chronic widespread pain by the age of 45 compared with children without behavior problems at all ages. A weaker link also existed for parent-reported behavior, possibly because teachers are more experienced and can be more objective, the researchers speculate.
In the journal Rheumatology, the authors conclude, “Maladjusted (social) behavior is associated with increased long-term chronic widespread pain beyond childhood and adolescence.”
Dr. Pang said, “Aspects of childhood behavior are strongly related to children reporting chronic widespread pain. However, until now, it was unknown whether maladjusted behavior in children was a long-term marker for chronic widespread pain in adulthood. Our study shows that it is.”
The association could not be explained by social class, says Dr. Pang, and was not thought to be due to the known link between psychological distress in adults and chronic widespread pain. He says that the underlying biological mechanism is not known, but suggested it may be “a long-term neuroendocrine dysfunction beginning in early life,” involving the hypothalamic-pituitary-adrenal axis which controls reactions to stress.
This dysfunction, possibly triggered by early trauma, could underlie both the childhood behavior and the adult chronic widespread pain, he believes. “Further research at molecular and genetic levels is needed to clarify this theory,” he states.
Psychological distress was measured at the age of 42, and this also showed a link with childhood behavioral problems. Long-term depression and anxiety, suicidal behavior, substance abuse and treatment for psychiatric illness were more common among those deemed to have early behavior problems.
Co-researcher Professor Gary Macfarlane added, “This study helps us to understand the factors in childhood that can lead someone to get on a trajectory of ill health, including chronic pain. The disruption to the hypothalamic-pituitary-adrenal (stress-response) axis is one biological marker of the effect of such experiences and this could help to identify persons at higher risk of chronic pain. Interventions would be lifestyle-focused and would include identification and treatment of behavioral and emotional factors, but would also address lifestyle factors such as increased physical activity.
“We plan to undertake some studies in children to understand what range of factors cause a disturbance to the stress-response axis; such work can then inform what intervention studies may be appropriate.”
The study of lifetime influences on chronic pain is still in its infancy, the team concludes. Future studies are required to confirm potential links between early life events and pain across the life course.
Other recent studies confirm that the hypothalamic-pituitary-adrenal axis is associated with at least some aspects of childhood behavior. Tests on a group of 1,768 10- to 12-yea-olds showed that girls with “externalizing” behavior problems (such as aggression, delinquency, and hyperactivity) had significantly higher cortisol levels, representing greater activity in the hypothalamic-pituitary-adrenal axis. But this link was not seen in boys, or for “internalizing” behavior problems (such as anxiety and depression).
A further study suggests that abnormalities in the hypothalamic-pituitary-adrenal axis may indicate a vulnerability to chronic pain. Current pain and psychosocial profiles were measured in a large group of adults. Of these, 267 were deemed to be at future risk of pain based on their psychosocial profile, and their hypothalamic-pituitary-adrenal axis function was tested.
Fifteen months later, 12 percent of the entire group had developed chronic widespread pain. They were significantly more likely to have dysfunction of the hypothalamic-pituitary-adrenal axis, represented by morning and evening cortisol levels. “Dysfunction of the hypothalamic-pituitary-adrenal axis helps to distinguish those who will and will not develop new-onset chronic widespread pain,” say the researchers.
Pang, D. et al. Influence of childhood behaviour on the reporting of chronic widespread pain in adulthood: results from the 1958 British Birth Cohort Study. Rheumatology, published online March 10, 2010.
Marsman, R. et al. HPA-axis activity and externalizing behavior problems in early adolescents from the general population: the role of comorbidity and gender The TRAILS study. Psychoneuroendocrinology, Vol. 33, July 2008, pp. 789-98.
McBeth, J. et al. Moderation of psychosocial risk factors through dysfunction of the hypothalamic-pituitary-adrenal stress axis in the onset of chronic widespread musculoskeletal pain: findings of a population-based prospective cohort study. Arthritis and Rheumatism, Vol. 56, January 2007, pp. 360-71.