Early negative and adverse experiences in one’s life, such as neglect, can amplify the occurrence of chronic pain and intensify the detrimental impacts of opioid pain medications like morphine, according to the latest research.

The study by experts at the University of Dundee’s Consortium Against Pain InEquality (Cape) suggests exposure to neglect in early life increases vulnerability to pain and the severe side effects of opioids in adulthood.

Scientists looked at mice and found those who had their care from their mother disrupted experienced increased vulnerability to persistent pain. The theory has not yet been tested on humans, however.

In addition, morphine used to treat the pain was less effective than in those mice who had not experienced disrupted care, the study found.

Morphine also causes rapid tolerance, associated with developing opioid dependence and misuse.

These changes may explain why people exposed to childhood neglect and trauma are also prone to persistent pain and opioid dependence, findings with significant implications for prescribing painkillers, the researchers said.

"We know that what happens in childhood can lead to multiple poor health outcomes in later life. The strongest association is with drug dependence. In addition, psychological trauma and neglect cause physical changes in the brain. Hence, it is not surprising that this can also increase vulnerability to pain," said Professor Tim Hales, principal investigator at Cape.

"We believe that altered coping mechanisms caused by persistent stressors such as neglect in early life mean some individuals are less able to regulate their pain and may also be less likely to benefit from opioid prescriptions, with vulnerability to their negative effects. This research will have an important impact as it identifies how this can happen."

Chronic pain affects millions of people in the U.K. and is often linked to arthritis, cancer, fibromyalgia and other disorders.

To help address treatment challenges and improve the lives of people affected by pain, a better understanding of the mechanisms and vulnerabilities is needed.

"Opioids have a role in treating pain, but they are potentially harmful drugs. In addition, addiction is a complex, multi-factorial condition," Hales continued. "A better understanding of the processes linking adverse early life events to chronic pain will lead to changes in our approach to prescribing analgesic medications."

A paper on the findings has been published in the journal Pain.