Childhood neglect can increase pain and harmful opioid side effects – study

Adverse experiences early on in life such as neglect can increase chronic pain and harmful effects of opioid painkillers such as morphine, research suggests.

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 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 caused rapid tolerance, a phenomenon associated with the development of 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 the prescribing of painkillers, the researchers said.

Professor Tim Hales, principal investigator of Cape, 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. Psychological trauma and neglect cause physical changes in the brain so it is not surprising that this can also increase vulnerability to pain.

“We believe that altered coping mechanisms caused by persistent stressors such as neglect in early life means 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.

“I think this research will have an important impact as it identifies how this can happen.”

Chronic pain affects millions of people in the UK 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.

Prof Hales continued: “Opioids have a role to play in treating pain, but they are potentially harmful drugs.

“Addiction is a complex, multi-factorial condition.

“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.”

Cape was funded by a near-£3 million grant from UKRI.

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