New Delhi, April 16 : People suffering from chronic pain -- or pain that lasts at least three months -- may be up to four times more likely to experience depression, according to a study.

Almost 30 per cent of people worldwide suffer from a chronic pain condition such as low back pain and migraines, and one in three of these patients also report co-existing pain conditions.

The study published in the journal Science Advances shows that having chronic pain in multiple parts of the body was linked to a greater risk of depression than having pain at a single site.

"Pain isn't only physical," said Dustin Scheinost, Associate Professor of radiology and biomedical imaging at Yale School of Medicine (YSM).

"Our study adds to the evidence that physical conditions can have mental health consequences," Scheinost added.

The researchers from Yale University also decoded that inflammation may explain the link between chronic pain and depression.

The team found inflammatory markers such as C-reactive protein (a protein produced by the liver in response to inflammation) helping explain the association between pain and depression.

"This gives us some preliminary evidence about the inflammatory mechanisms underlying the association between pain and depression," said Rongtao Jiang, a postdoctoral associate at YSM.

The team leveraged data from 431,038 participants in UK Biobank with 14-year follow-ups.

The categories for pain sites included head, face, neck, back, stomach, hip, knee, and general pain.

The researchers found that both types of pain from all body sites were associated with depression and that chronic pain was more strongly associated with acute pain.

"We often think of brain health or mental health as separate from cardiac health or liver health, for instance," Scheinost said. "But all of these body systems influence each other."

Further research into the underlying drivers of pain and depression could help scientists develop new intervention strategies, he noted.

/IANS