For people with a painful cartilage condition, common pain relievers may have small benefits for depression symptoms as well, a new study hints.

Depression is more than twice as common among people with osteoarthritis, which happens when cartilage wears down around the hands, lower back, knees or other joints.

As many as 27 million Americans have osteoarthritis, according to the Centres for Disease Control and Prevention. To help manage their pain, those patients often take nonsteroidal anti-inflammatory drugs, or NSAIDs, like ibuprofen or naproxen.

“This work suggests that anti-inflammatory agents may play a role in reducing the burden of depression,” senior author Michael E. Farkouh of Mount Sinai School of Medicine in New York, said.

The relationship between depressive symptoms and chronic pain is complex

His team’s study includes data from five previous trials of over-the-counter NSAIDs and prescription Celebrex, a NSAID manufactured by Pfizer, which provided the Celebrex results. In each of the trials, people with osteoarthritis were randomly assigned to take one of those medications or a drug-free placebo pill for six weeks.

Almost 1,500 people not taking antidepressants took part in the studies, which involved multiple depression questionnaires.

People on each treatment, including the placebo, tended to report fewer depression symptoms at the end of the trials than at the beginning, according to results published in The American Journal of Medicine.

But depression scores – measured on a scale of 0 to 27 – fell by 0.3 more points in the over-the-counter NSAID groups and by 0.6 more points in the Celebrex groupsthan among people taking a placebo.

Arthritis patients started those studies with an average depression score of three, far below the threshold of 10 used for a depression diagnosis.

“The relationship between depressive symptoms and chronic pain is complex, and important,” David A. Walsh, director of the Arthritis Research UK Pain Centre in Nottingham, said.