Depression , which is characterized by feelings of profound sadness and lack of interest in enjoyable activities, may cause a wide range of symptoms, both physical and emotional. According to the National Institute for Mental Health (NIMH), approximately 10 million American adults experience a major depression in a given year, and another 11 million suffer from a mild depression at some point during their lifetimes.

Osteoarthritis (OA) , or degenerative joint disease, is the most common type of arthritis. It is characterized by the breakdown of the joint's cartilage (the part of the joint that cushions the ends of bones). When this cartilage breaks down, it causes the bones to rub against each other, resulting in pain and loss of movement. Approximately 33% of Americans over the age of 65 have osteoarthritis in their knees, and 80% over the age of 70 have osteoarthritis somewhere in their bodies.

Arthritis is a leading cause of disability in elderly Americans, reducing their quality of life, and restricting their activity. Depression is also very common among elderly Americans and is often associated with functional disability, such as the kind caused by OA. This relationship led a group of researchers to wonder what effect (if any) treating depression would have on the pain levels and functional ability of patients who suffered from both diseases.

The results of their study, published in the November 12, 2003 issue of The Journal of the American Medical Association found that among elderly Americans who suffered from both OA and depression, improving the quality of care they received for their depression not only improved their depression, but also decreased their level of pain, and increased their functional status and their quality of life.

About the study

The researchers enrolled 1001 elderly patients (age 60 or older) who had been diagnosed with both depression and arthritis (primarily osteoarthritis). They then divided the participants into two groups: the intervention group (those who would be treated for their depression) and the usual care group (those who would not be treated for their depression).

The intervention group could choose the treatment for depression they preferred. These choices consisted of either taking antidepressant medications or receiving six to eight psychotherapy sessions.

All of the participants completed a survey of their symptoms at the time of their enrollment in the trial (referred to as baseline) and every three months thereafter for one year. The survey assessed the participants’ depressive symptoms, intensity of arthritic pain (scale of 0 to 10), difficulty carrying out activities of daily living (scale of 0 to 10), general health status, and overall quality of life.

The findings

The researchers found that after one year, regardless of the type of treatment, the patients who received treatment for depression (the intervention group) not only had fewer symptoms of depression, but also experienced less pain (5.62 vs 6.15), less interference with their daily activities due to arthritis (4.40 vs 4.99), less interference with daily activities due to pain (2.92 vs 3.17), and an improved sense of overall health and quality of life than the patients who did not receive treatment for depression (the usual care group).

How does this affect you?

The study found that among older adults who suffered from both osteoarthritis and depression, improving the quality of care they received for their depression benefited both their depression and arthritis. This finding is consistent with the notion that the perception of pain is highly subjective and influenced considerably by emotional states.

One possible explanation for this is that the neurotransmitters (such as serotonin and noradrenaline) commonly affected by antidepressant medications actually help reduce the number of pain signals being transmitted by the peripheral nervous system (the part of the nervous system outside the brain and spinal cord). It is also possible that the patients who received psychotherapy in this study learned steps to help them cope with their pain more effectively.

Based on the results of this study, the researchers recommend that, particularly in the primary care setting, physicians take a biosocial (psychological and physiological) approach to the management of arthritis. This includes screening for depression in all elderly patients with osteoarthritis.

According to the researchers, the benefits of this two-pronged approach may extend far beyond reduced pain levels and improved functional outcomes. It may actually help reduce the considerable public health burden presented by comorbid arthritis and depression in the elderly.