MONDAY, April 30 (HealthDay News) -- Depression or anxiety affect one-third of Americans with arthritis who are aged 45 or older, a new study shows.

Researchers from the U.S. Centers for Disease Control and Prevention also found that even though anxiety is nearly twice as common as depression among people with arthritis, doctors tend to focus more on depression in these patients.

The study included nearly 1,800 people with arthritis or other rheumatic conditions who took part in the CDC's Arthritis Conditions and Health Effects Survey. Among the study participants, 31 percent reported anxiety and 18 percent reported depression.

One-third of the patients reported at least one of the two conditions and 84 percent of those with depression also had anxiety. Only half of those with anxiety or depression sought mental health treatment in the previous year, according to the study, which was published in the April 30 issue of the journal Arthritis Care & Research.

"Given their high prevalence and the effective treatment options that are available, we suggest that all people with arthritis be screened for anxiety and depression," study leader Dr. Louise Murphy, of the Arthritis Program at the CDC, said in a journal news release.

"With so many arthritis patients not seeking mental health treatment, health care providers are missing an intervention opportunity that could improve the quality of life for those with arthritis," she added.

In the United States, 27 million people age 25 and older have osteoarthritis, and 1.3 million adults have rheumatoid arthritis, according to the American College of Rheumatology.

More information

The U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases offers advice on how to live with arthritis.