The study, published in the journal Psychiatric Services, found that approximately 4.7 percent of the nation's population suffers from persistent depression or anxiety disorders, with a minority of those afflicted receiving adequate medication or counseling.

The study also found 12 percent of patients with persistent illness were getting both medication and counseling -- the appropriate treatment in this situation.

Researchers at the University of California, Los Angeles, used data from Healthcare for Communities, a nationally representative household survey of U.S. adults. The researchers analyzed responses from 1,642 adults with major depression or anxiety disorders. The surveys, conducted in 1997 and 1998, with follow-ups approximately 2 1/2 years later, assessed diagnosis, quality of life, treatment satisfaction, medical conditions, suicidal thoughts, insurance and the use of medications and counseling.

"From a policy perspective, this study indicates that we have to do much better in terms of helping people in the population and clinicians in primary care," lead author Dr. Alexander S. Young said in a statement. "We need to understand that psychiatric disorders are treatable with psychotherapy and/or medication."