LITTLE ROCK, Ark. — Old-age symptoms can mask signs of depression, making it difficult to diagnose and treat about the more than two million older North Americans who suffer from depression, doctors say.

Seniors do not present classic signs of depression during visits to their family doctors, but instead complain of various aches and pains, which Dr. Bradley Diner says are likely related to depression.

"One of the biggest red flags is when they have symptoms with no obvious cause, when in fact, what they have is depression," said Diner, a psychiatrist who specializes in treating the elderly.

Because doctors and patients have been conditioned to expect certain ailments in seniors - weight loss, fatigue, poor concentration, forgetfulness - some doctors overlook the possibility of depression and some patients forego seeking help. Both sides simply regard the ailments as an inevitable side-effect of aging.

"People would think, 'If you're old and sick, you'd be depressed, too.' We don't buy that anymore," said Dr. Mark Miller, an associate professor of psychiatry at the University of Pittsburgh. "A lot of people are under the impression that depression is a weakness, it's not - it's not a character flaw to admit you have it."

Miller, author of Living Longer Depression Free, said most people see depression as something they can "get over," but it is a debilitating illness.

"Once it gets a hold of you, it can be just as fatal as pneumonia," he said. "You can look physically normal, but it's not something you can snap yourself out of."

The National Institute of Mental Health, a federal group established in 1946 to fund mental-illness research, found depression is a significant predictor of suicide in older adults who, the group said, are disproportionately more likely to take their own lives than other age groups.

Miller said 98 per cent of all suicides at any age are due to depression, but it can be prevented.

"If you treat it adequately and treat it early, it's preventable," he said. "When depression is removed, attitude and the ability to cope changes."

Diner is conducting a clinical trial to examine the effects of a new drug that he hopes will provide better treatment for older adults. His Little Rock clinic is one of 50 sites in the United States recruiting seniors 62 and older to participate in the experimental study.

One of his patients, a 68-year-old woman from Sheridan who has had major depression for about four years, said she is finally starting to feel normal again. The woman said doctors could not find a physical cause when she complained of extreme fatigue four years ago.

"I was just tired all the time and I felt like I had gotten to the point where I couldn't handle it on my own," she said. "I used to read, do crosswords and volunteer at church, but it got worse and worse and all I could do was get up, eat and go back to sleep."

The woman, who has been married for 51 years, said her two children and five grandchildren wanted her to get well.

"I didn't see them too much," she said. "But my daughter didn't give up, she kept pursuing this."

She has been on the new medication for about six months and is now active again.

Dr. Helen Lavertsky, a researcher in geriatric depression at the University of California at Los Angeles, said the elderly are not comfortable admitting they might be depressed.

"Elderly citizens see it as a stigma, something embarrassing," Lavertsky said. "Some older primary care physicians may also not feel comfortable asking their patients if they feel depressed - they (the doctors) just weren't trained that way."

Dr. Richard Smith, chief of psychiatry at the University of Arkansas for Medical Sciences, helped develop a new questionnaire, called the Depression-Arkansas Scale, which can help primary care physicians better diagnose and treat patients. Some of the 11 questions on the form seek to determine whether the patient feels sad, lethargic, guilty, distracted or suicidal.

Smith said that for every 10 people with depression, five receive treatment; of those five, only one receives appropriate care.