Anna Hill’s mother-in-law had suffered from depression for years, it was clear in hindsight, and had denied it for years, too. Only 73, she’d lost interest in doing much of anything. In chronic pain after an earlier accident, she was taking high doses of methadone. Last November, she stunned her family by declining, at the eleventh hour, to come to Thanksgiving dinner.

“I’d only seen her in a nightgown for a year straight,” said Ms. Hill, 42, an accountant in Atlanta. “She was just rotting away in bed, watching TV and taking methadone.”

Depression in the elderly is a mixed picture these days.

For years, mental health specialists lamented that depression was seriously underdiagnosed and undertreated in the elderly. Laypeople saw it not as a disease but as an inevitable part of aging. Doctors missed it because depression didn’t always look the way it did in younger patients — less sadness and weepiness, more physical symptoms and disengagement. Older people themselves often rejected help because mental illness carried a stigma.

In primary care practices, Dr. Jürgen Unützer and colleagues found in a large study published in 2000, only 12 to 25 percent of older people with probable depression were getting a diagnosis and being treated.

Not anymore. Over the past decade, “we’ve seen a really big increase in the recognition of depression and the initiation of treatment,” said Dr. Unützer, a geriatric psychiatrist now at the University of Washington.

Why the change? He credits stepped-up education for primary care doctors, new antidepressants that seniors find easier to take and tolerate, and a recommendation by the United States Preventive Services Task Force that older adults be screened for depression when there’s staff available for treatment and follow-up. Under the Affordable Care Act, depression screening became part of the free Welcome to Medicare visit for new beneficiaries and of free annual wellness visits thereafter.

Now, in primary care practices, about half of older adults with depression have the condition diagnosed and treated, Dr. Unützer said. A recent study also shows higher diagnosis and treatment rates among nursing home residents.

Over all, “that’s a very good thing,” Dr. Unützer said. Then he delivered the less happy follow-up: “The bad news is that a lot of these folks aren’t a lot better.”

A study he published last year found that only 19 percent of elders with diagnosed depression who received “usual care” in primary care practices showed substantial improvement. “We find it more and we treat it more, but we don’t treat it very well yet,” he concluded.

One apparent explanation: the setting. A great majority of older people seek treatment through their primary care doctors, few of whom are able to offer much more than a prescription.

A Rutgers/Columbia team found last year that as diagnosis rates climbed, more than two-thirds of older patients with depression received antidepressants, but the proportion receiving psychotherapy declined, to less than 15 percent.

Yet not everyone responds to antidepressants. J. Craig Nelson, director of geriatric psychiatry at the University of California, San Francisco, has published an analysis showing that the drugs’ efficacy in older patients only modestly exceeds that of placebos. Moreover, patients often need to try a series or combination at varying doses to find a drug regimen that works.

“We should treat this more like other medical problems,” Dr. Unützer said. “If you have high blood pressure or diabetes, we wouldn’t just ask, ‘How’s it going?’ We’d take your blood pressure or your blood glucose. We’d keep making changes.” If drugs alone didn’t provide relief, doctors would refer to a specialist — in this case, a psychotherapist or psychiatrist.

“Spending time, giving support, providing education to people increases the response to the medication at any age,” Dr. Nelson said. Yet it can still be difficult to steer older patients toward mental health services. The stigma remains. A pill seems easier.

One approach that has proved successful is to move more comprehensive care for late-life depression into existing offices and clinics. Dr. Unützer and his team looked at these “collaborative care” practices, in which a trained nurse or psychologist served as “depression care manager,” working with patients to develop treatments and monitor progress and to refer them to psychiatrists when necessary.

Among 1,800 depressed people over age 60, a group randomly assigned to collaborative care showed far greater improvement. After a year, 45 percent had at least a 50 percent reduction in depressive symptoms, compared with that dismal 19 percent in usual care. They reported less functional impairment, greater quality of life.

The program reduced costs, too, because people with depression pay more visits to doctors and emergency rooms and are more frequently hospitalized. “It increases complications associated with diabetes,” Dr. Nelson said. “Increases mortality after a heart attack. Increases mortality after a stroke.”

There’s an advocacy role for family members to play. Talking to a primary care doctor may be a good way to start treating depression, but in many cases that’s not where to stop. It can take four or five tries to calibrate the most effective medication, said Dr. Unützer. Your relative might benefit from collaborative care or psychotherapy. “You shouldn’t give up,” he said, “until you find something that makes you feel better.”

Ms. Hill’s mother-in-law offers a case in point. After much discussion, her family united and got her into treatment. She sees a psychiatrist, who prescribed Cymbalta and is helping to wean her off methadone. A therapist visits her twice weekly in her assisted living apartment. “It has turned back the clock 10 years,” Ms. Hill said.

Last month, wearing a jaunty hat, her mother-in-law came to a son’s birthday party, her first family function in months. As treatment continues, “she’s out in the world again,” her daughter-in-law said. “It’s wonderful to see.”