“An interesting article by Judith Graham.”

For decades, older adults with depression, anxiety and other psychological conditions have received unequal treatment under Medicare. The program paid a smaller share of the bill for therapy from psychiatrists, psychologists or clinical social workers than it did for medical services. And Medicare imposed strict lifetime limits on stays in psychiatric hospitals, although no such limits applied to medical care received in inpatient facilities.

There was never a good rationale for this disparity, and in 2008 Congress passed the Medicare Improvements for Patients and Providers Act. The law required Medicare to begin covering a larger share of the cost of outpatient mental health services in 2010 and to phase in additional increases over time.

On Jan. 1, that process will be complete, and for the first time since Medicare’s creation seniors who seek psychological therapy will be responsible for 20 percent of the bill while Medicare will pay 80 percent, the same percentage it covers for most medical services. (Payment kicks in once someone exhausts an annual deductible — $147 next year.)

In 2008, Medicare covered 50 percent of the cost of psychological treatment. Last year, it covered 65 percent.

The Medicare change follows new regulations issued last month by the administration for the Mental Health Parity and Addiction Equity Act, which expanded the principle of equal treatment for psychological illnesses to all forms health insurance. But that law does not apply to Medicare.

“Hopefully, older adults who previously were unable to afford to see a therapist will now be more likely to do so,” said Andrea Callow, a policy lawyer with the Center for Medicare Advocacy.

But parity under Medicare remains incomplete, and hurdles still stand in the way of older adults receiving services. A 190-day lifetime limit on inpatient services at psychiatric hospitals is the most notable example. There is no similar cap on any other inpatient medical services provided through Medicare.

“It’s just an arbitrary cap that targets people with serious mental illnesses who need care,” Ms. Callow said.

Are mental health services covered under Medicare otherwise on equal footing with medical and surgical services? And do Medicare Advantage plans — private, managed-care-style arrangements that serve more than 14 million elderly people — apply the same sort of controls to mental health that they do to medical and surgical services?

Sadly, no one knows. “There are no analyses of this issue that I’m aware of,” said Ron Manderscheid, a leading expert on mental health care and the executive director of the National Association of County Behavioral Health and Developmental Disability Directors.

By far the largest group of Medicare beneficiaries needing mental care have psychological conditions such as minor depression that, while painful, can be treated successfully and are not permanently disabling. But the move toward parity may not help many of them, because the law does little to remedy a lack of access to appropriately trained professionals.

“There are a lot of mental health providers out there, but very few have training to work with older adults,” said Dr. Gary Kennedy, director of the division of geriatric psychiatry at Montefiore Medical Center in New York City. And there is little incentive for that to change, because Medicare reimbursement rates are relatively low, given the amount of time providers spend with patients.

A study published this month in JAMA Psychiatry reported an alarming trend: a nearly 20 percent decline in the number of psychiatrists willing to accept new patients covered by Medicare between 2005 and 2010. Just over half of psychiatrists (54.8 percent) reported being willing to take payments from Medicare in 2010, potentially compromising care for the elderly.

What is needed to bring adequate mental health care to more older adults? Kimberly Williams, director of the Geriatric Mental Health Alliance in New York City, suggests that Medicare should pay more to providers who care for psychologically troubled homebound seniors. A wider range of therapists with varying levels of training should be approved to deliver services, she said.

And Medicare should pay for much-needed coordination between primary care doctors and psychiatrists, psychologists or social workers – something that rarely happens at present.

What problems have you observed with Medicare’s coverage of mental health? And what kinds of changes do you think are necessary?