When Dr. Benjamin Han, a geriatrician and addiction medicine specialist, meets new patients at the School of Medicine at the University of California, San Diego, he talks with them about the usual health issues that older adults face: chronic conditions, functional ability, medications and how they’re working.

He asks, too, about their use of tobacco, alcohol, cannabis and other nonprescription drugs. “Patients tend to not want to disclose this, but I put it in a health context,” Han said.

He tells them, “As you get older, there are physiological changes and your brain becomes much more sensitive. Your tolerance goes down as your body changes. It can put you at risk.”

That’s how he learns that someone complaining about insomnia might be using stimulants, possibly methamphetamines, to get going in the morning. Or that a patient who has long taken an opioid for chronic pain has run into trouble with an added prescription for, say, gabapentin.

When one 90-year-old patient, a woman fit enough to take the subway to his previous hospital in New York City, began reporting dizziness and falls, it took Han awhile to understand why: She washed down her prescribed pills, an increasing number as she aged, with a shot of brandy.

He has had older patients whose heart problems, liver disease and cognitive impairment were most likely exacerbated by substance use. Some have overdosed. Despite his best efforts, some have died.

Until a few years ago, even as the opioid epidemic raged, health providers and researchers paid limited attention to drug use by older adults; concerns focused on the younger, working-age victims who were hardest hit.

But as baby boomers have turned 65, the age at which they typically qualify for Medicare, substance use disorders among the older population have climbed steeply. “Cohorts have habits around drug and alcohol use that they carry through life,” said Keith Humphreys, a psychologist and addiction researcher at the Stanford University School of Medicine.

Aging boomers “still use drugs far more than their parents did, and the field wasn’t ready for that.”

Evidence of a growing problem has been stacking up. A study of opioid use disorder in people older than 65 enrolled in traditional Medicare, for instance, showed a threefold increase in just five years — to 15.7 cases per 1,000 in 2018 from 4.6 cases per 1,000 in 2013.

Tse-Chuan Yang, a co- author of the study and a sociologist and demographer at the University at Albany, said the stigma of drug use may lead people to underreport it, so the true rate of the disorder may be higher still.

Fatal overdoses also have soared among seniors. From 2002 to 2021, the rate of overdose deaths quadrupled to 12 from 3 per 100,000, Humphreys and Chelsea Shover, a co-author, reported in JAMA Psychiatry in March, using data from the Centers for Disease Control and Prevention. Those deaths were both intentional, such as suicides, and accidental, reflecting drug interactions and errors.

Most substance use dis­orders among older people involve prescribed medications, not illegal drugs. And since most Medicare beneficiaries take multiple drugs, “it’s easy to get confused,” Humphreys said. “The more complicated the regimen, the easier to make mistakes. And then you have an overdose.”

The numbers so far remain comparatively low — 6,700 drug overdose deaths in 2021 among people 65 and older — but the rate of increase is alarming.

“In 1998, that’s what people would have said about overdose deaths in general — the absolute number was small,” Humphreys said. “When you don’t respond, you end up in a sorrowful state.” More than 100,000 Americans died of drug overdoses last year.

Alcohol also plays a major role. Last year a study of substance use disorders, based on a federal survey, analyzed which drugs older Americans were using, looking at the differences between Medicare enrollees younger than 65 (who may qualify because of disabilities) and those 65 and older.

Of the 2% of beneficiaries older than 65 who reported a substance use disorder or dependence in the past year — which amounts to more than 900,000 seniors nationwide — more than 87% abused alcohol. (Alcohol accounted for 11,616 deaths among seniors in 2020, an 18% increase over the previous year.)

In addition, about 8.6% of disorders involved opioids, mostly prescription pain relievers; 4.3% involved marijuana; and 2% involved non-opioid prescription drugs, including tranquilizers and anti-anxiety medications. The categories overlap, because “people often use multiple substances,” said William Parish, the lead author and a health economist at RTI International, a nonprofit research institute.

Although most people with substance use problems don’t die from overdoses, the health consequences can be severe: injuries from falls and accidents, accelerated cognitive decline, cancers, heart and liver disease, and kidney failure.

“It’s particularly heartbreaking to compare rates of suicidal ideation,” Parish said. Older Medicare beneficiaries with substance use disorders were more than three times as likely to report “serious psychological distress” as those without such disorders — 14% versus 4%. About 7% had suicidal thoughts, compared with 2% who didn’t report substance disorders.

Yet very few of these seniors underwent treatment in the past year — just 6%, compared with 17% of younger Medicare benefi­ciaries — or even made an effort to seek treatment.

“With these addictions, it takes a lot to get somebody ready to get into treatment,” Parish said, noting that almost half of the respondents older than 65 said they lacked the motivation to begin.

But they also face more barriers than younger people. “We see higher rates of stigma concerns, things like worrying about what their neighbors would think,” Parish said. “We see more logistical barriers” such as finding transportation, not knowing where to go for help and being unable to afford care.

It may be “harder for older adults to try to navigate the treatment system,” Parish said.

Uneven Medicare coverage also presents obstacles. Federal parity legislation, mandating the same coverage for mental health (including addiction treatment) and physical health, guarantees equal benefits in private employer insurance, state health exchanges, Affordable Care Act marketplaces and most Medicaid plans.

But it has never included Medicare, said Deborah Steinberg, senior health policy attorney at the Legal Action Center, a nonprofit working to expand equitable coverage.

Advocates have made some inroads. Medicare covers substance use screening and, since 2020, opioid treatment programs such as methadone clinics. In January, following congressional action, it will cover treatment by a broader range of health professionals and cover “intensive outpatient treatment,” which typically provides nine to 19 hours of weekly counseling and education. Expanded telehealth benefits, prompted by the pandemic, also have helped.

But more intensive treatment can be hard to access, and residential treatment isn’t covered at all. Medicare Advantage plans, with their more limited provider networks and prior authorization requirements, are even more restrictive. “We see many more complaints from Medicare Advantage beneficiaries,” Steinberg said.

“We’re actually making progress,” she added. “But people are overdosing and dying because of lack of access to treatment.” Their doctors, unaccustomed to diagnosing substance abuse in older people, may also overlook the risks.

In an age cohort whose youthful drinking and drug use have sometimes provided amusing anecdotes (a common refrain: “If you can remember the ’60s, you weren’t there”), it can be difficult for people to recognize how vulnerable they have become.

“That person may not be able to say, I’m addicted,” Humphreys said. “It’s a Rubicon people don’t want to cross.”

A joke about dropping acid at Woodstock “makes me colorful,” he added. “Crushing OxyContin and snorting it is not colorful.”