5 ways daily cannabis use can affect your body and mind

Monica Romano was 13 when she first tried cannabis in the 1980s. It started out as a social way to spend a Friday night behind the bleachers at football games, she said, but it soon became a daily habit.

“I was reaching for it to quell anxiety,” said Romano, now 59, a health and lifestyle journalist and former nurse in Coeur d’Alene. “I was an uneasy teen, never feeling like I was good enough.” Cannabis minimized her social anxiety and helped her process what she calls an “unstable home life.”

She continued to smoke marijuana daily until she was 30. It didn’t stop her from earning two college degrees and raising her son largely on her own, she said. “I started looking back and wondered: How did I do that? I worked, I studied, I showed up, I raised my son, but pot was always there.”

Marijuana is a constant for a growing number of young and middle-aged adults, 8% to 11% of whom now use cannabis every day, according to Monitoring the Future, an ongoing research project from the University of Michigan. Daily use in older adults 55 and up has decreased.

Young adults 19 to 30 are nearly three times as likely to use cannabis daily than drink alcohol daily, while adults ages 35 to 50 use both about equally, per data in the journal Addiction in 2024. And as daily cannabis use becomes more common, it’s natural to wonder what such frequent consumption may or may not be doing to our health.

Some people like to compare cannabis to other widely used substances, such as caffeine.

“If you drink too much coffee every day, there’s a tipping point, but research has shown that about two to three cups of daily caffeine use for a majority of Americans is fine,” said Rebecca Abraham, a critical care nurse who has worked on cannabis policy and is the founder and CEO of Plesio Health, a software and telehealth platform for cannabis care that’s based in Chicago. “In cannabis, we don’t know what safe daily use is for the average person and [at] what point it tips over.”

Why daily cannabis use is hard to study

There’s so much we still don’t know about daily cannabis use partly because marijuana use has been famously difficult to research.

“It’s been illegal with so much stigma for so long,” Abraham said.

In observational studies looking at past cannabis use, there’s no way to control for what types of cannabis products were used or how, said Peter Grinspoon, a primary care physician and board-certified addiction specialist at Massachusetts General Hospital, an instructor in medicine at Harvard Medical School and the author of “Aging Well With Cannabis.” We simply don’t have data yet on long-term health effects of daily use of, say, low-dose gummies, he said.

Plus, all daily use isn’t the same. “If you’re puffing on your vape pen 60 times a day, that’s very different from a medical cannabis patient taking two and a half milligrams of a gummy at night to fall asleep when they have some chronic pain,” Grinspoon said.

Here are some of the side effects research has identified so far and where we need to know more.

Cannabis hyperemesis syndrome

When daily cannabis users end up in the emergency room, it’s often because of cannabis hyperemesis syndrome, a condition that causes cycles of nausea and vomiting, sometimes with severe stomach pain. It’s associated with daily or frequent long-term cannabis use.

“We don’t really know what causes it, but we see the highest population getting this are long-term, heavy THC users,” said Abraham, who also has a certification in cannabis nursing. THC is the main psychoactive compound in cannabis.

“If I talk to a patient [with cannabis hyperemesis syndrome] and ask how much they were smoking, they smoked all day, every day, often with high-concentration THC,” said Troy Alexander-El, a board-certified internal medicine physician and cannabis educator in Portland, Oregon.

Mental health changes

Lauren Mundell, 53, in Berthoud, Colorado, uses cannabis daily to calm her mind.

“Without cannabis, my brain is like a fire hose of thoughts, anxiety, concerns,” she said. “But when I use cannabis, the fire hose goes down to a little stream, and I can focus on the things that are important.”

When she began using small doses daily at age 43, she said, “it affected me like the wellness supplement I never knew I needed.” She now consults with brands and influencers on cannabis marketing and PR.

Anxiety is one of the main reasons people say they use cannabis. Research has shown that cannabis can both ease and worsen anxiety, often depending on the dose, Grinspoon said. But there aren’t comprehensive studies on the effects of daily cannabis use on anxiety and stress so far.

It can be hard to tell what daily cannabis use does for anxiety or depression in the long term.

“Does it get better or worse or are you just blunting the symptoms?” Grinspoon said. “Of course, you could say the same thing about SSRIs,” he added, referring to selective serotonin reuptake inhibitors, a type of antidepressants.

If you’ve been using cannabis daily and then stop suddenly, you may experience withdrawal symptoms including trouble sleeping and worse anxiety, Grinspoon said. Some people conflate this with cannabis itself worsening anxiety, he said.

Frequent cannabis use is also linked to higher chances of developing schizophrenia or psychosis, especially if people start using it as teenagers. That said, it’s still unclear whether cannabis use is actually causing these mental illnesses or if it “opened the gate a lot faster to what was already going to happen,” Alexander-El said.

Cardiovascular health risks

In a 2024 study in the Journal of the American Heart Association, daily cannabis use was associated with a greater risk of heart disease and stroke. More research is needed to fully understand this potential link, but it could be due to the fact that smoking is still the predominant form of cannabis use, Grinspoon said.

If you primarily smoke cannabis rather than consuming it in other forms, you’re exposing yourself to many of the same unhealthy combustion products in cigarette smoke that can harm your arteries, he said. That’s why doctors who work with cannabis typically recommend edibles, tinctures or topicals, he added.

Changes in pain

One 2023 study found daily cannabis use may help with pain in the short term but make it worse in the long term by reducing tolerance to pain. This is common with opioid painkillers but less established in connection to cannabis, Grinspoon said.

In fact, daily cannabis use often helps people avoid or get off of other pain medications that typically cause more side effects, such as opioids, which have a high risk of addiction, or nonsteroidal anti-inflammatory drugs (NSAIDs), which can cause ulcers or gastrointestinal bleeding.

“They’re using it instead of other pharmaceuticals that very likely are as dangerous, if not more dangerous,” he said.

If you are having surgery, tell your anesthesiologist about your usage. Daily cannabis users may need up to 30 percent more anesthesia and higher doses of opioids for pain control after surgery.

Sleep effects

Alexander-El works with a number of patients who use cannabis nightly to help them fall asleep or stay asleep, and for these folks, she typically recommends edibles because of their slower onset, she said.

Daily cannabis use has been linked to better sleep quality, but also shorter- or longer-than-normal sleep duration in other research. More studies are needed to identify which cannabinoids or compounds may be most effective for sleep, Abraham said.

When you start using cannabis matters

Like with many substances, how old you are when you begin using cannabis makes a difference in the effects it may have on your health.

Romano, who is writing a memoir on addiction, was a teenager when she first started smoking.

“A lot has come out since then about how it affects the young brain,” she said. “I have often thought – and now I’m kind of convinced – that even though I quit so many years ago, I still have hauntings of paranoia or even brain fog or forgetfulness as long-term effects.”

This concern is grounded in science.

“If teenagers use cannabis every day, there’s concern that they’re hurting their brain development,” Grinspoon said, just like alcohol use is more dangerous at younger ages.

At the peak of her cannabis use, Romano would sometimes smoke six or seven times a day, including when she woke up. Leading up to when she finally quit, she was experiencing frequent bouts of bronchitis and even spitting up blood.

She eventually started taking prescription medication for anxiety. The cannabis had been helping her sleep, and she navigated insomnia for years after quitting. Now she takes CBD gummies to help her sleep, but she doesn’t use any cannabis products that contain THC.

What we still don’t know

Mundell isn’t naive about the lack of research on the effects of long-term, daily cannabis use.

“I definitely have come to terms with the fact that I am a guinea pig in this,” the Coloradoan said. “But I firmly believe that it’s a plant I can grow in my backyard and then use it and it makes me feel good, so how could that be bad?”

We need more research surrounding possible drug interactions with cannabis, Grinspoon said, especially in older adults who are more likely to be taking other medications.

The experts we spoke with hope research will one day help answer other big questions, including:

• What are the safest ways to consume cannabis?
• What’s the most effective minimum dose?
• What’s the maximum daily dose after which side effects become more common or more harmful?
• How does daily cannabis use compare with daily use of other medications, such as NSAIDs or sleeping pills?

The recent rescheduling of medical cannabis from a Schedule I to a Schedule III drug will remove some of the red tape that had previously prevented some of this research, Grinspoon said.

Abraham is optimistic about the potential of medical cannabis use. But until we have research to establish some of the missing information around cannabis dosing, “try to use as little as you can to get the maximum effect,” she said.

Reporting by Sarah Klein, Special to The Washington Post.