Ask a Doctor: Is marijuana as bad for me as alcohol?

Advice by Salomeh Keyhani, MD
December 12, 2022 at 6:00 a.m. EST
Original Post:

Q: I keep hearing about people quitting alcohol and switching to cannabis because they think it’s better for them. Is that true?

A: We have decades of research on the health effects of drinking. But research on cannabis is still evolving and the public health consequences of its commercialized use — in new products and doses — will take years to understand.

From a medical standpoint, there is no level of alcohol use that is completely safe, as studies have shown harms even with light drinking.

If my patient drinks daily, I advise that they reduce their drinking. If they can’t reduce their drinking despite trying, I offer treatments to help cut back or stop: Many people are surprised to learn that there are three FDA-approved medications (naltrexone, acamprosate and disulfiram) that help with drinking less, and that behavioral treatments — individual or group therapy — are similarly effective.

In terms of cannabis, I tell my patients that we still aren’t sure if there’s a safe level of use, but that in general, scientists consider frequent and higher-THC use to be riskier. 

If my patients are using cannabis, I ask them if they’re using it for a medical reason and suggest alternatives that have more rigorous scientific support. If they’re still planning on using, I advise against smoking and vaping to protect their lungs, and I suggest using products with low concentrations of tetrahydrocannabinol (THC) or trying cannabidiol (CBD) instead.

THC and cannabidiol (CBD) are two of the active ingredients in cannabis: THC, the psychoactive component that makes people feel “high,” has been associated with more health risks. I suggest they try edible CBD products with a THC content of less than 5 percent — with the caveat that edibles can enter the system more slowly and unpredictably, so patients should start low and go slow if they plan to increase the dose.

One reason we know less about the harm of cannabis relative to alcohol is that — until recently — cannabis use was illegal in many states. Now, as the number of people using cannabis is increasing, we will have a better understanding of the potential risks using studies in which we follow large groups of people who use cannabis and those who don’t over time.

Similar observational studies over decades have been critical to our current knowledge base regarding alcohol. We also need randomized, controlled trials to understand the potential benefits of different cannabinoid compounds.

If you’re considering using alcohol or cannabis, here are a few things to keep in mind:

Alcohol is linked to adverse health outcomes

Some of my patients believe that drinking wine is beneficial and reduces their risk of a heart attack. But new research has challenged the idea that there is any cardiovascular benefit to moderate drinking.

It is clear that heavy drinking is associated with multiple cardiovascular risks, including hypertension, stroke and heart failure. Long-term heavy drinking is also linked with other serious health conditions, such as depression and dementia. In addition, alcohol is a carcinogen, and moderate drinking is associated with an increased risk of multiple types of cancer. Even light drinking — half a drink a day — is associated with a mild increase in the incidence of breast cancer in women and colorectal cancer in men.

Alcohol can cause driving accidents and contributes to assaults and suicide. In large doses, it can even cause respiratory depression and death.

Cannabis can cause harm too

Cannabis doesn’t cause respiratory depression, so it doesn’t cause what we think of as an “overdose.” But use of high-potency cannabis has been associated with acute psychosis and, in some cases, this has resulted in death or suicide.

Contrary to popular belief, it is possible to become physically dependent on cannabis or develop a cannabis use disorder. Individuals with frequent cannabis use may grow dependent and experience withdrawal symptoms when they cut down or stop use. Individuals who use cannabis in a way that causes significant impairment may have a cannabis use disorder. These individuals may need treatment to assist with cutting down or stopping use.

Most health claims for cannabis aren’t backed by science

Only three drugs containing cannabinoids have been approved by the FDA: Dronabinol and nabilone contain synthetic THC and can be used to treat nausea and vomiting from chemotherapy among patients who haven’t responded to other drugs; CBD is being used to treat rare forms of childhood epilepsy; and dronabinol is also approved to treat anorexia due to AIDS. Studies suggest that cannabis extracts may be useful in managing pain and spasticity from multiple sclerosis, and that cannabinoids may be effective in the management of neuropathic pain.

Though common marketing practices — and countless anecdotal reports — tout cannabis as a proven treatment for anxiety, pain, insomnia and more, all these claims require further research until we can make firm recommendations. Cannabis use may actually make the treatment of depression more difficult.

But we shouldn’t conflate the potential therapeutic uses of pharmaceutical-grade cannabis with products sold in dispensaries. Many products in dispensaries may have contaminantsmay not actually contain CBD and may be high in THC concentration.

Smoking and vaping cannabis has risks

A few years ago, my patient had a heart attack. It was somewhat unexpected because he was healthy and physically active. While I had documented that he wasn’t a tobacco smoker, given the recent heart attack, I asked him again: “Do you smoke?”

He said no. Then he paused and clarified that he didn’t smoke tobacco. But he did smoke cannabis every day after work and had for years. While the available evidence is limited, some studies suggest that cannabis use, like tobacco use, is associated with heart attacks.

We need studies that examine the health effects of smoking cannabis daily, because daily use of cannabis is becoming more common among young adults and multiple studies have reported individuals who use it daily are at higher risks of adverse health effects.

Our research group conducted several systematic reviews of literature. We found that smoking cannabis was associated with coughing, wheezing and testicular cancer.

Concerns about THC use and mental health

Cannabis use during adolescence has been linked to the development of depression and suicide attempts during young adulthood. It’s also associated with psychosis, a potentially devastating disease in this age group.

According to the National Institutes of Health, cannabis use among young adults reached an all-time high in 2021.

I’m also concerned about older patients who take multiple medications and use cannabis, given limited data on how the two interact. Cannabis use is increasing among older adults but there is very limited data on its effects in this group.

Given the available evidence, I don’t recommend alcohol use or cannabis use to my patients for any medical or psychiatric conditions.

Proponents of cannabis like to say that it’s “natural,” so it can’t be bad for us. We should remember that tobacco is also a “natural” leafy green plant. It had been used for thousands of years. Yet in the 20th century, the tobacco industry designed highly addictive products and incited a worldwide epidemic in tobacco addiction and subsequent cancer, cardiovascular and lung disease.

It’s clear what excessive drinking can do to our bodies and minds. It’s too soon to say what effect commercialized cannabis — and its pervasive use — will have on our health.

Salomeh Keyhani is a professor of medicine at the University of California at San Francisco.

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