Past-Month Nicotine versus THC E-Cigarette Use and Moderate-to-Severe Anxiety Symptoms Among U.S. Adults: A Cross-Sectional Analysis of the 2024 National Survey on Drug Use and Health

The Vaping Puzzle: Nicotine, Weed, and the Worry Machine

Imagine your brain is a bustling city. Sometimes, the traffic gets a little heavy, and the sirens start wailing—that's anxiety. It's a common feeling for many adults, and scientists have long known that when people reach for substances like nicotine or cannabis (the active part of marijuana, called THC), their "worry traffic" often gets worse. But here's the tricky part: for a long time, researchers treated all "vaping" as if it were just one big, blurry cloud. They didn't ask if the person was puffing on a nicotine-only cartridge, a THC-only one, or a mix of both. It's like trying to understand why a car is overheating by just saying, "It's a vehicle," without checking if the engine is burning diesel, gasoline, or a weird homemade fuel mix.

This study dives into that mix using a massive, nationwide survey from the United States called the NSDUH. Think of this survey as a giant, super-accurate snapshot of millions of American adults. For the first time in 2024, this survey asked people to fill out a specific "worry checklist" (known as the GAD-7) to see how many were feeling moderate-to-severe anxiety. The big question wasn't just "Do vapers worry?" but rather, "Does the type of vape matter?" By separating the nicotine users, the THC users, and the dual-users, the researchers hoped to clear up the fog and see which specific habit was most tightly linked to that heavy feeling of anxiety.

The Great Vape Breakdown

The researchers took a look at nearly 47,300 adults (which represents about 262 million people when you count the whole country) and asked them two main things: "Have you used an e-cigarette in the last month?" and "How anxious have you felt in the last two weeks?" They sorted the vapers into four distinct groups: those who didn't vape at all, those who only vaped nicotine, those who only vaped THC, and those who vaped both.

The results painted a clear picture: the more you vape, the more likely you are to report feeling anxious. In fact, among people who didn't vape at all, about 5.9% reported moderate-to-severe anxiety. But for those who vaped, the numbers jumped. Nicotine-only users sat at 15.8%, THC-only users at 17.3%, and the group that vaped both substances together had the highest rate at 21.6%.

When the researchers ran the numbers to see if these links were just a coincidence or something real (by accounting for things like age, income, alcohol use, and smoking regular cigarettes), the connections held strong.

• Nicotine-only vapers were about 1.65 times more likely to have moderate-to-severe anxiety symptoms compared to non-vapers.
• THC-only vapers were about 2.45 times more likely.
• Dual users (both nicotine and THC) were about 2.23 times more likely.

This suggests that vaping, regardless of the substance, is linked to higher anxiety. However, the story gets a little more interesting when they dug deeper.

The "Over-Adjustment" Twist

The researchers wanted to know if these links were just because vapers also happened to use marijuana in other ways or were dealing with depression. So, they ran a second set of calculations, this time adding "past-month marijuana use" and "past-year depression" into the mix.

Here is where the plot thickens:

• The link for nicotine-only vaping stayed strong and steady. Even after accounting for marijuana use and depression, nicotine vapers were still 1.50 times more likely to have anxiety symptoms. This suggests the nicotine connection is very robust.
• The link for THC-only vaping got weaker, dropping to a "borderline" level of significance (1.51 times).
• The link for dual use (both substances) disappeared entirely, becoming statistically non-significant (1.21 times).

Why did the THC and dual-use numbers drop? The authors explain that this might be a case of "over-adjusting." Since vaping THC is a form of using marijuana, asking "Does THC vaping cause anxiety?" and then also asking "Does using marijuana cause anxiety?" in the same math equation is like trying to measure the weight of a single apple while also weighing the whole fruit basket it's sitting in. You end up subtracting the apple's weight twice. The authors suggest that the anxiety seen in THC users is likely shared with the broader habit of using marijuana and dealing with depression, rather than being a unique effect of the vape device itself.

Who Feels It Most?

The study also peeked at whether men and women felt these effects differently. It turns out the connections were stronger in women. For women who vaped THC-only, the odds of anxiety were 3.16 times higher, and for dual users, 2.22 times higher. For men, the numbers were lower (1.83 and 2.29, respectively). While this difference was statistically significant, the authors are careful to say this is an "exploratory signal"—a hint that needs more research—rather than a final rule, because the number of people in these specific groups was moderate.

What This Means (and What It Doesn't)

The most important takeaway is that nicotine-only vaping shows the most consistent and stubborn link to anxiety symptoms. Even when you account for other factors, that link remains. The link for THC vaping is also there, but it seems to be tangled up with the broader habits of using marijuana and experiencing depression.

However, there is a big "but" to keep in mind. This study is a snapshot in time; it looked at what people were doing and feeling right now. It cannot prove that vaping caused the anxiety. It's possible that people who are already anxious are reaching for vapes to calm their nerves (a concept called self-medication). The researchers explicitly state that they cannot determine the order of events: did the vape cause the worry, or did the worry lead to the vape?

In short, this paper suggests that we shouldn't treat all vaping as the same thing. Nicotine vaping seems to have its own strong connection to anxiety, while THC vaping's connection is deeply intertwined with other substance use and mental health struggles. For doctors and public health officials, this means that when they ask a patient about vaping, they need to ask what they are vaping, because the answer might tell them a lot about the patient's mental well-being. But for now, we know there is a strong association, even if the exact cause-and-effect story is still being written.