Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email questions to youdocsdaily@sharecare.com.

QUESTION: I was driving to work the other day and I had to pull over because I couldn’t stay awake. I took a quick nap, and I was fine.

That’s not the first time it’s happened. Could I have narcolepsy? — Brendon M., Austin, Texas

ANSWER: You were lucky you found a place to pull over! Drowsy driving causes up to 72,000 crashes a year. Around 200,000 Americans have narcolepsy, a disorder that causes excessive daytime sleepiness, and no one knows how many of those folks are involved in car accidents.

Did you know the late-night host Jimmy Kimmel has narcolepsy? It’s said that Thomas Edison and Winston Churchill both contended with the disorder.

If you do have narcolepsy, there are medications to treat it — although only about 25% of folks with the disorder are receiving care. A recent breakthrough in understanding the disease may revolutionize treatment options.

Danish researchers published a study in Nature Communications that found people with narcolepsy have a certain kind of activated immune system T-cell. This cell interferes with the body’s ability to regulate sleep by attacking a needed chemical (hypocretin) produced by neurons. In short, wakefulness is short-circuited. This discovery could lead to newer and better treatments.

For a diagnosis, we recommend you contact a sleep specialist who focuses on the disorder.

The National Sleep Foundation has a search tool to find a qualified physician. Narcolepsy is a very complex condition (there are two types) and a Narcolepsy Network survey found that on average people say it took six years to get a proper diagnosis after the onset of symptoms, and 38 percent were initially misdiagnosed, often with depression.

If it turns out you don’t have narcolepsy, talk with your doc about your sleep habits and get tested for sleep apnea and insomnia. If you’re nodding off while driving, whatever the cause, you want to make sure it never happens again.