It can cause disabilities such as paralysis, speech and, especially among young people, emotional problems.
The first hours are critical in treatment. In the case of an ischemic stroke, the most common among the young, doctors can administer the clot-busting drug tissue plasminogen activator, or tPA, the only U.S. government-approved treatment for acute stroke. It must be given within three hours of the onset of symptoms to reduce permanent disability.
"Recovery rates in the young are much better than when you are older, but up to half of all patients still have symptoms and a third are unable to return to work," said Singhal. "The psychological impact, the social and emotional changes after stroke are much bigger in the younger population."
Risk factors for ischemic stroke in young adults include a personal and familial history of migraines, smoking and, in women, oral contraceptives.
Women who have all three risk factors have a 16 times greater chance of having a stroke, according to Singhal. There have been some associations between stroke and preeclampsia in pregnancy.
In younger people, stroke can be related to cardiac and blood vessel abnormalities, substance abuse, contraception or even lupus. Drugs, such as cocaine, ecstasy, amphetamines and other drugs that cause arterial narrowing can precipitate stroke.
Arterial dissection -- when arteries tear due to a minor trauma -- can also be a cause.
"If you stretch your neck in an awkward position or have a contact injury in racquetball or tennis or fall and hit your head, a little tear in the artery can be a source of clot formation," he said.
Another common cause in both males and females is a congenital hole in the heart.
Such was the case with Dina Pagnotta, whose heart defect was only discovered when she suffered a stroke at age 30. Today, she has been symptom-free for eight years and has since run three marathons.
Pagnotta, a physical therapist, was waiting for a group pilates class when she began to feel "odd." Thinking her blood pressure had dropped or she was dehydrated, she went for sip of water but then realized she couldn't even swallow.
"I was spitting the water out, and my friend looked at me and said I had a strange look on my face," said Pagnotta, who is now 38. "I felt as if I had been injected with a shot of novocaine, like I was sinking into my left side and my speech was slurred."
The paramedics were called but when she arrived in the emergency room, doctors were initially baffled.
"They were poking and prodding and asked if I had done drugs or been on a recent flight," she said. "No one expects a 30-year-old to have a stroke."
"I was terrified," said Pagnotta, who has now fully recovered and works with young stroke survivors. "Strokes don't discriminate."
Leean Hendrix, a Miss America pageant contestant who suffered a stroke at the age of 26, was not so lucky.
Stroke hit when she was living in Phoenix, winding down her reign as Miss Arizona.
"I was at home doing the laundry, feeling fine," she said. "It didn't hurt -- it felt like the muscles behind my eyes broke, kind of like my eyes were doing loop-de-loops. I thought maybe I hadn't eaten well enough. But I closed my eyes and it got worse."
When a friend helped Hendrix to clumsily make her way to the bathroom mirror, bumping into furniture along the way, she could see the right side of her face was "droopy."