Researchers have confirmed in recent years what people long suspected: Extreme stress can literally break your heart. And as they learn more about the relatively rare condition, they are finding that it's not only caused by the loss of a loved one. Medical treatments, job loss, and other major life stressors have been linked to the condition.

The syndrome, known medically as takotsubo cardiomyopathy, mainly affects women. While the medical literature on broken heart syndrome is sparse, more cases are coming to light, with additional information about how it happens and how long-term the risks are.

Last year, Canadian researchers reported a case of broken heart syndrome in a 63-year-old woman on treatments for metastatic breast cancer.

Over a 6-year period, researchers from MD Anderson Cancer Center in Houston found 30 patients having cancer treatment fit the criteria for broken heart syndrome. Fortunately, none had a recurrence, but the researchers say the diagnosis should be considered in cancer patients who get chest pain.

In another report, a doctor presented case histories of two older women, one treated for chronic lung disease and the other for gastritis, who had broken heart syndrome.

When a patient's heart "breaks," the main pumping chamber, the left ventricle, weakens, leading to pain and shortness of breath. The condition is reversible and temporary but can lead to complications similar to those after a heart attack. Experts think it's caused by a flood of hormones -- such as adrenaline -- produced during a stressful situation that stuns the heart.

More than 6,200 cases of broken heart syndrome were reported in 2012 in the United States, up from about 300 in 2006, says Abhijeet Dhoble, MD, a cardiologist at Houston's Memorial Hermann Heart & Vascular Institute. Most patients are women. The increase, he says, is likely because more people know about the condition.

The condition doesn't just happen after a person or a pet dies, says Jeffrey Decker, MD, section chief of clinical cardiology at Frederik Meijer Heart & Vascular Institute of Spectrum Health in Grand Rapids, MI. Nor is it always centered on a health issue.

"I had a lady who was frustrated with the cable company present with this," he says. Another was a woman who found out her daughter lost her job, says Decker, also an assistant professor of medicine at Michigan State University.

Severe pain can trigger the syndrome. So can an asthma attack, a fierce argument, a surprise party, or even public speaking. Symptoms mimic a heart attack -- most often, chest pains and shortness of breath. Nausea, vomiting, and palpitations can also happen. But only testing can show the diagnosis, says Dhoble.

"Takotsubo" means "octopus pot" in Japanese. Decker says it got that name because when it happens, certain portions of the heart muscle do not move well. Other parts make up for that lack of movement, making the heart look like a pot used by Japanese fishermen to trap octopuses.

About 95 percent of patients recover within a month or two. "Usually the prognosis is quite favorable," Decker says. Patients usually get the same medications used to treat congestive heart failure to support and strengthen the heart. Death is uncommon in people who don't have complications, with less than a three percent fatality rate.