A shooting at Johns Hopkins Hospital in September, where a distraught man wounded a surgeon and killed his cancer-stricken 84-year-old mother before turning the gun on himself, grabbed headlines around the world. But hospital gunplay remains rare, say researchers, even though workplace assaults in health care settings are four times more common than in many other industries.

Two Johns Hopkins doctors, prompted in part by the attack, examined hospital violence in a commentary published in the Journal of the American Medical Association last week.

The doctors said from 1997 to 2009, less than 1 percent of workplace killings happened in health care settings. According to figures reported by the Centers for Disease Control and Prevention, 73 of the 8,127 occupational killings tracked were at a medical facility, with 20 of them happening in hospitals.

Of these victims, 12 were doctors and 15 nurses. To put that in perspective, in the same period, 282 cab drivers and 307 cashiers were slain on the job.

Even if killings are rare, assaults are surprisingly more common than in many other industries. For most private-sector jobs, there are two assaults per 10,000 workers, say the researchers. In health care, it's eight assaults per 10,000.

Information on shootings was less formal. Using data gathered from an Internet search, the doctors said since 2008, there have been at least 18 shootings at or nearby hospitals. In about half of all cases, the motivation was revenge, or the shooter committed suicide. One-third of cases involved blasting sick relatives, and two shootings were between coworkers.

The doctors said contrary to general perception, most hospital shootings are not at facilities in high-crime areas. Rather, they happen at random, often at smaller hospitals.

They also suggest little should be done. The rarity of shootings and the fact that deterring a determined shooter is "nearly impossible" mean prevention efforts should focus on other kinds of violence, they said. They had little use for metal detectors.

"Magnetometers may also create a false sense of security," write study authors Drs. Gabor D. Kelen and Christina L. Catlett. "They do not detect nonmetal weapons and have no effect on preventing nonweapon assaults."

The violence in health care settings is a reflection of the violence in society as a whole, the doctors said (the U.S. leads other developed nations in violent crime rankings). But they also noted the decline in the public's perception of medicine.

"There was a time when physicians were viewed with reverence and hospitals were considered sanctuaries," they write.

As an example, they cite a study looking at television portrayals of doctors. In the 1950s TV show City Hospital, doctors were omnipotent healers. But in today's Grey's Anatomy, they're bickering and self-absorbed.

Read DOTmed News' July report on violence against nurses.