A new report that reviews research on assaults against doctors, nurses and other medical personnel concludes that health care workers often experience physical and verbal attacks, and, all too often, little is done to address it.

“Health care workplace violence is an underreported, ubiquitous, and persistent problem that has been tolerated and largely ignored,” said Dr. James Phillips of Harvard Medical School and Beth Israel Deaconess Medical Center in Boston, writing in the New England Journal of Medicine.

“Our industry is, statistically, the most violent non-law-enforcement industry in the United States. And that’s using government statistics that have been shown to under report the actual violence that takes place by up to 70 percent,” he told Reuters Health in a telephone interview. The violence is often tied to patients with dementia and mental health or substance abuse problems.

But in a significant number of cases, firearms can be involved. “Between 2000 and 2011, there were 154 shootings with injury either inside or on the grounds of American hospitals, most frequently outdoors on the hospital campus (41%), in the emergency department (29%), or on inpatient floors (19%),” Phillips writes. “The most frequently ascribed motives were revenge (27%), suicide (21%), and mercy killing (14%).”

Armed security guards may not be the answer. “In 8% of all events the perpetrator took the gun from a police or security officer,” he said. “In 28% of events involving firearms, a law enforcement officer shot a perpetrator in the hospital.”

Patients in police custody have been involved in 29% of shootings that took place in the emergency departments, 11% of which occurred during escape attempts, he said. In a mental health setting, 70% of staff members are physically assaulted each year and “among psychiatric aides, the rate is 69 times the national rate of violence in the workplace,” he writes. And in nursing homes, where dementia is a problem, one survey found that 59% of nursing home aides reported being assaulted weekly. Health care workers were the victims in 93% of hospital-related assaults in 2014. Most verbal assaults never get reported at all.

A 2015 study found that 80% of emergency services personnel had been the target of physical violence but only 49% had reported it to police. A separate study that looked at violence against doctors found that 89% of the assaults were done by patients, 9% by family members and 2% by a friend of the patient.