Adults with disabilities are more likely to be victims of violence than adults who are not disabled, according to a new study published online in The Lancet.
Mentally ill adults are at four times higher risk for violence, and adults with intellectual impairments are also particularly vulnerable.
A team of researchers from the United Kingdom's Liverpool John Moores University and the World Health Organization analyzed 26 studies on violence against disabled adults, with more than 21,000 participants from around the world.
"About 3 percent of individuals with non-specific impairments [eg, physical, mental, or emotional, or health problems that restrict activities] will have experienced violence within the past 12 months, rising to almost a quarter of people with mental illnesses," said lead author Mark Bellis of Liverpool John Moores University in a press release.
The violence, he explained, was either physical, sexual or by an intimate partner.
Experts not involved in the research say the study calls attention to the plight of many disabled adults who become targets for a variety of reasons.
Jack Levin, professor of sociology and criminology at Northeastern University in Boston, said the disabled often suffer in silence.
"It happens all too often, but we have ignored a very serious issue," he said.
He cited the case of 30-year-old Jennifer Daugherty as an example of what a surprisingly high number of mentally ill and intellectually challenged adults suffer.
Daugherty, described by her stepfather as having the mental abilities of a 12 to 14-year-old was allegedly tortured and murdered by a group of six people in western Pennsylvania in 2010. Prosecutors say a 17-year-old girl served as the group's ringleader and saw Daugherty as a romantic rival.
The group was accused of abducting Daugherty, beating her, forcing her to consume human waste and bleach, then forcing her write a suicide note before stabbing her multiple times.
Levin said that while people view what happened to Daugherty as particularly heinous, most people don't see it for the hate crime that it is. Hate crimes, he explained, are more likely to be viewed as crimes against a certain race or against people of certain sexual orientations.
Dehumanization, Power and Thrills Among Reasons
The U.S. Department of Justice found that disabled adults were victims of twice as many violent crimes as adults who are not disabled, and about 15 percent of these victims believe they were targeted as a result of their impairments.
"There are a number of reasons why adults with disabilities are more vulnerable to violence," said Dick Sobsey, professor emeritus at the University of Alberta in Edmonton, Canada.
"Many of them are more vulnerable or may have limited communication abilities, either by impairment or by situations they are in," he said.
Levin added that they may not be able to fight back or to report the incidents to the authorities.
The disabled, especially those who have cognitive impairments, are often viewed as non-human.
"They have a deficit or a defect, so they can be more easily treated like animals or subhumans," said Levin, also the author of "The Violence of Hate."
Many people with disabilities are also often dependent on others, making them vulnerable to people who may feel the desire to exert power over them, Sobsey added.
Perpetrators may also be exacting revenge on people with disabilities, Levin said. Since the passage of the Americans with Disabilities Act (ADA) in 1990, which prohibits discrimination based on disabilities, people may feel that the disabled get special privileges.
"A person may want to get even for some loss. He or she may blame the disabled person for some personal miseries, such as getting passed over for a job."
"Since the ADA was enacted, those who have disabilties are seen as costing us a lot of money," Levin added. "Many Americans see them as a threat to their economic well-being."
And people may simply be motivated by the thrill of killing and see the disabled as easy targets, Levin said.
Study Just a First Step
Experts have different opinions on the best ways to address the problem, but they do agree that a solution will not be easy to come by.
While the study identifies a trend of abuse against people with disabilities, more research is needed to determine the cause-and-effect relationship.
"It's not yet clear whether violence comes first, or the disability in some cases," said Sobsey. "Violence is a major cause of psychiatric symptoms and disabilities."
In an accompanying editorial, Esme Fuller-Thomson and Sarah Brennenstuhl of the University of Toronto wrote that health care providers need better tools to screen for and identify violence among their patients.
"In addition to improved identification of victims is the need for appropriate care and support services," they wrote.
Levin believes that the first step should be better recognition of the violence against the disabled.
"We don't need any more laws," he said. "We need to change the thinking of ordinary Americans who are unaware that people with disabilities are being targeted. If Americans recognized the harm that was being done, they might be more likely to intervene."
The Associated Press contributed to this report.