Years ago, when a young child couldn't respond verbally to a question, parents called it "cocking a deaf ear."
Now that inability to speak has a medical name — selective mutism — and some suggest that it may have led Seung Hui Cho to cock a gun and shoot 32 victims and then himself at Virginia Tech in April.
Cho was treated for selective mutism as a high school student in the Fairfax County, Va., schools, according to media reports this week.
His emotional condition was considered so severe — he was virtually unable to speak in social settings — that he was placed in a special education program, and a plan was devised to help him.
The condition was one of an array of psychological disorders that the troubled student displayed throughout his short life.
Selective mutism is a type of social anxiety disorder, though some research suggests a biological link to the amygdala, the part of the brain that governs emotions and the "fight or flight" mechanism.
Those who suffer from the disorder "feel afraid," Dr. Elisa Shipon Blum, director of the Selective Mutism Anxiety Research and Treatment Center in Jenkintown, Pa., told ABC News.
"Many of them say, 'The words won't come out,'" she said. "Their voice box feels like it's closing up. Their stomach hurts. Their body won't let them speak."
In a classic case, the child can be a chatterbox at home and with familiar friends, but be paralyzed and speechless in group settings or around strangers. Like a panic attack, the behavior becomes learned, especially when parents speak for the child.
Most selective mutes "self correct" or start talking on their own between grades 3 and 5, due to peer pressure, according to Bill Garrison, professor of pediatrics at University of Massachusetts Medical School.
"The boys do not, however, become highly verbal," he said. "They just begin to talk enough so that they are not noticed," Garrison said.
Cause Not Known
The cause of the disorder is not known, though it may be inherited. It can strike at any age, but most develop sufferers will develop selective mutism before the age of 5.
It is more common in girls than in boys, according to Shipon Blum, and about 70 percent of those with the disorder have an immediate family member who also struggles with it.
Some studies say it is twice as common as autism, affecting about 1 percent of the population, according to the American Academy of Child and Adolescent Psychiatry.
"Selective mutism implies that the child refuses to speak, but not speaking is the end result," Shipon Blum said. "It's a social communication impairment, an anxiety."
Her research points to several risk factors: language difficulties — including bilingualism, as in the Cho case — and speech and sensory issues. Pressure from parents and teachers can exacerabate the disorder.
The difference between ordinary shyness and selective mutism is the degree to which the child is functioning, said Shipon Blum.
"A shy child can function socially, even if they are not the most popular or outgoing in the class," she said. "They may not be emotionally thrilled with themselves, but they function."
Treatment involves not just lowering the anxiety, but using different strategies to help the child to communicate in stages with buddies and peers. Parents should seek help from pediatricians and psychologists. Unfortunately, many health care professionals are not that well-educated in the disorder.
No Violent Connection
News reports about Cho worried Shipon Blum's patients, but she asserts there is no connection between selective mutism and violence.
"Frankly, when this first came out I knew [Cho] had symptoms of selective mutism," said Shipon Blum.
But scientists at the Shyness Research Institute at Indiana University Southeastern point to research that suggests that shyness can pose a real danger to society.
At the annual meeting of the American Psychological Association earlier this month in San Francisco, director Bernie Carducci presented research showing that a certain type of shyness — "cynical shyness" — is a characteristic of many high school shooters.
"Selective mutism being offered as an explanation for violence is pretty much off the wall as far as I am concerned," said Bill Winslade, a psychology and law professor at the University of Texas. "People say lots of things caused them to do things that are bad, but that's way down on the list."
Most psychiatrists and child specialists argue that Cho was probably psychotic.
Is Diagnosis a Red Herring?
Dr. Michael McGrath, clinical associate professor of psychiatry at the University of Rochester Medical Center in New York, said selective mutism is best understood as "a symptom and not a diagnosis" and is "hardly ever associated with violence."
Without seeing Cho's medical records, Dr. Donald Black, professor of psychiatry at University of Iowa College of Medicine, concluded a diagnosis of selective mutism is a "red herring."
"I have never seen such a thing in adults, and very much doubt it applies to this guy," said Black. "He was odd and seclusive, and had paranoid ideas. This comes under the realm of a personality disorder."
Black suggests that Cho might have suffered from schizophrenia, which usually strikes in the late teens or college age.
"From what I read in the newspapers, he appeared to be in the early stages that didn't quite reach the level of psychosis, but with the passage of time, they might fully emerge."
The college years are often a time when earlier psychological problems may worsen, according to Dr. Spencer Eth, medical director of behavioral health at St. Vincent's Hospital in New York.
"Students who have had difficulties with social phobia, selective mutism, marijuana abuse, attention deficit, or depression, may later be found to be suffering from more serious psychiatric disorders."
"It is also possible that adolescent troubles resolve in a new college environment," he said. "It may not be practical, or helpful, to try to link an earlier issue with a later illness or behavior."
Sharing Troubling Mental Health Information
Doctors suggested that even if federal privacy and disability laws prohibit high schools from sharing private information with colleges, parents can take the lead.
"The proper care would have been to set up an appointment with a psychiatrist in advance of Mr. Cho's move to Virginia Tech, so he would have his first appointment soon upon his arrival," said Dr. Igor Galynker, associate chairman of the department of psychiatry at Beth Israel Medical Center in New York City.
"Ideally this transfer of care should be done in close collaboration between the patient, the family and the psychiatrist."
Cho's psychological profile — with or without the suggestion of selective mutism — had much in common with other school shooters that better explain his violence, psychiatrists said.
"He is male, he is a loner — and most loners are not selective mutes," said pediatric professor Garrison.
"He had an extremely active fantasy life related to video-related sources, and he had a long history of peer rejection," he said. "In my opinion, these are the factors that probably accounted for his violent ideation and eventual outburst."
For more information on selective mutism, visit The Selective Mutism Anxiety Research and Treatment Center