In the Diagnostic and Statistical Manual of Mental Disorders selective mutism is described as a rare psychological disorder in children. Children (and adults) with the disorder are fully capable of speech and understanding language, but fail to speak in certain social situations when it is expected of them. They function normally in other areas of behavior and learning, though appear severely withdrawn and might be unwilling to participate in group activities. It is like an extreme form of shyness, but the intensity and duration distinguish it. As an example, a child may be completely silent at school, for years at a time, but speak quite freely or even excessively at home.
The disorder is not regarded as a communication disorder, in that most children communicate through facial expressions, gestures, etc. In some cases, selective mutism is a symptom of a pervasive developmental disorder or a psychotic disorder.
In diagnosis, it can be easily confused with autistic spectrum disorder, or Aspergers, especially if the child acts particularly withdrawn around his or her psychologist. Unfortunately, this can lead to incorrect treatment.
Selective mutism is usually characterized by the following:
Consistent failure to speak in specific social situations (in which there is an expectation for speaking, e.g., at school) despite speaking in other situations.
The disturbance interferes with educational or occupational achievement or with social communication.
The duration of the disturbance is at least 1 month (not limited to the first month of school).
The failure to speak is not due to a lack of knowledge of, or comfort with, the spoken language required in the social situation.
The disturbance is not better accounted for by a Communication Disorder (e.g., Stuttering) and does not occur exclusively during the course of a Pervasive Developmental Disorder, Schizophrenia, or other Psychotic Disorder.
The former name elective mutism indicates a widespread misconception even among psychologists that selective mute people choose to be silent in certain situations, while the truth is that they are forced by their extreme anxiety to remain silent; despite their will to speak, they just cannot make any voice. To reflect the involuntary nature of this disorder, its name had been changed to selective mutism in 1994. However, misconceptions still prevail; for instance, the ABC News erroneously attributed the cause of selective mutism to trauma and described it as willful in a report dated May 26, 2005.
The incidence of selective mutism is not certain. Owing to the poor understanding of the general public on this condition, many cases are undiagnosed. Based on the number of reported cases, the figure is commonly estimated to be 1 in 1000. However, in a 2002 study in The Journal of the American Academy of Child and Adolescent Psychiatry, the figure has increased to 7 in 1000.
No single cause has been established, but there is some evidence that there is a hereditary component and that it is also more common in girls than boys.
Typical sufferers have some of the following traits when anxious, all of which are often perceived as rudeness:
They find it difficult to maintain eye contact. (anxiety)
Often don't smile and have blank expressions. (anxiety)
They move stiffly and awkwardly. (anxiety)
They find situations where talk is normally expected particularly hard to handle. Answering school registers, saying hello, goodbye, thank-you.
They tend to worry about things more than others
They can be very sensitive to noise and crowds
Find it difficult to talk about themselves or express their feelings
On the positive side, many sufferers have
Above average intelligence, perception, or are inquisitive
Are sensitive to others' thoughts and feelings (empathy)
Have very good powers of concentration (focused)
Often have a good sense of right/wrong/fairness (justice)