Selective mutism (SM) is an anxiety disorder in which a person who is normally capable of speech does not speak in specific situations or to specific people. Selective mutism usually co-exists with shyness or social anxiety. People with selective mutism stay silent even when the consequences of their silence include shame, social ostracism or even punishment.
Besides lack of speech, other common behaviors and characteristics displayed by selectively mute people include:
-Shyness, social anxiety, fear of social embarrassment, and/or social isolation and withdrawal
-Difficulty maintaining eye contact
-Blank expression and reluctance to smile
-Stiff and awkward movements
-Difficulty expressing feelings, even to family members
-Tendency to worry more than most people of the same age
-Desire for routine and dislike of changes
-Sensitivity to noise and crowds
According to a more recent systematic study it is believed that people who have selective mutism are not more likely than other people to have a history of early trauma or stressful life events. Children who have experienced trauma however are known to suddenly stop speaking.
Contrary to popular belief, people with selective mutism do not necessarily improve with age. Effective treatment is necessary for a child to develop properly. Without treatment, selective mutism can contribute to chronic depression, further anxiety, and other social and emotional problems.