There are several risk factors for selective mutism, all of which play a key role in the development of the disorder. These factors include a family history of anxiety, speech issues, language problems, and a tendency to avoid unfamiliar settings. There is no evidence that abuse or neglect can cause selective mutism in children or adolescents.
Most children with the condition are genetically predisposed to anxiety disorder. They show signs of severe anxiety, including tantrums and crying, separation anxiety, moodiness, sleep issues, and shyness right from infancy. These children have severe inhibitions, which make them more prone to anxiety.
Some children who suffer from selective mutism also have a sensory processing disorder, which makes it tough for them to process some sensory information. Such children might be sensitive to light, sound, touch, smell, and taste. This can sometimes make children misinterpret social and environmental cues, thus leading to anxiety and frustration. The child thus starts shutting down and withdrawing from such situations.
Studies show that children with selective mutism have a low threshold of excitability in a portion of their brain called the amygdala, which explains most of the behavioral issues these children exhibit. The amygdala senses potential danger by processing signals from the sympathetic nervous system. In a fearful situation, it triggers a series of reactions that help people protect themselves. Children with the disorder perceive settings such as school, birthday parties, and gatherings as fearful scenarios and hence their amygdala senses “danger” at these situations thus triggering anxiety.
Speech or language abnormalities are seen in about 25% of children with selective mutism. Others may experience minor learning disabilities and shyness. These disabilities add to the child’s stress and make the child insecure in fearful situations where they are expected to speak. However, some studies show that many children affected by selective mutism are early and fluent speakers and don’t show any signs of any other abnormality or processing disorder.
According to the Selective Mutism Anxiety Research and Treatment Center, some kids with selective mutism are part of a multilingual family or were exposed to new languages in childhood or have lived in a foreign country. In these children, there is this added stress of speaking multiple languages, which causes a sense of insecurity gradually leading to higher anxiety levels and thus mutism.
A small proportion of children affected by selective mutism do not exhibit timidity or shyness or any signs of social anxiety. They are good performers and even attention seekers. Research shows that causes for mutism in these children can be different and they may be just stuck with non-verbal expressions and are not confident enough or reluctant to try out verbal communication.
Negative reinforcement of mutism helps in maintaining selective mutism in children. When a child is caught up in a fearful scenario and is mute, usually an adult who can be a parent or teacher tries to help him out by answering the question on the child’s behalf or in other words “rescues” the child. This is a quite common scenario for children with selective mutism at school, a store, or when guests come over.
‘Rescue’ behavior reinforces mutism in these children as the child realizes if he or she keeps quiet, there are others who will rescue her from the situation by talking for her. Each “rescue” makes the child feel better temporarily as it relieves him or her of anxiety, but this gradually leads to a cycle of anxiety avoidance in the child. In a few months, this becomes a habit for the child and the adults who rescue the child and it becomes harder to break.