Child and Adolescent Psychiatry

Selective Mutism 143

Differential diagnosis

1 Normality. Young children vary markedly in how forthcoming they
are in unfamiliar situations. Is transient mutism at school entry an
exaggeration of normal shyness? Is persistent mutism also on the same
continuum, or is it qualitatively distinct? There are no definitive answers
yet.
2 Serious developmental or acquired language disorderscan only be ruled out
when there is convincing evidence that the child’s language is fairly
normal in some settings.
3 Autistic spectrum disordersare ruled out by evidence from reports or direct
observations that the child not only has fairly normal language in some
settings, but can also engage in imaginative play; has normal social
interactions with family members or friends; and is free from marked
ritualistic or repetitive behaviours, or restricted interests.
4 Hysterical mutenessgenerally involves loss of speech in all settings. It is
usually sudden in onset (sometimes following a definite stress), and is
not typically preceded by marked lifelong shyness.

Causation

Selective mutism may result from a combination of constitutional and
environmental factors. Perhaps marked constitutional shyness is exacer-
bated by stress at home, by immigrant status, or by self-consciousness
about relatively minor articulation difficulties or cognitive problems. The
mutism may be rewarded by extra attention and affection at home and
at school. Without twin or adoption studies, it is impossible to determine
whether family clustering points to genetic transmission or social mod-
elling. Do anxious and over-protective parents fill their children with social
anxieties? Or do the same genes that predispose parents to be anxious
and over-protective also predispose their children to be anxious and
selectively mute? Or do constitutionally sensitive children evoke greater
protectiveness from their parents?

Treatment

Behavioural techniques may be helpful, for example, desensitising the
child to speaking in large groups by starting with just one familiar person
and gradually increasing the size of the group. It is obviously essential to
ensure that the rewards for speaking are greater than the rewards for not
speaking (in terms of attention, for example). Since selective mutism is
usually a school-based problem, teachers and classroom assistants are often