Selective mutism is a severe anxiety disorder where a person is unable to speak in certain social situations, such as with classmates at school or to relatives they don't see very often.

It usually starts during childhood and, left untreated, can persist into adulthood.

A child or adult with selective mutism doesn't refuse or choose not to speak, they're literally unable to speak. 

The expectation to talk to certain people triggers a freeze response with feelings of panic, rather like a bad case of stage fright, and talking is impossible.

In time, the person will learn to anticipate the situations that provoke this distressing reaction and do all they can to avoid them.

However, people with selective mutism are able to speak freely to certain people, such as close family and friends, when nobody else is around to trigger the freeze response. 

Selective mutism affects about 1 in 140 young children. It's more common in girls and children who are learning a second language, such as those who've recently migrated from their country of birth.

Signs of selective mutism

Selective mutism usually starts in early childhood, between the ages of two and four. It's often first noticed when the child starts to interact with people outside their family, such as when they begin nursery or school.

The main warning sign is the marked contrast in the child's ability to engage with different people, characterised by a sudden stillness and frozen facial expression when they're expected to talk to someone who's outside their comfort zone.

They may avoid eye contact and appear:

• nervous, uneasy or socially awkward
• rude, disinterested or sulky
• clingy
• shy and withdrawn
• stiff, tense or poorly co-ordinated 
• stubborn or aggressive, having temper tantrums when they get home from school, or getting angry when questioned by parents 

More confident children with selective mutism can use gestures to communicate – for example, they may nod for "yes" or shake their head for "no".

But more severely affected children tend to avoid any form of communication – spoken, written or gestured.

Some children may manage to respond with a word or two, or they may speak in an altered voice, such as a whisper.

Few people see the child or young person as they really are – a sensitive, thoughtful individual who's chatty, outgoing and fun-loving when relaxed and unaffected by their selective mutism.

What causes selective mutism? 

Experts regard selective mutism as a fear (phobia) of talking to certain people. The cause isn't always clear, but it's known to be associated with anxiety.

The child will usually have inherited a tendency to experience anxiety and have difficulty taking everyday events in their stride.

Read more about anxiety in children.

Many children become too distressed to speak when separated from their parents and transfer this anxiety to the adults who try to settle them.

If they have a speech and language disorder or hearing problem, it can make speaking even more stressful.

Some children have trouble processing sensory information like loud noise and jostling from crowds – a condition known as sensory integration dysfunction.

This can make them "shut down" and be unable to speak when overwhelmed in a busy environment. Again, their anxiety can transfer to other people in that environment.

There's no evidence to suggest that children with selective mutism are more likely to have experienced abuse, neglect or trauma than any other child.

When mutism occurs as a symptom of post-traumatic stress, it follows a very different pattern and the child suddenly stops talking in environments where they previously had no difficulty.

However, this type of speech withdrawal may lead to selective mutism if the triggers aren't addressed and the child develops a more general anxiety about communication.

Another misconception is that a child with selective mutism is controlling or manipulative, or has autism. There's no relationship between selective mutism and autism, although a child may have both.

Diagnosing selective mutism

Left untreated, selective mutism can lead to isolation, low self-esteem and social anxiety disorder. It can continue into adolescence and adulthood if not tackled.

However, a child can successfully overcome selective mutism if it's diagnosed at an early age and appropriately managed. 

It's also possible for adults to overcome selective mutism, although they may continue to experience the psychological and practical effects of years deprived of social interaction or not being able to reach their academic or occupational potential.

It's therefore important for selective mutism to be recognised early by families and schools so they can work together to reduce the child's anxiety. Staff in early years settings and schools may receive training so they're able to provide appropriate support.

If parents suspect their child has selective mutism and help isn't available, or there are additional concerns – for example, their child struggles to understand instructions or follow routines – they should seek a formal diagnosis from a qualified speech and language therapist.

You can contact a speech and language therapy clinic directly or speak to a health visitor or GP, who can refer you. Don't accept the assurance that you or your child will grow out of it, or you or they are "just shy".

Your GP or local clinical commissioning group (CCG) should be able to give you the telephone number of your nearest NHS speech and language therapy service.

Older children may also need to see a mental health professional or school educational psychologist. 

Adults will ideally be seen by a mental health professional with access to support from a speech and language therapist or another knowledgeable professional.

The clinician may initially want to talk to parents without their child present, so they can speak freely about any anxieties they have about their child's development or behaviour.

They'll want to find out whether there's a history of anxiety disorders in the family, and whether anything is causing distress, such as a disrupted routine or difficulty learning a second language. They'll also look at behavioural characteristics and take a full medical history.

A person with selective mutism may not be able to speak during their assessment, but the clinician should be prepared for this and be willing to find another way to communicate.

For example, they may encourage a child with selective mutism to communicate through their parents, or suggest that older children or adults write down their responses or use a computer. 

Selective mutism is diagnosed according to specific guidelines. These include observations about the person concerned as outlined:

• they don't speak in specific situations, such as during school lessons or when they can be overheard in public
• they can speak normally in situations where they feel comfortable, such as when they're alone with parents at home, or in their empty classroom or bedroom
• their inability to speak to certain people has lasted for at least a month (two months in a new setting)
• their inability to speak interferes with their ability to function in that setting
• their inability to speak isn't better explained by another behavioural, mental or communication disorder

Associated difficulties

It's important to understand how selective mutism can affect a child's education and development, and the impact it can have on a young person's or adult's everyday life.

A person with selective mutism will often have other fears and social anxieties, and they may also have additional speech and language difficulties in childhood.

They're often wary of doing anything that draws attention to them because they think that by doing so others will expect them to talk.

For example, a child may not do their best in class after seeing other children being asked to read out good work, or they may be afraid to change their routine in case this provokes comments or questions. Many have a general fear of making mistakes.

Additional difficulties can also arise from the inability to start a conversation.

Accidents and urinary infections may result from being unable to ask to use the toilet and holding on for hours at a time. School-aged children may avoid eating and drinking throughout the day so they don't need to excuse themselves.

Children may have difficulty with homework assignments or certain topics because they're unable to ask questions in class and seek clarification.

Teenagers may not develop independence because they're afraid to leave the house unaccompanied. And adults may lack qualifications because they're unable to participate in college life or subsequent interviews.

Treating selective mutism

With appropriate handling and treatment, most children are able to overcome selective mutism. But the older they are when the condition is diagnosed, the longer it will take.

The effectiveness of treatment will depend on:

• how long the person has had selective mutism
• whether or not they have additional communication or learning difficulties or anxieties
• the co-operation of everyone involved with their education and family life 

Treatment doesn't focus on the speaking itself, but reducing the anxiety associated with speaking.

This starts by removing pressure on the person to speak. They should then gradually progress from relaxing in their school, nursery or social setting, to saying single words and sentences to one person, before eventually being able to speak freely to all people in all settings. 

The need for individual treatment can be avoided if family and staff in early years settings work together to reduce the child's anxiety by creating a positive environment for them.

This means:

• not letting the child know you're anxious
• reassuring them that they'll be able to speak when they're ready
• concentrating on having fun
• praising all efforts the child makes to join in and interact with others, such as passing and taking toys, nodding and pointing
• not showing surprise when the child speaks, but responding warmly as you would to any other child

As well as these environmental changes, older children may need individual support to overcome their anxiety.

The most effective types of treatment are behavioural therapy and cognitive behavioural therapy (CBT). These are described below, along with some commonly used techniques to overcome anxiety. 

Behavioural therapy

Behavioural therapy is designed to work towards and reinforce desired behaviours while replacing bad habits with good ones.

Rather than examining a person's past or their thoughts, it concentrates on helping combat current difficulties using a gradual step-by-step approach to help conquer fears.

Several of the techniques below can be used at the same time by individuals, family members and school or college staff, possibly under the guidance of a speech and language therapist or psychologist.

Stimulus fading

In stimulus fading, the person with selective mutism communicates at ease with someone, such as their parent, when nobody else is present.

Another person is introduced into the situation and, once they're included in talking, the parent withdraws. The new person can introduce more people in the same way.

Positive and negative reinforcement

Positive and negative reinforcement involves responding favourably to all forms of communication and not inadvertently encouraging avoidance and silence.

If the child is under pressure to talk, they'll experience great relief when the moment passes, which will strengthen their belief that talking is a negative experience.

Desensitisation

Desensitisation is a technique that involves reducing the person's sensitivity to other people hearing their voice by sharing voice or video recordings.

For example, email or instant messaging could precede an exchange of voice recordings or voicemail messages, leading to more direct communication, such as telephone or Skype conversations.

Shaping

Shaping involves using any technique that enables the person to gradually produce a response that's closer to the desired behaviour.

For example, starting with reading aloud, then taking it in turns to read, followed by interactive reading games, structured talking activities and, finally, two-way conversation.

Graded exposure

In graded exposure, situations causing the least anxiety are tackled first. With realistic targets and repeated exposure, the anxiety associated with these situations decreases to a manageable level.

Older children and adults are encouraged to work out how much anxiety different situations cause, such as answering the phone or asking a stranger the time.

Cognitive behavioural therapy

Cognitive behavioural therapy (CBT) works by helping a person focus on how they think about themselves, the world and other people, and how their perception of these things affects their thoughts and feelings. CBT also challenges fears and preconceptions through graded exposure.

CBT is carried out by mental health professionals and is more appropriate for older children, adolescents – particularly those experiencing social anxiety disorder – and adults who've grown up with selective mutism.

Younger children can also benefit from CBT-based approaches designed to support their general wellbeing.

For example, this may include talking about anxiety and understanding how it affects their body and behaviour, and learning a range of anxiety management techniques or coping strategies.

Medication

Medication is only really appropriate for older children, teenagers and adults whose anxiety has led to depression and other problems.

Medication should never be prescribed as an alternative to the environmental changes and behavioural approaches described above.

However, antidepressants may be used alongside a treatment programme to decrease anxiety levels and speed up the therapy process, particularly if previous attempts to engage the individual in treatment have failed.

Advice for parents

You may find the advice below helpful if your child has been diagnosed with selective mutism.

• Don't pressurise or bribe your child to encourage them to speak.
• Let your child know you understand they're scared to speak and have difficulty speaking at times. Tell them they can take small steps when they feel ready and reassure them that talking will get easier.
• Don't praise your child publicly for speaking because this can cause embarrassment. Wait until you're alone with them and consider a special treat for their achievement.
• Reassure your child that non-verbal communication, such as smiling and waving, is fine until they feel better about talking.
• Don't avoid parties or family visits, but consider what environmental changes are necessary to make the situation more comfortable for your child.
• Ask friends and relatives to give your child time to warm up at his or her own pace and focus on fun activities rather than getting them to talk.
• As well as verbal reassurance, give them love, support and patience.  

Getting help and support

It's only relatively recently that selective mutism has been properly understood and effective treatment approaches have been developed.

The body of expertise among healthcare professionals, educational psychologists and teaching staff is growing, but those seeking help need to be prepared for the fact that professionals in their area may not have up-to-date knowledge or experience of working with selective mutism.

If this is the case, you should seek out teachers and healthcare professionals who are willing to listen, learn and develop their specialist knowledge to provide appropriate support.

Teenagers and adults with selective mutism can find information and support at iSpeak and the facebook group SM SpaceCafe.

The Royal College of Speech and Language Therapists and the Association of Speech and Language Therapists in Independent Practice can help you find treating professionals.