What Causes Stuttering?

Stuttering is fairly common and affects between 5% to 10% of people at some time in their life. Most stuttering starts in childhood, with 98% of cases beginning before age 10. It tends to run in families and is about four times more likely in males than females. 

Stuttering can be of concern not only to the person who stutters, but to their families as well. As you watch someone you care about struggle to get their words out, you can feel their stress and anxiety, too. You may be unsure what you can do to help them or whether it’s part of normal development or something you should worry about. 

We’ll review the different causes of stuttering, how to know if it could become a longer-term problem, and what to do about it.

What is stuttering?

Stuttering is a type of speech disorder. People with speech disorders know the words they want to use, but have trouble making the sounds to say the words. Stuttering is a specific speech disorder in which sounds are repeated and sometimes stretched out. Sentences can have breaks or pauses as if the speaker is “stuck.” 

Stuttering can affect the muscles that help with talking as well as muscles in the face and arms, which play a role in communication and expression. For this reason, you may notice that stuttering is accompanied by eye or face twitches.

What causes stuttering? 

Despite many research studies, there is not one clear reason. Stuttering can have a number of causes, and these are a little different in kids versus adults.  

Stuttering causes in children

For the most part, stuttering that starts in childhood is considered developmental (part of the natural way that some children learn speech). Some of the factors that may contribute to stuttering include:  

• Genetics: There have been several genes that seem to be associated with stuttering, which may explain why it tends to run in families. 

• Brain development: When looking at brain images of people who stutter in comparison to those who don’t, there seem to be areas of the brain that work harder in people who stutter. But it is unclear whether these differences cause stuttering, or if they are the result of it. 

• Growth and fatigue: When the brain is busy learning new skills like walking or new words, stuttering can develop or be worse. Stuttering can also worsen when children are very tired. Think of it as the brain having less time to focus on speech because it is too tired or focusing on other things.

• Environment: If a child is surrounded by fast talkers, they may feel the need to speak fast as well. This can make stuttering worse. In families where children may feel they are competing for time and attention, they might feel pressured to speak quickly to be heard. Stuttering can also be triggered when a child has their speech corrected or they are criticized for the way they speak. 

• Anxiety: Similar to above, when children are in stressful situations, such as having to speak in public, stuttering can start or worsen. 

Stuttering causes in adults

For adults, stuttering can carry over from childhood. But it can also start in adulthood for the first time. When someone starts stuttering for the first time in adulthood, potential causes include: 

• Brain injury: Stuttering can happen in adults after a brain injury, like a stroke or head trauma. 

• Medications: Some medications can cause people to start stuttering. Examples are antidepressants like selective serotonin reuptake inhibitors (SSRIs) and tricyclics, as well as some medications for attention deficit hyperactivity disorder (ADHD) like methylphenidate. 

• Emotional trauma: Psychological stress or a traumatic event can cause a person to start stuttering.  

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Sometimes, people who have grown out of their stutter can relapse due to the above factors, too. 

When should I worry about stuttering?

Most cases of stuttering go away on their own. But certain factors make it more likely that stuttering will persist:

• Gender: People assigned male at birth are more likely to continue stuttering. This could also be due to the fact that there are a much larger number of males who stutter than females. 

• Duration: Children who stutter for longer than 6 months tend to have a harder time outgrowing it. 

• Age of onset: If stuttering begins after preschool years, it is less likely that a child will outgrow stuttering on their own.

• Certain patterns of stuttering: A high frequency of stuttering as well as multiple repetitions of the same sounds tends to mean a more severe case of stuttering. These patterns usually require treatment.

• Avoidance: People who avoid speaking because they are ashamed of their stuttering also have a harder time overcoming it. 

How do you fix stuttering? 

Just as there are many factors that contribute to stuttering, there are many different approaches to treatment. And a combination of several different methods may be needed to resolve the problem. 

There are several categories of treatment to consider. First, there are strategies to improve the environmental factors that contribute to stuttering. Many of these techniques can be done while waiting to see a specialist: 

• Respond neutrally: Multiple researchers point out that families should have a neutral response to stuttering. There should not be a lot of attention, especially negative, given to stuttering. Those who stutter tend to improve more quickly in environments where their stuttering is more accepted. 

• Model slow speech/pace: Parents and older siblings can model slower patterns of speech for a child who stutters. By slowing the pace of interactions, some of the pressure to speak quickly is removed and can thereby improve stuttering. 

• Manage negative feedback: For children, this may mean managing bullying at school. For adults, the negative feedback may be more subtle and more challenging to manage. Words of encouragement as well as strategies to manage stress and anxiety can be helpful. Sometimes patience will give a person struggling with stuttering the space and confidence to overcome their challenges. 

These are also strategies that are specifically targeted at changing speech patterns:

• See a speech language pathologist: These experts help to diagnose speech problems and find strategies and techniques to help improve speech fluency. Treatment with a speech pathologist seems to have the biggest impact on resolving stuttering. 

• Find a counselor: Counselors and therapists can help people work through any negative feelings about stuttering, which can improve the fluency of their speech. Like the indirect strategies above, counseling may also help people manage their anxiety around speaking. 

• Keep medications in mind: Researchers have looked at different medications to help with stuttering. A category of medications called dopamine antagonists have shown some promise. But these also have significant side effects. So more research is needed before they can safely be used to treat stuttering. 

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Written by:

Jill L. Jaimes, MD

Jill L. Jaimes, MD, is a board-certified pediatric emergency medicine physician with over 20 years of clinical experience. She received her medical degree from Baylor College of Medicine and completed her residency and fellowship training at Texas Children’s Hospital.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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