Selective mutism in autistic adults

Selective mutism is often misunderstood as a childhood disorder. But for many autistic adults—especially the gifted and AuDHDers—it remains a painful, invisible reality.

Introduction

Recently, a late-diagnosed, twice-exceptional (AuDHD + gifted) friend came to me and shared that they were distressed about something but were literally unable to speak about it. They described how, when faced with certain emotional topics, their body would freeze and their words would disappear, even when they wanted to communicate.

Selective mutism is still frequently framed as a condition that occurs in childhood; it is typically imagined as a school-age child who speaks freely at home but falls silent at school. But for many neurodivergent adults—especially those who are gifted or autistic—selective mutism does not disappear with age. It simply changes form, becoming more situational, more internalized, and often more difficult for others to recognize.

For adults living with selective mutism, the experience can be profoundly isolating. It is not a matter of unwillingness to speak; it is a matter of being unable to. It is an experience rooted in the nervous system’s deep, protective survival responses, not personal failure or social opposition.

Definitions: selective mutism & twice-exceptionality

Before we go deeper, it is important to start with a shared understanding of two key concepts: selective mutism and twice-exceptionality (2e). Selective mutism is the primary focus of this article, and individuals who are twice-exceptional are particularly vulnerable to experiencing it.

Selective mutism

Selective mutism is a condition characterized by an individual’s persistent inability to speak in specific social situations, despite having the ability to speak comfortably in others.

It is not a choice, stubbornness, or a refusal to engage. Rather, it is a nervous system-based shutdown response. Selective mutism is often triggered by anxiety, sensory overwhelm, or emotional flooding, where the brain and body disable voluntary speech as a survival strategy.

In adults, selective mutism often presents not as a global silence across all settings, but as situational, topic-specific shutdowns: moments where words simply will not come, even when the individual desperately wants to communicate.

Understanding selective mutism through a neurodiversity-affirming lens helps reframe it from a behavioural problem into what it truly is: an automatic, protective response to perceived threat.

Twice-exceptionality (2e)

Twice-exceptional (2e) individuals are those who are both:

• Gifted — Demonstrating advanced cognitive, intellectual, or creative abilities; and
• Neurodivergent or disabled living with one or more neurodevelopmental differences or challenges, such as autism, ADHD, dyslexia, anxiety disorders, or other emotional or learning differences.

In other words, 2e means being exceptional in two different ways:

• Exceptional strengths such as high intelligence, creativity, and deep insight.
• Exceptional challenges such as difficulties with learning, emotional regulation, or social communication.

Because of this dual profile, 2e individuals are often profoundly misunderstood:

• Their giftedness can mask their disabilities.
  • “They’re too smart to have ADHD!”
• Their disabilities can mask their giftedness.
  • “They can’t be gifted if they struggle to write!”
• Or both can cancel each other out, leading to chronic underachievement, deep frustration, anxiety, and emotional distress.

A twice-exceptional individual might have incredible verbal fluency in safe environments, writing brilliant essays at home or speaking passionately among trusted friends, but experience complete speech shutdowns in emotionally charged or evaluative situations.

Imagine a university student who writes eloquent, thoughtful essays alone but is unable to speak during an oral presentation because of a shutdown. Without recognizing the full 2e profile at play, teachers and peers might misinterpret these shutdowns as laziness, defiance, disinterest, or inability, when in truth, it is a complex, overlapping neurodivergent experience shaped by anxiety, sensory sensitivities, and nervous system dysregulation. My best friend was considered a troublemaker in high school because, despite being incredibly bright, he had selective mutism during classes. He came across as sullen and moody.

This misunderstanding can be profoundly shaming, leaving the 2e individual feeling unseen, unsupported, and deeply alone.

How selective mutism presents in adults

Selective mutism in adulthood often looks very different from the childhood version described in traditional diagnostic manuals. Rather than falling completely silent across entire environments, many neurodivergent adults experience situational, topic-specific shutdowns, sudden losses of verbal ability triggered by emotionally charged conversations, overwhelming environments, or internal sensory overload.

This isn’t simply avoidance or discomfort. It is an involuntary physiological shutdown. A state where the brain and body lock down speech pathways as a protective response.^[1]Treatment of selective mutism: a 5-year follow-up study (Oerbeck et al., 2018)

The term selective can be misleading. It does not mean the individual consciously chooses when and where to speak. Rather, it means the nervous system unconsciously selects, shutting down verbal communication in contexts that feel unsafe, overwhelming, or emotionally unbearable.

Common features of selective mutism in adults include:

• Complete verbal shutdown when specific subjects are raised.
• Body freezing or locking, making it difficult to move or respond.
• Anticipatory anxiety, where even thinking about the triggering topic causes panic or dread.

It is critical to understand that:

• This is not a choice.
• It is not rudeness, stubbornness, or avoidance.
• It is a nervous system response, an automatic, protective shutdown rooted in anxiety, sensory overload, and emotional overwhelm.^[2]Fear and the Defense Cascade Clinical Implications and Management (Kozlowska et al., 2015)

For autistic individuals in particular, trauma responses such as flop or shutdown states are well-documented, deeply rooted survival mechanisms usually observed in animals exposed to extreme threat. As described by Stephen W. Porges in his Polyvagal theory (PVT) and Peter A. Levine in his work on trauma, when the nervous system perceives overwhelming danger, it may trigger a collapse into immobility, muteness, and dissociation, prioritizing survival over social engagement or speech.^[3](The Polyvagal Theory: Neurophysiological Foundations Of Emotions Attachment (Porges, 2011)^[4]In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness (Levine, 2010)

These are not mild reactions; they are profound physiological collapses into silence, disconnection, and immobilization.

Prevalence & overlap with autism

Although exact prevalence rates are difficult to determine, research highlights a strong and clinically important connection between selective mutism and autism. In a clinical study by Steffenberg et al, (2018), 63% of children diagnosed with selective mutism also met full diagnostic criteria for autism, with an additional 20% exhibiting significant autistic traits.^[5]Children with autism spectrum disorders and selective mutism (Steffenburg et al. (2018) Similarly, Klein et al, (2019) found that approximately 80% of children with selective mutism surpassed the clinical cut-off for autistic traits on the BASC-3 autism probability index.^[6]Symptoms of Selective Mutism in Non-clinical 3- to 6-Year-Old Children: Relations With Social Anxiety, Autistic Features, and Behavioral Inhibition (Klein et al., 2019)

While these studies focus primarily on the prevalence of autism within selective mutism populations, rather than the prevalence of selective mutism within autistic populations, the overlap is substantial and cannot be ignored. It is likely that selective mutism remains significantly under-recognized in autistic individuals, particularly given the effects of masking, diagnostic overshadowing, and the persistent misconception that mutism is purely an anxiety-based phenomenon.

Further research is needed to clarify precise prevalence rates, especially among autistic adults, where shutdown responses and selective mutism may be easily misinterpreted or missed altogether. Nevertheless, current evidence underscores the importance of explicitly screening for selective mutism traits within autism assessments, particularly when shutdowns, communication difficulties, or high-masking profiles are present.^[7]Selective Mutism and Its Relations to Social Anxiety Disorder and Autism Spectrum Disorder (Muris & Ollendick, 2021)

What happens physiologically in selective mutism

Selective mutism is not simply a refusal or a reluctance to speak.
It is a biological survival response—a profound reaction of the nervous system to perceived overwhelming threat.

At the physiological level, here’s what happens:

1. Perception of threat triggers the autonomic nervous system

When an individual with selective mutism encounters a stressful situation, whether emotionally charged topics, overwhelming sensory environments, or intense social demands—the brain interprets the situation as dangerous.

The amygdala, the brain’s threat detection center, becomes hyperactivated. This activation triggers the autonomic nervous system (ANS) to prepare the body for survival, entirely outside of conscious control.^[8]The Polyvagal Theory: Neurophysiological Foundations Of Emotions Attachment (Porges, 2011)

2. Bypassing fight-flight: shutdown (“flop”) response

When the nervous system perceives that neither fighting nor fleeing will ensure safety, it can initiate a shutdown or flop response instead.

The body engages the dorsal vagal complex of the parasympathetic nervous system, which governs immobilization behaviors^[9]The Polyvagal Theory: Neurophysiological Foundations Of Emotions Attachment (Porges, 2011) This can lead to:

• Inability to speak
• Physical freezing (muscle tension or collapse)
• Flat or muted facial expressions
• Reduced voluntary movement
• Emotional numbing or dissociation^[10]In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness (Levine, 2010)^[11]Fear and the Defense Cascade Clinical Implications and Management (Kozlowska et al., 2015)

These are not behavioural choices. They are deeply embedded survival strategies, triggered automatically when the nervous system prioritizes collapse over engagement.

3. Motor inhibition shuts down speech

Speech production relies on the prefrontal cortex (the part of the brain involved in planning and executive function) and Broca’s area (involved in language expression).

During states of perceived threat:

• Activity in these brain regions diminishes dramatically.
• Primitive brainstem circuits take over, focused solely on survival.

As a result, the pathways required for voluntary speech become functionally inaccessible.^[12]Fear and the Defense Cascade Clinical Implications and Management (Kozlowska et al., 2015) An individual with selective mutism may desperately want to speak, but find themselves biologically unable to do so.

4. Sensory overload & emotional flooding amplify shutdown

In gifted and autistic individuals:

• Sensory sensitivities (to noise, light, touch) are often heightened.
• Emotional intensity may be profoundly amplified.

These sensitivities lower the threshold for perceiving threat, leading to more rapid and intense shutdowns.^[13]The Polyvagal Theory: Neurophysiological Foundations Of Emotions Attachment,(Porges, 2011)^[14]In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness (Levine, 2010) Even seemingly benign situations can trigger a full shutdown cascade.

5. Chronic activation can lead to conditioned shutdowns

When shutdowns occur repeatedly in particular contexts, the brain can form conditioned responses.

The nervous system begins to anticipate danger, sometimes even before the individual is fully aware of the threat, and initiates shutdown preemptively.^[15]In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness (Levine, 2010) Over time, shutdowns can become faster, more automatic, and harder to interrupt, explaining why some individuals experience anticipatory anxiety and preemptive silence.

A nervous system, not a behavioural problem

When an adult with topic-specific selective mutism freezes, it is not a sign of defiance, rudeness, or avoidance. It is a nervous system response, an automatic, protective shutdown rooted in fear, sensory overload, and emotional overwhelm.^[16]Fear and the Defense Cascade Clinical Implications and Management (Kozlowska et al., 2015)

For autistic individuals especially, trauma responses such as flop and shutdown are well-documented. These survival responses are usually observed only in animals exposed to extreme threat and overwhelm , a profound collapse into immobility, muteness, and dissociation.

As described in polyvagal theory and somatic trauma research, trauma responses like flop and shutdown emerge when the nervous system perceives extreme threat and prioritizes survival through collapse rather than through fight or flight.^[17]The Polyvagal Theory: Neurophysiological Foundations Of Emotions Attachment (Porges, 2011)^[18]In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness (Levine, 2010)^[19]Fear and the Defense Cascade Clinical Implications and Management (Kozlowska et al., 2015)

These are not mild reactions. They are profound physiological collapses, shutting down movement, speech, and emotional connection to protect the individual from further harm. To illustrate this, let me share a story.

When our dog Mowgli first came to us, we didn’t realize he was in a state of flop. At first, we simply thought he was unusually calm, passive, and agreeable. But over time, in the safe and loving environment of our home, we saw the truth emerge: Mowgli is vibrant, playful, and full of strong opinions. His true self had been locked beneath layers of fear, mistaken for compliance.

Imagine being so terrified, so overwhelmed, that your body will not allow you to speak, no matter how much you want to. That is the lived reality for many individuals experiencing selective mutism.

And for those who mask heavily, the struggle becomes even harder to recognize. High-masking individuals may appear superficially functional in certain settings, but underneath, they may be fighting invisible battles with shutdown, fear, and the profound distress of being unable to speak. Without a neurobiological understanding, these experiences are too easily misinterpreted. But when we recognize selective mutism as a nervous system response, rather than a behavioral problem, we shift from judgment to compassion — and from harm to healing.

Why autistics are especially vulnerable

Several factors make autistic individuals—particularly those who have ADHD, or are twice-exceptional—more vulnerable to developing selective mutism.

Autism

Autistic individuals often experience sensory overload, emotional flooding, and difficulty retrieving language under stress.^[20]Selective Mutism and Its Relations to Social Anxiety Disorder and Autism Spectrum Disorder (Muris & Ollendick, 2021)

Differences in interoception, the internal sense of bodily states, can make it harder to recognize early signs of escalating distress. As a result, shutdowns can occur suddenly and completely, without much internal warning.

When the environment feels unpredictable, overwhelming, or emotionally threatening, the nervous system may move rapidly into a state of defensive immobilization, silencing speech as part of a broader collapse into survival mode.

ADHD

For individuals with ADHD, emotional reactivity tends to be heightened, particularly around frustration, fear, or shame.^[21]Emotion Dysregulation in Attention Deficit Hyperactivity Disorder (Shaw, 2014)

Combined with difficulties in emotional regulation and executive functioning, this can make it harder to manage rising stress once a shutdown response begins. Difficulties with task-shifting, calming oneself mid-crisis, or generating alternative coping strategies can all make selective mutism episodes more prolonged and intense.

Giftedness (2e Profiles)

Gifted individuals often experience extreme emotional intensity, a phenomenon sometimes described as overexcitability, and asynchronous development, where advanced cognitive skills coexist with less mature emotional regulation.^[22]Overexcitabilities and Giftedness: Their Interrelationships and External Environmental Consequences in the Light of the Theory of Positive Disintegration (De Bondt & Van Petegem, 2025)

The result is a deep insight into emotional pain, but difficulty expressing or regulating it under pressure. In high-stakes situations, the emotional and sensory demands can overwhelm coping capacities, leading to shutdown and mutism despite intellectual abilities.

Anxiety

Anxiety acts as the accelerant for shutdown. Over time, the brain can condition a freeze response to specific topics or contexts, predicting that speaking will cause distress and, preemptively, “turning off” the motor and speech pathways as a protective measure.^[23]Fear and the Defense Cascade Clinical Implications and Management (Kozlowska et al., 2015)

This means that even thinking about a triggering topic can set off physiological shutdown long before a word is spoken.

The shame cycle & internalized ableism

Many adults living with selective mutism carry a deep and painful burden of shame. Growing up in environments that reward performance and punish differences, they may have learned, explicitly or implicitly,  that their shutdowns were failures of character, willpower, or effort.

Over time, these experiences often foster internalized ableism: the belief that if they cannot meet certain social expectations, speaking fluidly, performing under pressure, appearing “normal”, it must mean they are inherently defective.

Talking about shame itself can be excruciating. The very act of trying to explain, to reach for words that will not come, can deepen the shame spiral. In this way, shame is not merely an emotion. It becomes a self-perpetuating cycle, hardening around isolation, misunderstanding, and self-criticism.

Many autistic adults wish deeply that others could see how hard they are trying. They are not giving up. They are not refusing effort. They are fighting invisible battles, summoning extraordinary reserves of energy and courage, only to feel as though they fall short again and again. It can be devastating to look around and see others seeming to thrive effortlessly, while their own Herculean efforts remain invisible, misunderstood, or judged.

A neurodiversity-affirming perspective reminds us:

• When words disappear, when bodies freeze, it is not a betrayal of effort or will.
• It is a profound act of survival, a nervous system doing its best under immense pressure.
• Healing begins not by demanding more effort, but by recognizing the immense strength it already takes simply to exist in a world that so often misunderstands these struggles.

Compassion, not correction, is the foundation for supporting growth.

Treatment & support recommendations

If you are supporting or working with someone experiencing topic-specific selective mutism, certain principles are essential. Support must center around radical safety, consent, and a deep respect for the nervous system’s limits.

Here are best practices:

• Never pressure them to speak. Pressure intensifies the shutdown.
  • Even well-meaning encouragement can feel invasive and escalate distress.^[24]Fear and the Defense Cascade Clinical Implications and Management (Kozlowska et al., 2015)
• Offer alternate communication modes such as writing, typing, texting, or drawing.
  • Allowing different channels of expression reduces fear and helps re-establish a sense of agency.
• Respect the body’s signals.
  • If they are frozen, pushing harder will not help. The body is already doing its best to survive.
• Use very gradual, consent-based exposure.
• This means gradually working towards a sensitive subject, provided the individual wishes to work toward verbal communication around sensitive topics.^[25]Treatment of selective mutism: a 5-year follow-up study (Oerbeck et al., 2018)
  • Healing must move at the individual’s pace, not the agenda of the environment.
• Prioritize somatic calming interventions.
  • Calming interventions include grounding exercises, deep pressure input, rhythmic movements to help regulate the nervous system and facilitate a return to safety.^[26]Fear and the Defense Cascade Clinical Implications and Management (Kozlowska et al., 2015)
• Provide psychoeducation that normalizes their experience.
  • Frame shutdown not as a failure, but as an intelligent survival response—one that evolved to protect, not betray.

Above all: Create an environment of radical safety, one where communication is not demanded, but invited; where presence, patience, and permission are more powerful than pressure. Healing happens through safety, trust, and relational attunement, not through force, correction, or expectation.

Final thoughts

Selective mutism in autistic adults deserves far greater recognition, understanding, and care. When we move away from framing shutdowns as “refusal” or “defiance,” and instead understand them as automatic nervous system responses, we open the door to much deeper, more compassionate support.

Healing starts with believing:

• They are not broken.
• Their body is doing its best to protect them.
• Their struggles are not failures of will, they are profound acts of survival.

With time, safety, trust, and relational attunement, growth becomes possible. And for many adults who have lived for years in the silent weight of misunderstanding, that healing begins with one simple but radical act: Being seen.