The featured image was generously provided by E-Furor Stock Production in Lviv, Ukraine.

Medical disclaimer:

It is essential to seek support from a licensed professional psychologist if you suspect you have a psychological condition such as autism or selective mutism. Licensed psychologists are the only professionals authorized to diagnose such conditions. In most countries worldwide, counselors, school deans, and other professionals are not authorized to diagnose such conditions, and their diagnoses are not considered credible. However, in the United Kingdom, certain non-psychologist professionals may be authorized to diagnose. It is also crucial to confirm that the psychologist is licensed. In nearly all countries, psychologists are required to be licensed to practice, and without a license, they are not authorized to diagnose or practice, and their diagnoses are considered invalid. A licensed psychologist should be able to provide you with their registration upon request.

This blog post was written with the support of three licensed practicing psychologists and a licensed practicing psychiatrist. Although we have made every effort to provide factual information, errors may still be possible.

The Difference Between Selective Mutism and Autism

Since my two posts about selective mutism in September of last year, I have seen a constant barrage of blog posts and tweets claiming that selective mutism is part of autism. Even just a moment ago on Twitter, I was reminded about it once again. Let me be clear and simple: Selective mutism is NEVER part of autism.

For anyone unaware, selective mutism is its own independent condition and diagnosis. It’s not part of any other diagnosis. In a simple comparison, it’s not sensory processing disorder, which is something that is often recognized in the exact opposite way. Meaning that people think it’s its own independent disorder, regardless of it only being recognized as a symptom, including among the autism and selective mutism diagnoses.

The great problem here is that people confuse two things: selective mutism and regular mutism. Mutism in itself only refers to an inability to speak. According to the American Psychological Association (APA), the difference between the mutism among autistic people and those with selective mutism is choice. Anyone with selective mutism has no choice. They are completely disabled in their attempt to speak. However, anyone who’s autistic does have a choice, in which many choose not to speak for various reasons, including due to developmental delays and social anxiety. The fact that most autistic people are freely able to speak is also among the reasons why autistic people receive so much stigma for their regular mutism.

The important thing to understand here is the actual difference in underlying reason between autism and selective mutism:

Understanding Selective Mutism

In the case of selective mutism, the underlying reason is fear of a situation. Due to this fear, a person locks down and is unable to speak. To be even clearer, these situations are public settings, such as school, work, stores, social gatherings, etc. That’s also the reason for the “selective” part in the name, as it’s based on situations and not just always. It’s not based on selection/choice as a lot of people incorrectly conclude. Selective is a synonym of situational in this case.

Understanding Autism

In the case of autism, the underlying reason is usually developmental delays, sensory overloads, difficulties in processing information, and/or social anxiety. Due to this, the mutism in autism is present in (almost) all situations. The difference between a public setting and home situation will usually not matter for mutism in autism, although the specific people might make a difference. In this regard, the mutism among autistic people is not selective/situational.

So, basically: Mutism in autism is an inability or reluctance to speak in almost all social situations.
Mutism in selective mutism is an inability, never a reluctance, to speak in certain social situations.

Misconceptions about Selective Mutism and Autism

So, what actually causes this misunderstanding? Again, the problem lies in that singular word, “selective”. When looking through the comments on the particular Tweet I mentioned before, this is part of a response, “I’ve seen a lot more people talking about situational mutism”.

Situational Mutism in the United Kingdom

What is situational mutism? Well, it is actually a synonym for selective mutism in the United Kingdom. While selective mutism is the accepted name in the USA and most of the world, based on the definition in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR®), situational mutism is an accepted name in the United Kingdom, which uses British English for clarity, and not American English or International English. The difference is the name, but nothing else. Well, apart from a lot of opposition to the British name…

High Functioning Autism: The Controversial Label

These kinds of problems in regard to the United Kingdom are hardly unique. The United Kingdom is also often negatively seen among psychologists around the world for another thing done in this country, which has to do with autism. You might have heard of the name, “high functioning autism” (HFA), a name that has a huge amount of stigma and is seen as a form of discrimination, regardless of some highly respected British psychologists using this term. The “high functioning” literally refers to the IQ of a person, as all someone has to have to get the label of HFA instead of classic autism is an IQ above 70… And I do indeed mean “label,” as it’s not a factual diagnosis.

But that is not even the greatest problem in regard to HFA, as it is the lack of understanding that it is significantly different compared to Asperger’s syndrome, as classic autism is as well. To be even clearer, something noteworthy in Asperger’s is the obsession in one specific field or area. As an example, a very commonly seen obsession is with trains, in which many Aspies can literally name you a whole train schedule from memory. In both classic autism and HFA, there’s no obsessive behavior in such a sense.

In an opposite example, there are always delays in language development when it comes to classic autism and HFA, which is not the case in Asperger’s. Another difference is in regards to motor skills, with Asperger’s showing far clearer difficulties in this regard, most often primarily shown in gross motor skills. Among both HFA and classic autism, the difficulties are far less pronounced and more often shown in fine motor skills.

CDD: A Different Autism Spectrum Disorder

Which is in itself interesting since the move towards autism spectrum disorder (ASD). (Many people, including myself, don’t support this move.) The reality is that it pushed two groups of people together that had significantly different disorders. And this is even more the case when adding the often-forgotten third group of autistic people, which are those who formerly had a diagnosis of childhood disintegrative disorder (CDD), also known as Heller’s syndrome and dementia infantilis.

When it comes to CDD, people often regard it as only different from classic autism in one aspect, which is that typically CDD develops after the age of 2, before the age of 10, whereas classic autism develops before the age of 2. However, this is not everything. CDD also has a far more pronounced form of sensory processing disorder compared to both classic autism and Asperger’s syndrome. Even more important is anxiety. Several studies have confirmed that the anxiety among CDD is far more pronounced, significantly so. Unlike Asperger’s and classic autism, CDD shows anxiety that is always present.

The Overlooked Sensory Processing Disorders in CDD

When looking at sensory processing disorder among CDD, the parts that many forget to consider show clearly. When people think of sensory processing disorder, they tend to think of how it causes difficulties in processing auditory, visual, olfactory (smell), gustatory (taste), tactile (touch), and possibly even vestibular (balance) stimuli. However, most people are not aware of the difficulty in processing proprioception (body awareness) and interoception (internal body senses) sensory stimuli.

Sensory Processing Disorders

If you remember just a few moments ago, I mentioned motor skill difficulties as part of autism. However, if you look up the DSM-5 TR’s symptoms of autism spectrum disorder, you would think it is missing. This is because people tend to forget that this is exactly one of the less noticed parts of sensory processing disorder, which has to do with proprioception. Similarly, incontinence is a noteworthy symptom of autism, which again has to do with sensory processing disorder, in this case interoception.

The Importance of Interoception in Autism

Let me delve deeper into interoception. Incontinence is not the only result of sensory processing disorder among autists and aspies in regard to interoception. Interoception affects the ability of your brain to make sense of messages related to hunger, fullness, itching, pain, body temperature, nausea, the need for the bathroom, ticklishness, physical exertion, and sexual arousal. However, the most important function of interoception is allowing us to feel emotions.

It should not be hard to understand certain outcomes. One of the most notable examples is that many autistic people have weight problems, both in terms of obesity and anorexia. The reason for this is that there are multiple forms of sensory disorders that could result in this. In the case of obesity, it could be due to a lack of ability to feel fullness, but also a constant feeling of hunger. Many people do not realize that people with sensory processing disorder could experience this, which includes those with neurodevelopmental conditions like autism spectrum disorder, selective mutism, and ADHD.

Example of Sensory Processing Disorder in Autism

One of the clearest examples of sensory processing disorder is illustrated by a friend of mine who is diagnosed with autism spectrum disorder. When you pretend to tickle him by making hand movements, he would start laughing and ask you to stop tickling him. As confirmed by his family member, this could even lead to him peeing his pants. This is due to a cross-wiring of sensory stimuli that can happen in sensory processing disorder. In his case, the visual stimuli is processed as proprioception stimuli, leading his body to respond as if he were truly touched and tickled.

Similarly, he is someone who walks outside in just a t-shirt and jeans while it’s minus 10 degrees Celsius. It’s another side that many people won’t realize – the fact that sensory processing disorder not only causes over-responsiveness to sensory stimuli, but also, at times, little to no response to sensory stimuli. It’s unknown what the exact cause of this is.

Differences between Classic Autism, Asperger’s, and Childhood Disintegrative Disorder

Anyhow, CDD is notably different from both classic autism and Asperger’s, and yet it will still be regarded as closer to classic autism. The reason for this is that most symptoms of CDD are the same as classic autism, just more profound in some parts. And just like classic autism, CDD has the exact same differences compared to Asperger’s.

In this regard, there are quite a few autistic children and adults with classic autism and CDD diagnoses who oppose calling autistic people with an Asperger’s diagnosis “autistic.” And it’s completely understandable. When looking at the demographics of autistic people, the vast majority are in fact diagnosed with Asperger’s. Last time I checked, which was about 3 weeks ago, over 80% of all autistic people worldwide are diagnosed with an Asperger’s diagnosis. As I said, I am opposed to this grouping as well, and I’m on the spectrum too. The differences are too significant, leading to stereotypes. And stereotypes almost always lead to misunderstandings and hatred, as they do in this subject as well.

However, this is also exactly why it’s important for autistic people to not incorrectly claim that they have selective mutism. The condition is known to be rare, especially among autistic people. If you have this combination, it’s unlikely you are active on social media in the way many people are who claim to have this combination. You would be in constant fear that you would say something wrong… And I’m saying this even from personal experience!

The Correct Term for Mutism in Autism

However, isn’t there a correct term for mutism in autism? Of course, there actually is. While you won’t hear this term in psychology classes today, any experienced psychologist will quickly give you the answer: the name “selective mutism” was once known as “elective mutism”. Unlike selective mutism, elective mutism was specifically known for a continuous refusal to speak in almost all social situations. That’s the right term for mutism in autism, as recognized by many psychologists worldwide. Please do us all a favor and use that, (elective mutism,) or simply use “mutism”. Just as autistic people don’t want stigma, misunderstandings, and hatred, the same applies to people with selective mutism.