Do Highly Sensitive People Have Autism?

New research suggests that not all sensitivity is the same.

Posted May 28, 2019

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If you're a highly sensitive person (HSP), you may already know that high sensitivity is often compared to autism. This can be surprising—after all, being an HSP is not a disorder, and it's a trait found in up to 20 percent of the population. It even comes with a ton of advantages, such as empathy, compassion, creativity, and the intuitive ability to see connections that others miss. Comparing it to autism spectrum disorder (ASD) can seem misplaced.

But there are some similarities. For example, both autism and being an HSP can involve extreme sensitivity to your environment. Any highly sensitive person understands what it's like to have the world "turned up too loud," and many autistic individuals have that same experience—especially about seemingly "small" stimuli, like the rub of clothing texture or an intrusive noise.

Likewise, both HSPs and individuals with autism tend to get overwhelmed by environmental stimuli. Autistic children, for example, may panic, have a tantrum, or "shut down" in response to overwhelming stimuli, and many HSP children will do the same thing when they get overstimulated, especially if their parents haven't taught them good strategies to avoid overwhelm.

But, despite those similarities, autism and high sensitivity are two different things. Not only that, but a recent study shows they are profoundly different—and that high sensitivity is also unrelated to other disorders, such as schizophrenia and PTSD. It suggests that being a highly sensitive person is a normal, healthy trait.

Here's what the study found, and what it means for highly sensitive people.

What Makes Autism Different From High Sensitivity?

The study, led by Dr. Bianca Acevedo of the Neuroscience Research Institute of the University of California, is an exhaustive analysis of 27 papers comparing high sensitivity, autism, and other conditions. (You can read the full study here.) It refers to high sensitivity by its formal name: Sensory Processing Sensitivity or SPS.

Acevedo and her team found three major differences between SPS and autism:

1. Autism comes with major social deficits; high sensitivity does not.

Acevedo's research noted that autism comes hand-in-hand with so-called "social deficits," such as difficulty making eye contact, recognizing faces, responding to others' emotional cues, and reciprocating another person's intentions (think of smiling back at someone who smiles at you). For autistic individuals, the social deficits are obvious as early as two or three months of age, and they're directly tied to how an autistic person's brain works—they tend to show less response in brain areas associated with empathy, social cues, and self-reflection.

For SPS or high sensitivity, exactly the opposite is true. Highly sensitive people don't show social deficits; in fact, they tend to be highly responsive to social cues, facial expressions, and the intentions of others. Likewise, the same areas of the brain that are less responsive among autistic individuals tend to be very active for HSPs, who present high levels of empathy, social awareness, and self-reflection.

2. For highly sensitive people, social situations are (extra) rewarding.

Human beings, in general, are wired to find social interactions rewarding. This encourages us to form strong bonds, help each other out, and cooperate with one another; it's always been a key to our survival. Highly sensitive people are no exception, and may even respond more strongly to social interactions than others do—feeling anywhere from calmed to downright jubilant about a positive interaction.

People with ASD, however, are the exception. For them, there simply isn't as much of a sense of reward, calmness, or emotion involved in socializing. An exchange with another person may get their attention, but not necessarily feel meaningful. This further affects their ability to respond appropriately to others.

3. Their brains handle stimuli in dramatically different ways.

Given that both HSPs and autistic individuals can be extremely sensitive to stimuli, it's no surprise that they do share some areas of high brain activity in common—specifically areas related to attention and reacting (physically or mentally) to stimuli. But that's about where the similarities in brain activity end.

The highly sensitive brain, for example, shows higher-than-typical levels of activity in areas related to calmness, hormonal balance, self-control, and even self-reflective thinking (the ability to process one's own actions and feelings and come to deeper conclusions about them). These go hand-in-hand with a greater level of empathy and depth of processing that define high sensitivity. All of these are either positive, useful traits or can be good or bad depending on the situation.

And all of them contrast starkly with the autistic brain, which is impaired when it comes to the brain regions related to calmness, emotion, and sociability.

(Notably, there are many autistic individuals who argue that autism is also a healthy, positive trait, and should not be classified as a disorder. And some researchers agree it can be advantageous.)

High Sensitivity Is Incorrectly Compared to Other Disorders, Too

Autism is not the only clinical disorder that's sometimes compared to high sensitivity. Other big ones are schizophrenia and post-traumatic stress disorder (PTSD). These two conditions have little in common on the surface (with each other or with being HSP), but all of them can involve increased sensitivity to sensory stimuli.

Acevedo and her colleagues delved into these disorders, too—and it turns out that none of them are connected to high sensitivity.

For starters, schizophrenia has even less in common with high sensitivity than autism does. Like autism, it comes without any of the increased empathy or self-reflection that HSPs exhibit, and unlike autism, it has almost nothing in common with high sensitivity when it comes to brain activity. (Also, although not mentioned in the study, unmanaged schizophrenia almost inevitably causes major problems in a person's life and relationships; high sensitivity does not.)

PTSD is a bit trickier, because highly sensitive people may be at higher risk of developing PTSD if they go through some kind of trauma. But PTSD patients show none of the enhanced activity in areas related to calmness, self-control, or social awareness that highly sensitive people show, and they suffer a variety of symptoms that HSPs without trauma do not. Disruptions in a PTSD sufferer's brain, for example, tend to affect their memory and their ability to integrate new information. These abilities—and the capacity to process information in general—are actually strong points for a highly sensitive person.

High Sensitivity May Be an Evolutionary Advantage

It makes sense why researchers would look for a connection between these various traits and disorders. After all, if they all involve some kind of increased sensitivity, it's worth checking whether they work the same way in the brain—especially if that could help people.

What's fascinating about this research, however, isn't just that it showed that being a highly sensitive person has almost nothing in common with these disorders. Frankly, if you've spent any time talking to HSPs, you probably could have seen that one coming.

No, what's interesting is what else this study suggests. It doesn't just reaffirm that being an HSP is "healthy" or "normal." Rather, at every step, it practically trips over the fact that high sensitivity is strongly beneficial. Being an HSP comes with heightened brain activity in useful brain regions; a strong association with desirable personality traits; and even a tendency toward positive, useful, prosocial behavior.

I think the study's own conclusion says it best: "We suggest that adaptive SPS strategies involving empathy, awareness, calmness and physiological and cognitive self-control may serve a species by facilitating deep integration and memory for environmental and social information, which may ultimately foster survival, well-being, and cooperation."

In other words, your high sensitivity might be an evolutionary advantage—one that helps our entire species.

This post originally appeared on Highly Sensitive Refuge, a community for HSPs.