If you're a highly sensitive person (HSP), you may already know that high sensitivity is often compared to autism. This can be surprising—the signs of the two traits are very different. But both have been treated very similarly by the general public. Just as autism is now increasingly seen as a healthy trait, being an HSP is not a disorder, and it's a trait found in up to 20 percent of the population. Both also come with a ton of advantages. In the case of high sensitivity, that includes empathy, compassion, creativity, and the intuitive ability to see connections that others miss.
The similarities go deeper than that, however. 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 various 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.
The study also refers to autism as Autism Spectrum Disorder, and uses some language that I think many autistic people would disagree with. I'll just say up front that many people argue that autism is highly advantageous and should not be classified as a disorder at all; a fair amount of research agrees, including evidence that autism may correlate with high intelligence.
Acevedo and her team found three major differences between SPS and autism:
1. Autism comes with "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. (One reason for this may be that autistic individuals have very different body language than neurotypical individuals, and they don't get to "mirror" people with their own body language nearly as much as neurotypical children. In other words, this so-called "deficit" may be much more of a lack of opportunity than an innate part of autism.)
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 autism, however, experience social interactions differently. For them, Acevedo's study points out, 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. The study says this further affects their ability to respond appropriately to others.
Interpretation matters a lot here. To be clear, autistic individuals can and do form deep, meaningful relationships like anyone else. The difference is in how rewarding they find social interaction, in its own right. Whereas it's extra-rewarding for HSPs, it is less inherently rewarding for autistic people.
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 Acevedo found to be less active when it comes to the brain regions related to calmness, emotion, and sociability.
High Sensitivity Is Incorrectly Compared to a Variety of Disorders
High sensitivity is also sometimes compared — wrongly — to various mental health disorders. The 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 an 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 these things have almost nothing in common with being a highly sensitive person. Frankly, if you know any HSPs, you probably could have seen that one coming.
No, what's interesting is what else this study suggests. It doesn't just say 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.