New Research Changes Everything We Know About the Genes of HSPs

Scientists have a new way of finding the genes behind personality traits — and it might have just revolutionized the study of HSPs. 

If you’re a highly sensitive person, chances are you were born that way. In fact, one of the few things that all sensitivity researchers agree on is that being sensitive is not a choice, a quirk, or something you can put on and take off. It is heavily influenced by your genes, and while life experiences can make you more or less sensitive to a degree, your overall sensitivity level is the same throughout your life. 

Beyond that however, our knowledge of the genes involved in highly sensitive people (HSPs) has always been sketchy. For decades, scientists tried to link sensitivity to a specific gene or genes that would “explain” it — with often mutually contradictory results. 

It turns out that has changed. In fact, as I learned while researching our book Sensitive, coauthored by Jenn Granneman and myself, the entire way scientists approach genes has changed in the last few years — and it has been a treasure trove of discoveries for HSPs. 

To lean more, I spoke with Michael Pluess, one of the leading researchers who studies highly sensitive people. Here’s what I learned about the genes that do (and don’t) make you a highly sensitive person — and what it means for HSPs. 

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The “Sensitivity Gene” That Wasn’t

There is no single gene that “makes” someone an HSP. However, for the past 20 years or so, researchers have believed that a handful of genes play a particularly important role in how sensitive someone is. The most prominent of these is a particular variation on the serotonin transporter gene (SERT). One crucial area of this gene contains two lines of genetic code which can each be either “long” or “short.” HSPs may be more likely to carry the short/short variant. 

The short SERT gene has been widely studied but also widely misunderstood. At one time, it was considered to be a depression gene, where people with the short version are more likely to have anxiety and depression. Fascinatingly, ethnic and racial data proved this theory wrong: East Asians are statistically more likely to have the short SERT variant, but as neuroscientist Joan Chiao showed, eastern Asia actually has lower rates of depression than North America. Something wasn’t adding up.

Chiao’s finding led to a theory that the short SERT gene actually gives people an advantage in more “collective” minded culture but stresses them out in more “individualistic” cultures, and thus shapes the way cultures evolve. That theory is not widely accepted, either. (Putting aside the questionable connotations of assigning a “collectivist” mindset to Asians writ large, Pluess explained that it’s extremely unlikely that any one gene can play such a big role in shaping culture.) 

Over time, researchers have narrowed in on a more likely answer: the short SERT variant is best described as a “plasticity” gene. In other words, it contributes to having a stronger response to one’s environment in general. 

The plasticity theory makes sense when considering the sensitive Boost Effect — the tendency of highly sensitive people to rocket ahead of others in a good environment, while also struggling more than others in a stressful one. 

It also explains the previous findings about depression: yes, HSPs may be more likely to be depressed when in unsupportive environments, but may actually be “depression resistant” compared to others when given social support. (The short SERT gene is even linked to greater emotional resilience!)

However, neither the SERT gene nor the dozen or so other “sensitivity genes” paint the entire picture. In fact, as Pluess explains, they are only a drop in the bucket.

A New Approach to Genes — and High Sensitivity

Until recently, the only way scientists could study the genes behind a trait was to identify a handful of “candidate genes” and then do extensive testing on people who carry them. The process was slow, uncertain, and forced to focus only on one gene at a time. 

This method led to a large numbers of seemingly breakthrough discoveries such as the “God gene” (which supposedly determined how religious you are) and the “depression gene” discussed above. Often, further research went on to disprove the original discovery, or at least show that the picture was far more complex. For example, while some researchers have indeed found that HSPs are more likely to have the “short” SERT gene, other studies have found no link at all. And not everyone with the short version necessarily tests as highly sensitive. 

As Pluess explained to me, “Most human traits are too complex to be caused by a single gene.” It’s the reason you aren’t the exact same height as one parent and may not have their exact skin color. 

When I asked Pluess how many genes are involved, I expected the answer to be a couple dozen or so. I was not prepred for Pluess’s answer: “Oh, thousands.” 

It’s only in very recent years that scientists can evaluate those thousands of genes all at once. That’s because the cost of doing DNA analysis has dropped from astronomical to dirt cheap, at least by university standards (think of how affordable it is to test your own DNA to research your ancestry, for example). It’s also much faster. DNA can be analyzed in batches, and databases have been created where researchers can look for patterns in the DNA of tens of thousands of people at once.  

These advances have revolutionized gene research. As we explain in Sensitive, researchers can now scan the entire genome of a person, checking for millions of gene variants simultaneously. If this process is repeated across a large-enough sample size — drawn from those big DNA databases — researchers can identify the thousands of gene variants that Pluess said are involved in a single trait. None of these genes are enough, on their own, to turn a trait on or off, but they all contribute to it in some way. Thus, sensitivity — and most other traits — can be seen as a pattern that emerges across a person’s entire genome. The more your genome matches the pattern, the more sensitive you are.

This is called the “polygenic” approach, and it explains a lot. For example, it makes sense why some studies don’t find any link between highly sensitive people and the SERT gene at all — you don’t need the a particular SERT if you have 83 percent of the other sensitivity-related genes. In fact, you don’t need any particular gene to be an HSP — like pixels on a screen, many of the relevant genes can be missing and the overall picture is still clear. 

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Can a DNA Test Tell You Whether You’re a Highly Sensitive Person?

Researchers are continuing to validate and fine tune the genetic “pattern” of high sensitivity in human DNA — it’s a work in progress. However, the model they currently have is so accurate that Pluess says it matches or surpasses the accuracy of the HSP Scale, the test that psychologists, in identifying whether someone is a highly sensitive person.

In other words, researchers can already tell whether you’re an HSP just by looking at your DNA, without ever talking to you.

That kind of test is not currently included in any of the consumer-oriented DNA tests like ancestry kits. However, some tests will at least mention which version of the SERT gene you have, given its role in mental health. (If your DNA test offers you access to the raw data, you can also feed it into a tool like Promethease to drill down into your genes — the gene you are looking for is SLC6A4, and the variant is 5HTTLPR.)

Even though SERT is the most studied sensitivity gene, however, remember that it does not on its own make you an HSP — nor are you necessarily “low sensitive” without it. For now, a simple HSP test remains the best way to find out if you’re a highly sensitive person. You can take one here.

How Does ‘Nurture’ Affect the HSP Genes?

Pluess says that your early childhood environment also contributes to your sensitivity in a significant way. Based on twin studies, he told me, your exact sensitivity level is determined almost exactly fifty-fifty by your DNA and your upbringing. Each one plays a different role, however.

Loosely put, your genes determine which “ballpark” of sensitivity you’ll be in — highly sensitive, average, or low-sensitive. Your life experiences — especially in early childhood — then “fine tune” you up or down within that category.

In other words, if you’re born an HSP you will likely always be an HSP, and nothing any parent, gym teacher, or angry politician says can change that. But you can become slightly more or less sensitive even by HSP standards.

At this point, researchers even know which kind of childhood environment does what. Broadly speaking, children with the “best” (most supportive) and “worst” (most stressful or abusive) environments tend to become more sensitive. Sensitivity pays off in both extremes, helping you get more of a boost from supportive environments and stay more alert for danger in stressful environments.

Children with pretty “average” or middle of the road environments, by contrast, may become slightly less sensitive. But genes still lead the way, and you can be an HSP regardless of what kind of upbringing you had.

What Does the Research Means for HSPs?

These findings mean two big things for highly sensitive people:

1. You can use your environment to change yourself. 

Even though the SERT gene may not get the credit, “plasticity” or responsiveness is indeed the main theme of the HSP genetic pattern. This environmental responsiveness is core to all three types of highly sensitive people. Often, we HSPs see it as a drawback: we struggle more in rushed or overwhelming situations, we are hit harder by emotions, and we sometimes overthink things. But it’s actually a lever most people don’t have — one that gives you tremendous control over yourself.

As a highly sensitive person, you can use your environment to boost your mood, deal with stress, improve creativity or productivity, find peace and happiness, and even become more successful. The key is to think of environment writ large — not just having a calming room where you can de-stimulate (although yes, please do that) but to look at all the factors that influence your life, mood, and self-image. For example:

• Do your friends boost you up, and do they believe in your goals and abilities? 
• Does your job have a good work environment, or is it a toxic culture? 
• Are there activities in your life that were once fulfilling, but are now a burden? 
• Do you have mentoring, therapy, coaching, classes, or some other form of formal support giving you a leg up on your goals? These 

Each of these are things we often overlook, assuming that it’s hard to make new friends, we’re stuck at our job, or mentoring and instruction won’t really pay off. But the data is clear that highly sensitive people get far more benefit out of these types of support (so much so that one of Pluess’s own studies, covered here, found that HSP teens were nearly the only ones who got long-term benefit out of a depression treatment — less-sensitive kids got little effect at all.) 

2. You are more than your genes. 

We often think of all highly sensitive people as all fitting the same mold, but we’re not. You can be a sensitive person who is extremely physically sensitive but not really all that emotionally reactive. Or you might have very big emotions, but not feel at all like an “empath” who sponges up emotions. You might be very athletic and use your sensitivity to stay aware of all the players on the field, or you mighty be a homebody who uses it for crafts and creative projects, or you might be a bubbly extrovert who uses it to connect with people. (Importantly, you might be a natural leader and not even know it — or the very thought of leading people might make your skin crawl). 

The reality is, there are as many different ways to be a sensitive person as there are sensitive genes — more, in fact, because they can mix in so many different ways, and everyone’s life experience is unique. Yes, we all have environmental responsiveness, and we roughly fit into three loose, overlapping categories — but neither your sensitivity nor your genes determine who you are. You get to decide that yourself. 

You Might Like:

• These 3 Sets of Genes May Make You a Highly Sensitive Person
• There Are 3 ‘Types’ of HSPs. Which One Are You?
• The 4 Wildly Different Theories Researchers Use to Explain Highly Sensitive People

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