We’re all different, each and all uniquely our own. And yet, we find connection and sense of place in those moments of sameness, consistency, and mutual recognition. And so it is with a unique segment of the population known as Highly Sensitive. Different from the majority. Recognizable precisely for their differences. And, because of more than one brain difference of Highly Sensitive People, often struggling to find its place.

Brain differences of Highly Sensitive People (HSP) can make navigating life challenging…exhausting…and lonely.

Emotional intensity, after all, isn’t a comfort zone for most.

(Not sure if you’re an HSP? Take this quiz.)

High sensitivity (HS) is a trait reserved for a minority who are, without choice, steeped in thought, feeling, and a propensity for overwhelm and/or anxiety. 

The absence of choice in this cognitive and emotional intensity comes down to more than one actual brain difference of Highly Sensitive People.

High Sensitivity is a trait, scientifically known as Sensory Processing Sensitivity. It’s innate to the HSP’s neurological makeup – an intensification of features already present.

What High Sensitivity is not is a flaw, disorder, or mental health condition. It has nothing to do with “something missing,” “something misfiring,” or “something disconnected.”

If anything, the brain differences of Highly Sensitive People that set them apart is enhanced activity in specific parts of the brain. 

Instead of having the convenience of neurological filtering in the face of high stimulation, for example, the HSP’s brain will register all incoming stimuli. 

The result?

A brain that is always on. 

And that means deep processing, a vulnerability to overstimulation/overwhelm, emotional sensitivity/empathy, and sensory sensitivity.

In the language of High Sensitivity, “DOES.”

To understand the brain difference of Highly Sensitive People, let’s break the trait down using this convenient acronym.

Depth of Processing

HSPs are deep thinkers, taking in lots of sensory information and nuance from the environment. They’re often highly conscientious and insightful and need time to reflect.

The reason? Highly Sensitive People have increased brain activity in the parts of the brain responsible for cognition, attention, emotional information processing, and sensory processing.

More specifically, brain scans indicate that the insula, which controls perception and awareness, is more active in the HSP’s brain compared to the brain of someone without the trait. 


HSPs are often highly impacted by input from their senses. As a result, they may be easily overwhelmed. 

High stimulation can be pleasurable (e.g. from the scent of a lilac) or aversive (e.g. from the odor of spoiled milk). 

The overstimulation can occur as a result of high (e.g. the sound of a jackhammer) or low (e.g. the sound of the faucet dripping) intensity.

Overstimulation can occur as a result of social, physical, or emotional stimuli. 

Social overstimulation could occur at a loud venue (AC/DC concert, no thank you), at a crowded party (please stay out of my personal space!), or in a hot environment (get me out of this sauna!).

Environmental overstimulation for HSPs could be triggered, for example, by bright lights, changes in barometric pressure, or cigarette smoke.

Emotional overstimulation could occur when viewing a campaign to feed starving children in Africa or when Sarah McLachlan asks viewers to help save abused and neglected animals. 

And none of this overstimulation has anything to do with choice, weakness, or a manipulative plea for attention or sympathy.

HSPs take in a colossal amount of sensory information because their brains never really turn off.

Emotional Intensity/Empathy

HSPs tend to respond to both positive and negative events with more emotion than people without the trait do. 

They may naturally soak in other people’s moods and intentionally avoid violent movies and programming.

The reason? You guessed it! The brain difference of Highly Sensitive People. 

Namely, the HSP has increased activity in those brain structures that process emotions.

Sensory Sensitivity/Environmental Subtleties

Because of how sensory information is processed in the brain, HSPs are highly perceptive. They notice things that other people simply do not.

This isn’t a function of the input itself, but of the way the brain processes the input.

If you want to know if there has been a one degree change in temperature, ask an HSP! They have more neural activity when it comes to small environmental changes than large environmental changes.

All features in the “DOES” framework are due to a brain difference of Highly Sensitive People.

Central Nervous System 

Senses are processed in the central nervous system (CNS), which comprises the brain and spinal column.

Through the use of fMRIs, researchers have identified that HSPs experience the world the way they do because of how much activity occurs in different parts of the CNS. 

Because of the depth and sheer amount of stimulation processing, the HSP’s brain structures are more active overall.

It’s kind of like having a lot of tabs open on your computer. You’d probably expect whatever you’re doing to glitch and/or respond more slowly until you close some tabs. 

There is just so much data processing in the HSP’s CNS, just as there is if too many tabs were open on your computer.

Gene Variants

The three gene variants that are responsible for the brain difference of Highly Sensitive People are serotonin, dopamine, and norepinephrine.

1. Serotonin is a neurotransmitter and hormone that helps neurons communicate with each other. Its main function is to stabilize mood.

HSPs have a variant of the serotonin transporter encoding gene, known as 5-HTTLPR

The 5-HTTLPR gene variant decreases serotonin in the brain and increases sensitivity to surroundings.

While the HS brain may have less mood-stabilizing serotonin than the non-HS brain, it does have an enhanced ability to learn from experience.

The presence of this gene variant enhances the effects of both good and adverse childhood experiences. It’s this equal-opportunity intensification that helps to explain why childhood experiences – both positive and difficult – so dramatically impact wellbeing for HSPs.

2. Dopamine is known as the reward chemical.

If you have a sensitive CNS, you don’t need much dopamine to feel “rewarded” by external stimuli. 

“Reward,” however, isn’t necessarily a favorable thing in this context.

Chaotic, noisy environments, for example,  will probably exhaust rather than excite you.

Carry that reality over to a loud football stadium, and you and your non-HS friends will likely have very different experiences. Their tolerable “dopamine hit” will probably register as unsettling for you.

The explanation for this difference lies in the variant-based higher sensitivity of dopamine receptors in the HSP brain.

As an HSP, you simply don’t need the same amount of “reward” from external stimuli to feel its effects.

3. Norepinephrine helps the body with the stress response.

It’s also important in the perception of emotional aspects in the world.

A variant of the norepinephrine gene, common in HSPs, boosts emotional vividness. If you have it, you experience emotional aspects of the world intensely.

As mentioned earlier, HSPs have more going on in parts of the brain that create internal emotional responses to experiences.

HSPs naturally respond more strongly to emotions than non-HSPs do. They also notice emotional subtlety when others don’t even blink an eye.

The ability to perceive emotional nuances – to really feel what others are feeling but not necessarily overtly expressing – is the basis for empathy.

If you’re Highly Sensitive, the norepinephrine gene variant may be at least partly responsible.

4. Mirror neurons are brain cells that help us understand what someone else is feeling. They’re involved in recognizing emotions and relating to them. 

HSPs have more active mirror neurons, which explains their super-sized capacity for empathy.

Because of how active their mirror neurons are, HSPs absorb emotions from people around them. Often they’re not even aware they’re doing so.

Blessing or Curse?

High Sensitivity is real, and the Highly Sensitive Person’s brain is a gift. 

The HSP brain allows for deep reflection, creativity, and sincere compassion for people, animals, and the environment.

We have proof from science that HS is associated with certain genes and patterns of brain activation. It’s not just hypothetical or theoretical.

If you’re Highly Sensitive, you are among the 15-20% of the population who have a built-in superpower. 

Self-knowledge is essential.

So learn about your trait, embrace it, and use it to thrive.

Dr. Elayne Daniels is a Boston-based psychologist and international coach whose mission is to empower HSPs to live and love their authentic way of being in the world.