You're Oversensitive, and Your Genes May Be Why.

COMT is an enzyme that breaks down dopamine, norepinephrine, and epinephrine in your prefrontal cortex. It’s your brain’s volume control knob for arousal and focus. When COMT is working well, you clear these stress chemicals at a steady pace and your nervous system stays calm and regulated.

But if you carry the Val158Met variant (specifically if you’re homozygous for Val, the fast version, or heterozygous), you have a slower version of the enzyme. Roughly 25% of people of European ancestry carry the slow homozygous variant. A slower COMT means dopamine and stress hormones accumulate in your prefrontal cortex, keeping your brain in a chronically heightened state of arousal.

You notice this as a hair-trigger nervous system. Unexpected sounds startle you easily. You feel jittery after caffeine when others don’t. You’re quick to feel anxious in social situations. Your thoughts race. You find it hard to ‘switch off’ at the end of the day. Crowded or unpredictable environments feel particularly overwhelming.

SLC6A4 encodes the serotonin transporter, the protein that recycles serotonin back into nerve cells after it’s been released. Think of it as the recycling bin for your mood buffer. When serotonin is recycled efficiently, you feel emotionally stable and less reactive to social and environmental stress.

The 5-HTTLPR short allele variant of this gene impairs serotonin recycling. Approximately 40% of the population carries at least one short allele. With the short variant, serotonin stays outside the cell longer, but you also have less serotonin available overall, leaving you more emotionally reactive and socially sensitive.

You notice this as heightened sensitivity to social cues. You pick up on subtle tension in a room or in someone’s voice. You feel rejected more easily. Criticism stings more. You’re more likely to cry during movies or sad conversations. Crowded social situations leave you feeling drained because you’re unconsciously processing everyone’s mood and energy.

MTHFR encodes an enzyme critical for the methylation cycle, the biochemical pathway that produces SAM-e, the universal methyl donor in your body. One of SAM-e’s key jobs is regenerating neurotransmitter synthesis and balancing your nervous system. When methylation is slow, your nervous system struggles to maintain adequate serotonin, dopamine, and other calming neurotransmitters.

If you carry the C677T variant (and especially if you’re homozygous), your MTHFR enzyme is less efficient at this conversion. Roughly 30-35% of people carry the homozygous C677T variant. Inefficient methylation means your nervous system can’t produce or recycle neurotransmitters fast enough to buffer sensory input, leaving you hyperresponsive.

You experience this as a nervous system that feels rawer than others’. Sensory stimuli hit harder. You have trouble recovering your mood after a stressful or overstimulating event. You might feel foggy or anxious despite sleep. You may have a history of depression or anxiety that doesn’t respond well to standard antidepressants.

BDNF is brain-derived neurotrophic factor, a protein that supports the survival of existing neurons and encourages growth of new neurons and synapses. BDNF is essential for your brain’s ability to adapt to new situations and recover from stress. When BDNF is high, your nervous system is flexible and can habituate to stimuli over time.

The Val66Met variant reduces BDNF activity. Approximately 30% of the population carries the Met allele. Lower BDNF means your nervous system is less able to adapt and habituate to repeated stimuli, so you stay in a state of heightened sensitivity longer.

You notice this as an inability to ‘get used to’ things. The sound of your roommate’s keyboard typing bothers you as much on day 100 as day 1. You don’t habituate to fluorescent lights or office environments. You recover more slowly from overwhelming situations. You may feel stuck in anxiety patterns even after the threat has passed.

ADORA2A encodes the A2A adenosine receptor, which sits on neurons and dampens their firing when adenosine (a sleep-promoting molecule) binds to it. This receptor is your nervous system’s brake pedal. When adenosine receptors work well, they keep your neurons from firing too easily and too often.

The rs5751876 variant (specifically the C/C genotype) reduces the effectiveness of these receptors. Roughly 10-15% of the population carries the C/C variant. With this variant, your neurons fire more easily and your threshold for sensory stimulation is lowered, making you acutely sensitive to sound, light, and social stimuli.

You experience this as a nervous system that seems to have no off switch. Small amounts of caffeine have outsized effects. Your heart races easily. You startle at sudden sounds. You feel ‘wired but tired.’ You may have been told you have anxiety when really your neural firing threshold is just set lower than average.

FKBP5 encodes a protein that sits on cortisol receptors and regulates how responsive they are. When FKBP5 works well, your cells hear the ‘all-clear’ signal from cortisol and your nervous system downregulates after stress. This is how you recover.

The rs1360780 variant impairs this feedback loop. Roughly 30% of the population carries this variant. With FKBP5 variants, your HPA axis (the stress response system) stays activated longer after a stressor, meaning cortisol remains elevated and your nervous system stays in alarm mode well past when the threat is gone.

You notice this as slow recovery from sensory overwhelm. After a loud event or crowded situation, you feel shaken for hours. Your heart rate takes a long time to come down. You feel physically exhausted after social interaction. You may replay mildly stressful conversations over and over. You’re more vulnerable to burnout because small stressors accumulate instead of being cleared.