Your child feels everything deeply. Their genes may explain why.

Serotonin is your child’s brain’s primary mood stabilizer and anxiety dampener. After serotonin does its job signaling between neurons, the SLC6A4 transporter pulls it back into the sending neuron so it can be reused. This recycling system keeps mood stable and keeps anxiety in check.

Children carrying the short allele of the SLC6A4 gene (5-HTTLPR short variant), present in roughly 40% of children, have a slower, less efficient transporter. That means serotonin stays in the space between neurons longer, which sounds good until you realize what actually happens: the signal becomes inconsistent, and your child’s brain struggles to maintain steady mood and anxiety dampening. This variant is directly linked to heightened anxiety reactivity and poor stress resilience, making your child more likely to spiral emotionally from smaller triggers.

For your child, this looks like: tears come faster, worried thoughts spiral, recovery from upsets takes much longer, and their nervous system stays on high alert. They may catastrophize small social interactions, worry excessively about things other kids let roll off, and have trouble “bouncing back” after an emotionally charged event. Their baseline anxiety is simply higher.

COMT is an enzyme that breaks down dopamine, norepinephrine, and epinephrine (the main stress hormones). After your child experiences something stressful, COMT should clear these hormones quickly so their nervous system can downshift and relax. When COMT works efficiently, your child recovers emotionally in a normal timeframe.

Children with the slow COMT variant (Val158Met), present in roughly 25% of European ancestry children, clear stress hormones much more slowly. That means after a trigger, epinephrine and norepinephrine stay elevated in your child’s body and brain longer than they should. Your child’s nervous system stays activated, their heart rate stays elevated, and their emotional reactivity persists even after the stressor is gone. It’s not that they’re overreacting, it’s that their chemistry hasn’t reset yet.

For your child, this feels like: they get activated from a social conflict or scolding, and hours later they’re still upset, still thinking about it, still tense. They may seem irritable or moody, not because of the original trigger anymore, but because their stress hormones are still circulating. They struggle to transition between activities. They’re sensitive to loud noises and surprises. Their nervous system is like a car that takes longer to downshift from high RPM.

MAOA is an enzyme that breaks down serotonin, dopamine, and norepinephrine in your child’s brain. When MAOA works efficiently, it maintains a stable level of these neurotransmitters so mood stays even. When MAOA is overactive or underactive, neurotransmitter levels fluctuate, and your child’s emotional state becomes unpredictable.

Children with the MAOA-L (low activity) variant, present in roughly 30 to 40% of males, metabolize these neurotransmitters more slowly. This causes serotonin, dopamine, and norepinephrine to accumulate and then drop unpredictably. Your child’s mood and emotional reactivity become inconsistent: they may be fine one moment and then suddenly upset, aggressive, or withdrawn as neurotransmitter levels spike and crash. This isn’t them “overreacting” to the moment, it’s their brain chemistry cycling through peaks and valleys.

For your child, this manifests as: sudden mood shifts that seem disconnected from what’s happening around them, unpredictable irritability or anger, difficulty maintaining emotional consistency, and periods where they seem to spiral emotionally for no clear external reason. A good day can turn bad in minutes. They may seem fine and then suddenly be in tears or in a rage. It’s exhausting because you can’t always predict when the emotional storm will come.

BDNF (brain-derived neurotrophic factor) is like fertilizer for your child’s brain. It strengthens neural connections, enables learning, and builds the brain’s ability to adapt and recover from stress. Children with high BDNF can “bounce back” emotionally because their brain is literally rewiring itself to handle stress better each time they experience it.

Children carrying the BDNF Met66 variant, present in roughly 30% of the population, produce less BDNF in response to activity and stress. Their brains have less “fertilizer” available to strengthen the circuits that regulate emotion and build resilience. This variant impairs activity-dependent BDNF secretion, meaning your child’s brain struggles to use stress and challenge as an opportunity to become more resilient. Instead of each difficult experience making them slightly stronger, they stay stuck at their baseline emotional capacity.

For your child, this looks like: slow recovery from emotional setbacks, difficulty “learning” emotional regulation through repeated practice, poor stress resilience despite having coping strategies, and feeling emotionally worse after therapy or coaching (because they’re not building new resilience through the process). They seem emotionally fragile. They don’t seem to get better with exposure or experience the way other kids do.

GABA is your child’s brain’s natural brake pedal. It dampens neural firing, slows down the stress response, and creates a sense of calm. GAD1 is the enzyme that synthesizes GABA, so if GAD1 isn’t working well, your child’s brain doesn’t have enough inhibitory tone. The nervous system runs too “hot,” and anxiety and emotional reactivity become the baseline.

Children with GAD1 variants that reduce enzyme activity, present in roughly 20 to 30% of the population, produce less GABA. Their brains have a weaker brake system, so the accelerator (excitatory neurotransmitters) runs unchecked. Without sufficient GABA to calm the nervous system, your child exists in a state of higher baseline activation, and their threshold for emotional overwhelm becomes lower. Everyday stimuli feel more intense, transitions are harder, and they’re more easily pushed into dysregulation.

For your child, this feels like: persistent low-level anxiety even when nothing is wrong, difficulty “turning off” their brain, high sensitivity to sensory input (lights, sounds, textures), trouble sleeping because their mind won’t quiet, and a tendency to become emotionally flooded more easily than peers. They may describe feeling “wired,” unable to relax, or “always thinking.” Their nervous system is simply running at a higher baseline state of activation.

Cortisol is the primary stress hormone. When your child faces a challenge, cortisol rises, then should fall back to baseline once the stress passes. FKBP5 helps your child’s brain “hear” and respond to cortisol signals, so the stress response can be switched off. When FKBP5 works well, cortisol rises briefly and then resets. When it doesn’t, cortisol stays elevated and the stress response lingers.

Children with the FKBP5 rs1360780 variant, present in roughly 30% of the population, have reduced glucocorticoid receptor sensitivity. Their brain doesn’t respond as well to signals telling it “the danger is over, reset cortisol now.” This means after a stressor, your child’s cortisol stays elevated much longer than it should, keeping their nervous system in a prolonged state of vigilance and emotional reactivity even after the trigger is gone.

For your child, this manifests as: slow recovery from emotional upset, persistent anxiety even after the stressor is removed, a feeling of dread or unease that lasts for hours after an event, difficulty “letting things go,” and a pattern of emotional sensitivity that seems tied to cumulative stress rather than single triggers. They may seem fine during a stressful event and then fall apart afterward as the cortisol buildup hits them. Their emotional wellbeing is directly tied to their stress load.