Genes by Condition

Genes Associated with ADHD.

Attention isn't just willpower. It's neurochemistry. Understanding the genes involved helps you support the system.

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Important reframe.

These genes don't "cause" ADHD. They reveal which neurotransmitter systems are more sensitive to environmental inputs. Same genes, different expression, different outcomes.

The genes.

ADHD genetics primarily involve dopamine, norepinephrine, serotonin, and circadian rhythm genes.

Dopamine System

Dopamine drives focus, motivation, and reward. Most ADHD medications target this system.

DRD4

Dopamine Receptor D4

Receives dopamine signals in the prefrontal cortex

Variant: 7-repeat allele associated with novelty seeking and ADHD

The 'explorer gene'—may have been advantageous for nomadic ancestors

DRD2

Dopamine Receptor D2

Major dopamine receptor in reward pathways

Variant: Taq1A variants affect receptor density

Lower receptor density may drive reward-seeking behavior

DAT1 (SLC6A3)

Dopamine Active Transporter

Clears dopamine from synapses

Variant: 10-repeat allele clears dopamine faster

Target of stimulant medications like Ritalin

COMT

Catechol-O-Methyltransferase

Breaks down dopamine in the prefrontal cortex

Variant: Val158Met affects clearance speed

Fast COMT may contribute to low prefrontal dopamine

Norepinephrine System

Norepinephrine regulates alertness, attention, and the stress response.

DBH

Dopamine Beta-Hydroxylase

Converts dopamine to norepinephrine

Variant: Low-activity variants reduce norepinephrine production

May explain why some respond better to norepinephrine-targeting meds

ADRA2A

Alpha-2A Adrenergic Receptor

Regulates norepinephrine release in prefrontal cortex

Variant: Associated with response to guanfacine/clonidine

Non-stimulant ADHD medications target this receptor

NET (SLC6A2)

Norepinephrine Transporter

Clears norepinephrine from synapses

Variant: Variants affect reuptake efficiency

Target of atomoxetine (Strattera)

Serotonin System

Serotonin affects impulse control, mood regulation, and emotional reactivity.

5-HTT (SLC6A4)

Serotonin Transporter

Clears serotonin from synapses

Variant: Short allele associated with emotional dysregulation

May explain ADHD-anxiety comorbidity

TPH2

Tryptophan Hydroxylase 2

Rate-limiting enzyme for brain serotonin synthesis

Variant: Variants affect serotonin production

Links ADHD to mood and impulsivity

MAO-A

Monoamine Oxidase A

Breaks down serotonin, dopamine, and norepinephrine

Variant: Low-activity variants associated with impulsivity

The 'warrior gene' in media—but context matters enormously

Circadian & Sleep

Sleep and circadian rhythm profoundly affect attention. Many with ADHD have delayed sleep phase.

CLOCK

Circadian Locomotor Output Cycles Kaput

Master circadian rhythm regulator

Variant: Variants associated with delayed sleep phase

Evening chronotypes more common in ADHD

PER2

Period Circadian Protein 2

Core clock gene affecting sleep timing

Variant: Affects morning vs evening preference

Circadian misalignment worsens ADHD symptoms

Neuroplasticity & Development

Genes affecting brain development and synaptic plasticity.

BDNF

Brain-Derived Neurotrophic Factor

Supports neuron growth, survival, and plasticity

Variant: Val66Met affects activity-dependent secretion

Exercise increases BDNF—one reason it helps ADHD

SNAP25

Synaptosome Associated Protein 25

Essential for neurotransmitter release

Variant: Associated with ADHD in multiple studies

Affects synaptic communication efficiency

The reframe.

The old narrative

  • ✗ADHD is caused by 'bad genes'
  • ✗These genes are defects to overcome
  • ✗Medication is the only solution
  • ✗ADHD brains are broken

The better frame

  • ✓These genes reveal dopamine/NE system vulnerabilities
  • ✓Many variants were advantageous in different environments
  • ✓Environment and lifestyle profoundly affect expression
  • ✓ADHD traits can be strengths in the right context

What actually matters.

Beyond medication, these factors profoundly influence ADHD symptom expression.

Sleep timing

Circadian misalignment dramatically worsens ADHD. Morning light exposure and consistent sleep schedules are foundational.

Exercise

Increases dopamine, norepinephrine, and BDNF. Often as effective as medication for symptom management.

Protein and tyrosine

Dopamine is made from tyrosine. Adequate protein intake supports neurotransmitter production.

Blood sugar stability

Blood sugar crashes devastate focus. Stable glucose = stable attention.

Screen hygiene

Constant dopamine hits from screens may be downregulating receptors. Dopamine fasting can help reset.

Iron and ferritin

Iron is a cofactor for dopamine synthesis. Low ferritin is common in ADHD and often overlooked.

The evolutionary perspective.

Many ADHD-associated gene variants were likely advantageous in ancestral environments. The DRD4 7-repeat "novelty-seeking" allele is more common in populations with nomadic histories.

ADHD traits as strengths:

  • • Hyperfocus when engaged
  • • Rapid context-switching
  • • High energy and drive
  • • Creative problem-solving
  • • Risk tolerance
  • • Novelty detection

"ADHD isn't a disorder of attention—it's a different distribution of attention."

Related patterns.

Slow Clearance Pattern

COMT variants affect dopamine clearance in the prefrontal cortex

COMT Gene

Deep dive into the worrier/warrior gene

Anxiety Genes

ADHD and anxiety share many genetic risk factors

Genes reveal the pressure points.

Understanding your genetic landscape helps you target support where it matters most.

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