What you carry at this position in your DNA and what research says about it.
Attention and Food Cravings: 5/10 evidence, 28 publications.
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Sample genotype (not yours): G/G
Higher Inattention and Stronger Sweet Cravings
This genotype is linked to reduced receptor expression, which may increase the risk of inattention and cravings for sweet foods. It also correlates with a higher susceptibility to motion sickness and specific medication sensitivities.
What this genotype means: Higher risk of inattention; Increased cravings for sweet foods; Elevated susceptibility to motion sickness.
Sample genotype (not yours): C/C
Typical Attention Span and Lower Cravings
This genotype is associated with optimal receptor expression, supporting typical attention control and a lower likelihood of intense sweet cravings. It also offers protection against motion sickness.
What this genotype means: Typical attention control; Lower likelihood of sweet food cravings; Reduced susceptibility to motion sickness.
Sample genotype (not yours): G/C
Variable Attention and Medication Responses
Carrying one copy of the G allele presents a mix of typical behavioral traits alongside unique sensitivities to certain medications. It represents an intermediate genetic profile for adrenergic receptor expression.
What this genotype means: Typical risk for sweet cravings; Better response to certain ADHD medications; Increased risk of antipsychotic-induced weight gain.
Gene function and biological role
Gene Function: The ADRA2A gene encodes the alpha-2A adrenergic receptor, a key protein that regulates the release of norepinephrine in the central and peripheral nervous systems [1]. This receptor is highly concentrated in the prefrontal cortex, a brain region critical for attention, executive function, and impulse control [2]. By modulating norepinephrine levels, the receptor helps fine-tune cognitive processes and coordinates the body's physiological responses to stress [1]. It also plays a role in metabolic processes, including insulin secretion and fat cell regulation [3]. Variations in this gene can alter receptor density and signaling efficiency, influencing behavioral traits and medication responses [1].
Variant Impact: The rs1800544 variant, also known as C-1291G, is located in the promoter region of the ADRA2A gene, where it directly influences how the gene is expressed [4]. Carrying the G allele is associated with significantly lower baseline levels of ADRA2A mRNA, leading to reduced receptor density in key brain areas. This reduction in receptor availability alters norepinephrine signaling, which can impact attention span, food preferences, and autonomic responses like motion sickness [5]. Additionally, this promoter change modifies how the receptor interacts with various psychiatric and anesthetic medications [6].
Read on the Motion Sickness page
Key Insight: The same genetic variant that influences attention span and ADHD medication response also plays a surprising role in determining your susceptibility to motion sickness and your cravings for sweet foods.
Location: ADRA2A. Chromosome 10 · 10q25.2 · 111.1 Mb
Estimated prevalence by population
Global 20.5%; European 6.9%; African 46.3%; East Asian 45.1%; South Asian 29.1%; Americas 14.2%; Ashkenazi 7.8%; Finnish 5.1%; Middle Eastern 14.3%; Amish 5.7%.
Estimated GG genotype frequency.
Global 41.2%; European 38.8%; African 43.5%; East Asian 44.1%; South Asian 49.7%; Americas 47.0%; Ashkenazi 40.2%; Finnish 34.9%; Middle Eastern 47.0%; Amish 36.3%.
Estimated GC genotype frequency.
Global 38.3%; European 54.3%; African 10.2%; East Asian 10.8%; South Asian 21.2%; Americas 38.8%; Ashkenazi 52.1%; Finnish 60.1%; Middle Eastern 38.7%; Amish 58.1%.
Estimated CC genotype frequency.
Showing effects for G/G genotype
Neurology & Mental Health
Memory, Learning & Attention
Inattention. Evidence: 3/10. Source: PMID 19922756. Increased Risk.
Behavioral & Personality Traits
Sweet Food Cravings. Evidence: 3/10. Source: PMID 17522710. Higher Consumption.
Organ Systems
Hearing & Balance
Motion Sickness. Evidence: 5/10. ~2x Higher Risk.
Pharmacogenomics
Antidepressant & Psychiatric Drug Response
Antipsychotic Weight Gain. Evidence: 5/10. Source: PMID 27217270. Increased Risk.
ADHD Drug Response. Evidence: 4/10. Source: PMID 19150055. Stronger Response.
Showing effects for C/C genotype
Inattention. Evidence: 3/10. Source: PMID 19922756. Typical.
Sweet Food Cravings. Evidence: 3/10. Source: PMID 17522710. Typical.
Motion Sickness. Evidence: 5/10. Typical.
Antipsychotic Weight Gain. Evidence: 5/10. Source: PMID 27217270. Typical Risk.
ADHD Drug Response. Evidence: 4/10. Source: PMID 19150055. Typical Response.
Showing effects for G/C genotype
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Having two copies of the G allele is associated with lower baseline expression of the alpha-2A adrenergic receptor in the brain. This reduction in receptor availability can lead to higher scores of inattention and hyperactivity, particularly during adolescence [1]. Research indicates that individuals with this genotype tend to consume significantly more sweet food products, suggesting a link between adrenergic signaling and dietary preferences [2]. Furthermore, this genotype is associated with a nearly twofold increase in the risk of motion sickness and vomiting during travel. In clinical settings, children with this genotype often show a more pronounced response to methylphenidate for ADHD, though they may also experience greater variability in their cognitive response times [3] [4].
Higher risk of inattention; Increased cravings for sweet foods; Elevated susceptibility to motion sickness.
Sample genotype: CC (Homozygous)
Carrying two copies of the C allele is associated with standard baseline expression of the alpha-2A adrenergic receptor. This optimal receptor density supports stable norepinephrine signaling, which is linked to typical attention spans and a lower risk of hyperactivity [1]. Individuals with this genotype generally report fewer intense cravings for sweet foods and a lower overall consumption of sweets compared to G allele carriers [2]. Additionally, this genetic profile provides natural protection against motion sickness, with a significantly lower incidence of travel-induced nausea and vomiting. While individuals with this genotype may show a more standard, less pronounced response to methylphenidate, they also maintain more consistent cognitive performance [3].
Typical attention control; Lower likelihood of sweet food cravings; Reduced susceptibility to motion sickness.
Sample genotype: GC (Heterozygous)
This heterozygous genotype provides a balanced genetic profile, resulting in intermediate levels of alpha-2A adrenergic receptor expression. Individuals carrying one G allele generally do not experience the elevated risk of sweet cravings or severe motion sickness seen in the GG genotype [1] [2]. However, they do share an increased likelihood of weight gain if prescribed certain antipsychotic medications [3]. On the positive side, this genotype is associated with a more favorable response to ADHD treatments like methylphenidate [4]. Additionally, some studies suggest a better therapeutic response to specific antidepressants, such as SSRIs and milnacipran, compared to those with other genetic profiles [5].
Typical risk for sweet cravings; Better response to certain ADHD medications; Increased risk of antipsychotic-induced weight gain.
Variants with shared genetic architecture
rs10885122 · ADRA2A Gene · Chr 10 · Fasting Blood Sugar
rs553668 · ADRA2A Gene · Chr 10 · Type 2 Diabetes Risk
rs4916723 · LINC00461 Gene · Chr 5 · ADHD and Autism Risk
Association analyses of adrenergic receptor polymorphisms with obesity and metabolic alterations.
Content updated August 2026.
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