The Genetics of ADHD

The genetics of ADHD and Inattentive ADD is in it's infancy but the information that has been gathered thus far is Interesting.   Several types (genotypes to be specific) of the DRD4 gene and the DAT1 gene have been found to be associated with ADHD and Inattentive ADD. These ADHD genes comes in various allele forms and certain alleles of the DRD4 and DAT1 gene may also be associated with spatial perception problems, sequential learning, symptomatic response to Ritalin, working memory and sustained attention.  

The ADHD genetic data is far from straightforward. There is definitely an association between these genes and ADHD, that is not in question, the role that these genes play in symptoms of ADHD is where the answers start to become confusing. The reason for this appears to be that these genes do not just influence the brain in one set manner.  These genes appear to interact with other genes, with each other, with individual biological brain enzymes and other factors as well as with environmental factors.  Given all of these interactions and  influences, it is a miracle that we know anything at all about ADHD genetics.

Luckily for us, behavioral geneticist are a persistent bunch and every day a new study is published that reports that a certain genotype of one gene or another is associated or linked somehow to a specific learning difficulties.  Mapping out what the DRD4 and DAT1 gene alleles contribute to the ADHD picture is a monumental effort but progress has been made.

According to a report in the Archives of General Psychiatry, for example, not everyone with ADHD has spatial problems but people that have the Homozygous DAT1 Haplotype are likely to have deficits is reorienting especially for spatial targets in the left visual field.

A study from the Journal Behavioral Genetics which was just published this month found that  the 10 repeat allele of the DAT1 gene was associated in Korean children with a poor response to Ritalin.  In this study only 28% of children with this DAT1 allele showed a positive response to Ritalin.  These finding have not been replicated in adults but some physicians have suggested that genetic testing prior to dispensing medication for ADD might lead to improved symptom response and to better medication compliance.

Some, but not all studies have found an association with DAT1 and the ADHD disorders not associated with conduct disorders (such as Inattentive ADD).  These genetic finding may explain why people with Inattentive ADD can have a poorer clinical response to Ritalin and why they can have increased problems with spatial orienteering.  

The DAT1 and DRD4 genetic study findinga vary by country of origin and these genetic findings are, as mentioned before also influenced by environmental factors.  One recent study found that these genes were especially sensitive to environmental stressors but were also especially responsive to environmental support.

Our genetic background may explain many of our ADHD symptoms.  I have a horrible sense of spatial perception and find myself lost in parking lots more often than I care to admit.  My spouse marvels at my approach to assembling toys or Ikea furniture.  I cannot even look at the instructions, they are like gobbly-gook to my brain.  I must look at the picture of the finished product, hold the pieces in my hands and work with them to fit them together.  The results often tend to be functional though I will not comment on the appearance of these assembled projects.

It appears, from some of the ADHD genetic studies published so far,  that this lack of spatial orientation fluency may be related to my ADHD genes.  The very best news here is that our genes are not our destiny.  Environmental factors can improve the behavior of these genes and there are other specific strategies that help with these spatial deficits as well (listening to a Mozart Sonata may help spatial orienteering, for example).   

I have tried listening to Mozart while assembling my Ikea furniture and the music just made we want to forget about the furniture and have a glass of wine.  My spatial orienteering inadequacies appear hopeless.  Luckily I never had my heart set on a career as a neurosurgeon, architect or space aviator.

I would love to hear about your spatial orientation and any strategies that you might have that have helped you find your car in large parking lots.  Write a comment and let us know?  


  1. My technique for finding my car in the parking starts when I get out of the car. In my mind I draw a line perpendicular with my car and a landmark on the building or location that I am visiting. When exiting I find my landmark on the building and reverse the perpendicular line back to the car.

    I read instructions and manuals before attempting any project. Needless to say I have to reread them again to figure out where the leftover parts have to go.


  2. I will try that. My son has been trying to get me to use my GPS but I keep forgetting....

    Thanks for this tip!!


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