Everything has a cause, so there must be a cause for ADHD, right? In this case, it's a bit more difficult to find definitive causes. "To date, all of the major ones fall in the realm of neurology and genetics (biological causation) with no evidence that social factors alone can account for the condition."(Barkley, 2017), according to Russell Barkley, who is a psychologist and researcher on ADHD. This does not mean that outside forces cannot be a cause, though. Barkley goes on to say that, "...most [such] environmental factors that are related to ADHD are in the category of biohazards, such as head trauma, other neurological injuries, lead poisoning or other toxin exposures such as alcohol use during pregnancy, significant premature birth, etc."(Barkley, 2017).
Genetics and ADHD
From all of the causes listed above, the one that is most common is genetics. Barkley states that there are six ways that genetics can cause ADHD in a child.
1) Inheritance
If the parents of a child have ADHD or carry the gene that causes it, there is a higher chance of that child having ADHD. Overall, there are "25-45 genes related to ADHD symptoms..."(Barkley, 2017). The large amount of genes may explain why ADHD is one of the most common neurological disorders in the world.
2) Genetic Mutation
If a child gets ADHD and their parents do not carry the gene for it, it most likely is from a genetic mutation. Mutations can be caused by outside forces at anytime, as we are always around "Mutation-causing agents"(Barkley, 2017). Gametes from the parents may be exposed to these and may mutate. The parents will not have the mutation in them, but it will be found in their child.
3) Gene-by-gene Interaction
This means that the more ADHD genes that are present, the higher the chance is of the child having it. Studies on this are not as far as others, but from the studies done it has shown to be true.
4) Gene-by-environment Interaction
The DNA of a child was affected by outside forces. This could range from X-ray waves to the mother drinking or smoking while pregnant.
5) "Epigenetics"
A chemical attaches to DNA as it travels to where the offspring is. If they activate, then the child will get ADHD. This can also cause other disorders, such as autism. This is also a newer study like the gene-by-gene interaction.
6) Damage to DNA
If there is "major damage, duplications, or deletions to entire chromosomes" (Barkley, 2017) of the DNA, it can cause ADHD and many other disorders. This is not as common as the others on here.
1) Inheritance
If the parents of a child have ADHD or carry the gene that causes it, there is a higher chance of that child having ADHD. Overall, there are "25-45 genes related to ADHD symptoms..."(Barkley, 2017). The large amount of genes may explain why ADHD is one of the most common neurological disorders in the world.
2) Genetic Mutation
If a child gets ADHD and their parents do not carry the gene for it, it most likely is from a genetic mutation. Mutations can be caused by outside forces at anytime, as we are always around "Mutation-causing agents"(Barkley, 2017). Gametes from the parents may be exposed to these and may mutate. The parents will not have the mutation in them, but it will be found in their child.
3) Gene-by-gene Interaction
This means that the more ADHD genes that are present, the higher the chance is of the child having it. Studies on this are not as far as others, but from the studies done it has shown to be true.
4) Gene-by-environment Interaction
The DNA of a child was affected by outside forces. This could range from X-ray waves to the mother drinking or smoking while pregnant.
5) "Epigenetics"
A chemical attaches to DNA as it travels to where the offspring is. If they activate, then the child will get ADHD. This can also cause other disorders, such as autism. This is also a newer study like the gene-by-gene interaction.
6) Damage to DNA
If there is "major damage, duplications, or deletions to entire chromosomes" (Barkley, 2017) of the DNA, it can cause ADHD and many other disorders. This is not as common as the others on here.