Attention-deficit hyperactivity disorder (ADHD) is a mental health condition characterized by impulsivity, inattentiveness, procrastination, hyperactivity and difficulties starting and finishing tasks. ADHD is typically diagnosed in childhood, though it may not be diagnosed until later years. ADHD can also range in severity from being relatively mild to disruptive. Individuals may find that even with prescribed medication, they have problems functioning in relation to everyday tasks, including school and work.
Though ADHD can be managed quite well, in many cases, a diagnosis has long-term ramifications. Many families wonder if ADHD is genetic. In other words, can ADHD be inherited or passed down through family generations? Scientists have raised the same questions about whether ADHD is a genetic disorder, and have done many studies to better understand the condition.
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What Parts of the Brain Are Affected by ADHD?
Before delving into the details about the potential causes of ADHD, you might be wondering: How does ADHD affect the brain? According to the American Academy of Child and Adolescent Psychiatry, the brains of individuals with ADHD may function slightly differently from others. For example, certain regions of the brain in children with ADHD are smaller than in children without ADHD. One brain region that is smaller in children with ADHD is the frontal lobe. The frontal lobe is the brain region responsible for many activities, including:
- Perception of time
- Judgments and impulse control
- Planning and decision-making
- Attention span
- Social interactions
Data suggests the frontal lobes of individuals with ADHD may mature less quickly than people without this condition. Additionally, there may be slight differences in neural networks (connections between brain cells) and neurotransmitter levels like dopamine and norepinephrine in individuals with ADHD.
Does ADHD Run in Families?
The short answer is yes, it is possible that a person can inherit ADHD from their mother, father or both parents. Current research suggests that children whose parents are diagnosed with ADHD are at a higher risk for developing the condition themselves. Nevertheless, more than one gene is likely involved in the inheritance pattern of ADHD, indicating that there are many complexities still surrounding this condition.
Identical Twins and ADHD
In order to understand if genetics or the environment plays a larger role in the development of a disease like ADHD, the research community relies on twin studies. Identical twins are studied in different environments to see how their biology differs. A twin study of ADHD conducted in 2016 found that environmental effects also played a substantial role in the development of ADHD and not just genetics. Thus, more research must be conducted in order to determine the true causes of ADHD.
Additional Risk Factors for ADHD
Though the exact genetic and environmental causes of ADHD are not fully understood, there are several risk factors for developing ADHD. Many of these factors are out of an affected individual’s control, such as being exposed to toxins or dangerous substances in utero. Other risk factors suggest that genetics also has a role. Some environmental risk factors of ADHD include:
- Being exposed to lead
- Being born prematurely
- Having a low birth weight
- Being exposed to tobacco in the prenatal period
It is possible that ADHD is heritable, as there are also genetic risk factors. Namely, children with blood relatives that have ADHD, like parents or siblings, are more likely to develop this condition.
Ongoing ADHD Genetic Research
Recent ADHD genetic research suggests that genes that regulate the neurotransmitters serotonin and dopamine could be misregulated in individuals with ADHD. Other ADHD research studies have shown that mutations in certain genes can lead to the development of ADHD-like symptoms. Mutations, in this case, refer to changes in genes which may impact their normal function. Some genes that are thought to contribute to the development of ADHD include:
- SLC9A9: This gene’s normal function is to make sure the cell maintains a stable environment
- DRD4 and DRD5: These genes are dopamine receptors and normally function in the regulation of dopamine signaling
As more research is conducted on ADHD, it is likely that more genes will be discovered that have a role in the development of this condition.
If you or a loved one struggle with managing ADHD and a co-occurring addiction, The Recovery Village can help. Call today to speak with a representative to discuss the best options for treating both ADHD and addiction together.
ADHD Institute. “Environmental risk factors.” March 2019. Accessed June 28, 2019.
American Academy of Child and Adolescent Psychiatry. “ADHD & the Brain.” February 2017. Accessed June 28, 2019.
Genetics Home Reference. “DRD4.” June 25, 2019. Accessed June 28, 2019.
Genetics Home Reference. “DRD5.” June 25, 2019. Accessed June 28, 2019.
Genetics Home Reference. “SLC9A9.” June 25, 2019. Accessed June 28, 2019.
Livingstone, LT et al. “Does the Environment Have an Enduring Effect on ADHD? A Longitudinal Study of Monozygotic Twin Differences in Children.” J Abnorm Child Psychol., November 2016. Accessed June 28, 2019.
National Health Service: United Kingdom. “Causes- Attention deficit hyperactivity disorder (ADHD).” May 30, 2018. Accessed June 28, 2019.
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