Is ADHD Genetic? Here’s What The Experts Say

Attention deficit hyperactivity disorder (ADHD) is a complex disorder that can have a significant impact on many different facets of an individual's life. If you have ADHD, you may wonder “is ADHD genetic?” or if you inherited it from a parent through family history of ADHD. Understanding the genetics of ADHD can help you assess the likelihood that you or a loved one will develop it.

Family and molecular genetics studies show that ADHD is influenced by genetic factors, but it is not solely determined by them. Brain function and dopamine levels are known to play a role in the development of ADHD symptoms. However, the exact cause of ADHD is still not completely understood, and environmental factors may also contribute to the disorder.

It is essential to consider that each child's symptoms may vary, and an ADHD diagnosis should be made based on a comprehensive evaluation. Proper treatment can help manage symptoms and improve the quality of life for children and parents affected by ADHD.

What is attention-deficit/hyperactivity disorder (ADHD)?

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by trouble focusing, impulsivity, and hyperactivity. While it is usually first diagnosed in children, symptoms often carry over into adulthood, though ADHD symptom trajectories can vary widely depending on several factors (e.g., the existence of a comorbid intellectual disability). It is estimated that 8.4% of children and 2.5% of adults live with ADHD.

Symptoms of ADHD include:

• Distractibility
• Difficulty organizing 
• Trouble listening when directly spoken to
• Avoiding or struggling to complete tasks that require consistent focus
• Forgetfulness
• Overactivity, fidgeting
• Inattentiveness to details
• Misplacing or losing things

ADHD is divided into three different subtypes, which can include some or all of the above symptoms. The subtypes of ADHD are:

• Impulsive/hyperactive type – Marked by overactivity, difficulty sitting still, and excessive talking, but not inattention
• Inattentive type – Marked by symptoms associated with trouble focusing, distractibility, and forgetfulness   
• Combined type – Marked by symptoms of both impulsive/hyperactive type and inattentive type

Both child and adult ADHD can have a serious impact on the lives of individuals who experience it. It can affect an individual’s ability to excel in school, foster healthy relationships, and maintain employment. It can also occur comorbidly with several other mental health conditions and developmental disorders, including depression, anxiety, bipolar disorder, and autism spectrum disorder. ADHD is a treatable condition, though, that may be managed with a proper plan, which we’ll discuss more later.

Causes of attention-deficit/hyperactivity disorder

There is no unified theory that explains how ADHD develops, but research suggests that it is a combination of genetics and environmental influences. 

At the core of ADHD causes is the brain—its structure and function are considered the primary contributors. The ADHD neurotransmitters show decreased levels of dopamine and serotonin. This affects the ability of persons with ADHD to control their mood and behavior. Studies point to genes that are responsible for neural pathways as having a likely influence on the development of the disorder. 

External contributors to ADHD can include brain injury, exposure to toxic substances, smoking or drinking alcohol during and after pregnancy, premature birth, and certain attachment styles. Some proposed environmental factors, such as the consumption of too much sugar, are considered unsupported by research.

How genetics contribute to ADHD

This means that 91% of variation among people who live with ADHD may be attributed to genetics, as opposed to external factors. It does not mean that genetics make up 91% of the cause of ADHD or that you have a 91% chance of developing ADHD if your parents have it. Still, this level of heritability is considered the highest among psychiatric disorders. Researchers (Faraone, SV, Larsson, H) in one study summarized the role genetics play in the development of this neurodevelopmental disorder: “There can be no doubt that DNA variants in genes increase the risk for ADHD.”

Meta-analyses, genome-wide association studies, and systematic reviews have shown that there are several specific genes, often called candidate genes, that may increase the likelihood of developing ADHD traits. Other studies also show that this genetic component of ADHD may be the result of several different variations of specific genes, each of which contributes in a small way to the disorder. In one genome-wide study, researchers found “27 genome-wide significant loci”, with 76 potential genetic risk variants.

Much of the research points to genes that are responsible for dopamine production and transportation as playing a prominent role. This makes sense given the proven links between brain-based alterations in structure and function of specific regions (e.g., the basal ganglia and cerebellum) and ADHD. Studies have shown that several different serotonin and dopamine receptors and transporters are associated with ADHD, along with certain proteins that support brain function. 

Variations in genes that play a role in neurotransmitter function, such as the susceptibility gene SNAP25, can affect the executive function of individuals with ADHD. Experts have found a connection between glutamate receptor gene networks and ADHD (glutamate receptors help facilitate transmission in the central nervous system). These findings highlight the differences in the genetic makeup of each child with ADHD. And, according to a study published in the Journal of the American Academy of Child and Adolescent Psychiatry (J Am Acad Child Adolesc Psychiatry), they help explain how different symptoms can persist throughout an individual’s life. 

Gene studies have also investigated genetic relationships between ADHD and other major psychiatric disorders. For example, there is thought to be genetic overlap between ADHD and bipolar disorder. The results of one study suggested a genetic correlation between ADHD five major psychiatric disorders, including schizophrenia and major depressive disorder. Genetic findings from a study published in the Journal of Child Psychology and Psychiatry (J Child Psychol Psychiatry) suggest that neurodevelopmental disorders share genetic factors with ADHD. For example, autism spectrum disorders are thought to share a novel susceptibility gene (FBXO33) with ADHD. 

Some risk factors and comorbidities—smoking, autism spectrum disorder, bipolar disorder, etc.—have a strong genetic association with ADHD. This suggests that, even when ADHD appears to be caused by environmental factors, genetic risk factors can still have an influence. For example, an individual with ADHD may have a genetic makeup that indicates a propensity for smoking—which could explain why they live in a household in which a parent smokes. So, because smoking can be a risk factor for ADHD, it may be an environmental factor that has a basis in genetic risk. 

Studies of ADHD in families

Much of the research that points to a partial genetic explanation for ADHD centers around ADHD in families. 

The evidence suggests that there is indeed a high prevalence of ADHD among twins when compared to the general population. While this prevalence could be due to similar environmental influences between siblings, research shows that genetic factors play the dominant role in the familial component of ADHD. For example, one study found that adoptive parents of children with ADHD are less likely to have ADHD than biological parents of children with ADHD. 

Can genetic testing identify your risk?

Genetic testing is a useful method of determining whether you have an increased likelihood of developing certain neurological disorders, genetic syndromes, and physical health concerns (e.g., Huntington’s disease, cystic fibrosis, certain forms of cancer). Some researchers have found that the use of polygenic risk scores—which can signal an increased risk of developing a disorder—may help with early diagnosis of ADHD. But testing is not yet considered a reliable way of identifying risk regarding ADHD. This is partly because we don’t know exactly why or how certain genes contribute to ADHD. As researchers continue to explore the genetic basis for ADHD, testing may become a valid method of finding out individual risks for ADHD—but that is not the case at present.

ADHD treatment

Although the exact causes of ADHD have not yet been determined, there are several treatment methods that are proven to help decrease its symptoms. According to a study published in the Journal of Child Psychology and Psychiatry (J Child Psychol Psychiatry), “multimodal interventions are recommended for ADHD”. The disorder is often treated with a combination of medication and therapy, though each individual’s treatment plan will depend on their specific symptoms, history, and a variety of other factors. 

Medication

ADHD medication can be separated into two categories: stimulant and non-stimulant. These medications are typically meant to increase the production of dopamine and norepinephrine, which may have been impeded through the presence of the above-mentioned genes. 

Therapy

Psychotherapy can help those with ADHD address complex emotions related to ADHD, reduce behavioral concerns, and treat comorbid conditions. One of the most effective methods of therapy for ADHD is cognitive behavioral therapy, which helps the individual reframe negative thought patterns that may lead to unwanted behaviors or feelings. 

Skill-building

People who live with ADHD often have trouble organizing their thoughts, prioritizing tasks, managing their time, and cleaning their space. Utilizing organizational tools and working with a therapist or ADHD coach can help those with ADHD develop useful skills for productivity. 

Lifestyle changes

There are several things individuals who live with ADHD can do in their daily lives to help manage symptoms associated with stress or comorbid conditions, like depression. These include exercising, eating a balanced diet, and getting plenty of sleep. 

Managing ADHD symptoms with online therapy

Research shows that online therapy is an effective method of managing symptoms of ADHD. In a review of six studies, including over 250 total participants, researchers found that online therapy can help improve symptoms of ADHD, including attentiveness and the ability of participants to function in social situations. The review specifically mentions online therapy’s convenience as a significant benefit compared to face-to-face therapy.

If you’re living with ADHD and want to know more about its symptoms or how you might have developed it, online therapy can help. You’ll also be able to reach out to your therapist outside of sessions. If you want to ask a question about ADHD symptoms or other treatment-related concerns—without having to remember it during a session—you can send your therapist a message, and they will respond when they’re able.