Is ADHD Hereditary?

Understanding ADHD and PGx Testing for ADHD Medications

Although the exact causes of Attention deficit hyperactivity disorder (ADHD) are unknown, there are certain factors that play a role in an individual having it. These factors include genetics, pregnancy issues, neurobiological factors and environmental factors. A huge part of those factors is genetics. Family history and genetic variants are commonly associated with ADHD, making it hereditary. 

What is ADHD?

Attention deficit hyperactivity disorder is a neurological disorder of unknown origin and is characterised by persistent inattention, hyperactivity, and impulsivity. It is a disorder that is typically diagnosed in childhood but can continue into adolescence and adulthood.

Family history and ADHD

Children with a parent or a sibling who has ADHD are more likely to also develop the disorder themselves. This suggests a family connection.

Studies show that:

·    If a parent has ADHD, the child has a 50% chance of developing it.

·    If an older sibling has ADHD, the younger sibling has more than a 30% chance of developing it.

Genetic studies and ADHD

Twin studies are beneficial and instrumental in estimating the heritability of ADHD. Twin studies have indicated that ADHD is highly heritable as the heritability estimates range from 60% to 80%. This indicates that a significant proportion of the variation in ADHD risk is due to genetic factors, although environmental factors also play a role.

Genetic variants associated with ADHD

Certain genes related to neurotransmitter systems, especially those that involve the neurotransmitter dopamine, have been cross-linked and implicated in ADHD. Some of these genes include:

·    DRD4 (Dopamine Receptor D4)

·    DAT1 (Dopamine Transporter Gene)

·    DRD5 (Dopamine Receptor D5)

·    SLC6A2 (Norepinephrine Transporter Gene)

·    HTR1B (Serotonin Receptor Gene)

·    SNAP25 (Synaptic Protein Gene)

·    FOXP2 (Gene involved in brain development and communication)

For example, the Dopamine Receptor D4 (DRD4) gene that codes for the D4 dopamine receptor and is involved in the dopamine signalling pathway has been consistently associated with ADHD. Individuals who have an altered dopamine function may have issues with attention and behaviour regulation which is linked to ADHD.

Using Pharmacogenetics (PGx) to Manage ADHD

At AttoDiagnostics, we are proud to be at the forefront of advanced, personalised psychiatric care. Pharmacogenetic testing can help determine potential drug-gene interactions by assessing genetic variants that affect the drug’s metabolism, efficacy, toxicity, transport or receptor activity. Ultimately allowing healthcare providers to personalise treatments, minimise adverse effects and optimise the drug’s efficacy based on a patient's genetic profile. The PGx test report for a patient will classify the drug-gene interactions as either “Mild”( where dose adjustments will not be required) , “Moderate”(where dose adjustments will be required) or “Serious” (where an alternative drug is recommended). This reduces overall unwanted side effects and ultimately improves the patient’s quality of life while on treatment.

What Medications Are Available for ADHD?

ADHD medications are divided into stimulants and non-stimulants. Stimulants are usually the first-line treatments for ADHD. Examples of stimulant medications include:  Ritalin, Concerta, Metadate, Daytrana, Quillivant XR (liquid form), Adderall, Vyvanse, Dexedrine, Evekeo, Mydayis. Non-stimulants are mostly prescribed when stimulants are ineffective for the patient and can cause unwanted side effects. Examples of non-stimulants include Atomexetine, Guanfacine, Clonidone and Bupropion.

The Efficacy of Pgx Testing to Improve ADHD Medication Outcomes

Pharmacogenomic testing for ADHD medications can help provide insight on which medications to prescribe and which to avoid based on an individual's genetic profile. This lessens the burden of unwanted side effects that the patient might potentially get when they start their treatment. Patients who receive PGx guided medications are 41% to 78% more likely to achieve remission and more likely to respond to medication than patients who receive traditional treatment.

For more information on our pharmacogenetic testing services and how they can benefit your service or patients, you can ask for a quote here.