Does ADHD run in the family?
By Nidhi Selvakumar
A question we are often asked at Chiltern ADHD Clinic CIC! Join Nidhi as she explores if people can suddenly develop ADHD? Or is it something that just ‘runs in the family’, as it tends to be described?
Much research has confirmed that children are more likely to have ADHD if their parents or relatives do. Family, twin, and adoption studies have shown that ADHD has a high heritability of 74% [1]. Other studies have proven that the passing on of certain genes are great contributors to its high heritability [1].
This all points to the conclusion that yes, ADHD clearly seems to ‘run in the family’, however, the full story is more complicated.
"While genes hugely influence ADHD’s presence, environmental factors can also influence its development."
Let’s look at the genetic side first:
First of all, what does it mean for a condition to be heritable?
The U.S. National Cancer Institute describes this as a condition that ‘can be passed from a parent to a child through the genes’ [2]. The keywords here are ‘can be’, NOT ‘will be’ - conditions like ADHD can be inherited from parents, but just because parents may have ADHD, it doesn’t guarantee that the condition will be inherited by their children. Jennie often uses the term ‘genetically predisposed’ 🤓
Does it make a difference which parent has ADHD?
A study in the Journal of the American Academy of Child & Adolescent Psychiatry showed that ‘both maternal and paternal ADHD are strong predictors of ADHD in offspring, without a significant difference between the two’ [1]. This means that there is no real difference between the chance of inheriting ADHD from your mother, and the chance of inheriting it from your father.
Other studies identifying the specific genes that lead to ADHD have shown that these genes can come from either parent [3]. But what are these specific genes?
What genes does ADHD come from?
ADHD is considered a polygenic condition, which means that it is inherited from a combination of multiple genes, not just one. This being said, there is still ongoing research to identify the full combination of these contributing genes, but here’s what we know so far:
Many studies show the involvement of genes related to the dopamine system [4][5], such as variations in the DRD4 and DAT1 genes, which are linked to dopamine regulation [3][6]. (please can you reference this section with [1] etc)
Dopamine is made in your brain and is a neurotransmitter – the ‘chemical messengers’ that neurones pass between each other to trigger electrical impulses that allow communication between the brain and the body.
The dopamine system acts as a ‘reward center’, giving you a sense of pleasure and motivation to do things that are good for survival, such as eating and drinking [7]. Dopamine is also essential for many body functions, such as memory, motivation, mood, and attention, so it’s no surprise that ADHD is associated with differences in dopamine transportation [3].
Research has also identified other genes associated with ADHD (called candidate genes), which are involved in processes related to brain functions, such as regulation of other neurotransmitters like serotonin and norepinephrine [8][9].
The importance of knowing family history:
The strong genetic component of ADHD makes it important for diagnosis to recognise whether it ‘runs in the family’, particularly if you suspect it is present in children. Clinicians often ask about family members who may have exhibited similar symptoms, even if they were never formally diagnosed.
If you’ve had an ADHD assessment with Jennie, she will ask about traits in your family as well as diagnoses, as this can give us a good insight into possible family history. Especially in older generations, ADHD might have gone undiagnosed, as awareness and diagnostic criteria have developed further over recent years. Adults with ADHD may also have developed coping mechanisms which mask some of their symptoms [10], so it is helpful to be aware of signs that may appear in undiagnosed adults, which may be worth raising with a specialist. Just as a caveat, the subsequent signs described should not be used as a checklist, as they don’t necessarily indicate the presence of ADHD on their own; they have just been commonly associated with it.
Common symptoms in adults include difficulty managing time, chronic disorganisation, and impulsive decision-making [10] [11]. These symptoms can show up in frequently missing deadlines, struggles to maintain an organised workspace, or making impulsive purchases.
In older individuals, signs include persistent restlessness, difficulty focusing on tasks, and chronic lateness [10]. Frequently changed jobs, struggling to remember appointments, and feeling constantly overwhelmed - these patterns are often associated with undiagnosed ADHD. To further complicate things for women, symptoms of ADHD may have been undiagnosed for years, then peri/menopause symptoms can amplify them, making them harder to deal with and appearing like they’ve just ‘appeared’.
It is useful to have open, non-judgemental conversations with family members about their childhood and adult experiences, including their school performance, work history, and social interactions, without prior assumptions about the conditions that they may or may not have.
Finding these signs in relatives can provide valuable context and aid in early identification and management of ADHD, leading to better outcomes for adults and children alike. If you’re having an ADHD assessment with us, don’t worry, Jennie will interrogate them on your behalf!
The patterns mentioned can (and often do) overlap with other conditions, such as depression or anxiety [1], so these should not be used for direct diagnosis, just as a starting point for conversations with specialists.
So, to conclude, we’ve learnt that ADHD is greatly influenced by family history; but are genes really the end-all, be-all cause of ADHD? Definitely not! There are a lot of environmental components that can lead to its manifestation. In fact, these components can even alter the expression of the very genes which are linked to ADHD - but more on that on the next post…
Sources:
[5] https://www.adhdcentre.co.uk/does-adhd-run-in-families-what-research-reveals-on-nature-vs-nurture/
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