When it comes to attention deficit hyperactivity disorder (ADHD), you may wonder whether nature or nurture plays the largest role in causing it.
For example, say more than one of your children has been diagnosed with ADHD. Maybe you’re wondering if you’re doing something to cause it. (You’re likely not, by the way).
Or, if you or your partner have ADHD and then your child is diagnosed with it, you might be wondering if the diagnosis was inevitable. (In short: Inevitable, no. Likely, yes).
The truth is, says Jessica Myszak, a licensed psychologist with The Help and Healing Center, “the cause of ADHD in an individual, like many other health conditions, cannot be clearly identified.”
Here’s what we do know: ADHD is a
neurodevelopmental disorder , which means that a brain with ADHD forms differently than most.
In other words, “you do not develop ADHD,” explains Amy Marschall, a licensed clinical psychologist. “The neurological differences appear to be something you’re born with.”
It’s these neurological differences that predispose you to ADHD and its symptoms.
Environmental factors don’t directly cause ADHD. At least, not on their own.
Nature, aka genetics, plays a big role. But your environment can also contain factors that lead to ADHD.
In fact, Myszak says, “there is clear evidence that certain environmental risk factors are strongly tied to later ADHD diagnoses.”
These environmental factors can include:
- in-utero, or in the uterus, exposure to substances or chemicals
- early birth or low birth weight
- environmental toxins
- illnesses like bacterial disease and encephalitis
In-utero exposure
One 2018 study found that kids were at greater risk of having ADHD if their mothers were heavy smokers, while another study found that mothers who drank at least 4 alcoholic drinks in one sitting were likely to have a child with ADHD.
Maternal diet can also play a role, as can an infection during pregnancy.
“Particular medications, such as antidepressants, antihypertensives, and caffeine,” Myszak says, can also factor in.
The American Psychiatric Association adds that babies born early or at a low birth weight also have a greater chance of having ADHD.
Exposure to environmental toxins
These can be toxins that you’re exposed to in utero or during your childhood. They can include:
- lead
- mercury
- pesticides
- specific chemical compounds
For example, the
The pesticide organophosphate, which is commonly sprayed on lawns and agricultural products, has been shown in a
2016 study to affect children’s neurological development. That’s why some researchers think it could play a role in causing ADHD.
Illness
A 2017 study found that bacterial meningitis can also be a risk factor for ADHD. Bacterial meningitis is a serious bacterial disease that is spread from person to person and through food.
Meanwhile, a 2015 Taiwanese study found that encephalitis, which is an inflammation in the brain due to infection or autoimmune response, could also be a risk factor for ADHD.
The truth? Researchers aren’t completely sure what the root cause of ADHD is. That’s likely because one thing doesn’t cause ADHD all by itself.
“Since each person is an individual, we can never definitively say ‘X causes Y,’” Marschall says.
One cause is pretty well supported by twin and family studies: genetics seems to play an important role in causing ADHD.
“Children of siblings with ADHD are 9 times more likely than other children to also have ADHD, with heritability estimates ranging from 74 percent to 88 percent,” Myszak says, citing a 2005 study.
Still, just because genetics predisposes someone to ADHD doesn’t mean they will have it.
A
“Instead, ADHD typically arises from multiple genetic and environmental risk factors that cumulatively increase the likelihood of a person having ADHD,” Myszak explains.
“It can be really complicated to tease apart environmental factors from genetic factors because family members share not only genetics but also certain lifestyle factors which may also contribute to ADHD risk.”
In other words, all factors are important, since it’s the cumulative effect of these factors that cause ADHD.
Yes, evidence suggests that other factors play a role too.
“In the last couple of years, there has been more research on the brain differences in individuals with ADHD, and there have been some variants consistently identified in ADHD brains,” Myszak explains, referencing a
It also appears that some ADHD diagnoses occur following brain damage, as seen in a 2014 research review. This includes damage from:
- early life injuries
- head trauma
- atypical brain development
There are a lot of rumors and myths surrounding ADHD. Many of these harm parents or make them feel guilty for doing something wrong in the way they raise their kids.
But these myths appear to be just that: myths.
For example, the
- eating too much sugar
- watching too much television
- poverty
- family dischord
ADHD is a neurodevelopmental disorder, and current research suggests that genetics plays a major role. Because genetics may predispose someone to ADHD, it can’t be prevented.
According to Myszak, some measures expecting parents can take to ensure their baby is healthy overall include:
- receiving prenatal healthcare
- avoiding exposure to drugs, alcohol, and tobacco during pregnancy
- limiting exposure to environmental toxins like pesticides and lead
However, you can also take steps to help manage symptoms of ADHD, such as:
- setting up structure and consistent expectations with your child
- doing daily physical activities
- getting plenty of sleep
- avoiding stimulating activities, especially before needing to focus or sleep
Stimulating activities can include electronics, computers, video games, and TV.
“There’s mixed data about diet at this point, so I would advise parents to talk to their pediatrician about what’s best for their child,” says Marschall.
Still, the
ADHD looks a little different for each person, and symptoms can vary between childhood and adulthood.
That said, according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), general symptoms of ADHD include:
- being forgetful
- being easily distracted
- being prone to reckless behavior
- losing or misplacing things
- being prone to impulsive behavior
- lack of motivation for specific activities
- difficulty organizing things
- difficulty completing tasks
Since ADHD is mostly diagnosed based on behavior, no medical tests exist to detect it. Instead, you or your loved one will have a few sessions with a mental health professional, such as a psychologist or psychiatrist. They can evaluate behavior, talk to teachers and family members, and arrive at a diagnosis.
Treatment for ADHD varies depending on your symptoms. But a 2005 research review found that it generally includes some combination of:
- medication
- psychotherapy
- behavior management
- organizational and social skills training
Medication
People with ADHD might be prescribed medications, which were assessed in a
Psychotherapy
Talk therapy can help people with ADHD develop the tools to better handle social situations, relationships, and stress.
Behavior management
Behavior therapy works with someone with ADHD to strengthen positive behaviors and reduce negative behaviors. This can help them do better in school, at work, and in their social lives.
Organizational and social skills training
People with ADHD may also benefit from organizational skills training or social skills training. Organizational and social skills therapies can include:
A number of ADHD organizations can be helpful for connecting people with ADHD, or parents of children with ADHD, with the resources they need. These include therapy, support groups, and workshops for people with ADHD.
You can reach out to:
- Learning Disabilities Association of America
- Attention Deficit Disorder Association
- Children and Adults with Attention-Deficit/Hyperactivity Disorder (CHADD)
If your child with ADHD is having a hard time at school, you might also find it helpful to reach out to school services or parent groups.
ADHD doesn’t appear to have just one cause.
Instead, ADHD has a number of causes, which makes it difficult to know exactly why any one person receives a diagnosis.
Still, genetics and environmental factors do play an important role.
The good news is: if you or your child has ADHD, you have many options once you have a diagnosis to manage the condition and thrive with it.
Simone M. Scully is a new mom and journalist who writes about health, science, and parenting. Find her on her website or on Facebook and Twitter.