ADHD affects a lot of us. Here's what causes it.

In a day and age of a lot of misinformation, it's easy to get facts confused about even easily identified medical conditions. Mental health disorders can be especially murky as some people misunderstand or misrepresent what each condition is, what causes it and whether it's actually preventable. This is often the case regarding attention deficit hyperactivity disorder, or ADHD.

While it's true that all causes of this mental health condition are not entirely defined, it's also accurate that some purported causes have been studied and ruled out. For instance, though some people say the disorder can be caused by dietary choices, vaccines or even exposure to allergens at an early age, these ideas are not supported by scientific evidence. 

But other causes or contributing factors are, and it can be helpful to understand the part each factor plays and how to treat ADHD if you or a loved one is living with the disorder. 

What causes ADHD? 

The first thing to understand is that, with the exception of some research on how technology use might impact ADHD in teens and adults, the disorder is something a person has since birth and childhood and is not something that is believed to be caused by later behavioral or environmental factors. "ADHD is a neurodevelopmental syndrome and is something that someone is born with," explains J. Russell Ramsay, PhD, a licensed psychologist and retired professor of clinical psychology with the University of Pennsylvania's Perelman School of Medicine. 

The most studied causes of ADHD is related to genetics, early child development, and risk factors associated with pregnancy. "Some risk factors for development of ADHD include premature birth, fetal exposure to substances like alcohol or tobacco, or low birth weight," says Emma Hepburn, PhD, a clinical psychologist and author of "A Toolkit For Your Emotions."

While these things explain the existence of ADHD in some people, various external factors can still contribute to or exacerbate symptoms. "ADHD is a complex genetic trait," says Ramsay. "Its genetic expression can be influenced by interaction with environmental factors and stressors."

Some of these external factors could include the overuse of technology, exposure to environmental toxicants such as lead, and early life adversity. "It is important to note that many of these risk factors came from studies that are correlational in nature," says Wan-Ling Tseng, PhD, an assistant professor at Yale School of Medicine. Because of this, she says more research is still needed to determine the degree to which these factors contribute to or affect the disorder. 

Can ADHD be prevented?

ADHD is not a condition that is usually thought to be preventable. "As a neurodevelopmental syndrome, ADHD is not something that you 'catch' or 'get,'" says Ramsay. One caveat is pregnancy and the avoidance of any substances that could cause or contribute to the fetus's development of the condition. "There is a well-documented association between maternal smoking during pregnancy and offspring (with ADHD)," notes one study.  

Even after a baby is born, avoidance of external factors that may contribute to or exacerbate ADHD symptoms is also important. So is fostering an ideal growing and learning environment for children. "Supporting children through childhood is a good practice to support healthy mental and physical development and a reduced risk of mental health conditions," says Hepburn. 

What's more, if any of the aforementioned known environmental risk factors turn out to be causal instead of correlational, "then those factors could also be targets for ADHD prevention," says Tseng. 

How to help someone with ADHD?

Regardless of the environmental and development factors that contribute to ADHD, it's a well-known and treatable condition. "There are many effective, evidence-supported medical and non-medical treatments and other supports for ADHD across the lifespan," says Ramsay. These include pharmacological medication and making adjustments to educational settings, workplaces, and home life that can help better manage the effects of ADHD. "Adult ADHD coaching also is another option that has been studied and can be helpful for adults with ADHD," offers Ramsay

For younger children, "non-medication treatments such as cognitive behavioral therapy are often considered the first line of treatment due to concerns about side effects and the effect of medications on the developing brain," says Tseng. 

Such decisions are important to make under the direction of one's primary care provider. "Treatment plans should be tailored to an individual’s ADHD presentation and needs," advises Hepburn. 

More:ADHD affects hundreds of millions of people. Here's what it is − and what it's not.