What Causes ADHD?

What Causes ADHD? Culture Vs. Biology

Most researchers point to genetics and heredity as causes of ADD or ADHD. Some scientists are investigating whether certain genes, especially ones linked to the neurotransmitter dopamine, may play a role in developing attention deficit disorder. Other experts contend that our fast-paced, stressed-out, consumer-driven lives are also triggers for ADHD.

Person holding two puzzle pieces to the sky signifying finding the right specialist for your child with ADHD
Person holding two puzzle pieces to the sky signifying finding the right specialist for your child with ADHD

What Causes ADHD?

Most researchers point to genetics and heredity as deciding factors for who gets attention deficit disorder (ADHD or ADD) and who doesn’t. Scientists are investigating whether certain genes, especially ones linked to the neurotransmitter dopamine, may play a role in developing ADHD.

But Michael Ruff, M.D., a clinical associate professor of pediatrics at Indiana University, believes DNA is just part of the story. He is convinced that at least some cases of ADHD are a byproduct of our fast-paced, stressed-out, consumer-driven lifestyles. Let’s compare other research and expert insights to Dr. Ruff’s controversial theory on what causes ADHD — genetic vs. environmental triggers.

In an article in Clinical Pediatrics, Dr. Ruff called ADHD an ‘epidemic of modernity.’1 What does that mean? Is it the only explanation for ADHD?

Dr. Ruff: “I’m talking about the cultural environment that prevails today — the modern way of life and its impact on the developing brain. Today’s children are immersed in a world of instant messaging and rapid-fire video games and TV shows. Today’s parents are rushing around and working so hard to earn money to buy more stuff that they have less time to spend with their kids.”

“When kids get accustomed to such a rapid tempo, it’s hard for them to adjust to the comparatively slow pace of the classroom. They transfer the sense of urgency they’ve seen at home to their academic endeavors.”

“Researchers Daphne Bavelier and Shawn Green have demonstrated that playing action-based video games can improve processing speed. Torkel Klingberg has shown that consistent use of adaptive video games improves working memory skills and alters brain structure.”

[Self-Test: Signs of Emotional Hyperarousal]

“Increases in grey matter in the right hippocampus, the cerebellum, and right prefrontal cortex were observed in a study of adults playing Super Mario Bros.2 Another study demonstrated that playing Tetris resulted in a larger cortex and increased brain efficiency.”3

“StarCraft, an action game, can lead to improved brain flexibility and problem solving. Playing Rayman Raving Rabbids can improve reading in children ages 7 to 13. Brain-training video games change brain functioning and slow the degree of mental decay in the elderly. All of these findings are well documented.”

“However, just as with virtually anything else in the world, too much of a good thing is bad for you. If you drink too much juice, eat too much fruit, or spend too much of your time jogging, there will be negative effects. Helping your child to have a balance of physical, social, unstructured, creative, and digital play, is vital. With video games, playing between 60 to 90 minutes a day appears to benefit kids the most.”

ADDitude editors: The effects of video games on children with ADHD are neutral, except in extreme cases of negative obsessive fixation . While many games are advertised to improve cognition, memory, or other skills, the benefits of brain training are not proven.

There’s evidence that ADHD has a biological basis. Doesn’t that mean it’s hereditary?

Dr. Ruff: “Not entirely. The young brain is highly malleable. As it matures, some brain cells are continually making new connections with other brain cells, a process known as ‘arborizing,’ while others are being ‘pruned’ back. Arborizing and pruning determine how circuitry is wired in the prefrontal cortex, the region that is largely responsible for impulse control and the ability to concentrate. We’ve failed to acknowledge the extent to which environmental factors influence these processes.”

ADDitude editors: Available evidence suggests that ADHD is genetic — passed down from parent to child. It seems to “run in families,” at least in some families.

  • A child with ADHD is four times more likely to have a relative with ADHD.
  • At least one-third of all fathers who had ADHD in their youth have children who have ADHD.
  • The majority of identical twins share the ADHD trait.

A number of studies are now taking place to try to pinpoint the genes that lead to susceptibility for ADHD.4 Scientists are investigating many different genes that may play a role in developing ADHD, especially genes linked to the neurotransmitter dopamine. They believe it likely involves at least two genes, since ADHD is such a complex disorder.

There’s also evidence that toxins and pollution contribute to the development of ADHD, though more research is needed on these environmental factors.

[ADHD Is More Than Just Genes]

The role of environment in causing ADHD is an interesting theory, but is there evidence to support it?

Dr. Ruff: “There hasn’t been much research on the role of the environment in ADHD, but some studies are suggestive. In 2004, University of Washington researchers found that toddlers who watch lots of TV are more likely to develop attentional problems5. For every hour watched per day, the risk rose by 10 percent.

“My group practice, in Jasper, Indiana, cares for more than 800 Amish families, who forbid TV and video games. We haven’t diagnosed a single child in this group with ADHD.”

“On the other hand, we care for several Amish families who have left the church and adopted a modern lifestyle, and we do see ADHD…in their kids. Obviously, the genes in these two groups are the same. What’s different is their environment.”

“There’s also some evidence to suggest that academic problems are rare in social and cultural groups that traditionally place a high value on education, hard work, and a tight-knit family structure. For example, a 1992 Scientific American study found that the children of Vietnamese refugees who settled in the U.S. did better in school and had fewer behavior problems than their native-born classmates.6 The researchers noted that the Vietnamese kids spent more time doing homework than did their peers, and that their parents emphasized obedience and celebrated learning as a pleasurable experience.”

ADDitude editors: While some environmental factors almost certainly do influence the development of ADHD, more than 1,800 studies have been conducted on the role of genetics in ADHD, creating strong evidence that ADHD is mostly genetic.

The genetic evidence for ADHD can be ignored, but not argued away. Studies of twins and families make it clear that genetic factors are the major causes of ADHD, says Russell Barkley, Ph.D., author of Taking Charge of Adult ADHD. In fact, an estimated 75 to 80 percent of variation in the severity of ADHD traits is the result of genetic factors.7 Some studies place this figure at over 90 percent.

How can parents reduce the likelihood that their children will develop severe ADHD?

Dr. Ruff: “I counsel parents to limit the amount of TV their kids watch. I urge them to read to their kids every day, starting at age one, and to play board games and encourage other activities that promote reflection and patience. I also urge parents to do more slow-paced, step-by-step activities with their children, like cooking and gardening. Carve out more quiet time, when you’re not so busy. Put down the cell phone, and stop multitasking.”

Edward Hallowell, M.D., practicing psychiatrist and founder of the Hallowell Center for Cognitive and Emotional Health: “We know enough about ADHD to offer science-based suggestions that can help reduce the likelihood of someone developing this condition.

He advises expectant mothers not to “indulge in alcohol, cigarettes, or illicit drugs, or mistreat yourself or your unborn child in any other way. And get good prenatal care. Poor health care [while expecting a child] brings the risk of developing ADHD.”

“Make sure you have excellent medical care during [your] delivery….Lack of oxygen at birth, trauma during birth, and infections acquired during delivery can cause ADHD.”

“Once you give birth or bring home your adopted child, rejoice. The exciting and momentous journey of parenthood begins. That being said, your enchanting infant requires a lot of work. You may be sleep- and time-deprived, and tempted to plant your [child] in front of the TV to keep him occupied. But don’t. Studies have shown that infants and toddlers who watch more than two hours of television a day are more likely to develop ADHD than other children.”

“As you turn off the TV, turn on human interaction. Social connectedness bolsters the skills that minimize ADHD’s impact. So have family meals often, read aloud together, play board games, go outside and shoot hoops or throw a Frisbee — play, play, play. Also make sure that your child’s school is friendly and encourages social interaction.”

“These are practical measures that can help reduce the likelihood of a child developing ADHD. Remember, too, that inheriting the genes that predispose toward this condition doesn’t guarantee getting it. It is not ADHD that is inherited, but rather the predisposition toward developing it. Simply by reducing your child’s electronic time while increasing interpersonal time, you reduce the likelihood that the genes for ADHD will be expressed as he grows older — even if they were inherited.”

“A final note: You may not be able to prevent your child from developing ADHD, and that’s just fine. I have ADHD, and two of my three kids have it as well. With proper interventions, ADHD need not be a liability. In fact, it can be a tremendous asset. While a person can learn the skills to compensate for its downside, no one can learn the gifts that so often accompany ADHD: creativity, warmth, sharp intuitive skills, high energy, originality, and a ‘special something’ that defies description.”

If a child already has ADHD, can a change in the environment help control symptoms?

Dr. Ruff: “The brain can relearn executive functions like planning and attention well into the fourth decade of life. Consistent discipline, less TV and video games, and an emphasis on exercise, seem to be key. Exercise promotes on-task behavior and helps relieve the ‘desk fatigue’ that makes it hard for kids to sit still in class.”

Colin Guare, a 24-year-old freelance writer and co-author of Smart But Scattered Teens: “If playing video games for hours guaranteed future success, I would be President by now.

“This isn’t the case, of course. Still, much of my mental dexterity and sharper executive function — brain-based skills required to execute tasks — can be chalked up to my hours spent in front of a screen. Gaming has helped me manage my ADHD-related shortcomings.”

ADDitude editors: Though parents will argue that video games are distracting, and an obstacle to learning, research suggests otherwise. In his book, What Video Games Have to Teach Us About Learning and Literacy, James Paul Gee, Ph.D., notes that what makes a game compelling is its ability to provide a coherent learning environment for players. Not only are some video games a learning experience, says Gee, but they also facilitate metacognition (problem solving). In other words, good games teach players good learning habits.

Several video games offer individuals with ADHD the chance to have fun and to polish their executive skills at the same time. Four popular, entertaining, mentally rewarding, and cool games for teens are: Portal and Portal 2, Starcraft and Starcraft II: Wings of Liberty, The Zelda Franchise, and Guitar Hero.”

Randy Kulman, Ph.D., founder and president of LearningWorks for Kids: “Watch your child play Minecraft or other skill building games for a few minutes, and you’ll see that he plans, organizes, and problem-solves while engaged in a video game — skills we’d all like our ADHD kids to develop. Wouldn’t it be great if he could transfer those game-playing skills to everyday tasks? He can, with a little help from you. Use the following three steps to tap into the skill-building potential of video games:

  1. Help your child identify the thinking and problem-solving skills that are necessary to play the game.
  2. Encourage metacognition and reflection by talking about how these skills are used in the real world.
  3. Engage your child in activities that use these skills, and then talk with your child about how the skills connect to game play.”

Kulman recommends the games Bad Piggies, Roblox, and Minecraft to build these skills.

How about medication?

Dr. Ruff: “There’s no doubt that medication can help control symptoms of ADHD. However, it’s problematic when doctors and parents believe ADHD to be simply the result of a ‘chemical imbalance,’ while failing to consider that a ‘lifestyle imbalance’ may also be involved. Even if medication is part of your child’s treatment plan, you still need to get the TV out of his bedroom.”

ADDitude editors: There’s no disputing that a healthy lifestyle — nutrient-rich foods, lots of water, exercise, and less stress — is better for ADHD. However, according to a study published online in the Journal of Attention Disorders in 2016, just the opposite is happening — children with ADHD engage in fewer healthy lifestyle behaviors than do their peers without the condition. There’s definitely room for improvement.

[When ADHD Is All In the Family]

1 Michael E. Ruff, MD, FAAP. ADD and Stimulant Use: An Epidemic of Modernity. Medscape (Feb. 2007). https://www.medscape.com/viewarticle/550918
2 Kühn, S., Gleich, T., Lorenz, R. C., Lindenberger, U., Gallinat, J. Playing Super Mario induces structural brain plasticity: Grey matter changes resulting from training with a commercial video game. Molecular Psychiatry (Oct. 2013). https://www.ncbi.nlm.nih.gov/pubmed/24166407
3 Richard J Haier, Sherif Karama, Leonard Leyba and Rex E Jung. MRI assessment of cortical thickness and functional activity changes in adolescent girls following three months of practice on a visual-spatial task. BMC Research Notes (2009). https://bmcresnotes.biomedcentral.com/articles/10.1186/1756-0500-2-174
4 Zhang, Liuyan et al. “ADHDgene: a genetic database for attention deficit hyperactivity disorder.” Nucleic acids research (Jan. 2012). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3245028/
5 Christakis DA, Zimmerman FJ, DiGiuseppe DL, McCarty CA. “Early television exposure and subsequent attentional problems in children.” Pediatrics (Apr. 2004). https://www.ncbi.nlm.nih.gov/pubmed/15060216?dopt=Abstract&holding=npg
6 Caplan, Nathan, Marcella H. Choy, and John K. Whitmore. “Indochinese Refugee Families and Academic Achievement.” Scientific American (1992). http://www.jstor.org/stable/24938938
7 Franke, B et al. “The genetics of attention deficit/hyperactivity disorder in adults, a review.” Molecular psychiatry (2012). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3449233/