ADHD Explained: Causes, Symptoms, And Treatments

ADHD has been known since 1902, when British pediatrician George Still wrote about kids who seemed unable to control their behavior (via US National Library of Medicine). The American Psychological Association (APA) first recognized the disorder in 1968, when it included a description of "hyperkinetic impulse disorder" in the Diagnostic and Statistical Manual of Mental Disorders. In 1980, the name was changed to "Attention Deficit Disorder," or ADD. In 1987 they added "hyperactivity" to get the acronym we know today.

Still, there are people who don't think ADHD is a real disorder. Some believe the symptoms are just normal kid behavior. Some even say it's the result of bad parenting. Much of the controversy seems to stem from the increase in ADHD diagnoses — today, the Stanford Institute for Economic Policy Research says close to one in 10 kids has an ADHD diagnosis, and no one is sure if it's because doctors are getting better at spotting ADHD or if they are overdiagnosing. Either way, few, if any, doctors deny the existence of ADHD. "No scientific meetings mention any controversies," professor of psychiatry Russell Barkley told RealClearScience. "The science is overwhelming that the answer to these questions is in the affirmative: it's a real disorder."

One thing that has been proven over and over again through decades of research is that ADHD is genetic (via American Journal of Medical Genetics). In fact, many adults have received their own diagnosis after their child is diagnosed with ADHD (via Healthline). Several studies, including one published in 2013 by Cambridge University Press, have confirmed that ADHD has a high heritability rate, which means if you have the disorder you've got a pretty good chance of passing it along to one or more of your kids. The study found that the genetic component of ADHD was about 72%.

According to PsychCentral, the task of identifying the genes responsible for ADHD is difficult because the disorder is so varied and complicated that it's hard to know with any certainty how much of a role any one gene might play. Some studies have, unsurprisingly, found evidence that the dopamine genes DRD4 and DRD5 may play a role. Most, though, have only been able to piece together small sections of the genetic puzzle. Some of the research has also found that the way people respond to ADHD drugs may also have genetic components, so continued research into the genetic component of ADHD may help doctors create more individualized treatment plans.

Parents may worry that something they are or aren't doing might increase their child's risk of developing ADHD. Most of the time, though, these concerns aren't justified. While there is some merit to the idea that chemical and lead exposure can trigger ADHD, there isn't any evidence that things like diet or screen time have anything to do with development of the disorder.

A 2012 study by Iowa State University looked at the gaming habits of 3,000 kids and found that the kids who played the most video games had problems with impulsivity and attention. But the Child Mind Institute criticized the study, saying it only proved that heavy gamers were more likely to be kids who already struggled with severe ADHD symptoms. Other things that haven't been found to cause ADHD: sugar (via Journal of Affective Disorders), gluten (Journal of Attention Disorders), or, according to Current Pharmaceutical Biotechnology, anything else in a child's diet. And Everyday Health says that bad parenting — a common scapegoat for ADHD symptoms — also isn't to blame, though it is worth noting that kids with ADHD usually have parents with ADHD, and ADHD symptoms can make parenting especially challenging (via Child Mind Institute).

Even today, ADHD is grossly underdiagnosed in girls. In fact, according to the Centers for Disease Control and Prevention (CDC), boys are more than twice as likely as girls to be diagnosed with ADHD. But according to a 2015 study published in the American Journal of Psychiatry, the numbers of adults with ADHD are evenly split between men and women, which suggests that a lot of girls just aren't getting diagnosed.

ADHD is often overlooked in girls because they can present different symptoms. According to a 2014 review by the Primary Care Companion for CNS Disorders, girls are often considered "subthreshold," which means they don't usually have the obvious symptoms that set off alarms with teachers and parents. Girls tend to display more inattentiveness than hyperactivity or impulsivity, so their symptoms can be more easily overlooked. They are also more likely to develop coping strategies, which means they don't always perform poorly in school the way boys with ADHD often do. Girls may also have symptoms like anxiety and depression, which are not ADHD symptoms but are common comorbidities. Because of this, they may be diagnosed with other disorders, and doctors may not even suspect ADHD.

There is a persistent myth that ADHD just goes away on its own once a person reaches adulthood. For a few people, that does seem to be true. However, data published in March 2021 by the ADHD Institute made an effort to correct the notion that this happens in most cases — according to its worldwide review, about 50 to 65 percent of kids with ADHD become adults with ADHD. But not everyone agrees that those are even the right numbers. A 2021 study published in the American Journal of Psychiatry found that only 10% of 588 kids with ADHD followed over a 16 year period "outgrew" the disorder when they reached adulthood. Researchers attributed that 50% number to the fact that most studies tended to only check in with participants one time when they were adults, and ADHD symptoms in adulthood often "wax and wane" over time as stressors and environments change. ADHD may also look different in adults than it does in children. According to the Cleveland Clinic, hyperactivity in adults may manifest as restlessness, and impulsivity may appear in the form of impulse buying and other irresponsible behavior.

The criteria for diagnosing ADHD seems pretty straightforward, but still, it's a really subjective process. You can't diagnose ADHD with a single test (via CHADD). Instead, clinicians have to do some sleuthing. They look at information about a child's behavior at school and at home, and compare it to that of other kids of the same age. If that seems problematic to you, that's because it is. In fact, according to a 2005 paper published in Psychiatry, the subjective nature of the diagnosis may be leading to overdiagnosis of ADHD. The doctor who determines whether or not a child has ADHD doesn't usually observe any of the symptoms firsthand — they have to rely on what parents and teachers have to say about a child's behavior. And because kids with ADHD are eligible for more academic support, there can be an incentive to obtain an ADHD diagnosis even when a child's problems may stem from elsewhere.

ADHD has long been thought of as a childhood disorder, and the idea that kids will just "grow out of it" almost certainly contributed to the myth that adults can't have ADHD (via ADHD Awareness). But not only has the research shown that most people don't outgrow their symptoms (via ADHD Institute), it's also starting to reveal that adult onset ADHD might actually be a thing.

Despite diagnostic criteria that at least some symptoms have to be present before age 12 (per the CDC), there is some evidence that childhood ADHD may not be a prerequisite for adult ADHD. A four decades-long study published by The American Journal of Psychiatry, in fact, found that adults with ADHD don't always have a history of childhood ADHD. And it's not just a few adults, either — the study found that a whopping 90% of people with adult ADHD had no history of the disorder as children. It is important to note that the authors weren't able to say for sure that the adults in the study had ADHD rather than another disorder with similar symptoms. And there is also the possibility that many of them did have ADHD as kids, but failed to accurately recall their symptoms.

Besides medication, clinicians usually recommend some form of behavior therapy to help patients manage ADHD symptoms (per CDC). For children, this includes support both for kids and for their parents. According to the CDC, a good behavioral therapy program teaches kids how to strengthen positive behaviors and eliminate or reduce behaviors that can be disruptive or counterproductive. Meanwhile, parents learn strategies for supporting their children and helping them deal with some of their most challenging symptoms. It's worth noting that the American Academy of Pediatrics doesn't recommend behavior therapy alone, but suggests combining it with medication in order to maximize its benefits.

For adults, cognitive behavioral therapy (CBT) has been shown to be helpful in managing ADHD symptoms. According to CHADD, this type of therapy focuses on the present instead of looking into the past. There are forms of CBT that have been developed specifically for adults with ADHD, so people who don't feel like their disorder is well-managed on medication alone may be able to find help with a CBT therapist. Again, it's a good idea to combine CBT with medication rather than trying to manage symptoms with CBT alone.