What Is ADHD? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Attention deficit hyperactivity disorder (ADHD) is a chronic condition characterized by impulsive behavior, inattention, and hyperactivity.

It's usually diagnosed in childhood, but symptoms of ADHD can continue unrecognized through adolescence and adulthood, so it may not be diagnosed for the first time until someone is an adult. With proper treatment, children and adults with ADHD can live successful, highly productive lives.

Attention deficit disorder (ADD) is an older term for what's now known as ADHD. While some people still use the terms ADD and ADHD interchangeably, and may call the condition ADD if a child only has trouble focusing and isn't hyperactive, ADHD is officially recognized as the correct term for the diagnosed condition by the current version of the American Psychiatric Association’s诊断与统计手册精神Disorders(DSM).

The condition was commonly referred to as ADD until 1987, when “hyperactivity” was added to the name in the third edition of the DSM. When the revised, fourth edition of the DSM was published in 1994, ADHD was divided into specific subtypes, taking into account the fact that an individual could be diagnosed with ADHD without having symptoms of hyperactivity. (1)

There are three forms — or “presentations” — of ADHD, as referred to in the fifth edition of the DSM (DSM-5), published in 2013. (2)

1. Predominantly Hyperactive-Impulsive

People with this type of ADHD mostly struggle with hyperactivity and impulsiveness, though they may also have some symptoms of inattentiveness.

Hyperactivity includes constant movement and excessive fidgeting and talking. In adults, this may take the form of exaggerated restlessness and an activity level that other people find tiring.

Impulsivity involves making important decisions and taking action without thinking through the consequences, especially when those actions might be harmful or detrimental and the resulting effects long lasting.

Impulsivity is also marked by a desire for instant gratification. In social situations, an impulsive person might interrupt others to an extreme degree, and be quick to grow impatient, frustrated, or angry. (3)

2. Predominantly Inattentive

People in this category mainly have symptoms of inattentiveness, though they may also have some problems with hyperactivity and impulsiveness. This form used to be (and sometimes still is) called ADD.

Inattentiveness is characterized by struggling to stay focused, being easily distracted from the task at hand, and a lack of persistence or organization. (4) This can result in professional and personal difficulties because of a lack of attention to detail and failure to make important deadlines, meetings, and social functions.

3. Combined Hyperactive-Impulsive and Inattentive

People in this group have symptoms of hyperactivity, impulsiveness, and inattentiveness. Most children have this combined type; but the most common symptom of ADHD in preschool-age children is hyperactivity. (2)

Children who are hyperactive may talk excessively, squirm and fidget, and have trouble sitting still. In childhood, impulsivity can take the form of impatience, disruptiveness, and difficulty waiting for a turn. Inattention can include daydreaming, difficulty following instructions, forgetfulness in daily activities, and trouble focusing.

In adults, ADHD symptoms may take the form of impulsiveness, frequent interrupting, restlessness, inability to concentrate, a lack of organization and follow-through, difficulty meeting deadlines, frequent mood swings, and difficulty coping with stress.

Learn More About ADHD Symptoms

Experts aren't sure what causes ADHD. Research suggests that the disorder has a neurobiological basis and a genetic component. (5)

Neuroimaging studies using magnetic resonance imaging (MRI) scans to look at brain structure have found neural circuits associated with ADHD. These circuits are related to sustained attention, control of inhibitions, motivation, and regulation of emotions. (6) But it’s unclear whether ADHD behaviors result from abnormal neural connections or whether there is neural adaptation because of symptoms. (6)

Not all people with ADHD show the same circuits or changes in circuits, but certain differences are more common in people with ADHD than those without it.

Several factors may increase a child's likelihood of developing ADHD.

Genetics

Current evidence suggests ADHD is genetic — meaning it seems to run in some families. (6)

The specific genes have not yet been identified, and scientists believe multiple genes may be involved because it’s such a complex condition. (7) These genes may have to do with the processes of certainneurotransmitters, such asdopamine, which plays a role in the brain’s reward systems and in regulating impulsivity and movement.

Environmental Exposure to Toxins and Chemicals

Exposure to substances, especiallylead, may be a contributing factor. Studies have indicated a relationship between ADHD and levels of lead in the bloodstream. One study, published in theJournal of Child Psychology and Psychiatry, found that lead exposure was associated with the impulsivity-hyperactivity combined type of ADHD, but not the inattentive type. (8)

Although the connection between lead and ADHD has been consistently demonstrated in research, it’s important to note that lead exposure is not the only cause of ADHD, nor does lead exposure guarantee that a child will develop ADHD.

Other environmental toxins, such as bisphenol A (BPA) and phthalates, have more recently been found to be potentially problematic for brain health. But the connections between these toxins and ADHD have not yet been established.

Alcohol or Tobacco Use During Pregnancy

Use of tobacco during pregnancy has been associated withADHD symptoms in childrenin a number of studies. But more recent research has questioned whether the use of these substances directly causes ADHD.

A study published in April 2016 in theJournal of Child Psychology and Psychiatryfound no support for a causal association between smoking during pregnancy and ADHD. (9) Similarly, a study published in October 2017 in theInternational Journal of Epidemiologyfound that maternal alcohol use during pregnancy was weakly, though perhaps causally, associated with reported ADHD symptoms but not with clinical diagnoses of ADHD. (10) Still, pregnant women should refrain from alcohol consumption and smoking because of other well-established risks.

Traumatic Brain Injury (TBI)

TBI in early childhood has been linked to the development of psychiatric disorders. Among those disorders, ADHD is the most common, with a prevalence of about 20 percent, notes a study published in the May 2018 issue ofJAMA Pediatrics.(11)TBI is not uncommon— more than two million Americans seek emergency treatment for it each year.

Premature Birth or Low Birth Weight

一些研究表明相关性沿着gradient — that the lower the birth weight or the earlier the birth is, the greater the risk of ADHD. A meta-analysis and review of 34 studies, published in January 2018 inPediatrics,confirmed this, showing an even stronger association with the development of ADHD when birth weight was extremely low or the birth was extremely preterm (defined as before 28 weeks). (12)

Diet and Behavioral Factors

Too much sugar or food additives in the diet and excessive screen time (television, smartphones, tablets, and computers) have been associated with ADHD. While these factors may affect or exacerbate symptoms, research doesn't support claims that they cause ADHD.

RELATED:What Is an Elimination or Exclusion Diet?

Though many people lose focus, get distracted, and act impulsively on occasion, these behaviors are more severe and more frequent for people with ADHD. Without proper identification and treatment, these behaviors negatively affect their quality of life, whether it’s at work, school, or home.

There’s no single ADHD test used to diagnose the disorder. A thorough evaluation by a professional — such as a psychologist,psychiatrist,pediatrician, or clinical social worker — is necessary for a proper diagnosis, which rules out other conditions and considers possible coexisting conditions.

The process involves several steps, and your healthcare provider may perform a full medical exam and get a detailed medical history, as well as conduct interviews with family members to gather an in-depth personal history. (4)

The DSM-5 requires that ADHD diagnoses include a statement about the severity of the condition, from mild to moderate to severe. (13)

ADHD in Adults

Adult ADHD can cause problems with relationships, work performance, and self-esteem. Many adults with ADHD don't know they have it; they may only know that everyday tasks are challenging. Symptoms can change over time. Some people notice that their symptoms improve as they age, while others continue to struggle.

According toRussell Barkley, PhD, a clinical professor of psychiatry at the Virginia Commonwealth University Medical Center in Richmond, ADHD symptoms arise in a set of mental abilities called the executive functions.

The executive functions encompass a range of processes in the brain, mostly in the frontal areas, that control and manage other brain activities that allow us to get work done — whether it’s creative or more routine; to set and achieve goals; and to take into consideration the potential consequences of our actions and regulate our behavior.

Dr. Barkley, the author ofAttention Deficit Hyperactivity Disorders: A Handbook for Diagnosis and Treatment, among many other books, breaks this down into several areas, including self-awareness, inhibition or self-restraint, working memory (meaning actively keeping in mind what you are supposed to be doing in order to achieve a goal or complete a task), time management, emotional self-control, self-motivation, and planning or problem-solving.

Prognosis of ADHD

The long-term prognosis of ADHD depends on whether a person is being treated with medication, behavioral or talk therapy, or both.

A meta-analysis published inBMC Medicinelooked at more than 351 studies in areas such academic performance, antisocial behavior, addictive behavior and drug use, self-esteem, and social function outcomes. Researchers found that without treatment, people with ADHD had poorer outcomes in all categories compared with people without ADHD. Investigators found that treatment for ADHD produced better long-term outcomes compared with untreated ADHD, though not usually to the levels of people without the disorder. (14)

A large Danish study published in theLancet发现ADHD是显著相关的increased mortality rates. The early deaths were largely driven by unnatural causes, especially accidents. (15)

Research indicates that ADHD persists in about 65 percent of adults who were diagnosed as children, including adults in partial remission. (16)This estimate is based on several large prospective long-term follow-up studies, but much of the research does not use the same criteria to determine diagnosis and rates of persistence and remission, which makes it difficult for experts to determine the precise number of people who have shown remission.(17)

There's no cure for ADHD, but the right treatment approach can help control many symptoms. This usually involves medication, certain behavioral strategies, and lifestyle changes to help with focus and organization.

For children ages 4 to 6 years old with ADHD, the American Academy of Pediatrics (AAP) recommends behavioral therapy as a first-line treatment, before medication. (18)

Medication is recommended for children age 6 and older. Medications used for treating ADHD include stimulants, nonstimulants, and sometimesantidepressants.

People with ADHD may also benefit from counseling — especially behavioral therapy — to improve behaviors and social skills. Parents and other family members may participate in counseling to develop strategies for dealing with problematic situations.

Certain lifestyle changes and accommodations can create a better environment for people with ADHD. These include routines and schedules, reorganization of your home or workspace, physical reminders of tasks at hand, and removal of distractions.

适当的,综合治疗可以帮助控制DHD symptoms and lead to improved quality of life.

Medication Options

Stimulants are used to improve focus and block out distractions in people with ADHD. This class of drug is considered to be the most effective and helps in 70 to 90 percent of people with ADHD. (19)

Nonstimulant medications can be used for ADHD in childrenwho haven’t had success with a stimulant medication or who have certain coexisting conditions. (20)

ADHD medications are available in different formulations: short-acting, intermediate-acting and long-acting. These drugs can have side effects such as appetite suppression, difficulty sleeping, and irritability. (19) A prescribing physician can determine whichmedication for ADHDis best, describe possible side effects, and explain the pros and cons of medication treatment for ADHD in general.

Alternative and Complementary Therapies

Although there are many different types of supplements and diets that people have tried to treat ADHD, most don’t have enough evidence for experts to recommend using them. You should always check in with a healthcare professional before trying a new diet or supplement.

According to the Academy of Pediatrics, the following alternative and complementary therapies are not supported by scientific evidence and are not recommended: (21)

• Megavitamins and mineral supplements
• Anti-motion-sickness medication (intended to treat the inner ear)
• Candidayeast infection treatment
• EEG biofeedback (training intended to increase brain wave activity)
• Applied kinesiology (intended to realign bones in the skull)
• Reducing sugar consumption
• Optometric vision training

Learn More About Treatment Options for ADHD

Prevention of ADHD

Although genetics are thought to be one of the main risk factors for ADHD, there are a few health behaviors that may reduce the likelihood that a child will have the disorder. (22)

• During pregnancy, the mother should avoid any activities or substances that could harm the development of the fetus. Examples include alcohol, smoking, and recreational drugs.
• Children should be protected from pollutants and toxins such as lead paint or cigarette smoke.
• Although a direct link between screen time and ADHD has not been established, experts recommend limiting the amount of TV and video games in the first five years of life.

Untreated ADHD can lead to several emotional and physical complications, including:

• Poor self-esteem
• Accidents and injuries
• Substance abuse
• Delinquent or risky behavior
• Trouble interacting with peers; relationship difficulties
• Excess weight andeating disorders
• Sleep problems

超过三分之二的人患有ADHD在least one other coexisting condition, whose symptoms can sometimes be hard to distinguish from those of ADHD. (23)

ADHD affects nearly 9 percent of school-age children. According to the Centers for Disease Control and Prevention (CDC), 11.7 percent of American boys and 5.7 percent of girls have been diagnosed with ADHD. (24)

ADHD is more frequently diagnosed in boys, but research suggests that it may be underidentified and underdiagnosed in girls.

A study published in the journalBMC Psychiatrynoted that girls more commonly present with the inattentive subtype of ADHD and that their behavior may sometimes be characterized as less outwardly disruptive. (25) Many women don’t receive a proper diagnosis until they’re adults. (26)

ADHD affects more than 4 percent of adults in the United States, according to the National Institute of Mental Health. (27) But that statistic includes only adults who have been formally diagnosed, so the actual number is likely to be much higher.

More than three-quarters of children with ADHD continue to experience significant symptoms in adulthood, according to the organization Children and Adults With Attention-Deficit/Hyperactivity Disorder (CHADD). (13)

Research has demonstrated the existence of racial and ethnic disparities when it comes to the diagnosis and treatment of ADHD.

A study published inPediatricsthat examined rates of ADHD diagnosis from kindergarten to eighth grade showed that Hispanic children were 56 percent less likely to be diagnosed with ADHD than white children, and Black children were 36 percent less likely to be diagnosed than white children. (28)

Investigators also found that Hispanic and African American children diagnosed with ADHD were much less likely than white children to use prescription medication for the disorder. (28)

Another study, published in March 2021 inJAMA Network Open, yielded similar findings. Researchers found that Black and Hispanic children were significantly less likely to be diagnosed with ADHD or receive treatment than white children.(29)

Children with ADHD may be more likely to have other conditions, such as:

• Anxiety
• Bed-wetting
• Bipolar disorder
• Conduct disorder, a condition characterized by behaviors such as lying, stealing, fighting, or bullying
• Depression
• Learning disabilities
• Oppositional defiant disorder (ODD), a condition characterized by a pattern of hostile behavior toward authority figures
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• Tourette syndrome, a neurological disorder characterized by nervous tics and repetitive mannerisms

From diagnosis to treatment, ADHD poses many challenges for people who have the disorder and their loved ones. Fortunately, there are resources available to help navigate life with ADHD. Use them to locate a medical expert or coach, and get advice on managing your own condition or parenting a child with ADHD.

Attention Deficit Disorder Association (ADDA)

This worldwide community of adults with ADHD aims to empower members to discover and reach their potential. ADDA offers virtual support groups, professional directories, and volunteer opportunities.

Child Mind Institute

This organization is an independent national nonprofit dedicated to transforming the lives of children and families struggling with mental health and learning disorders through education, research, and care.

Children and Adults With Attention Deficit/Hyperactivity Disorder (CHADD)

This nonprofit aims to improve the lives of people affected by ADHD. The organization has chapters all over the country that offer support, education, and advocacy.

Learning Disabilities Association of America

The vision of the organization is to create opportunities for success for all individuals affected by learning disabilities through support, education, and advocacy.

Learn More About ADHD Resources and Terminology