What is adult ADHD?

Adult ADHD (attention deficit hyperactivity disorder) is a disorder characterized¹ by impulsive behavior, hyperactivity, inattention, and/or trouble focusing.

ADHD starts in childhood. However, many adults don’t realize they have had it for their whole lives. They may have adapted strategies to compensate for the ways it has negatively impacted their lives. They also may have learned coping skills that mitigate the symptoms or methods of making their symptoms less apparent to those around them.

While ADHD occurs in people of all ages, its symptoms present somewhat differently in adults than in children. They may appear minor compared to the same symptoms in children. In some cases, symptoms may be camouflaged so well that only those very close to a person would suspect or be able to tell that they have ADHD.

How common is ADHD in adults?

About 10 million² adults have ADHD. In the United States, about 4%³ of adults have the condition (roughly 8 million people).

Despite these large numbers, it is suspected that only about 20% of people with ADHD have been diagnosed with the disorder. Of those people, only 25% seek help in any given year.

Because adults aren’t diagnosed with ADHD as frequently as children, it’s hard to determine the exact number of cases there are. There may be quite a few more people struggling with adult ADHD than is suspected. Any information about these numbers is extrapolated from the most accurate data available at the time.

Adult ADHD causes

Research into the exact causes of ADHD is ongoing. While scientists are not yet sure of the exact cause or causes of the disorder, some factors⁴ that may contribute to one’s likelihood of developing ADHD include:

• Genetics: Adult ADHD—and ADHD in general—runs in some families. Some research indicates that certain genes may play a role in who has the disorder and who does not.

Even if genes do play a part, scientists believe that they are not the sole determinants of who gets ADHD. Having a specific gene may predispose a person to ADHD, but that gene can be activated or inactivated based on other factors in a person’s life.

• Issues during development: ADHD is, in part, a disorder of the central nervous system. Problems at key points in the central nervous system’s development may contribute to the disorder.

Research has not shown which issues or which developmental points are key, though it appears that smoking and drinking during pregnancy makes it more likely that the child will be born with ADHD.

• Environmental factors: Environmental factors, such as exposure to lead during childhood, seem to produce similar to those of ADHD. These factors may interact with genes to turn them or cause the genes to change, resulting in ADHD.

As of now, researchers have identified correlations between environmental factors and ADHD but do not know the mechanisms behind how they determine who ends up developing the disorder.

Risk factors for ADHD

These factors⁵ can contribute to a person’s likelihood of developing ADHD. Not everyone who experiences these risks will go on to develop ADHD. However, exposure to these risks raises the chances that a person will have the condition.

• Brain injury: This can take place during birth or in an accident afterward. Those with brain injuries are more likely to have ADHD than those without. ADHD caused by brain injury may be fundamentally different than ADHD caused by genetic or environmental factors, even though the symptoms present similarly.
• Alcohol and tobacco use during pregnancy: While it is not a guarantee that doing so will cause ADHD in a child, mothers who use these substances more frequently give birth to babies with ADHD than mothers who do not.
• Premature delivery: Babies born early (before the 37th week of pregnancy) are more likely to have ADHD than those born after a full term. This may be caused by the trauma that early birth can cause in the central nervous system.
• Low birth weight: This can sometimes occur along with premature delivery. Babies born with low weight have an increased risk of ADHD. Researchers aren’t yet sure exactly how birth weight affects the brain.

Adult ADHD symptoms

Adults with ADHD experience similar signs and symptoms as children with the same diagnosis. However, the symptoms may be milder or less apparent in adults.

Common signs of ADHD in adults⁶ include:

• Impulsivity
• Poor time management; difficulty prioritizing tasks
• Disorganization
• Trouble multitasking
• Poor planning or an inability to plan ahead
• Restlessness
• Difficulty focusing
• Excessive fidgeting or moving around
• Frequent mood swings
• Low frustration tolerance
• Short temper, especially under stress
• Difficulty dealing with stress or functioning in stressful situations
• Difficulty following through on or completing tasks
• Difficulty meeting deadlines
• Making careless mistakes, especially on tasks not seen as enjoyable or worthwhile
• Inability to pay attention to details
• Forgetting routine tasks or chores
• Frequently losing or misplacing important everyday items (such as car keys, house keys, phone, wallet, etc.)
• Difficulty listening intently during conversation or paying attention without the appearance of listening

There are three types⁷ of adult ADHD: hyperactive, inattentive, and combined. While any person with ADHD can exhibit any of the symptoms listed above, certain symptoms will be more prominent based on the type of ADHD that is diagnosed.

People with hyperactive ADHD do not struggle with inattention. Instead, they are overactive. They may seem to be constantly moving around, no matter what is going on. They may fidget or walk around the room. They might also interrupt people or struggle with impulse control. People with this type of ADHD often find it hard to wait in line or listen to directions. They may even be more prone to accidents than others.

Those with inattentive ADHD aren’t overactive—instead, they struggle to focus on the tasks in front of them. They may become easily distracted during everyday tasks or seem to frequently daydream. They may be forgetful: frequently missing appointments, forgetting names, or getting things wrong in their calendars. People with inattentive ADHD often have trouble sticking to routines because they may not remember what to do next or may become distracted and forget where they were in a task.

A person with combined ADHD has symptoms of both hyperactivity and inattentiveness in equal parts.

ADHD in adult women

ADHD often looks different in women (and in girls) than it does in men. In fact, women are more likely to present with inattention rather than with hyperactivity or even impulsivity.

Because of this, they may not fit the stereotypical notion that people with ADHD are restless or overactive. In fact, they may seem more passive than active because their minds have trouble focusing. As a result, many women with ADHD go undiagnosed⁸.

Women tend to have more internalized symptoms of ADHD, like inattentiveness, rather than externalized symptoms, such as hyperactivity. They may also have developed effective coping strategies⁹ to help hide their symptoms or to achieve their goals in spite of these symptoms. Research is unclear as to whether women are inherently more likely to develop these strategies, or whether they simply have more time before they are diagnosed with ADHD to develop them.

As adults, many women¹⁰ are diagnosed only after one of their children receives a diagnosis of ADHD. When a child is diagnosed with the disorder, parents often try to learn more about ADHD and, sometimes, the mother realizes that she struggles with those same symptoms herself. At that point, she may seek a diagnosis for herself and learn about treatment options alongside her child.

While women may have the same symptoms of ADHD that are listed above, they are more likely to experience the following problems¹¹, as well:

• Dysphoria (bad, unpleasant, or “down” moods)
• Depression
• Anxiety
• Psychological distress caused by the above conditions
• Low self-esteem
• Compulsive overeating
• Alcoholism
• Chronic sleep deprivation
• Underachievement
• Smoking at a young age
• Teen pregnancy
• Learned helplessness¹²: being more likely to resign in the face of negative situations than blame themselves (which is a more common reaction in women without ADHD) Women may place heavier emphasis on different areas of treatment in order to manage and overcome the symptoms of ADHD. Women may also be more likely to need multiple treatments to learn to live with ADHD and its negative impacts on life. While women may choose to take medication for their ADHD, they may also need therapy to overcome the psychological impacts of ADHD, such as learned helplessness, low self-esteem, anxiety, and more.