While doctors generally consider attention deficit hyperactivity disorder (ADHD) a childhood neurodevelopmental disorder, they may diagnose late onset ADHD in adults.

ADHD typically presents in children. The average age at diagnosis is 7 years old for people with mild symptoms and 4 years old for those with more severe symptoms. ADHD is the most common neurodevelopmental disorder in children and often lasts into adulthood.

For years, experts believed that ADHD in adults was a continuation of the childhood disorder and that a diagnosis in adulthood may be due to missed symptoms or past misdiagnosis.

More recently, researchers have looked into the idea that adults may develop a form of ADHD independent of the childhood version.

This article examines what the medical community knows about adult ADHD, how doctors diagnose ADHD in adults, the symptoms of ADHD, and more.

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The Centers for Disease Control and Prevention (CDC) and other agencies refer to ADHD as a condition that occurs in childhood and can last into adulthood. However, growing evidence suggests that ADHD can develop for the first time in adults.

A 2016 study found enough evidence to conclude that ADHD in adulthood is not necessarily a continuation of childhood ADHD. Instead, adult ADHD and childhood ADHD may be two distinct syndromes.

Another 2016 study noted that childhood ADHD and late onset adult ADHD may have different causes. The authors suggest that future research should look into possible genetic differences to further understand the condition.

These findings support a 2015 study, which found evidence suggesting that adult onset ADHD may not occur with earlier childhood symptoms or diagnosis of the condition.

Evidence suggests that adult ADHD may affect 2.5–5% of the population.

Read more about ADHD.

Doctors can diagnose ADHD in adults. However, research suggests that fewer than 20% of adults with ADHD receive a diagnosis and treatment. Additionally, 17–22% of adults who seek help for other mental health conditions end up getting an ADHD diagnosis.

To receive an ADHD diagnosis, a person must meet the following criteria:

  • They have 5 or more persistent symptoms of inattention or 5 or more persistent symptoms of hyperactivity-impulsivity.
  • Their symptoms occur in 2 or more settings.
  • Their symptoms interfere with school, work, or social functioning.

Inattention symptoms can include:

  • difficulty paying attention for long periods
  • difficulty completing forms
  • a tendency to lose their phone, their keys, or other important items
  • trouble staying organized
  • easy distraction
  • forgetfulness
  • trouble focusing when speaking to someone

Hyperactivity symptoms can include trouble with:

  • engaging in leisure activities
  • sitting still
  • taking turns
  • interrupting others
  • fidgeting or tapping the feet or fingers

Like children with ADHD, adults may present with more inattention, more hyperactivity, or a combination of the two.

Symptoms of ADHD can change over time. Also, a person may present with symptoms differently based on their age.

Early years

In young children, symptoms of ADHD may appear as:

  • making careless mistakes in schoolwork
  • running around and displaying a lot of energy
  • disrupting class or getting up when they should be seated
  • easily losing things
  • talking too much
  • having difficulty staying focused or completing tasks

Teenage years

Symptoms can present differently in teenagers than in younger children. ADHD diagnosis in teenagers is often challenging for several reasons:

  • The criteria require symptoms to be present before age 12, but parents or teens may not remember what symptoms occurred before.
  • Many of the symptoms listed as criteria are geared toward younger children and may not be present or as obvious in teens.
  • It may be more challenging to identify and report behaviors because no one person sees the teen throughout the day.
  • The symptoms may be similar to those that occur in children but more subdued in teens.
  • The presence of other mental health conditions may complicate the diagnosis or cause misdiagnosis of another condition, such as depression, anxiety, or substance use disorders.


Adults may present with similar symptoms affecting their attention or activity levels, but symptoms will likely look slightly different from those in children. Symptoms can include:

  • restlessness
  • an inability to complete work on time
  • disorganization
  • trouble staying focused on tasks or conversations
  • a tendency to lose important items
  • a tendency to try to do more than one thing at once
  • a desire for quick fixes to issues
  • difficulty keeping employment

Learn more about adult ADHD.

Experts do not yet know the exact cause of ADHD, but research is looking into possible genetic factors.

Researchers also suspect that several factors may interact to cause ADHD. Social environment, brain injuries, and nutrition may play a role.

There is no cure for ADHD. However, treatments can help a person manage their symptoms. Treatment may include one or more of the following therapies:

  • Medications: These work on the brain to help improve focus or attention to tasks.
  • Psychotherapy: Though it may not be effective by itself, therapy can provide additional support when a person uses it in conjunction with medication.
  • Complementary approaches: The use of complementary treatments, such as supplements and other therapies, may help some people manage their symptoms.

A person should consider discussing their concerns with a healthcare professional before starting or stopping any treatments for ADHD.

The following sections provide answers to frequently asked questions about ADHD.

What can trigger ADHD in adults?

Experts do not know the exact cause of ADHD, but they suspect that genetics, brain injuries, nutrition, and social environment may all play a role in its development.

What are signs of ADHD in adults?

ADHD can display differently in adults than in children. Adults may present with symptoms such as:

  • trouble holding down a job
  • restlessness
  • trouble focusing on large tasks or conversations
  • a tendency to lose things
  • forgetfulness of events, schedules, or appointments
  • disorganization
  • a tendency to fidget when sitting

How does ADHD show in females?

Young females may be better able to mask their symptoms due to factors such as getting better grades and having different social support than males. They may start to notice symptoms of ADHD in adulthood or the older teenage years as the factors responsible for their ability to mask the condition start to disappear.

Learn more about ADHD differences in males and females.

What does untreated ADHD in adults look like?

Adults with ADHD may have difficulty getting along with others at work or in social settings. They may forget things often, have trouble finishing projects, or display constant high energy levels. They may seem disorganized or interrupt conversations.

Learn more about untreated ADHD in adults.

ADHD can develop in adults or become apparent for the first time in adulthood. Evidence suggests that adult onset ADHD may have different causes than childhood onset ADHD.

ADHD at any age can cause issues with attention or hyperactivity. However, the condition can present differently in children, teens, and adults. Adults with ADHD may have trouble at work or in social settings.

Treatment can help with ADHD in both children and adults. The main treatment is medication, but psychotherapy and complementary therapies may also help.