Some people with ADHD mostly have symptoms of inattention. Others mostly have symptoms of hyperactivity and/or impulsivity. Some people have both types of symptoms.

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It is common for people to experience inattention, excess activity, and impulsivity some of the time. But, for people with ADHD, these behaviors:

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• Are more severe

• Occur more often

• Interfere with or impair functioning in social situations, at school, or at work

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Inattention

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People with symptoms of inattention may often:

• Overlook or miss details and make seemingly careless mistakes during school, work, or other activities

• Have difficulty sustaining attention during play, work, or tasks, such as conversations, lectures, or homework

• Not seem to listen when spoken to directly

• Find it hard to follow through on instructions or finish work, chores, or assignments  

• Start tasks but lose focus and get easily sidetracked

• Have difficulty organizing tasks and activities, doing tasks in order, keeping track of materials and belongings, managing time, and meeting deadlines

• Avoid tasks that require sustained attention, such as doing homework, preparing reports, completing forms, or reading long papers

• Lose important things, such as school supplies, books, wallets, keys, paperwork, eyeglasses, and cell phones

• Be easily distracted by unrelated thoughts or stimuli

• Be forgetful in daily activities, such as completing chores, running errands, returning calls, and keeping appointments

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Hyperactivity-impulsivity

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People with symptoms of hyperactivity and impulsivity may often:

• Fidget and squirm while seated

• Leave their seats in situations when staying seated is expected, such as in the classroom or at the office

• Run, dash around, or climb at inappropriate times or, in teens and adults, feel frequently restless

• Be unable to play or engage in hobbies quietly

• Be constantly in motion or act as if driven by a motor

• Talk excessively or interrupt others

• Answer questions before they are fully asked, finish other people’s sentences, or speak when it is not their turn in a conversation

• Have difficulty waiting, for example, in conversations, games, or activities

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Primary care providers sometimes diagnose and treat ADHD. They may also make a referral to a mental health professional, such as a psychiatrist or psychologist, who can do a thorough evaluation and make an ADHD diagnosis.

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For a person to receive an ADHD diagnosis, the symptoms of inattention and/or hyperactivity and impulsivity must:

• Be chronic or long-lasting

• Impair functioning

• Cause them to fall behind typical development for their age

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Stress, sleep disorders, anxiety, depression, and other physical conditions or illnesses can cause similar symptoms to those of ADHD. Therefore, a thorough evaluation is necessary to determine the cause of symptoms.

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Most people with ADHD receive a diagnosis during the elementary school years. For teens or adults to be diagnosed with ADHD, their symptoms must have been present before age 12.

Symptoms of ADHD can be mistaken for emotional or disciplinary problems or missed entirely in children who primarily have symptoms of inattention, leading to a delay in diagnosis. Adults with undiagnosed ADHD may have a history of poor academic performance, problems at work, or strained relationships.

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ADHD symptoms can change as a person ages.

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• In young children, hyperactivity and impulsivity are the most common symptoms.

• In elementary school, inattention may become more prominent, leading children to struggle academically.

• In adolescence, hyperactivity often lessens, and symptoms are more likely to include restlessness or fidgeting. Many teens with ADHD struggle with relationships and have a greater tendency to engage in risky behaviors, such as substance use or unsafe sexual activity.

• Adults with ADHD may be irritable, have a low tolerance for frustration and stress, or show frequent or intense mood changes. Inattention, restlessness, and impulsivity tend to persist into adulthood, although, in some people, those symptoms become less severe and less impairing.