What Is Adult ADHD? Defining ADHD in Adults

ADHD is often thought to be a childhood condition. And in many ways, it is; ADHD is one of the most common neurodevelopmental disorders affecting children. But it doesn’t only affect children. Adults can and do, live with ADHD, too.

Medically reviewed

Last update: August 16, 20225 min read

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    Around 4% of U.S. adults have a diagnosis of ADHD, and many more adults with ADHD symptoms are thought to be mis-or undiagnosed.

    What is ADHD?

    ADHD, or attention-deficit hyperactivity disorder, is a neurodevelopmental condition that causes people to have difficulty paying attention or controlling their impulses. ADHD also causes hyperactivity, making people have extra energy and find it hard to sit still.

    ADHD is understood as a mental health disorder that is usually diagnosed in childhood. But it is common for many people to not receive a diagnosis until adulthood. 

    What ADHD looks like in adults

    When many people think of ADHD, they imagine children running amuck in a classroom. But for adults, ADHD may present in different ways. 

    Although the settings in adulthood are different, adults with ADHD experience similar symptoms as in children. They may find their minds wandering during work meetings or long conversations, and have a hard time paying attention to detailed instructions. It might be hard for adults with ADHD to sit still for long periods of time. Although adults often develop some coping mechanisms they didn’t have as children, these symptoms can interfere greatly with their quality of life. 

    Adults with ADHD may also be forgetful; they may miss deadlines and important meetings or often lose things. Their space might be disorganized.

    Having ADHD in adulthood is also associated with being more impulsive than people without ADHD. For example, they might drive more recklessly, make big purchases on a whim or struggle with emotional regulation and reactions.

    ADHD, especially when it’s untreated, can severely disrupt adults’ day-to-day functioning. For example, it is common for an adult with unmanaged ADHD to have problems at work or in their relationships.

    Related: ADHD Symptoms in Adults: An Overview

    Types of ADHD

    According to the Diagnostic Statistical Manual (DSM-5), the book that mental health professionals use to diagnose psychiatric conditions, there are 3 types of ADHD. These are:

    • Hyperactive-impulsive type

    • Predominantly inattentive type

    • Combined type

    Related: ADHD Types: Hyperactive, Inattentive, Combined

    Hyperactive-impulsive type

    Adults with the hyperactive-impulsive type of ADHD have a hard time sitting still. You may have this type of ADHD if you often feel restless or you fidget or squirm a lot. People with this subtype of ADHD often feel the need to get up out of their seat even when they’re expected to stay seated. They usually have a hard time waiting their turn in line, sitting through movies or lectures. 

    If you have this type of ADHD, you might also struggle with impulsiveness. People may have told you that you talk too much or have “no filter.” You may interrupt people or finish their sentences even when you’re not intending to be rude.

    People with hyperactive-impulsive ADHD often say that they feel like they’re driven by a motor. They’re always on the go and find it hard to wind down even after an exhausting day.

    Predominantly inattentive type

    People with the inattentive type of ADHD have a harder time with focus than with hyperactivity. These are the people whose minds wander off during conversations or meetings because they are easily distracted by external or internal stimuli. If you have this type of ADHD, you might need to listen to instructions several times because you keep missing the details.

    Notes: Predominantly inattentive ADHD used to be called ADD, or attention-deficit disorder (without the hyperactivity). However, this diagnosis was changed (to ADHD, predominantly inattentive type) in the latest editions of the DSM.

    People with inattentive ADHD often have a hard time remembering or organizing their daily tasks. For example, you might miss important meetings or deadlines, and forget to complete tasks like paying your bills or even eating regular meals.

    You might also lose things on a regular basis. People with inattentive ADHD are the ones who are always searching for their car keys or phone. Their space might be very messy and disorganized.

    Women & ADHD

    Women are more likely to have the predominantly inattentive type of ADHD, which may contribute to the fact that women are less likely to be diagnosed as children.

    Related: How ADHD Is Different in Women: Signs & Symptoms

    Combined type

    This is the most common type of ADHD. People with combined ADHD have symptoms of both inattention and hyperactivity/impulsivity.

    What causes ADHD?

    Like other mental health conditions, there isn’t just one thing that causes ADHD. ADHD can be caused by many different factors, including genetics, neurobiology, and the environment.

    Is ADHD hereditary?

    ADHD does run in families. Research has shown that people who have a direct blood relative (like a parent or sibling) with ADHD are more likely to have ADHD themselves. In most cases, genetics are a significant factor in whether or not you have ADHD.

    That doesn’t necessarily mean that there’s an “ADHD gene” that you inherit. The way genetics interacts with your likelihood to have ADHD is a lot more complex than that.

    Can you develop ADHD as an adult?

    Although it may present differently, adult ADHD is the same condition as ADHD in childhood. Officially, you must have experienced symptoms of ADHD in childhood for a diagnosis. 

    In most cases, adults with ADHD did have symptoms in childhood. Whether or not they were ever noticed and addressed by their parents and teachers is another story. If you have ADHD symptoms as an adult, you probably had at least some symptoms as a child, as well.

    Late-onset ADHD

    Some experts now say that there is such a thing as “late-onset ADHD,” which is when ADHD symptoms don’t develop until young adulthood. Late-onset ADHD may be distinct from childhood-onset ADHD, although we need a lot more research to be able to say for sure.

    Getting help for ADHD

    ADHD is a chronic condition, but its symptoms can be managed. Many adults with ADHD live successful and fulfilling lives.

    Related: How Is Adult ADHD Treated?

    Common treatments for ADHD

    There are many different treatment options available to you if you have ADHD. These options include:

    • Stimulant medications

    • Non-stimulant medications

    • Behavioral intervention and strategies (like time management techniques)

    • Mental health therapy

    • ADHD coaching

    About ADHD stimulants

    Stimulant medications have been found to be effective around 70% of the time. Stimulants are a controlled substance, and some people with past or current stimulant use disorder decide to go with other treatment options.

    However, there is no evidence that suggests that taking stimulant medication as prescribed increases your risk for substance use disorder if you have ADHD.

    Each treatment option has pros and cons, and you should consider these carefully to choose options that are right for you. You don’t need to choose only one treatment option for ADHD, and a combination may be the most helpful. For example, many people with ADHD take medication but also use behavioral management tools. 

    Related: Choosing the Best Treatment Option for Adult ADHD [Pros and Cons]

    I think I may have ADHD

    If you think you might have ADHD, or you know someone who might, there are screening tools you can take that can help treatment providers provide an accurate diagnosis. Frida’s free assessment questionnaire is one tool that can let you know whether you might be eligible for an ADHD diagnosis.

    If you do receive a diagnosis of ADHD, there are treatment options available. Frida can help if medication is an option you want to pursue; we can also set you up with other treatment providers if you’re interested in non-medication options.


    Lisa Batten, PhD, CPT, PN1

    Lisa Batten is a clinical scientist, therapist, and writer specializing in neuroscience and clinical pharmacology. She has a master’s degree in clinical psychology and a Ph.D. in developmental psychology.