ADHD in Adults vs Children: Key Differences

In order to really understand the differences between ADHD in adults and ADHD in children, it’s important to recognize that ADHD symptoms change over time. This is why many of us have a hard time recognizing the signs of adult ADHD!

The “classic” ADHD symptoms we are used to hearing about and seeing in movies start to evolve over time. They shift away from the stereotypical outward hyperactivity symptoms seen in children, towards more subtle, internalized challenges that can be harder to spot.

There’s a long-standing myth that ADHD is something you “grow out of.” In most cases, this isn’t true. As you get older your life changes, the same is true for your ADHD symptoms. Oftentimes, new responsibilities in adulthood are what leads a person to seek a diagnosis.

Whether you’re pursuing an ADHD diagnosis for yourself, for your child, or simply want to be more educated on how ADHD presents differently in adults compared to children, reading this blog is a step in the right direction. Keep reading to learn more!

Key Points:

• ADHD symptoms can change as you get older.
• ADHD tends to present as externalized “easy to spot” behaviors in children, while ADHD in adults tends to present as internalized “harder to spot” behaviors.
• Adult ADHD is often overlooked, but that doesn’t mean it’s not serious. Even highly successful people who put in great effort to mask symptoms can experience repercussions of undiagnosed ADHD, whether in the form of emotional distress or tangible daily impacts.
• The diagnostic requirements for ADHD are different for adults and children.

ADHD in Children vs Adults: Common Signs and Behaviors

I’d like to start by pointing out that there are three different types of ADHD under the general ADHD umbrella, each with different presentations. The three types of ADHD are Inattentive, Hyperactive-Impulsive, and combined type. Let’s go over how inattentive type ADHD and hyperactive-impulsive type ADHD presents in both children and adults.

Inattentive ADHD Signs in Children vs Adults

First, let’s talk about inattentive ADHD signs. You might relate to these situations/behaviors or you might notice them in your kids.

Children:

• Getting distracted easily
• Making mistakes that seem careless to others
• Trouble organizing tasks or activities
• Losing focus or getting sidetracked when completing tasks at home or at school
• Losing items necessary for activities more often than other kids
• Avoidance, dislike of, or reluctance to engage in tasks requiring sustained mental effort
• Often seeming as though they aren’t listening when spoken to directly
• Trouble holding attention on tasks or play activities.
• Forgetfulness.

Adults:

• Trouble listening
• Difficulty prioritizing or planning
• Avoidance, dislike for, or reluctance to engage in tasks requiring sustained mental effort
• Frequently misplacing, losing, or leaving important items behind
• Getting distracted more easily than others
• Trouble following instructions properly or fully, starting but not finishing tasks
• Often forgetting things like bills, appointments, social commitments, and deadlines.
• Making seemingly careless mistakes, unintentionally overlooking details.
• Difficulty sustaining attention on tasks or activities.

Hyperactive-Impulsive ADHD Signs in Children vs Adults

Now let's go over the hyperactive-impulsive ADHD signs in both children and adults.

Children:

• Always being “on the go" or acting as though they’re “driven by a motor”
• Interrupting or intruding on others
• Leaving their seat at times when remaining seated is expected, such as in the classroom or at a restaurant.
• Often running around or climbing in situations where it’s inappropriate to do so.
• Trouble waiting for their turn
• Blurting out answers to questions before they’ve been completed.
• Fidgeting, squirming, or tapping hands and feet.
• Difficulty playing quietly.
• Excessive talking

Adults:

• Making rash decisions without thinking about the consequences.
• Trouble partaking in activities quietly
• Fidgeting or needing/struggling not to move around often
• Always needing to be busy, jumping from one activity or interest to another.
• Interrupting or intruding on other people’s conversations and activities.
• Easily feeling impatient, low frustration tolerance.
• Blurting things out.
• Excessive talking.
• Feeling restless.

While some of the listed ADHD symptoms might seem similar in both kids and adults, there is a clear difference in how children and adults deal/cope with these symptoms.

Adults also have more responsibilities than children and daily stressors that create different challenges than those faced in childhood. Let’s dive into identifying what the key differences between adult ADHD and childhood ADHD really are.

Key Differences Between Adult and Childhood ADHD

As we saw above, kids and adults with ADHD can share some symptoms. But, how they manifest–and the way they impact a person's life—differs significantly. Key differences in adult vs. childhood ADHD often include:

Internalized ADHD Symptoms

ADHD symptoms often become more internalized as an adult. What does that mean? A kid with ADHD might show more observable external symptoms, like running around in class or jumping up and down while struggling to wait their turn.

Adults however, tend to have better control and are good at internalizing any signs of struggle. For example:

• An adult with ADHD waiting their turn might feel restless or impatient. They are internally struggling but are able to bottle up that restlessness and hide it from people.
• A child with ADHD waiting their turn will be more likely to make disruptive movements to signal that they are impatient and tired of waiting. They might wave their arms around, jump up and down, or try to interrupt others. It’s important to note that not all children aggressively externalize their symptoms but most do. For instance, female children with inattentive ADHD have been known to be good at internalizing their symptoms. This is why ADHD can be harder to spot in females than in males.

Masking ADHD symptoms

Masking is when you “camouflage” signs of a condition through intense effort. It can involve things like excessive planning, over-organizing, suppressing hyperactivity, and over-compensating. Adults tend to be better at masking then children are, however, masking creates its own set of problems.

Masking isn’t sustainable. It can cause exhaustion, burnout, and new or worsened mental health symptoms (e.g., increased anxiety, depression, low self-esteem), a lost sense of identity, and difficulty understanding your own needs.

Life Stressors and Responsibilities

Life stressors and responsibilities play a role in differentiating adult ADHD from childhood ADHD. As we get older, we take on more daily responsibilities and challenges in life, such as:

• Financial strain (impulse buying, forgetting to pay bills on time, trouble organizing or managing finances, forgetting about money you spent).
• Problems at work (struggling to hold a job, making mistakes at work, choosing jobs where symptoms don’t interfere).
• Strained relationships or trust (due to things like frequent lateness, forgetting about events, or double-booking).

While children often have parents or teachers to provide external structure, reminders, and guidance, adults have to manage on their own and usually don’t have the needed support system. On top of that, adults are managing a higher volume of high-stakes tasks compared to children.

Adult ADHD can take a serious emotional toll, particularly if it’s unmanaged or you don’t have the needed support. Low self-esteem, anxiety, depression, and substance abuse are some examples of risks associated with undiagnosed ADHD.[1]

How ADHD Symptoms Change Over Time

Now that we’ve pointed out three of the main ways ADHD can affect adults vs children differently, let’s go into more detail on how these symptoms change over time. We picked two ADHD symptoms to help put things into perspective:

Forgetfulness

• Children: A child is given instructions to put pajamas on and brush their teeth before bed. Their parent goes to check on them and finds the child playing on the bathroom floor with pajamas in hand. While they started the task, they might have gotten distracted and forgotten that they had to brush their teeth. The parent will then remind them to put their pajamas on and brush their teeth.
• Adults: An adult might forget to pay rent or their electricity bill. Because of this, they run the possibility of falling behind on payments, incurring late fees, getting evicted, or getting the power turned off.

Organizational Struggles

• Children: A child who struggles with organization often leaves a trail of physical clutter behind them. This looks like a messy desk at school, a bedroom floor covered in toys, or a backpack filled with crumpled assignments. Because they struggle to prioritize tasks or manage their time, they are often late to get ready for school, requiring a parent to step in and help them organize their day so they don't fall behind.
• Adults: An adult with these same struggles often experiences "mental" and professional disorganization. Instead of a messy desk, this might look like a chaotic digital inbox, a calendar full of double-booked appointments, or an inability to break a large work project into manageable steps. These struggles can lead to missing major deadlines or arriving late to important meetings, which may result in a job loss or passed-over promotions.

Both the children and the adults in these examples are experiencing the same core ADHD symptoms. However, as these examples illustrate, the way those symptoms manifest and impact a person's life evolves significantly over time

For a child, forgetfulness is often managed by an adult who provides the 'executive function' they lack—reminding them to finish a task or to get ready on time. Children often have an adult to serve as their "safety net”.

For an adult, that safety net is gone. The same 'mental glitch' that caused a child to forget their homework now causes an adult to forget a project deadline or a mortgage payment.

In adulthood, the symptom doesn’t just result in a scolding; it results in a 'stress loop' where real-world consequences of being forgetful or disorganized (along with all the other ADHD symptoms) create a cycle of anxiety and stress which can make it even harder to manage ADHD symptoms.

ADHD Diagnosis: Adults vs Children

What’s different about diagnosing ADHD in adults vs. children? ADHD requires a thorough diagnostic process no matter what. But, there are a few key factors that change. Mainly:

• The number of symptoms you need for a diagnosis: Rather than needing 6 or more symptoms, which is the case for those ages 16 or under, people ages 17 or older must have 5 or more symptoms of inattention, hyperactivity, or both, to get diagnosed with ADHD, according to DSM-5 criteria.[2]
• Symptom presentation: For older teens and adults, diagnostic criteria acknowledges that ADHD symptoms may present in different ways. As a common example, “Running about or climbing in inappropriate situations” as a child may turn into feeling restless as an adult.
• History taking: While history-taking is always part of the process to some degree, there may be a special focus on questions about your symptoms in childhood if you’re an older teen or adult. Medical records, report cards, and bringing someone who has known you for a long time to your evaluation can be helpful.

ADHD Treatment Approaches: Adults vs. Children

Just as symptoms can present differently in adults vs. children, the recommended treatment approach varies by age.[3]

• For kids aged six or younger: It’s recommended that you start with therapy options such as parent training in behavior management. Parent training in behavior management for ADHD provides guardians with specific skills and strategies to help children with the condition. Since younger kids can have more medication side effects, they’re not typically started on ADHD medication unless interventions like parent training do not work on their own.
• For kids aged 6+: It is recommended that interventions like parent training, classroom accommodations/modifications, and skills training be combined with medication. There are stimulant and non-stimulant medication options for ADHD. Stimulants are effective for 70-80% of children with ADHD. They are considered the first line of treatment, as they're safe for most and usually work the best.
• Teens and adults: Teens and adults may need to implement new strategies as they get older and their responsibilities grow. Psychoeducation (education regarding how ADHD works and how to manage it), medication, and therapy options tailored to the person's needs are often ideal.

When to Seek an ADHD Evaluation

Are you wondering if you should seek an ADHD evaluation for yourself or your child? Early detection and intervention is always best, as it can reduce the impact of misunderstood or unmanaged symptoms. It’s never a bad idea to get a professional opinion if you suspect ADHD. It will also help rule out other possible causes as part of the diagnostic process.

You may want to consider an ADHD evaluation for your child if:

• They display symptoms of inattention, hyperactivity, or impulsivity for six months or more.
• There is functional impact (e.g., grades, ability to complete homework or school work, emotional outbursts, trouble maintaining friendships, not keeping up with their grade level in areas like reading–these can differ from child to child).
• These symptoms affect two or more areas of their life (e.g., school, chores, hobbies or play, friendships).

Adults may want to consider an ADHD evaluation for themselves if:

• Symptoms affect two or more areas of your life (home, work, school, family life, relationships, self-care).
• Symptoms started before age 12, even if they changed over time or you learned to hide them.
• Symptoms impede functioning or quality of life.

There is no need to try to "tough it out” or struggle in silence. The information and self-understanding that comes with a proper diagnosis can make a world of difference in a person’s life.

ADHD Testing and Treatment in Chicago

Finding a professional who approaches mental health care with both compassion and expertise matters. Clarity Clinic provides a wide range of mental health specialists who specialize in testing and treating ADHD for children, teens, and adults.

We have multiple convenient clinic locations throughout the Chicagoland area such as the Loop, River North, Lakeview Belmont, Lakeview Broadway, Evanston, and Arlington Heights. For added flexibility, we also offer online appointments for Illinois residents.

Give us a call at (312) 815-9660 or book an appointment with us online for comprehensive, caring, and personalized ADHD services. Click the button below to begin browsing our list of qualified nurse practitioners, physician assistants, Psychiatrists, and therapists for ADHD. 

Related Readings:

• ADD Vs ADHD: What You Need to Know
• Is ADHD a Disability?
• ADHD vs Autism: Signs, Symptoms, & Differences

ADHD In Adults vs Children FAQs

References

[1] French, B., Daley, D., Groom, M., & Cassidy, S. (2023a, October). Risks associated with undiagnosed ADHD and/or autism: A mixed-method systematic review. Journal of attention disorders. https://pmc.ncbi.nlm.nih.gov/articles/PMC10498662/

[2] Substance Abuse and Mental Health Services Administration. (n.d.-a). Table 7, DSM-IV to DSM-5 attention-deficit/hyperactivity disorder comparison - DSM-5 changes - NCBI bookshelf. DSM-5 Changes: Implications for Child Serious Emotional Disturbance [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK519712/table/ch3.t3/

[3] Centers for Disease Control and Prevention. (2024, May 15). Treatment of ADHD. https://www.cdc.gov/adhd/treatment/index.html