ADHD

ADHD Assessments

Have you felt different?

What is ADHD?

Attention-Deficit/Hyperactivity Disorder, is a neurodevelopmental condition that affects how people pay attention, stay still, and control impulses. It usually shows up in childhood but can continue into adolescence and adulthood. Key features include Inattention and Hyperactivity-impulsivity.

ADHD Facts

Undiagnosed ADHD can be detrimental to mental health. Inattentiveness is not laziness, lack of motivation or incompetence. Hyperactivity is not insensitivity or self-centeredness. Understanding how your brain works allows necessary accommodation, personal growth and a kinder inner voice.

ADHD symptoms often feel like stress, anxiety and frustration about not following through. You are, however, not alone. 6.2% of adults in the US live with ADHD. 56% of adults with ADHD, lived with undiagnosed ADHD through adolescence, only receiving their diagnoses in adulthood. Advances in research and assessment methods now make it possible to accurately diagnose those who have flown under the radar, providing clarity and support with a condition that impacts all areas of your life.

We provide the highest quality clinical assessments, considering all possible contributing factors and the impact of undiagnosed ADHD on your development.

Kinds of ADHD?

There are three possible presentations. 

  • ADHD, predominantly inattentive presentation, where the main challenge is inattention and distractibility. People with the inattentive presentation may seem forgetful, have trouble organizing tasks, and miss details.
  • ADHD, predominantly hyperactive-impulsive presentation, struggle with hyperactivity and impulsivity, with fewer or milder inattentive symptoms. People with the hyperactive/impulsive presentation may fidget, have trouble staying seated, talk a lot, and act without thinking.
  • ADHD, combined presentation, have both inattention and hyperactivity-impulsivity  impairing functioning.
What conditions are required for a formal Diagnosis?
  • ADHD is diagnosed when a persistent pattern of inattention and/or hyperactivity-impulsivity occurs, that interferes with functioning or development. 
  • Several symptoms of inattention were present before age 12.
  • Several symptoms are present in two or more settings (e.g., home, school, work).
  • Clear evidence that the symptoms interfere with, or reduce the quality of, social, academic, or occupational functioning.
  • The symptoms are not better explained by another mental disorder and are not exclusively during the course of another condition (e.g., schizophrenia, mood disorder) or by another medical issue.
How does ADHD impact a person?

ADHD can affect many parts of a person’s life. The impact of ADHD goes far beyond inattention and impulsivity. It often has a serious effect on social, emotional and occupational functioning and identity formation. Difficulties with staying organized can strain relationships, frequent frustration by others about forgetfulness can lead to discouragement and low self-esteem and other might misinterpret symptoms as laziness and carelessness. People with ADHD are more likely to be involved in motor vehicle accidents, not complete college, lose a job, get divorced, struggle with obesity, depression and anxiety. Some people do not like the idea of being labelled, feeling there is something wrong with them.

What is ADHD Screening?

ADHD screening is a quick process used to check whether an individual displays common ADHD symptoms and should have a full diagnostic evaluation. Screening is usually done with brief questionnaires or checklists, and its purpose is to identify people who may need a more thorough assessment. Screening is not a diagnosis.

What is a Formal Assessment for ADHD?

The purpose of a formal assessment is the diagnosis of ADHD. When symptoms are very clear and obvious, a diagnosis can be made by a general practitioner. For others, symptoms may be more subtle, hidden behind strong intellectual abilities or career successes, requiring more in-depth assessment by a qualified clinical psychologist. 

What to Expect for ADHD Assessment (Adults)

An adult evaluation for ADHD will include a review of developmental, medical and psychological history, structured activities to assess cognitive functioning, and completion of questionnaires. An important part of an ADHD evaluation is collecting information on the adult’s childhood and developmental history. This could involve the participation of someone such as a parent, sibling, or relative who can report on early developmental history.

What Kinds of Tests are used to Assess ADHD?

There are a number of different psychological and neuropsychological measures used in an ADHD evaluation. Assessment starts with a clinical interview and self-report measures like the ASRSv1.1, Conners Adult ADHD Rating Scale and the Copeland Symptom List clarifying the extent and severity of experienced symptoms. Self-report measures are cross referenced with objective tests like the Test of Variable Attention or QbCheck, measuring certain cognitive abilities and then comparing them to other same age peers who have been diagnosed with ADHD. Finally, observer measures like the Conners Adult ADHD Rating Scale, observer report and collateral interviews are provide important confirmatory data.

What Causes ADHD?

ADHD isn’t caused by one factor. It’s best thought of as the result of multiple interacting influences - genetic, brain development, and environmental factors. Genetics is a big factor. ADHD runs in families. Heritability is high (roughly 70–80% in many studies). A family history of ADHD or related traits increases risk.

Differences in brain networks involved in attention, self-control, and impulse regulation are related. Other contributing factors include prenatal exposure to substances, premature birth or low birth weight, lead exposure or other environmental toxins. Early adversity or high-stress environments may influence how symptoms appear or persist, though they’re not sole causes.

Why do some clients only get tested in Adulthood?

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Our Process

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ADHD Facts

Undiagnosed ADHD can be detrimental to mental health. Inattentiveness is not laziness, lack of motivation or incompetence. Hyperactivity is not insensitivity or self-centeredness. Understanding how your brain works allows necessary accommodation, personal growth and a kinder inner voice.

ADHD symptoms often feel like stress, anxiety and frustration about not following through. You are, however, not alone. 6.2% of adults in the US live with ADHD. 56% of adults with ADHD, lived with undiagnosed ADHD through adolescence, only receiving their diagnoses in adulthood. Advances in research and assessment methods now make it possible to accurately diagnose those who have flown under the radar, providing clarity and support with a condition that impacts all areas of your life.

We provide the highest quality clinical assessments, considering all possible contributing factors and the impact of undiagnosed ADHD on your development.

Hand holding a sticky note with 'ADHD' written in colorful letters.

Why Adult Seek ADHD Assessment

1. Symptoms were masked by intelligence, structure, or support

Many adults with ADHD did “well enough” in childhood:

  • High intelligence, strong memory, or creativity compensated for attention issues
  • Parents, teachers, or routines provided external structure
  • School demands didn’t yet exceed coping capacity

Once adult life removes structure (college, work, parenting), symptoms become unmanageable—and finally visible.

2. ADHD stereotypes focused on hyperactive boys For decades, ADHD was narrowly defined as:

  • Young
  • Male
  • Physically hyperactive

Adults—especially women, inattentive types, and high-masking individuals— were overlooked. Many were mislabeled as:

  • Lazy
  • Anxious
  • Depressed
  • “Not trying hard enough”

They often seek assessment only after learning that ADHD can look very different in adults.

3. Symptoms were misattributed to personality or mental health

Common adult ADHD traits are often misinterpreted as:

  • Anxiety (constant overwhelm, racing thoughts)
  • Depression (burnout from chronic effort)
  • Low self-esteem (years of perceived failure)
  • Character flaws (“disorganized,” “irresponsible”) Adults may pursue assessment only after years of ineffective treatment for these secondary issues.

4. Adult responsibilities expose executive function deficits

ADHD often becomes unmistakable when life requires:

  • Long-term planning
  • Self-directed work
  • Time management without supervision
  • Balancing work, relationships, finances, and health

Many adults say, “I was coping… until I wasn’t.” The assessment is triggered by burnout, job instability, or relationship strain.

5. Growing awareness and reduced stigma Recent changes have made adult assessment more likely:

  • Increased public education and social media awareness
  • Better diagnostic criteria for adults
  • Seeing themselves in others’ stories
  • Greater acceptance of neurodiversity

Many adults seek assessment after a child, partner, or colleague is diagnosed— and it suddenly clicks.

Our Process

Step 1: Contact Our Care Coordinator

a. Register as client
b. Complete administrative documents
c. Receive links for pre-assessment
d. Provide contact details of someone that can tell us about you. Someone that knows you very well and preferably has known you since childhood. Parents or close family or friends are often good options.

Step 2: Complete Pre-Assessment

a. Complete all questionnaires as accurately as possible. The accuracy of results depends on the accuracy of your answers
b. Once submitted your scores will be available for Dr. N’s review

Step 3: Meet With Dr. Nieuwenhuizen (2-4 hours)

a. This online meeting may last 2-3 hours. Feel free to have snacks available. We can take short breaks when needed
b. Dr. Nieuwenhuizen will ask questions about your symptoms, mental health history, medical history, family history and your early development.
c. Additional assessments requiring real-time interaction will be administered.
d. Dr. Nieuwenhuizen will answer any questions you may have.
e. Following your one-on-one meeting, Dr. Nieuwenhuizen will gather, score and interpret your data and write your report.

Step 4: Feedback.

a. One all the data is collected, your report will be complete in less than two weeks. At that time Dr. N will email you and schedule your online feedback session/
b. The feedback session can be anywhere from 15 minutes to 1 hour, depending on the discussion.
c. After the feedback session, Dr. N will forward a signed PDF copy of the report to your email.

Famous People with ADHD

ADHD poses challenges and opportunities. If managed effectively you can be very successful.

Top 7 Famous Actors/actresses Diagnosed With ADHD

7- Zooey Deschanel

Zooey Deschanel is famous actress who has demonstrated that living with ADHD may not be that difficult. Although she is not using any ADHD treatment, she is proudly overcoming Attention Deficit Hyperactivity Disorder with her own methods by doing craft projects on Hello Giggles.

Close-up portrait of a young woman with blue eyes and dark hair.

6- Emma Watson

She is best known for her Hermione Granger role in “Harry Potter.” She was diagnosed with ADHD when she was a kid. Although she has never talked about her condition and that she has struggled with ADHD for a long time, many sources like ADDitude Magazine have confirmed that it’s true.
Close-up of a woman with light makeup and a serious expression.

5- Michelle Rodriguez

She has been one of the most open famous people with ADHD by willingly sharing the story of her condition in one of the interviews she had with Cosmopolitan Magazine. She didn’t let ADHD move ahead of overtake her career. In fact, she got to play important roles in famous TV series and movies such as Lost and Fast & Furious.
A young woman with long dark hair smiling, wearing a white tank top and a heart-shaped necklace.

4- Woody Harrelson

Another award-winning actor that we would like to mention among famous people with ADHD is Woody Harrelson. Obviously ADHD symptoms couldn’t beat his passion for becoming a great actor.
Portrait of a middle-aged man with a friendly expression and a close-cropped beard.

3- Ryan Gosling

He won not only hearts but also a Golden Globe. Ryan Gosling is another example of someone who struggled in school years because of his ADHD, but had the strength to turn it into an award-winning career in Hollywood.
Close-up of a man with light hair and beard wearing a striped suit jacket.

2- Will Smith

Not only an award-winning actor, but also a producer and rapper, Will Smith also claims that he has ADHD. Forbes ranked him among the “most bankable stars” so his success is more than evident despite his condition.

Smiling man with a neatly trimmed beard and short hair.

1- Jim Carrey

Award-winning actor Jim Carrey is also a celebrity who struggles with ADHD. The famous actor has actually won our hearts by bravely using all the symptoms to his advantage - in the characters he plays.

Portrait of a smiling man with dark hair in a dark setting.

Top 5 Famous Athletes Diagnosed With ADHD

5- Karina Smirnoff

Karina is a great example of athletes who have ADHD and who always strive for more. She has a variety of interests like dancing, ice skating, playing the piano, and gymnastics. She is using medication to stay focused and it seems to work for her. So far, she has become a five-time champion U.S., National Champion, World Trophy Champion.

Smiling woman with red lipstick and yellow blouse.

4- Simone Biles

She is an award-winning gymnast. She has won 19 world championships and Olympic gold medals despite her struggle with Attention Deficit Hyperactivity Disorder. She was diagnosed with ADHD when she was a child and has used medication ever since.

Focused gymnast preparing for a routine in a sparkling leotard.

3- Michael Phelps

When he was a child, his teacher told him that he wouldn’t be able to succeed in anything in life. But Michael didn’t surrender to his ADHD and became a great swimmer winning 23 Olympic gold medals.

Swimmer celebrating a victory with a fist pump at the poolside.

2- Terry Bradshaw

Focusing and standing still can be challenging for children and adults with ADHD. Terry was also experienced difficulties in school and decided to shift his concentration to sports. Eventually, he became a Super Bowl Champion.

Football player in black and yellow uniform running with the ball.

1- Michael Jordan

He is known as the greatest basketball player of all time. Yet, he was never completely content with what he had achieved and he always tried to discover himself, which is also considered a common symptom of ADHD.

Michael Jordan in a Bulls jersey during a basketball game.

Top 6 Famous Singers Diagnosed With ADHD

6- Loyle Carnel

Carnel is a believer that Attention Deficit Hyperactivity Disorder helped him in becoming a successful singer and musician. When he was young, he couldn’t figure out what the problem was, but after he was diagnosed with ADHD and dyslexia, he turned it into something positive for his life.

A man with curly hair wearing a white shirt stands against a light background with palm tree shadows.

5- Solange Knowles

Solange is one of the famous people who initially refused to believe that she had Attention Deficit Hyperactivity Disorder. Yet, she managed to become a successful, famous singer, songwriter, and artist. However, after becoming more aware of the symptoms, she claimed that many people in the industry may have ADHD.

Woman with voluminous curly hair and pink lipstick smiles at the camera.

4- Will.i.am

You may rogue l remember him as a member of the Black Eyed Peas. William is a great example of someone who can see ADHD’s positive sides. In an interview with the Mirror, he claims that this disorder helped him become successful in his music career by saying “For every obstacle, there’s some type of solution. So if you have ADHD it’s your passion point.”

Black and white portrait of a man with glasses and a leather jacket.

3- Adam Levine

Levine was diagnosed with ADHD when he was a child. Although he started medication, he still struggles with ADHD symptoms. Being the frontman of the famous Maroon 5 group, Adam proved that you can be a successful famous regardless of your ADHD condition.

Portrait of a smiling man with dark hair and beard.

2- Justin Timberlake

He is one of the most famous stars in the world. He managed to rock ADHD as he did rock your body. Although he doesn’t speak too much about how he succeeded to live with ADHD, in an interview with Collider he mentions his condition by saying “I have OCD mixed with ADD. You try living with that.”
 
Portrait of a smiling man in a checkered shirt and blazer.

1- John Lennon

The singer, songwriter, and peace activist John Lennon is also believed to have had Attention Deficit Hyperactivity Disorder. He was having so much difficulty in class that he dropped out of school. However, he successfully managed to live with ADHD and became one of the most famous people in the world.
Close-up of a man with glasses and long hair.

Top 4 Famous Authors Diagnosed With ADHD

4- Dav Pilkey

The famous writer and illustrator Dav Pilkey is known for his Captain Underpants book series. He was punished at school several times because of his acting out that was a result of his ADHD. He started creating the famous book series during a detention time at school.
Man drawing a cartoon character on a large paper pad.

3- Agatha Christie

Agatha Christie is one of the most famous writers of all time. Her books are translated in 103 different languages and four billion copies are sold in total. She had not been diagnosed with ADHD in her lifetime but it is commonly known that she had difficulties due to dysgraphia.
Black and white portrait of a man sitting with a book in hand.

2- George Bernard Shaw

The writer of more than 100 plays, Shaw deeply criticized the existing education system of his time . A lot of people believe Shaw had ADHD that prevented him from accepting the education system as it was at the time.
Black and white portrait of an elderly man with white hair and beard.

1- Jules Verne

The father of the science fiction genre and a huge inspiration for the steampunk stream, Verne had a hard time in school He was unable to focus on the school tasks and projects but he was into writing from an early age. Although he was not diagnosed with ADHD, it is commonly accepted today that he probably suffered from this condition.
Black and white portrait of an elderly man with white hair and beard.

Top 6 Famous Historical Figures Diagnosed With ADHD

6- Walt Disney

Walt Disney, the creator of Mickey Mouse, one of the first and biggest cults of the animation world, is also on the list of those who struggled with ADHD especially due to the difficulties he experienced during his school years.
Black and white photo of Walt Disney with a Mickey Mouse puppet.

5- Wolfgang Amadeus Mozart

Mozart, the genius of classical music and one of the biggest composers of the 18th century, is among those who struggled with ADHD according to the US National Library of Medicine National Institutes of Health.
Portrait of Wolfgang Amadeus Mozart in 18th-century attire.

4- Alexander Graham Bell

Bell, the inventor of the phone, gained his innovative and problem-solving personality thanks to his struggle with ADHD even though he had serious problems during his school years.
Portrait of a distinguished elderly man with white hair and beard.

3- Thomas Edison

The man who brought light to our lives, the award-winning American inventor Edison, is also believed to have had ADHD. His hyperactivity led him to the urge to always learn and discover something new.
Black and white portrait of Thomas Edison in a suit and bow tie.

2- Albert Einstein

Einstein is one of the most important physicists of the 20th century. He was known for his carelessness and forgetfulness. But Einstein is another award-winning, famous person to prove that it is possible to be successful and productive with ADHD.
Black and white portrait of Albert Einstein with thoughtful expression.

1- Leonardo Da Vinci

Da Vinci is another instance of a famous person that lived with ADHD. The difficulty of focusing on one single thing due to ADHD caused him to be interested in many different subjects. He was an artist, sculptor, inventor, scientist, musician, architect, anatomist, astronomer, and a mathematician.
Portrait of an elderly man with a long white beard and solemn expression.