What Is ADHD? An Overview of Attention-Deficit/Hyperactivity Disorder in Children and Adults
Many individuals and families seek support not only to understand ADHD, but to learn how to navigate attention, emotional regulation, and performance demands in daily life.
Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental condition that affects how a person pays attention, regulates impulses, and manages energy levels. ADHD shows up differently across individuals and across the lifespan, which is why understanding what ADHD is — and what it isn’t — can be incredibly helpful for parents, adults, and caregivers.
How Common Is ADHD in Children and Adults?
According to the CDC approximately 11.4% of children in the US (ages 3-17) have been diagnosed with ADHD. Boys are diagnosed more often than girls at 15%. However, there is research to suggest that ADHD symptoms present differently in girls and therefore symptoms are often missed. Approximately 6% of US adults have an ADHD diagnosis.
What Causes ADHD? (Brain-Based Differences)
ADHD is primarily related to differences in the structure and function of the brain, particularly in areas responsible for executive functions like planning, focusing, and self-control.
The main impacted areas are:
Neurotransmitters:
People with ADHD often have lower levels and/or less efficient use of key neurotransmitters (the messengers in the brain) especially dopamine and norepinephrine which are important for regulating attention and motivation.
Brain Structure & Activity:
The prefrontal cortex, the brain's "command center" for executive functions, may develop slower or have less activity.
Other circuits connecting this area to the rest of the brain may also be different.
This leads to difficulties in switching focus, managing impulses, and staying organized.
These differences are not a result of laziness, lack of effort, or poor parenting. ADHD is a brain-based condition, and with the right understanding and support, individuals with ADHD can thrive.
The Three Types of ADHD
According to the latest diagnostic manual (DSM-5-TR), there are three main presentations, or types, of ADHD, depending on which set of symptoms are most prominent.
Combined Presentation
This is the most common type. Significant number of symptoms from both the Inattention and the Hyperactivity-Impulsivity categories.
Predominantly Inattentive Presentation
This type is often referred to as "ADD" (Attention Deficit Disorder) though the official term is now ADHD.
Symptoms are often less disruptive in a classroom setting, so this type is sometimes missed, especially in girls, who may seem quiet or "daydreamy" rather than disruptive.
Predominantly Hyperactive-Impulsive Presentation
This is the least common type of the three, especially as people age.
Symptoms include constant movement, excessive talking, restlessness, and difficulty waiting their turn.
Common ADHD Symptoms
ADHD exists on a spectrum, and not every individual will experience all of the symptoms listed below. Many people with ADHD also show incredible creativity, energy, empathy, and problem-solving skills.
Symptoms of ADHD typically fall into two main categories. It’s important to note, this is not an all-inclusive list of symptoms. Additionally, ADHD is just one of several concerns some of these symptoms can be attributed to, and therefore, experiencing these symptoms is not a guarantee for an ADHD diagnosis.
Inattention (Difficulty with Focus)
Making careless mistakes or overlooking details.
Having trouble sustaining attention during tasks or play.
Not seeming to listen when spoken to directly.
Failing to follow through on instructions and finish schoolwork, chores, or work duties.
Having difficulty organizing tasks and activities.
Frequently losing necessary items (e.g., keys, wallets, homework).
Being easily distracted by unrelated thoughts or stimuli.
Hyperactivity and Impulsivity (Difficulty with Self-Control)
Fidgeting, tapping hands or feet, or squirming in their seat.
Inability to stay seated when expected to.
Running or climbing in situations where it is inappropriate.
Being unable to engage in leisure activities quietly.
Talking excessively.
"Blurting out" answers before questions have been completed.
Having trouble waiting their turn.
Interrupting or intruding on others.
Note: For a diagnosis, these symptoms must be long-lasting, present in multiple settings (like at home and school/work), and interfere with social, academic, or occupational functioning.
ADHD and Co-Occurring Conditions
ADHD is often comorbid with other mental health diagnoses. According to a national 2022 parent survey, nearly 78% of children with ADHD had at least one other co-occurring condition. Some of the most common comorbidities were anxiety, behavioral or conduct issues, depression, autism spectrum disorder, Tourette Syndrome.
How Is ADHD Diagnosed?
If you or your child are wondering if you have ADHD, a comprehensive evaluation by a qualified healthcare professional is the best next step. ADHD cannot be accurately diagnosed through online quizzes or checklists alone. Dr. Katie provides thorough ADHD evaluations and is happy to discuss whether an assessment may be appropriate.
You can learn more about the evaluation process and what to expect by exploring our assessment services.
References
American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.).
Centers for Disease Control and Prevention. (2024, November 19). Data and statistics on ADHD. Retrieved from https://www.cdc.gov/adhd/data/index.html
Danielson ML, Claussen AH, Bitsko RH, et al. ADHD Prevalence Among U.S. Children and Adolescents in 2022: Diagnosis, Severity, Co-Occurring Disorders, and Treatment. J Clin Child Adolesc Psychol. Published online May 22, 2024.
