What is ADHD?
Attention Deficit Hyperactivity Disorder (ADHD), also referred to as Attention Deficit Disorder (ADD), is the most common neurodevelopmental condition. ADHD is known to arise from various genetic and neurological sources, though these can be influenced by interactions with hazards in the environment that lead to neurological damage or maldevelopment, especially during prenatal development.
- An estimated 8.4 percent of children are diagnosed with ADHD. Two-thirds of children diagnosed with ADHD continue to have signs of ADHD as adults. An estimated 2.5 percent of adults are diagnosed with ADHD.
- ADHD is one of the most common conditions that we evaluate in teenagers and adults. If left untreated, ADHD can cause significant impairment in school, at work, and in an individual’s social life.
- ADHD might seem like a fairly straightforward condition to diagnose but based on our experience that’s not always the case.
- ADHD is often incorrectly diagnosed and most people don’t understand what ADHD is.
- ADHD symptoms include poor attention, hyperactivity, and impulsivity, yet, how these symptoms manifest and affect children, adolescents, and adults can differ greatly.
- The presentation of ADHD is often different in females. Females typically experience internalizing disorders such as anxiety and depression and much more rarely exhibit externalizing disorders such as oppositional-defiant disorder. Research indicates a greater risk of suicidal behavior in girls.
- Over 80% of children and adults with ADHD are likely to have a second psychiatric, learning, or developmental disorder and more than 50% have two or more such disorders, such as oppositional defiant disorder, learning disabilities, conduct disorder, anxiety disorders, depression, and to a much lesser extent autism spectrum disorder and bipolar disorder.
Individuals with ADHD have difficulty with skills that involve executive function. Executive functions include the following:
- Working Memory: The ability to keep information in your mind to use it later. For example, to read a paragraph and answer questions or to read a math problem and solve it in your head.
- Cognitive Flexibility (Flexible thinking): The ability to think about something in more than one way. For example, figuring out an alternate way to achieve a goal or the desired result.
- Inhibitory Control (Self-Control): The ability to ignore distractions, resist impulses and control your emotions and behaviors. For example, waiting for your turn to speak in class rather than blurting out a question or answer.
Neurobiology of ADHD
Brain Regions of Interest in ADHD
In ADHD, several brain regions have been of interest in understanding the underlying neurobiology and symptoms associated with the disorder, while the exact mechanisms and involvement of each region may vary among individuals.
The main regions of the brain that are impacted by ADHD include the following:
- Dorsolateral Prefrontal Cortex (DLPFC): regulates working memory, sustained attention, executive functions
- Orbitofrontal Cortex (OFC): regulates impulsivity and reward processing
The above-mentioned regions of the brain are responsible for a variety of executive functions ranging from those that require inhibition of motor responses to those that require task switching and cognitive flexibility.
Additional regions that are impacted by ADHD include the following:
Limbic System: The limbic system, which includes structures like the amygdala and hippocampus, regulates emotions, memory formation, and motivation.
Reticular Activating System: regulates wakefulness, attention, and sleep-wake transitions)
ADHD Diagnostic Process
Several types of professionals can diagnose ADHD, including clinical psychologists, clinical social workers, nurse practitioners, neurologists, psychiatrists, and pediatricians.
Regardless of who does the evaluation, he or she will make a clinical decision following a comprehensive clinical evaluation, which can include, but is not limited to:
1. Physical examination
2. Clinical interviews
3. Parent/teacher/self-reports by use of validated rating scales
4. Objective ADHD tests, such as the T.O.V.A.®
What Are the Signs & Symptoms of ADHD?
Based on information gathered during a clinical comprehensive evaluation, a diagnosis is made when the child or adult’s ADHD symptoms meet the criteria as set out in a medical classification system called the Diagnostic and Statistical Manual of Mental Disorders – 5th edition (DSM-5). ADHD can look different depending on the type of ADHD that the person has. We’ve included an overview of The DSM-5 diagnostic criteria for ADHD below.
Based on the types of symptoms, three subtypes of ADHD can occur:
- Combined Presentation: if enough symptoms of both criteria inattention and hyperactivity-impulsivity were present for the past six months
- Predominantly Inattentive Presentation: if enough symptoms of inattention, but not hyperactivity-impulsivity, were present for the past six months
- Hyperactive-Impulsive Presentation: if enough symptoms of hyperactivity-impulsivity, but not inattention, were present for the past six months.
1. Inattention
Six or more symptoms of inattention for children up to age 16, or five or more for adolescents 17 and older and adults; symptoms of inattention have been present for at least 6 months, are inappropriate for developmental level, and negatively impact directly on social and academic/occupational activities.
Symptoms are:
- Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or with other activities.
- Often has trouble holding attention on tasks or play activities.
- Often does not seem to listen when spoken to directly.
- Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (e.g., loses focus, side-tracked).
- Often has trouble organizing tasks and activities.
- Often avoids, dislikes, or is reluctant to do tasks that require mental effort over a long period of time (such as schoolwork or homework).
- Often loses things necessary for tasks and activities (e.g. school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).
- Is often easily distracted.
- Is often forgetful in daily activities.
2. Hyperactivity and Impulsivity
Six or more symptoms of hyperactivity-impulsivity for children up to age 16, or five or more for adolescents 17 and older and adults; symptoms of hyperactivity-impulsivity have been present for at least 6 months to an extent that is disruptive and inappropriate for the person’s developmental level and negatively impact directly on social and academic/occupational activities.
Symptoms are:
- Often fidgets with or taps hands or feet, or squirms in seat.
- Often leaves seat in situations when remaining seated is expected.
- Often runs about or climbs in situations where it is not appropriate (adolescents or adults may be limited to feeling restless).
- Often unable to play or take part in leisure activities quietly.
- Is often “on the go” acting as if “driven by a motor”.
- Often talks excessively.
- Often blurts out an answer before a question has been completed.
- Often has trouble waiting for his/her turn.
- Often interrupts or intrudes on others (e.g., butts into conversations or games)
In addition, the following conditions must be met...
- Several inattentive or hyperactive-impulsive symptoms were present before age 12 years.
- Several symptoms are present in two or more settings, (such as at home, school, or work; with friends or relatives; or in other activities).
- There is clear evidence that the symptoms interfere with, or reduce the quality of, social, school, or work functioning.
- The symptoms are not better explained by another mental disorder (such as a mood disorder, anxiety disorder, dissociative disorder, or personality disorder).
- The symptoms do not happen only during schizophrenia or another psychotic disorder.
