ADHD Overview and Symptoms

Attention Deficit Hyperactivity Disorder (ADHD)

• ADHD is classified as a developmental disorder in the DSM-5.
• The core feature is a persistent pattern of inattention and/or hyperactivity-impulsivity.
• These behaviors must significantly impact development.
• Symptoms are not limited to one setting (e.g., school only).
• Context matters; symptoms may be less apparent under close supervision or during engaging activities.

Neurotypical Behavior

• A five-year-old is expected to sit through a lecture, listen to instructions before beginning an activity, follow directions, raise hands before speaking, and follow classroom rules.
• Age-related improvement occurs in memory and attention.
• Executive functions, such as attending to directions, raising hands, waiting quietly, and following rules, develop with age.

Introduction to ADHD

• ADHD is classified as a developmental disorder.
• Disorders often first evident in childhood are labeled as developmental disorders.

Diagnosis of ADHD

• ADHD is diagnosed as one of three types: inattentive type, hyperactive/impulsive type, or combined type.
• Diagnosis is based on symptoms that have been present for at least six months.
• Onset typically occurs before age 12.
• Defined diagnostic criteria are outlined in the DSM-5-TR.

Inattentive Type

• Easily distracted by extraneous stimuli (e.g. unrelated ideas or thoughts).
• Difficulty focusing on tasks and activities, including lectures, conversations, and reading.
• Difficulty with sustained attention to tasks.
• Does not seem to listen attentively when spoken to directly.
• Often loses items needed for tasks or daily activities.
• Makes careless mistakes in schoolwork, tasks or projects.
• Difficulty organizing tasks and work.
• Avoids tasks requiring sustained mental effort.
• Misses deadlines.
• Problems organizing tasks.
• Easily distracted by irrelevant thoughts, sounds, or other stimuli.
• Has difficulty focusing on tasks, even when there is a reward.
• Often loses focus and attention in conversations.

Hyperactive/Impulsive Type

• Fidgeting or squirming in seat
• Inability to stay seated for long periods (in classrooms or workplaces).
• Running about or climbing inappropriately in settings where it is not appropriate.
• Excessive talking/verbal outbursts.
• Difficulty playing or engaging quietly in leisure activities.
• Interrupts or intrudes on others (cutting in on conversations, interrupting others or taking over activities).
• Difficulty waiting turns.
• Answers questions before they are completed.
• Difficulty remaining quiet during social activities.

Combined Type

• This type involves symptoms of both inattention and hyperactivity-impulsivity.
• Requires six or more symptoms that meet criteria A1 and six or more symptoms that meet criteria A2.

Key Features of ADHD

• ADHD symptoms must manifest in multiple settings (e.g., school, home).
• The presence or absence of symptoms depends upon context; they may be less apparent in situations involving close supervision, interesting activities or rewards.
• Academic performance can suffer as well as social acceptance.

Prevalence of ADHD

• Approximately 7.6% prevalence rate.
• Male to female ratio is roughly 3:1.
• Adult prevalence can be as high as 2.5%.
• There is variation in the prevalence of ADHD across different geographic regions and populations, but significant differences are often not apparent.

Prevalence of ADHD: Importance of Culture

• ADHD diagnosis may be influenced by cultural context.
• Current diagnostic criteria are largely based on North American elementary school-aged boys.
• Diagnostic criteria might not fully capture the expression of ADHD in other cultural contexts.

Comorbidity of ADHD

• About 2/3 of children with ADHD experience comorbid conditions.
• Commonly comorbid diagnoses include oppositional defiant disorder, conduct disorder, mood disorder, anxiety disorders, and tic disorder.

What Causes ADHD?

• Genetics: A strong genetic component, believed to account for up to 80% of cases.
• Environmental/Developmental factors: Interactions between genes and environment plays a role, which has been proven with children whose mothers smoked during pregnancy or experiencing perinatal hypoxia. There is no scientific evidence or convincing evidence regarding food coloring, preservatives or sugar as related factors.

Behavioral Markers of ADHD

• Difficulty waiting turns.
• Difficulty sustaining focus throughout tasks.
• Impulsiveness and frequent disruptions.
• Difficulty filtering out distractions.

Brain Areas Implicated in ADHD

• Prefrontal cortex
• Parietal cortex
• Thalamus
• Striatum (caudate and putamen)
• Cerebellum
• Dorsolateral & Ventrolateral prefrontal cortex
• Dorsal & Ventral Anterior Cingulate Cortex

Alerting Network

• The frontal, parietal cortex, and thalamus form a network that supports attention.
• This network is often weaker in people with ADHD.

Frontostriatal Circuit

• The ventral anterior cingulate and dorsal anterior cingulate cortexes work with the putamen, nucleus accumbens, and caudate nucleus to control affective and cognitive components of executive function.

Treatment of ADHD

• Pharmacological treatment is often effective; drugs are effective in 70-90% of cases.
• Common pharmacological treatments are psychostimulants(methylphenidate, amphetamine), usually prescribed in a sustained release format to avoid the “rush."

How Do Treatments Work?

• ADHD medications target the dopamine system, in particular, they block the dopamine transporter in order to allow more dopamine to be available at the synapse to receptor.

Ethics of ADHD Treatment

• Treatment should be tailored to the child's age, and consider factors like academic performance and social success.
• Emerging research suggests that long-term, chronic use of psychostimulants might pose certain side effects that need to be taken into account when considering the most appropriate form of treatment.