Epidemiology

Etiology

Core Features: A persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.
Inattention: Difficulty sustaining attention, makes careless mistakes, doesn’t seem to listen, trouble organizing tasks, avoids sustained mental effort, loses things, easily distracted, forgetful.
Hyperactivity/Impulsivity: Fidgets, leaves seat when sitting is expected, runs/climbs inappropriately, unable to play quietly, often “on the go,” talks excessively, blurts out answers, difficulty waiting turns, interrupts others.
Patients generally have normal intelligence, but school/work performance is impaired due to symptoms.

Options include stimulant and nonstimulant therapy. Stimulant therapy is usually first-line treatment for children ≥ 6 years of age and adults.

Options: methylphenidate or amphetamine analogues (e.g., lisdexamfetamine, dextroamphetamine)
Mechanism of action
- ADHD is understood to involve hypoactivity (under-activity) in key brain circuits, particularly the prefrontal cortex, which is responsible for executive functions like attention, impulse control, and planning.
- This dysfunction is linked to insufficient levels or inefficient signaling of the neurotransmitters dopamine (DA) and norepinephrine (NE).
Adverse effects
- Sympathomimetic effects
  - Anxiety, agitation, restlessness, bruxism, tics
  - Difficulty falling asleep (insomnia)
  - Reduced appetite, nausea, vomiting, weight loss
  - Increased arterial blood pressure, tachycardia

SSRI
- Options: atomoxetine or viloxazine
Alpha-2 adrenergic agonists
- Options: guanfacine extended-release or clonidine extended-release