- Clinical science
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that presents in childhood with symptoms such as impulsivity, hyperactivity, and inattention. A core feature of this disorder is that symptoms must impair social, occupational, or academic performance. The diagnosis of ADHD may be established at any age, though core symptoms must have been present prior to the patient's 12th birthday. Management of ADHD is multimodal and typically consists of stimulants (e.g., methylphenidate) in combination with behavioral and school-based interventions. ADHD is associated with adverse long-term consequences including impaired educational and occupational performance and higher rates of substance use and personality disorders.
- Sex: ♂ > ♀
- Age of onset: usually before age 6
- Prevalence: estimated to be 8–11%
Epidemiological data refers to the US, unless otherwise specified.
- The general mechanism is hypothesized to be related to altered catecholamine metabolism.
- Genetic predisposition: family history of ADHD, polymorphisms of the dopamine, serotonin, or glutamate receptor subtypes
- Environmental factors: prematurity, in-utero exposure to alcohol; A subset of patients may have symptoms that are susceptible to dietary factors (e.g., food additives, food sensitivities, mineral deficiencies, sugar).
- Symptoms of inattention and/or hyperactivity (see diagnostics below)
|Diagnostic criteria (according to the DSM-5)|
Pattern of inattention and/or hyperactivity that is inconsistent with the developmental level of the individual and lasts for ≥ 6 months
|B||Several symptoms were present at < 12 years of age.|
|C||Symptoms present in ≥ 2 settings (e.g., school, home, work)|
|D||Interfere with important levels of functioning (e.g., school or work)|
|E||Not due to a mental disorder|
Establishing a diagnosis of ADHD involves identifying comorbid disorders (e.g., learning disability, psychiatric disorders) as well as ruling out disorders that may mimic ADHD (e.g., hearing or visual impairment, thyroid disorders, sleep disorders)!References:
- Indications: :first-line therapy for preschool-aged children, and adjunct therapies for school-aged children and adults
- Socio-educational measures
- Behavioral parent training (BPT)
- Operant conditioning
- Indication: first-line therapy for patients ≥ 6 years of age
- Substance class: psychostimulant, amphetamine derivative
- Increased mental performance: improved concentration, cognition (learning, remembering, combining), short-term memory, and fine motor skills
- Reduced potential for conflict
- Adverse sympathomimetic effects
- Epileptogenic potential: methylphenidate reduces the threshold for seizures
- Decreased growth rate (reversible if medication is stopped)
- Rarely, priapism
- Dosage: slow titration schedule, as the drug affects each individual differently
- Other stimulant alternatives with similar efficacy include amphetamine salts and amphetamine derivatives.
- Indications: second-line therapy for patients ≥ 6 years of age; preferred in cases of substance abuse (patient or family member)
- Substance class: selective norepinephrine reuptake inhibitor (NRI) that increases the concentration of norepinephrine in the synaptic cleft
- Advantage: : no potential for addiction → not a schedule II prescription drug (normal prescription drug)
- Limitations: Meta-analyses revealed an increased rate of suicidal actions in children and adolescents being treated with atomoxetine. Close monitoring (especially at the beginning of the therapy) is indicated!
- Other nonstimulant alternatives with less proven efficacy include clonidine, bupropion, nortriptyline, and SSRIs.
- The persistence of symptoms after treatment predicts prognosis into adulthood.
- In 35-65% of patients, symptoms of ADHD and their associated functional impairment will persist into adulthood.
- Patients with ADHD are at higher risk of injury (both unintentional and self-injury), substance use disorder, and antisocial personality disorder.