ADHD

Characteristics

Inattention
- including increased distractibility and difficulty in sustaining attention
poor impulse control and decreased self inhibitory capacity
motor overactivity and motor restlessness

DSM 5 diagnostic criteria

A persistent pattern of inattention and/or hyperactivity that interferes with functioning or development as characterized by
- Inattention (>6 of the following for >6 months to a degree that is inconsistent with developmental level and negatively impact on social and academic/occupational activities)
  - often fails to give close attention to detail, makes careless mistakes
  - often has difficulty in sustaining attention
  - often does not seem to listen when spoken directly
  - often does not follow through instructions
  - difficulty in organizing tasks and activities
  - avoids or dislikes tasks that require sustained mental effort
  - often loses things
  - distracted by external stimuli
  - forgetful in daily activities
- Hyperactivity/impulsivity (>6 of the following for >6 months to a degree that is inconsistent with developmental level and negatively impact on social and academic/occupational activities)
  - fidgets with hands/feet and squirms in seat
  - leaves seat in classroom or other places when remain seated is expected
  - runs or climbs about excessively
  - difficulty in playing or engaging in leisure activities
  - acts "on the go" or acts as if "driven by motor"
  - talks excessively
    impulse symptoms
  - blurts out answer before question is completed
  - difficulty waiting for turn
  - intrudes others
several inattentive or hyperactive/impulse symptoms present before 12 yrs of age
several inattentive or hyperactive/impulse symptoms present in 2 or more setting (home, work/school) and documented independently
evidence of clinically significant impairment in social, academic or occupational functioning
not better accounted for other mental disordets

DSM 5	ICD 10
either or both of - at least 6 of 9 of inattentive symptoms - at least 6 of 9 of hyperactive or impulse symptoms	all of - 6 of 8 inattentive symptoms - 3 of 5 hyperactive symptoms - 1 of 4 impulse symptoms
Symptoms associated with ADHD

Fragile X syndrome
fetal alcohol symptoms
pervasive developmental disorders
OCD
Gilles de la Tourette syndrome
Attachment disorder

Differential diagnosis

migraines, absent seizures, asthma, diabetes, childhood cancer can affect 20% of children and can cause problems in attention and school performance
substance abuse
sleep disorders including those secondary to chronic upper airway obstruction from enlarged tonsils and adenoids
Restless leg syndrome
depression and anxiety
OCD
adjustment disorders, PTSD
child neglect, over protected child

Etiology

toxemia, lengthy labor
maternal drug use
2 genes - strong association
- Dopamine transporter gene (DAT1)
- Dopamine 4 receptor gene (DRD4)
other genes
- DOCK2 involved in cytokine exchange
- sodium hydrogen exchange gene
- DRD5
- SLC6A3
- DBH
- SNAP25
- SLC6A4
- HTR1B
structural and functional abnormalities in the brain of children
- dysregulation of frontal subcortical circuits
- small cortical volume
- abnormalities of cerebellum particularly in the midline/ vermian elements
H/o previous brain injury
poverty
exposure to violence
malnutrition

Epidemiology

5-10% in school going children
2-6% in adults
increased in children with neurological disorders such as epilepsies, neurofibromatosis and tuberous sclerosis

Pathogenesis

reduction in the brain volumes in the basal ganglia and prefrontal cortex
low blood flow to striatum
deficits in dispersed functional networks for selective and sustained attention in ADHD that include striatum, prefrontal regions, parietal lobe and temporal lobe (areas rich in dopamine receptors) - dopamine hypothesis
supported by flourodopa positron emission tomography

Clinical manifestations

current DSM5 criteria

must begin before 12 yrs of age
persist for at least 6 months
present in 2 or more settings

Inattentive symptoms more in females
Hyperactivity and impulsivity more in males

varies with age

children	adolescents and adults
motor restlessness	disorganized
aggressive and disruptive behavior	inattentive symptoms
ADHD is difficult to identify in preschoolers as these symptoms are considered developmental norms

clinical Interview and History

history relating to presenting problems
history related to overall health and development
history related to the integrity and development of central nervous system, sensory impairment, sleep disorders, medication use that might affect the children's functioning
family history of first degree relatives with ADHD or mood disorders, learning disabilities, antisocial or substance abuse

Behavioral rating scales

useful for establishing the magnitude and pervasiveness of the disease rather than diagnosis
examples

vanderblit ADHD diagnostic rating scale
the conner rating scales (parent and teacher)
ADHD rating scale 5
Swanson, Nolan, and Pelham checklist (SNAP)
ADD-H: Comprehensive teacher rating scale (ACTeRS)
Achenbach child behavior checklist
behavioral assessment scale for children

Physical examination and laboratory findings

no specific lab findings
presence of hypertension, ataxia, thyroid or sleep disorders should prompt investigation
should also check for blood lead levels
examination of the child in a structured laboratory setting or physician's office might not reflect the child's typical behavior at home

Treatment

Psychosocial treatments

educating parents and children on ways which ADHD could affect the learning, behavior, self esteem, social skills, and family function
Parent support groups
Physician should help setting goals for the children to achieve interpersonal relationship, develop study skills and decrease disruptive behavior

Behaviorally oriented therapy

first line therapy
over a time frame of 8-12 settings
identification of the targeted behaviors that cause impairment in the child's life
help setting appropriate expectations
rewards to encourage desired behavior and consequences to discourage undesired behavior
helpful when combined with medications

medication

psychostimulants
- presynaptic dopaminergic agonists
  - methylphenidate
  - dexmethylphenidate
  - amphetamine
- increased over the period of four week to reach a tolerable dose
Atomoxetine
- nor adrenergic reuptake inhibitor
- starting dose 0.3 mg/kg/day
- maximum total dose of 1.2 to 1.4 mg/kg/day BD
guanfacine and clonidine
- also FDA approved
- also helpful in tic disorder
TCA
- rarely used because of the sudden death
medications alone may not be enough, supportive therapy is essential
stimulant drug are associated with increased risk of cardiovascular events, stroke due to underlying problems such as hypertrophic cardiomyopathy
prior cardiology consult is necessary before prescription of stimulants

prognosis

60-80% continue to adolescence
40-60% continue to adulthood