Attention Deficit Hyperactivity Disorder

Outline

• Introduction• Aetiology• Epidemiology• Pathogenesis• Clinical features • Diagnosis & Differentials• Treatment• Prognosis

Introduction

• ADHD is a syndrome 1st described by Heinrich Hoff in 1854

• Since then it has been known by a variety of names like– Minimal Brain dysfunction– Hyperkinetic syndrome– Strauss Syndrome– Organic Driveness

• It is the most common neurobehavioral disorder of childhood

• It is one of the most prevalent chronic health conditions affecting school-age children and the most extensively studied mental disorder of childhood.

• It is characterized by1. Inattention 2. Impulsivity 3. Motor over activity

Aetiology• Multiple factors have been implicated in the

aetiology of ADHD• Birth Complications• Maternal Drug use • Maternal Smoking & Alcohol use during

pregnancy• Genetics• Minimal Brain Damage• Structural abnormalities of the brain• Psychosocial Family Stressors

Epidemiology

• The prevalence of ADHD globally is about 5-10% of school-age children.

• Prevalence rate in adolescents is 2-6%• In adults the prevalence is approximately 2%• Males are 6-8 times more affected than

women

Pathogenesis• In children with ADHD, MRI studies indicate small

brain volumes of specific structures, such as the prefrontal cortex and basal ganglia.

• Functional MRI finding suggest low blood flow to the striatum.

• This knowledge, plus data about the dopaminergic mechanisms of action of medical treatment for ADHD, has led to the dopamine hypothesis, which postulates that disturbances in the dopamine system may be related to the onset of ADHD.

Clinical features

1. ADHD with hyperactivity(commonest) Poor attention span with distractibility Hyperactivity Impulsivity

2. ADHD without hyperactivity (rare)3. Residual type of ADHD4. ADHD with conduct disorder

Diagnosis

• History• Physical examination• Investigation

DSM-IV diagnostic criteria for ADHD

A. Either 1 or 21. Six (or more) of the following symptoms of

inattention have persisted for > 6 month to a degree that is maladaptive and inconsistent with development level

Inattention Often fails to give close attention to details or

makes careless mistakes in schoolwork Often has difficulty sustaining attention in tasks

Cont Often does not seem to listen when spoken to

directly Often does not follow through on instruction and

fail to finish school work Often has difficulty organizing tasks and activities Often avoids, dislikes or is reluctant to engage in

tasks that require sustained mental effort Often loses things necessary for tasks or activities Often easily distracted by external stimuli Often forgetful in daily activities

Cont

2. Six (or more) of the following symptoms of hyperactivity-impulsivity have persisted for > 6 months to a degree that is maladaptive and inconsistent with developmental level.

HyperactivityOften fidgets with hands or feetOften leaves seat in classroom or in other

situations in which remaining seated is expected

Cont

Often run about or climbs excessively in situations in which it is inappropriate

Often has difficulty playing or engaging in leisure activities quietly

Often “on the go”Often talks excessively

Impulsivity Often blurts out answers before questions are

completed

ContOften difficulty awaiting turnOften interrupts or intrudes on others

B. Some hyperactive-impulse or inattentive symptoms that caused impairment were present before the age of 7

C. Some impairment from the symptoms is present in 2 or more settings.

D. There must be clear evidence of clinically significant impairment in social, academic or occupational functioning.

Cont

E. Symptoms do not occur exclusively during the course of a pervasive developmental disorder, schizophrenia or other psychotic disorder and are not better accounted for by another mental disorder.

Differential diagnosis

• Chronic illnesses• Substance abuse• Sleep disorders• Mental retardation• Depression and anxiety disorders• Obsessive-compulsive disorder• Adjustment disorders

Treatment

• Psychosocial treatment• Behaviourally oriented treatment• Medical treatment

Psycho stimulants such as Dextro-amphetamine (10-40mg/day) Methylphenidate (10-60mg/day) Atomoxetine (a noradrenergic reuptake inhibitor)

Prognosis

• A childhood diagnosis of ADHD often leads to persistent ADHD throughout life

• 60-80% of children with ADHD continue to experience symptoms in adolescence

• Up to 40-60% adolescents exhibit ADHD symptoms into adulthood

• In children with ADHD, a reduction inhyperactivity behaviour often occur with age

Cont

• However other symptoms associated with ADHD can become more prominent with age such as inattention, impulsivity and disorganization

• Risk factors affecting children with untreated ADHD as they become adults include– Engaging in risk taking behaviour– Educational underachievement– Employment difficulties

Cont

• With proper treatment, risks associated with ADHD can be significantly reduced.

Thank you all for your attention.