Impulsivity

1. Often blurts out answers before questions have been finished.
2. Often has trouble waiting one’s turn
3. Often interrupts or intrudes on others (e.g., butts into conversations or games).

PLUS

• Some symptoms that cause impairment were present before age 7 years.
• Some impairment from the symptoms is present in 2 or more settings (e.g., at school/work and at home).
• There must be clear evidence of significant impairment in social, school, or work functioning.
• The symptoms do not happen only during the course of a Pervasive Developmental Disorder, Schizophrenia, or other Psychotic Disorder. The symptoms are not better accounted for by another mental disorder (e.g., Mood Disorder, Anxiety Disorder, Dissociative Disorder, or a Personality Disorder).

Based on these criteria, 3 types of ADHD are identified:

1. ADHD, Combined Type: if both criteria 1A and 1B are met for the past 6 months
2. ADHD, Predominantly Inattentive Type: if criterion 1A is met but criterion 1 B is not met for the past six months
3. ADHD, Predominantly Hyperactive-Impulsive Type: if Criterion 1B is met but Criterion 1A is not met for the past six months

Though it has been reported that ADHD is three times more common in boys than girls, this claim is now being challenged. Girls are more likely to have predominantly inattentive type of ADHD which is more likely to be missed.
While evaluating a child for ADHD, one must remember that ADHD, majority of times, is co-occurring with other psychiatric conditions like learning disabilities (Dyslexia), oppositional disorder, conduct disorder, anxiety disorder or mood disorder. These co-morbid conditions need to be assessed and treated.
The physical conditions that may be considered in differential diagnosis include severe anemia, thyroid dysfunction and lead toxicity.
Contrary to common perception, ADHD is practically a lifelong condition for at least 50% of ADHD children. With advancing age, there is likely to be some symptomatic improvement which is maximum in hyperactivity, medium in impulsivity and minimal in inattention.

Etiology and Pathogenesis:
ADHD is a heterogeneous condition with multiple etiologies. It is largely an inherited disorder. 30% to 40% of ADHD children have at least one close relative who has the disorder.
Neuro-chemically, irregularities in norepinephrine and dopamine in CNS is thought to be responsible for its manifestations. Some Neuro-structural differences have also been identified in children with ADHD. These include smaller brain size, especially in areas like prefrontal cortex, striatum, basal ganglia and the cerebellum. PET studies reveal reduced global cerebral glucose metabolism. Though not diagnostic, these findings strongly suggest that ADHD has a neurobiological base.
ADHD may be acquired through various conditions that cause insult to brain. These include prenatal, perinatal and postnatal complications.

Management :
ADHD symptoms are disruptive for child’s learning and development and adversely affect not only the school life but family and social life of the child. The repeated negative feedback from parents and teachers and rejection by peers creates a negative self image in the child’s mind. Early diagnosis and treatment reduces the hyperactivity, improves the attention span and controls the impulsivity. This helps in better academic achievement and peer acceptance. It also reduces the likelihood of worse outcome like antisocial personality or alcohol/drug abuse.

The management of ADHD needs a multimodal approach. This includes individual and family education, counseling, behavioral management and pharmacotherapy. The treatment also should include consultations with the school.

Need for assessing co-morbid conditions, especially learning disabilities (seen in 30-40% of children with ADHD) cannot be overemphasized. ADHD symptoms might be controlled with medications, but still child’s performance at school may not improve if the learning disability is addressed. Thus a comprehensive diagnostic profile of the child should be prepared. This will help us to set treatment goals which can be monitored regularly.

Pharmacotherapy: Psycho-stimulants have emerged as the treatment of choice for ADHD. These include dextroamphetamine, methylphenidate and pemoline of which methylphenidate is the drug used in our country. The stimulants work by increasing the production of norepinephrine.

Medications used to treat ADHD
First line Medicines

• Methylphenidate
  
• Dextroamphetamine
  
• Pemoline

Second line Medicines
Tricyclics: Imipramine, Desipramine, Nortryptiline. Other antidepressants: Bupropion, Venlafaxine. Alpha2 Blockers: Clonidine, Guanfacine. Atomoxetine when using stimulants like methylphenidate, we have to remember that it is a short acting drug with effect lasting up to 4 hours and so frequent dosing is required. The dose required depends more on rate of metabolism of the drug (which varies from individual to individual) than on body weight. Methylphenidate is recommended for use in children above 6 years of age and the starting dose is usually 5 mg after breakfast and lunch. The dose can be increased by 5 mg each week regularly monitoring for reduction is symptoms and side effects. The common side effects are loss of appetite, sleep difficulties, abdominal pain, headache, tics and emotional lability.

Second line medications work by reducing the breakdown or inhibiting the re-uptake of noradrenalin at the nerve endings, thus effectively increasing it’s level. Second line medications are used when psycho-stimulants do not work or are not tolerated. Alternatives they can be used as adjuncts as they are long acting. Next to stimulants, atomoxetine is now introduced as the second line or adjunct treatment. It is a specific noradrenalin re-uptake inhibitor. It’s starting dose is 0.5 mg/kg and can be increased up to 1.2 mg/kg. Antidepressants (tricyclics, bupropion and venlafaxine) can be used as independent treatment or adjunct to stimulants, especially when trying to improve the patient’s appetite and sleep or treat a co-morbidity of enuresis. The alpha2 blocker clonidine has also been used as an adjunct. When extreme oppositional behavior is a problem, antipsychotic like risperidone can be used.