Attention Deficit Hyperactive
Disorder
See Also:
ADHD: Introduction
& Types
ADHD: Causes
& Risk Factors
ADHD: Signs & Symptoms
ADHD: Medical Tests &
Diagnosis Methods
ADHD: Treatment
Options
Causes & Risk Factors
Even though the exact causes of this disorder are not
known, some of them could be as follows:
Brain
Injury:
One of the earliest theories stated that children
who suffered from brain injury might show signs
of ADHD, but it was found that only a small
percentage of children suffered from ADHD after a
traumatic brain injury.Brain Volume:
Brain volume of the children suffering from ADHD
is about 3-4% less in regions such as the frontal
lobes, temporal gray matter, caudate nucleus and
cerebellum. An interesting point to be noted here
is that the patients treated with appropriate
medication had a different brain volume as
compared to the untreated ones (5).
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Brain Chemicals:
Neurotransmitters & dopamine play a major role in
controlling emotions and reactions, concentration,
reasoning and coordination. Dopamine dysfunction and low
levels of other neurotransmitters, such as epinephrine
and serotonin, cause the three basic symptoms of ADHD -
inattention, impulsiveness and hyperactivity.
Medical Conditions:
Brain trauma experienced by a child during pregnancy,
delivery or post partum are at a higher risk of suffering
from ADHD. Approximately 50% of children with Pediatric
Autoimmune Neuropsychiatric Disorder Associated with
Streptococcal infections (PANDAS) suffer from ADHD.
Alcohol and drug abuse by pregnant mothers can cause
poor motor and muscular development and sensory
impairment. The newborn child experiences problems in
learning, memory, attention and problem solving; and
problems with mental health and social interactions (6).
Environmental Toxins:
Preschool children exposed to Polychlorinated Biphenyls
(PCBs) and lead found in paint and pipes of older
buildings are susceptible to ADHD (7).
Genetic Factors:
Hereditary link of the disease is an important risk
factor with 10-35% affected children having near
relatives with a past or present history of ADHD. Studies
are in progress to pinpoint two genes - namely the
dopamine-receptor (DRD) gene on chromosome 11 and the
dopamine-transporter gene (DAT1) on chromosome 5. Studies
have also shown genetic variations in one of the
dopamine-receptor genes (DRD4) in children suffering from
ADHD (8).
See Also:
ADHD: Introduction
& Types
ADHD: Causes
& Risk Factors
ADHD: Signs & Symptoms
ADHD: Medical Tests &
Diagnosis Methods
ADHD: Treatment
Options

Article by Kona Vishnu, MS
Medical Writer,
OmniMedicalSearch.com
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