ADHD Causes & Risk Factors - OmniMedicalSearch.com

Conditions & Diseases: Brain & Nervous System

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 connected to the following issues.

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)

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 (immediately after birth) 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 close 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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Page Last Modified:
11/30/2010