CAUSES

OUTLINE:

oDefinitiono CAUSES OF ADHD

oNeurological Factors• Brain structure• NeurotransmittersoGenetic and Heredity Factors• Family Studies• Adoption Studies• Twin Studies

(CONT)o Molecular Genetic Research

• Dopamine Geneso Environmental Factors• Brain Injury and diseases• Natal Exposure• Natal Complications• Sugar/Food• Childhood Exposure to toxins

DEFINITION:

DSM V describes ADHD as:

“A persistent pattern of inattention, hyperactivity and/or impulsivity that interferes with development, has symptoms presenting in two or more settings (e.g. at home, school, or

work), and negatively impacts directly on social, academic or occupational functioning”. 

The symptoms must be present before age 12.

Causes Of ADHD:

No true cause of ADHD has been identified but certain hypothesis have been developed which points towards: 1. Neurological Factors2. Genetic and heredity Factors3. Environmental Factors

NEUROLOGICAL FACTORS:

1. Brain Structure: In individuals with ADHD parts of the

brain like:

• pre-frontal and frontal lobes

•basal ganglia and

• cerebellum are affected.

In ADHD children these parts are found to:

a) Be structurally smaller.b) Have less activity and blood flow

These children also have less total gray matter.

More cognitive aspects of ADHD are related to impairments in the pre-frontal and frontal cortex.

The hyperactivity aspect of ADHD is related to the impairments in the basal ganglia and/or cerebellum.

2. Neurotransmitters:

The disturbances in the neurotransmitters have been found a probable cause of ADHD.

Two neurotransmitters named:• Dopamine • Nor-epinephrine are found to be more

involved with ADHD.

GENETIC AND HEREDITY FACTORS:

According to researches genetic and heredity factors accounts for about 80% of children with ADHD.Most of our information about the

heritability of ADHD comes from:

• Family Studies

•Adoptive studies

•Twin Studies

1. Family Studies:ADHD has been found to seen in families.

Dr. Joseph Biederman (1990) and his colleagues at the Massachusetts General Hospital in their studies learned that ADHD runs in families

According to studies carried out over the past 30 years ADHD is more common in biological relatives of children with ADHD than it is in the biological relatives of children who do not have ADHD.

2. Adoption Studies:

According to researches hyperactive children resembled their biological parents more than they did their adoptive parents with respect to hyperactivity.

3. Twins studies:

Studies with identical twins and non identical twins reveals that the probability of having ADHD among the pairs of identical twins is far greater than the non identical twins.  

 

MOLECULAR GENETIC RESEARCH:

Dopamine Transporter Gene (DAT1):

It has been estimated that this particular gene is responsible for causing ADHD by sucking up dopamine too fast and not leaving it in the synapse long enough and then causing impairment in brain’s connectivity.

 Dopamine D4 receptor gene (DRD4) :

This gene is involve in ADHD by causing specific neurons, less sensitive to

dopamine. Through this impairment, there arises serious breaks in the connectivity of

the different neurons thus resulting ultimately in the impairment of

neurological functioning

ENVIRONMENT FACTORS:

1. Brain Injury:

A child may be affected by brain injury and brain diseases at any time during prenatal or past natal stages.

These factors can cause problems with inattention and poor regulation of motor activity and impulses.

2. Natal Exposure: Researchers have found development of behavior

and learning problems in children with mothers who smoked tobacco products or used alcohol during their pregnancy.

Smoking drug abuse or high levels of lead during pregnancy have also been linked with ADHD.

Many researches have been carried out on:• Maternal smoking• Pre natal exposure to lead• Use of Alcohol during Pregnancy

3. Natal Complications:ADHD can be caused by complications during

pregnancy and birth.

4. Sugar/FoodRefined sugar or food additives were also

suggested to cause or aggravate the symptoms of ADHD.

However, a more recent study contradicts parental beliefs that sugar affects children’s hyperactivity.

5. Childhood exposure to toxins

Poor living conditions with exposure to lead paint and rusted pipes may contribute to a short attention span and hyperactivity in kids.

It has been observed that ensuring a healthy living environment, free from lead and harmful materials, may help kids lead a life free from ADHD symptoms.

REFRENCES American Psychiatric Association. (2013). Diagnostic and

statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.

Millichap, J. G. (2008), Etiologic classification of attention-deficit/hyperactivity disorder. Pediatrics, 121(2), e358-e365.

Mangal, S.K. (2007), Educating Special Children, An introduction to special education, New Delhi: Prentice Hall of India Private Limited.

Price, Crawfold, Tottle, Maunula. (2006), focusing on success: teaching students with Attention Deficit/Hyperactivity Disorder, grades 1–12, Canada: Alberta Education.

Harvey C. Parker, J. Parker, M. Frisch, R. Parker,S Frisch. (2003), Causes of ADHD. My ADHD.com. Retrieved on 25th, September, 2013, retrieved from: http://www.myadhd.com/causesofadhd.html

Thomas. (2012), Attention Deficit Hyperactivity Disorder.National Institute of Mental Health (12-3572). Retrieved on 24th, September, 2013, retrieved from: http://www.nimh.nih.gov/health/publications/attention-deficit-hyperactivity-disorder/index.shtml

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"Can Environmental Factors Cause ADHD?" Reader's Digest. N.p., 2013. Retrieved on 22 Oct. 2013. <http://www.rd.com/health/conditions/can-environmental-factors-cause-adhd/>.

American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). Washington, DC: Author.