Attention Deficit and Hyperactivity Disorders
Meet Cody
--About a Year ago, Cody was Diagnosed with ADHD. He's going to help us along in
our journey today.
Yay.
Of particular interest to ADHD researchers are the areas of the brain known as
the prefrontal cortex and the
basal ganglia. --These centers are thought to control behavior and behavior
planning, and are thus critical in
a behavioral disorder such as ADHD.
You may be asking yourself, what is ADHD?
--ADHD is a disorder of the brain which results in loss of concentration,
hyperactivity, and/or impulsiveness.
Statistics
•ADHD affects 4-12% of school-aged children (2 million kids).
•Boys are 3 times as likely to be diagnosed than girls.
•Diagnosis typically occurs between the ages of 5 to 12 years, although adult
ADHD isn’t uncommon.
The Brief History
•ADHD has been a recognized medical condition since the early 1900’s.
•ADHD was once known as “minimal brain dysfunction” and thought to be caused by
minor head injuries,
complications from birth, or an early infection.
So What Causes ADHD?
--It is unknown what exactly causes ADHD at this point.
--Research suggests that Dopamine and Norepinephrine imbalances play a key
role.*
--MRI Studies indicate that in some cases, the prefrontal cortex and basal
ganglia regions of affected people
are slightly underdeveloped.*
How is ADHD diagnosed?
--Patient history as well as a clinical evaluation is plugged into an algorithm
such as this one, and the results
determine whether or not the patient has the disorder or another type of
behavioral disorder.
--DSM-IV Guidelines are strictly followed.*
The 3 Types of ADHD
--Predominantly Hyperactive-Impulsive Type
--Predominantly Inattentive Type
--Combined Type
3 Classes of medication
--Stimulants
--Adjuvants to Stimulants
--Alternatives
Stimulants
--Methylphenidates
----Focalin
----Methylin
----Ritalin
----Concerta
----Generics
--Amphetamines
----Adderall
----Dexadrine
----Dextrostat
----Dexadrine Generics
Adjuvants
--α2-Adrenergic agonists
----Clonidine
----Guanfacine
Alternatives
--Selective Norepinephrine Reuptake Inhibitors
----Strattera
How it all works:*
The stimulants work by increasing production of Dopamine via agonist binding
sites on the presynaptic
neuron. This causes increased amounts of Dopamine, which in turn counters any
imbalance that may have
occured. These stimulants also have an effect on the reuptake of Dopamine, but
it is not well understood.
The alpha-2 stimulants (adjuvants) work in much the same way, only on the
norepinephrine agonist binding
sites.
The selective norepinephrine reuptake inhibitors work just as they are named,
the slow reuptake of
norepinephrine in the synapse. This causes the norepinephrine to have a
prolonged effect without increasing
the amount present.
It is thought that autoreceptors on the presynaptic neurons act as sort of a
thermostat to the cell. The receptors monitor the concentrations of
neurotranmitter in the synapse and help regulate a stimulatory or depressant
response.*
Areas with an * are of particular interest.