|
Medical Imaging
Shows Addiction Alters Brain's Perception
U-WIRE
By Wynne Parry
(U-WIRE) SALT LAKE CITY -- Someone who craves the
next cigarette, eats uncontrollably or forgoes every
other need for the next cocaine fix has altered
his or her brain's ability to perceive pleasure.
In the past, doctors looked down upon their colleagues
who studied addiction, something often perceived
as symptomatic of a weak personality or due perhaps
to the willful pursuit of pleasure, according to
Joanna Fowler, a senior chemist at Brookhaven National
Laboratory. However, the use of medical imaging
technology is changing this perception.
"We are beginning to conceptualize addiction
as a medical illness," said Fowler at a presentation
Wednesday night in the auditorium of the University
of Utah's Aline Wilmot Skaggs Building. Ultimately,
Fowler believes this shift will open the door to
an increased understanding of the biological nature
of addiction. Information supplied by her research
using medical-imaging technology could lead to improved
treatments not only for addiction, but for other
diseases caused indirectly by addictions, such as
cancer.
"We should think about treating cancers as
diseases of the brain," Fowler said. If the
addictive effect of nicotine can be overcome, some
cancers can be prevented. To understand the biological
nature of addiction, one must look closely at the
interactions of cells within the brain responsible
for creating a feeling of well being, an area also
known as the pleasure center. Within this system,
the release of a chemical called dopamine stimulates
the cells which receive it. According to Fowler,
addiction alters the balance of dopamine's release
and reception. Different types of addictions interfere
with this system in unique ways.
Cocaine, for example, one of the most addictive
drugs in existence, gives its users a rush by prolonging
the presence of dopamine between the brain cells,
Fowler said. Her research has used PET, or Positron
Emission Tomography, scans to visualize both the
long- and short-term effects of cocaine use. PET
scans create images from radioactive markers injected
into a patient. The areas targeted, often the brain,
heart or cancerous tumors, show up in an array of
bright colors.
According to Fowler, scans taken from heavy cocaine
addicts revealed that cells in their pleasure centers
may have a reduced ability to respond to dopamine.
As a result, the system is altered and under stimulated
in the long run. Knowing about long-term biological
changes is as essential as understanding initial
cravings when treating addiction successfully, according
to Fowler. In addition, more effective forms of
treatment to improve the function of the dopamine
system in addicts may be developed.
Like cocaine, components of tobacco smoke alter
the dopamine system in the brain. While nicotine
is commonly viewed as the primary addictive element
of tobacco, other substances in the smoke inhibit
the brain cells' abilities to breakdown dopamine,
Fowler said. It has been shown that over 90 percent
of alcoholics and people addicted to other drugs
smoke cigarettes. In addition, a large proportion
of people suffering from schizophrenia and depression
also smoke. Fowler speculates that these people
are 'self-medicating.' By taking in tobacco smoke,
they elevate the dopamine levels which may be reduced
by their disease.
Pathological over-eaters or extremely obese people
experience the same loss of control as those suffering
from chemical addiction, Fowler said. As with other
addictions, their cells display a reduced capacity
to respond to dopamine. The implications of Fowler's
research extend beyond pathological over-eating
and chemical addictions. Gambling, risk-taking,
sex and many other activities initiate an intense
response from the pleasure center and can lead to
addictive behavior. According to Fowler, research
in this area is just "scratching the surface."
|
