Pubdate: Sat, 01 Apr 2006
Source: Charlotte Observer (NC)
Copyright: 2006 The Charlotte Observer
Contact:  http://www.charlotte.com/mld/observer/
Details: http://www.mapinc.org/media/78
Author: Ronald Kotulak, Chicago Tribune
Bookmark: http://www.mapinc.org/pot.htm (Cannabis)

VIOLENCE, POT MAY DAMAGE MINDS

Influences During Adolescent Growth Spurt Under Examination

The discovery that the brain undergoes a second growth spurt during 
adolescence has potential implications not only for teen driving but 
also for other behavioral problems that have their roots in this 
period of development.

Just as bad experiences or the absence of proper stimulation can 
stunt a young child's brain during the first surge in brain growth, 
too much of the wrong kind of stimulation may adversely affect the 
vulnerable adolescent brain, researchers say.

For example, brain-imaging studies show that if normal, healthy 
adolescents are exposed to violent videos for a long time, they show 
similar neural network patterns in the areas governing emotions and 
self-control as youngsters who are chronically aggressive, according 
to two Indiana University School of Medicine researchers.

Viewing violent videos does not turn all adolescents into aggressors, 
of course. But scientists now want to know what might make some 
youngsters more vulnerable to aggression after watching violent scenes.

"The brain is reacting biologically to the experiences that the 
teenagers are having," said clinical psychologist William 
Kronenberger, who worked with radiologist Dr. Vincent Mathews on the study.

Heavy marijuana smoking also can restructure the adolescent brain in 
ways that are disturbingly similar to the neural pathways found in 
schizophrenics, said Dr. Sanjiv Kumra and Dr. Manzar Ashtari of the 
Albert Einstein College of Medicine in New York.

Like the Indiana team, the researchers used magnetic resonance 
imaging, or MRI, to peer into the brain. In this case they compared 
the brains of adolescent schizophrenics and healthy teens who had 
smoked marijuana heavily for a year. Repeated exposure to marijuana, 
they found, might interfere with development of the fiber bundles 
connecting the brain area that processes speech to the frontal cortex 
where executive decisions are made.

"The same pattern of abnormalities that you could see in 
schizophrenia you could also see in adolescents who don't have 
schizophrenia but who just smoke marijuana," Kumra said.

Several studies of adolescent marijuana smokers suggest that they are 
two to four times more likely to develop schizophrenia than 
nonsmokers, she said.
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