Pubdate: Tue, 12 Jan 2016
Source: Chatham Daily News, The (CN ON)
Copyright: 2016 Chatham Daily News
Author: Jonathan Sher
Page: B2


Western Researchers Found Marijuana Poses Serious Consequences for 
Teens, but Not Adults

Turns out getting stoned on marijuana carries much more dire 
consequences for teenagers than for adults -- at least if you're a 
rat and part of a new study released Monday by researchers in London.

Researchers at Western University's Schulich School of Medicine & 
Dentistry have published a study that shows that the psychoactive 
component of marijuana caused long-term harm on the adolescent brains 
of rats, producing changes similar to what is found in schizophrenia.

"Adolescence is a critical period of brain development and the 
adolescent brain is particularly vulnerable," said Steven Laviolette, 
a professor in the departments of anatomy and cell biology, and 
psychiatry. "Health policy makers need to ensure that marijuana, 
especially marijuana strains with high THC levels, stays out of the 
hands of teenagers. In contrast, our findings suggest that adult use 
of marijuana does not pose substantial risk."

After adolescent rodents were exposed to delta-9-tetrahydrocannabinol 
(THC) - the psychoactive component in marijuana - researchers found 
substantial and persistent behavioural, neuronal and molecular 
changes that are identical to neuropsychiatric conditions, such as 

Adolescent rodents with THC exposure were socially withdrawn, and had 
increased anxiety, cognitive disorganization and abnormal levels of 
dopamine - all factors present in clinical populations of 
schizophrenia. These changes continued into early adulthood, well 
past the initial exposure.

Adult rodents showed no harmful long-term effects, though both 
adolescents and adults exposed to THC experienced deficits in social 
cognition and memory.

With the common use of marijuana by teenagers and the federal 
government's move toward legalizing marijuana, researchers say that 
pot should be kept out of the hands of teens.

"Our research improves our knowledge of how adolescent exposure to 
THC may lead to the onset of schizophrenia in adulthood," lead author 
Justine Renard said. "With the current rise in adolescent cannabis 
use and the increasing THC content in newer cannabis strains, it is 
critically important to highlight the risk factors associated with 
exposure to marijuana, particularly during adolescence."

Researchers identified and performed tests in areas of behaviour that 
are commonly observed in schizophrenia and other neuropsychiatric 
disorders, such as social interaction, motivation and cognition, 
exploratory behaviours, levels of anxiety, cognitive disorganization 
(the inability to filter out unnecessary information), and various 
neuronal and molecular changes.
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MAP posted-by: Jay Bergstrom