The
Daily Mail (UK), 5th July 2006
Researchers have found that cannabis acts as a 'gateway'
drug, because exposure during adolescence primes the system to crave the
chemical stimulation of hard drugs.
Previously it has been argued teenagers move to harder drugs
because of peer or emotional pressures, or easy availability.
The study, published online today in the journal
Neuropsychopharmacology, looked at the behaviour of young rats exposed to
cannabis. These rats took in much larger doses of opium when trained to self
administer than other rodents.
Dr Yasmin Hurd of the Mount Sinai School of Medicine, New
York, said cannabis affects some of the brain's natural chemicals which
heighten positive emotions.
The same system is stimulated by hard drugs meaning the
brain may 'remember' previous usage.
The adolescent brain is particularly sensitive to drug
exposure, she said, because of cell changes in areas essential for behavioural functions.