According to a new
research early cannabis use may have more
harmful effects on people's cognitive functioning. The study says that regular cannabis users who start using the
drug before 15-years of age perform worse on brain tests than those who start
using it later.
who were part of the study were asked to participate in a series of neuro-psychological tasks which tested their executive
functioning, attention, perseverance, ability to form abstract concepts, mental
flexibility, visual and motor skills. The participants were divided in three
groups- early onset users (those who started using the drug before 15-years),
late onset users (those who started using the drug before 15-years) and control
group (those who never used cannabis).
No difference was noted in the IQ levels
between the three groups. It was found that the early-onset group performed
significantly worse than the late-onset group and the control group on tasks
which tested their sustained attention, impulse control and executive
Adolescence is a period during which
the brain appears to be particularly vulnerable to the neurotoxic effects of
cannabis. Brain imaging studies have shown that the brain is still maturing and
developing before 15-years of age and exposure to cannabis during this period
may be more harmful and lead to lower mental flexibility.
research has been published in the June issue of the British Journal of Psychiatry.