1. Mary Grace Bermundo
Teenage cannabis use leads to cognitive decline
The downside to cannabis use has been made clearer. The most detailed
study yet of the drug's long-term effects shows that those who start a weed
habit as teens enter middle age with an 8-point deficit in IQ compared to non-
users.
Evidence is growing that cannabis-based drugs can benefit health, but
suspicions remain that persistent cannabis use from an early age can have a
detrimental effect on cognition. Confirming those suspicions is tricky, though,
since cognitive impairment observed later in life could have been present
before the drug was first used.
To get around the problem Madeline Meier at Duke University in Durham,
North Carolina, and her colleagues have taken the long view. They used a
detailed health study which followed 1000 people in Dunedin, New Zealand,
from birth until age 38. The data allowed them to compare IQ tests taken by
the participants at age 13 – before any of them began using cannabis – with
the same participants' IQ scores as adults, in some cases after years of
cannabis use.
The study showed that those who developed the most persistent dependence
on the drug showed the greatest subsequent decline in IQ, losing 6 points on
average regardless of how early the habit began. Within that group, those
who began taking the drug before their 18th birthday saw a subsequent
decline in IQ of 8 points, on average.
Furthermore, friends and relatives close to the persistent cannabis users
reported that these users had more everyday memory and attention
problems, including forgetting to pay bills and misplacing common items like
keys and wallets.
The bad news is that the damage does not appear to be reversed after
dropping the habit. But the good news is that people who picked up their
drug habit after their 18th birthday did not suffer such severe cognitive
decline. Although previous research has hinted at the potential impacts of
cannabis on the adolescent brain, this study is the first to provide evidence
that cannabis does in fact have neurotoxic effects on young brains, says
Meier.

2. Date of publication: 27 August 2012
BY: Hannah Krakauer
Reference:http://www.newscientist.com/article/dn22213-teenage-cannabis-use-leads-to-
cognitive-decline.html
Reaction:
The sample was only 1000 people, only a fraction of which would have
actually smoked the drug. It seem like a very small to sample to base such
definite conclusions on.The alcohol/cannabis combination forms a potent mix
in the body and is likely much more damaging than either alone. Was the use
of alcohol factored in?The IQ tests were done at 13 and 38. Both ages seem
pretty arbitrary and most probably chosen to show the greatest loss in
IQ.Were the subjects intoxicated when they took the test? Apparently it can
stay in your system for 3 weeks.The brain is plastic and its physical space is
limited so losing abilities in one area may actually increase abilities in other
areas. I say give people the real facts and let people try things so they can
figure it out for themselves (obviously not children).The results of this study
are sobering, excuse the pun. IQ is important and has been closely looked at
as a marker of intelligence for good reason, as it correlates closely with later
success in life. Presumably it measures some aspects of intelligence that are
universally practical to have. My own take on the IQ test is that it assesses the
integration of different areas of the brain at the same time and therefore is a
measure of how well an individual can think outside the box. Anything that
lowers this measure should be a big red flag that an agent is causing
widespread harm to the brain. Trying to diminish the value of the IQ test is
just another way of enabling harmful behavior, and for every dysfunctional
abuser there is by definition at least one enabler.Simply put, habitual
marijuana usemakes you dumber and more forgetful in a meaningful way
than you otherwise would have been. So do not habitually use this drug. Since
it is inherently habit forming, then you should not use it at all, lest you fall into
that vicious downward spiral.