Pubdate: Thu, 30 Aug 2012
Source: Portland Press Herald (ME)
Copyright: 2012 MaineToday Media, Inc.


A formal study has shown that heavy use can produce permanent loss of 
critical IQ points.

In a report released online this week by the prestigious Proceedings 
of the National Academy of Sciences, a team of U.S. and British 
researchers has found that heavy use of marijuana by teenagers and 
young adults can reduce their IQ scores by as much as 8 points in later life.

No such results were found in people who smoked the same amount of 
pot but started using the drug later in life, the report said. People 
who started young also were found to have weaker memory and 
attention-focusing skills.

The public policy implications of this finding indicate that, if 
marijuana use for recreational purposes ever becomes widely 
permitted, there still remains a strong case for keeping it out of 
the hands of young people.

That would make it similar to the legal age for buying alcohol and 
tobacco, set by federal law at 21, which is higher than the age (18) 
of legal adulthood for other purposes, such as marriage, signing 
contracts and voting.

The researchers, from Duke University and King's College of London, 
analyzed long-term data provided by the University of Otago in New 
Zealand to evaluate a group of marijuana users of all ages whose 
intelligence quotients had been measured beginning when they were 
young and before they had begun using marijuana.

Comparison of IQ scores at age 13 and at age 38 showed a drop only in 
those who had become "dependent" on pot-smoking prior to turning 18.

The researchers said an average 8-point IQ decrease may not seem like 
much, but if a person has an average IQ of 100 and drops to 92, it 
means that instead of measuring a higher intelligence than 50 percent 
of the general population, that person will only measure higher than 
29 percent of it.

Marijuana is reported to be the most widely used illegal drug in the 
world, with the United Nations estimating that in 2010 there were 
between 119 million and 224 million regular users between the ages of 
15 and 64.

In June, the U.S. government said that 23 percent of high school 
students reported smoking pot "recently," more than reported smoking 
tobacco in the same period, the first year ever in which that was the case.

Marijuana is widely believed to be less harmful than tobacco, but 
ounce for ounce it has long been known to be more carcinogenic.

Now, it is also been found to be harmful to developing brain matter. 
Young people should think hard about becoming dependent on it -- 
before it becomes hard for them to think at all.
- ---
MAP posted-by: Jay Bergstrom