Navigation Links
Pot Use-Low IQ Link Challenged in Study
Date:1/15/2013

By Randy Dotinga
HealthDay Reporter

MONDAY, Jan. 14 (HealthDay News) -- A new analysis challenges previous research that suggested teens put their long-term brainpower in danger when they smoke marijuana heavily.

Instead, the analysis indicated that the earlier findings could have been thrown off by another factor -- the effect of poverty on IQ.

The author of the new analysis, Ole Rogeberg, cautioned that his theory may not hold much water. "Or, it may turn out that it explains a lot," said Rogeberg, a research economist at the Ragnar Frisch Center for Economic Research in Oslo, Norway.

The authors of the initial study responded to a request for comment with a joint statement saying they stand by their findings. "While Dr. Rogeberg's ideas are interesting, they are not supported by our data," wrote researchers Terrie Moffitt, Avshalom Caspi and Madeline Meier. Moffitt and Caspi are psychology professors at Duke University, while Meier is a postdoctoral associate there.

Their study, published in August in the Proceedings of the National Academy of Sciences, attracted media attention because it suggested that smoking pot has more than short-term effects on how people think.

Based on an analysis of mental tests given to more than 1,000 New Zealanders when they were 13 and 38, the Duke researchers found that those who heavily used marijuana as teens lost an average of eight IQ points over that time period. It didn't seem to matter if the teens later cut back on smoking pot or stopped using it entirely.

In the short term, people who use marijuana have memory problems and trouble focusing, research has shown. So, why wouldn't users have problems for years?

"The question reminds me of something adults say when kids make weird faces: 'Careful, or your face will stay that way,'" Rogeberg said. "It is certainly possible that in the long term, heavy cannabis use has permanent or persistent effects on the brain. But to find out what these changes are and what they mean is not easy. We can't just look at the short-term effects and assume that these gradually become fixed and permanent over time."

In his report, Rogeberg used simulation computer modeling to argue that the initial study was possibly flawed because of the effects of poverty on IQ.

"Recent research indicates that IQ and brainpower are kind of like muscular strength: strengthened if it is regularly challenged. IQ is strengthened or sustained by taking education, studying hard, spending time with smart, challenging people, doing demanding work in our jobs," he said. "Some kids, unfortunately, are burdened with a poor home environment, poor self-control and conduct problems. These kids are likely to gradually shift away from the kinds of activities and environments that would exercise their IQs."

Rogeberg, whose report appears in this week's online issue of the Proceedings of the National Academy of Sciences, suggests that the initial study didn't properly take this into account. "Although it would be too strong to say that the results have been discredited, the methodology is flawed and the causal inference drawn from the results premature," he wrote.

In their response, the Duke researchers said that only 23 percent of the people they studied were from poor families, making it unlikely that these participants threw off the overall results. And, they added, their results were the same when they only focused on people from middle-class families.

The Duke team also noted that another group shows similar results from marijuana exposure: rats. And, as they pointed out, rats don't go to school or fall into rich, middle-class or poor categories.

More information

For more about marijuana, visit the U.S. National Library of Medicine.

SOURCES: Ole Rogeberg, Ph.D., research economist, Ragnar Frisch Center for Economic Research, Oslo, Norway; Terrie Moffitt, Ph.D., and Avshalom Caspi, Ph.D., professors, and Madeline Meier, Ph.D., research associate, Duke University, Durham, N.C.; Jan. 14-18, 2013, Proceedings of the National Academy of Sciences, online


'/>"/>
Copyright©2012 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Tampa Residents Challenged to Lose Weight for Cash
2. Are Rhesus Monkeys Musically Challenged?
3. Even Some Scientists Are Math-Challenged
4. Proposed testosterone testing of some female olympians challenged by Stanford scientists
5. Doctors Often Miss Signs of Problem Drinking in Patients, Study Finds
6. No Link Between Low Birth Weight, Asthma: Study
7. Study finds knee replacement surgery may lead to weight gain
8. NIH scientists identify protective role for antibodies in Ebola vaccine study
9. Thigh Is Safer Vaccination Site Than Arm for Toddlers, Study Finds
10. Saliva gland test for Parkinsons shows promise, study finds
11. Study finds poorer outcomes for obese patients treated for lumbar disc herniation
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Pot Use-Low IQ Link Challenged in Study
(Date:10/13/2017)... ... October 13, 2017 , ... Lori R. Somekh, founder of the ... national organization of elder law and special needs planning attorneys. “Membership in ElderCounsel helps ... provides a forum to network with elder law attorneys nationwide,” said Somekh. , ...
(Date:10/13/2017)... ... October 13, 2017 , ... Ellevate Network, the leading network for professional ... action towards gender equality at their inaugural Summit in New York City in June. ... a social audience of over 3 million. To watch the Mobilize Women video, ...
(Date:10/13/2017)... Fairfax, VA (PRWEB) , ... October 13, 2017 ... ... provider of DevOps and Agile Software Development, has been awarded a contract by ... (EATS) Blanket Purchase Agreement (BPA) aims to accelerate the enterprise use of Agile ...
(Date:10/12/2017)... ... October 12, 2017 , ... CitiDent ... sleep apnea using cutting-edge Oventus O2Vent technology. As many as 18 million ... by frequent cessation in breathing. Oral appliances can offer significant relief to about ...
(Date:10/12/2017)... ... October 12, 2017 , ... The American College of Medical Informatics ... PhD, FACMI, during the Opening Session of AMIA’s Annual Symposium in Washington, D.C. AMIA’s ... of Morris F. Collen, a pioneer in the field of medical informatics, this prestigious ...
Breaking Medicine News(10 mins):
(Date:9/18/2017)... 2017 EpiVax, Inc. ("EpiVax") a ... immune engineering, today announced a new NIH-funded ... ... and presents a challenge for traditional flu ... be effective. Using state-of-the-art bioinformatics and molecular modeling methods, ...
(Date:9/12/2017)... , Sept. 12, 2017   EcoVadis , the leading platform ... published the first annual edition of its Global CSR Risk and Performance ... evaluated by EcoVadis, based on Scorecard Ratings that analyzed nearly 800,000 data ... ... ...
(Date:9/12/2017)... 12, 2017  ValGenesis Inc., the global leader ... pleased to announce the appointment of Dr. ... Board of Directors and Chairman of Advisory Board ... science companies to manage their entire validation lifecycle ... in this process. Furthermore, ValGenesis VLMS enables rigorous ...
Breaking Medicine Technology: