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
All rights reserved