The conclusion of a recent study conducted via University of Southern California has proven that there is no significant link to teen marijuana use and a lower IQ. The study, conducted on sets of identical twins that either used or abstained from marijuana use for a period of 10 years concludes these findings.
According to University of Southern California statistician, Nicholas Jackson, it is impossible to decipher which came first, the marijuana use or poor cognitive skills. He says, “It’s a classic chicken-egg scenario,” reports ScienceMag.org.
The study was conducted over a 10 year period with participants between the initial ages of 9 and 11. The groups of twins were located in Minnesota and California. During the study period, confidential marijuana use surveys and a series of 5 intelligence tests were completed.
Additional study findings include:
- Marijuana use of 6 months or longer did not show any change in IQ in comparison to teens that used marijuana 30 times or less
- Surveys inquiring about additional substance use were given
- Studying identical DNA-sharers provided ideal information regarding changing IQs
A total of 789 pairs of twins were studied. The results indicate that the twins using marijuana lost roughly 4 IQ points, and the twins who did not use marijuana, lost the same number of IQ points. This indicates that there is another piece to the puzzle, such as stress and family life.
At the conclusion of the study, Jackson went on to say, “Our findings lead us to believe that this ‘something else’ is related to something about the shared environment of the twins, which would include home, school, and peers.”
Researchers involved in the study agree that more in-depth research needs to be conducted to further the conclusion of their findings on a larger scale.