Research has proved that adolescents who smoke marijuana face a decline in the IQ which could continue even when they stop using the substance. Research studies have suggested that the developing adolescent brain is harmed by the use of marijuana and other addictive substances. Carrying out research on this topic poses specific because adolescents cannot be arbitrarily chosen to use the drug or not use it for several years as part of the research study. However, researchers have obtained information from people who are doing it on their own. Researchers carried out this experiment by giving youngsters IQ test when they were 9-12 years old before any of them had used marijuana.
The tests were administered again when these youngsters had grown up and were between 17-20 years old. The researchers kept track of test scores and studies where there was any difference in the brains of the 17-20 after they had used marijuana. Although tests showed no basic differences in their brains, users scored poorly on tests of vocabulary and general knowledge as compared with non-users. If marijuana was really that harmful, then results of those who smoked more marijuana would have been different than those who smoked less marijuana or casual users. However, the test results showed no marked difference in both groups.
The study also compared IQ results of twins where one twin had used marijuana and the other had not. Even here the marijuana users fared no better or worse than the nonusers. This proved that in essence smoking marijuana was not solely responsible for the decline in IQ scores or about any other potentially harmful consequences of smoking marijuana in adolescence. Although the study has several limitations, it is important and should be followed up with further research because several researchers are of the opinion that adolescents who smoke marijuana have a great possibility of IQ decline.
There are other complications arising from smoking marijuana, but scientists have not been able to pinpoint what another harm to the brain is caused by smoking this weed. It is commonly known that using drugs and other related substances does cause some decline in IQ but other effects are not clear and now known. Researchers are trying to link the decline in IQ with marijuana and if there is a substantial decline because marijuana has been used or there are other factors which could have caused the decline, and marijuana smoking was just a helping agent.