Smoking marijuana during one ’s teenaged old age may not have a direct impact on cognitive development , although those who do apply cannabis may be more at jeopardy of scrawny intelligence due to a range of other environmental factors . This is according to a couple of survey inquire how the intelligence quotient of adolescent marijuana user compare to that of their abstentious peers , while accounting for other factors that may contribute to any differences .
The first of these appeared in theJournal of Psychopharmacologylast week , and institute that in a sample distribution of 2,235 British teenagers , IQ levels were lower among those who had smoked marijuana at least 50 times by the long time of 15 . However , their results also uncover higher rates of childhood behavioral problems , depressive symptoms , and other substance use of goods and services – particularly alcohol and cigarettes – among cannabis smoking compartment , raising the possibility that these factors may have been responsible for their reduce IQ .
Through statistical analysis , the researchers cover that cannabis economic consumption could not be used to predict reduced teenage IQ scores once these other variables had been accounted for . Interestingly , however , they key out that even after excluding those who had never assay cannabis , cigarette smoker exhibited lower educational performance , dropping by up to two tier in any given academic subject . Since cannabis users were 17 times more likely to also smoke cigarette , the study generator situate that cigarette use may be a more dependable predictor of decreased IQ in this group .
By way of explanation , they propose that those who smoke both tobacco and hemp may do so due to “ social adversityduring adolescence , ” possibly halt from behavioural problems or an unstable kinsperson environment . This , in turn , could have anegative result on IQand academic attainment . While this estimate is endorse up by previous research , currently it is just conjecture as they have no supportive data .
Building on this research , a second subject appeared in theProceedings of the National Academy of Sciences , in which researchers test the result of marijuana on the intelligence of counterpart , where one Twin Falls was a regular user while the other was not .
To conduct the study , the authors mensurate the I.Q. of around 2,000 juvenile twin dwell in Los Angeles and Minnesota , over a period of roughly a decennary . As with the previous study , they found that those who began fume ganja during this period tended to develop broken - than - average intelligence information levels . However , they discovered that the non - using twins of marijuana smoker also obtained lower score , indicate that this outcome may have been determined by a range of screen background factor such as family surround or genetical sensitivity , rather than cannabis .
enquiry has indicated that marijuana - using twins do not suffer from a grim IQ than their non - using similitude . Stokkete / Shutterstock
In improver , they note that participants who became marijuana users during the course of instruction of this study also fall upon abject baseline IQ score , which were recorded before their teenage yr , at a time when they had not yet been innovate to cannabis . Subsequently , the research worker claim that decoct baseline IQ may be an indicator of a tike ’s likelihood to begin using hemp , and may well be a ware of genic or family - wide fox factors .
in conclusion , the authors of this study are keen to point out that their research differs from mostprevious workon the subject since it is of a longitudinal rather than a cross - sectional nature . In other run-in , it tracks subject ’ development over a tenacious menstruum of time , rather than only observing a mathematical group of participants at a single stage . This approach provide more reliable information since it allows research worker to note how a compass of agent may touch a child ’s maturation , thereby enable them to nail the various causes of their lower IQ as opposed to position itall down to hemp .
