The Effects of Marijuana on Visuospatial Working Memory: an FMRI Study in Young Adults - Article Example

It would thus make some sense that marijuana might have a negative effect on those abilities, because it has a direct impact on the parts of the brain that control them. Previous studies have used fMRI technology to understand what if any changes to the structure of the brain occur based on MRI use, and have found that brains of heavy MRI users differ significantly from people with brains that have been unaffected. These tests have had their limitations, however, because they do not control all variables that could be important, such as the natal use of drugs by parents or other environmental factors (Smith et al, 2010, pg 430).

The authors of the present study addressed these issues by using a long-term longitudinal study, the Ottawa Prenatal Prospective Study (OPPS), which could control for all of those variables. Methods The study used a group of ten marijuana users, age 19-20, who were “regular” users based on their consumption of at least one marijuana cigarette (“joint”) per week. The range of the target group was quite high, from 2-37 joints/week, with a mean at 11.48. The mean smoking range was 4.55 years (Smith et al, 2010, pg 431).

It also had a control group of fourteen non users of similar demographics. Both groups had been subjected to a wide variety of psychoanalytical testing, which showed no significant difference between users and non-users. The researchers subjected both the control group and the study group to the visuospatial 2-back task. This test involved reporting the movement of a black “O” on a white background, with participants needing to identify when the O was matched to the centre, or when the image was the same as it was two previous images ago.

This test allowed the researchers to control for mental loads, meaning that they were able to subtract mental activity not associated with the task at hand from the results (Smith et al 2010) Results The results showed no significant difference in ability between the control and the test grou