Daily marijuana use not associated with brain abnormalities
A recent study has checked the homework of another study which proclaimed that daily marijuana use was associated with brain abnormalities and has found it to be incorrect.
Published in the Journal of Neuroscience, the new study says that the results indicate that, when carefully controlling for alcohol use, gender, age, and other variables, there is no association between marijuana use and physical changes such as size and shape in the brain.
In response to the study claiming to have found abnormalities, researchers stated “replication of such results in well controlled studies is essential to clarify the effects of marijuana.”
Groups were matched on a critical confounding variable, alcohol use, to a far greater degree than in previously published studies. This alludes to alcohol as being the culprit for changes in brain shape and size.
The study concludes, “No statistically significant differences were found between daily users and nonusers on volume or shape in the regions of interest. Effect sizes suggest that the failure to find differences was not due to a lack of statistical power, but rather was due to the lack of even a modest effect. In sum, the results indicate that, when carefully controlling for alcohol use, gender, age, and other variables, there is no association between marijuana use and standard volumetric or shape measurements of subcortical structures.”