I bet a lot of people will be happy to know this. According to a study on teen brains the use of marijuana over an 18 month period did not show any changes to brain tissue. Some may hate this following part, regular alcohol consumption over this period of time did show some changes in the brain. Once again alcohol proves to be worse than weed, yet it’s stigma remains the same. Although the findings did not clearly show whether the changes and growing white matter in the brain were permanent.