A new study shows there may be some truth to pot head stereotypes.
Researchers at Northwestern University studies the brains of 40 young adults, half of whom smoked marijuana casually.
The study showed pot users brains were different compared to those who never used the drug.
The parts of the brain associated with emotion and motivation were altered among the marijuana smokers.
The more marijuana smoked, the more detrimental the effect.
Experts say they now need to look at how these brain changes impact marijuana users overall ability to function.