A new study shows using marijuana a few times a week is enough to significantly alter your brain. It's published in the Journal of Neuroscience.
In the study, scientists looked at the brains of 20 relatively light marijuana users and 20 people who didn't use it at all. They found volume, shape and density changes in two areas of the brain - the areas involved with emotion, motivation and mental illness.
They say the more marijuana the people smoked, the more their brains differed. Neurologists say the brain continues to develop into your 30s, so it's important to recognize that consequence of smoking marijuana.