Five states are voting this fall on whether marijuana should be legal, like alcohol, for recreational use. That has sparked questions about what we know – and don’t know – about marijuana’s effect on the brain. One long-term study in New Zealand compared the IQs of people at age 13 and then through adolescence and adulthood to age 38. Those who used pot heavily from adolescence onward showed an average 8 percent drop in IQ. People who never smoked, by contrast, showed slightly increased IQ.
As More States Consider Legalizing, Questions About Pot And The Brain
