The term “pothead” has long been used to describe someone as being less-than-bright. Now that characterization is backed by scientific data.
New research concludes teenagers who routinely smoke marijuana experience a long-term drop in IQ. The study tested the IQ of more than 1,000 13-year olds in New Zealand, then conducted five follow-up interviews through the years, and concluded with another IQ test when the individuals turned 38.
The study recorded mental decline only for participants who regularly smoked marijuana before age 18. Many teenagers will turn down a cigarette because of its association with health problems, but see marijuana as harmless.
For a government survey, roughly 23 percent of American high school students reported smoking marijuana, compared with just 18 percent who smoked cigarettes. It appears that if they smoke enough marijuana, they may lose the ability to mentally make that distinction.