Smoking is kind of a funny thing in that everyone has heard and fully understands the risks associated with smoking but people choose to do it anyway. The general theory on why people keep smoking (other than becoming addicted) is denial. If you can convince yourself that the hazards are old news and it “couldn’t happen to you” then maybe you can justify it.

Now let’s take a look at something that isn’t old news. According to a brand new study that took place in Israel, people who smoke have lower IQ’s than those who don’t. Researchers studied 20,000 young adults and stumbled upon a revealing conclusion. 18- to 21-year-olds who do not smoke have an average IQ of 101. The typical smoker’s IQ, however, was found to average only 94.

To make matters even worse, researchers found that IQ decreases when smoking increases. While typical smokers have an IQ averaged at 94, people who smoke more than a pack a day had IQ’s around 90. Just for the record, a normal IQ range is 84 to 116. So, those heavier smokers are literally just a few points away from having a below average IQ.

Although still too premature to draw a scientific conclusion, many scientist believe that smoking puts the brain oxidative stress, which in turn damages DNA and lowers your IQ.