The persistent use of cannabis before age 18 has been linked to lasting harm to intelligence, according to a large study.

Analysis of more than 1000 New Zealanders found those who took up cannabis in adolescence and used it for years afterwards experienced an average decline in IQ of eight points when measured at age 13 and 38.

People who did not begin using cannabis until they were adults, with fully formed brains, did not show the same declines.

Do you believe prolonged cannabis use when young affects IQ? Here is the latest selection of Your Views:

  1. your views
  2. BiGdAdDyNz says
    "From dealing with youths, some of whom started smoking regularly as young as 11, I can tell you that they do not perform well in education or staying motivated on task. There is a reason they call it Dope!"
  3. Nimrod says
    "No, it more than likely improves your IQ. Cannabis opens the mind you see things in a different light than you would normally."
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