New study claims young cannabis smokers are permanently damaging their intelligence and memory

Young people who smoke cannabis regularly are risking permanent damage to their intelligence and memory. That's according to a major new international study. It examined about a thousand people in New Zealand over a twenty-year period. For those who take up the habit in their teens, the damage may be permanent. Researchers say there's no sign that cutting back, or stopping cannabis use later in life can restore the lost IQ.