I’ve read if a child or a teenager does too much smoking, they could reduce their IQ PERMANENTLY!! That, plus the law (and my parents) was enough to keep me away from it back in the old days of High School 1970s. Some say there are medicinal benefits for cancer patients. Those who have gone through the rigors of chemotherapy, say it helps to stimulate the appetite and relax them. So there may be therapeutic uses for this, but I’d be very careful giving it to children without doing mucho research first!
Very, very dangerous for teens.
Measuring the IQ of someone before and after ten years of drinking a fifth of liquor, snorting cocaine, injecting heroin, or watching MSNBC for five hours straight every day would probably yield a similar if not worse result. Except for the last one finding survivors could be a challenge but the levels of induced dementia about the same.