Teenagers who smoked marijuana daily for three years performed poorly on memory tasks and showed abnormal changes in brain structure, according to a Northwestern Medicine study. Researchers in Chicago observed the brains of teenagers who were heavy users of marijuana. In those individuals, memory-related structures in the brain appeared to shrink and collapse inward, possibly indicating a decrease in neurons.
These abnormalities were recorded two years after the teens stopped using marijuana, possibly indicating long-term effects, and look similar to schizophrenia-related brain abnormalities.
The brains were shaped more abnormally for individuals who began marijuana use at a younger age, according to the reports, which suggest that memory regions of the brain are more susceptible to the drug at earlier ages.
The research was published in the December issue of Schizophrenia Bulletin.
Can you drink if you have heart disease? Moderate drinking should be OK, if your doctor approves, but you shouldn’t count on alcohol to be a major part of your heart health plan.
“If you don’t drink alcohol now, there is no reason to start,” says Mark Urman, MD, a cardiologist at Cedars-Sinai Heart Institute in Los Angeles.
It’s true that there have been studies linking drinking small amounts of alcohol — no more than two drinks a day for men and one drink a day for women — to better heart health.
But the exact link isn’t clear. Those studies don’t prove that the alcohol (whether it was wine, beer, or liquor) was the only thing that mattered.
Other lifestyle habits could have been involved, the American Heart Association notes. Or the important thing could have been nutrients that are in grapes, which you can get from the grapes themselves, without drinking wine.
“One drink a day is probably healthy for people with heart disease and those without it,” says James Beckerman, MD, a cardiologist at Providence St. Vincent Heart Clinic Cardiology in Portland, OR.
But whether or not you drink, you also need to keep the rest of your diet healthy, not smoke, and get regular exercise. Read More.
New NIDA-funded research shows that heavy marijuana use (at least four times per week over the past six months) is linked to adverse changes in the function and structure of brain areas associated with reward, decision making, and motivation. Heavy marijuana use can also enhance some brain circuits – possibly to compensate for reduced function in specific brain regions. This effect was more pronounced in those who started using at a young age, indicating that developing brains are particularly vulnerable to marijuana’s effects.
Although further long-term studies are needed to determine whether marijuana caused these effects, these scientific findings add to the growing literature showing that heavy marijuana use may harm the brain.
For a copy of the abstract (published online November 10), go to www.pnas.org/content/early/2014/11/05/1415297111.abstract.