How Pot Harms Fetal Brain Development

Marijuana's Key Ingredient May Hamper Nerve Cell Development

By Miranda Hitti
WebMD Medical News

Reviewed By Louise Chang, MD

May 24, 2007 -- Scientists may have figured out how marijuana use during pregnancy harms the fetal brain.

Basically, marijuana's active ingredient, tetrahdyrocannabinol (THC), may interfere with the development of nerve cells, according to the researchers.

They included Tibor Harkany, PhD, who works in Stockholm, Sweden, at the Karolinska Institute's molecular neurobiology division.

Harkany's team studied mice and cell cultures from frogs.

According to the National Institute on Drug Abuse (NIDA), previous research has shown that some children born to women who abused marijuana during pregnancy may show signs of neurological problems in development and problems with memory and attention.

Harkany and colleagues studied a certain type of receptor in the brain. Those receptors latch onto chemicals called endocannabinoids.

The researchers explain that in a fetus, those receptors guide the development of axons, which are the long fibers of nerve cells. As the fetal brain develops, axons position themselves so they can communicate with each other.

But that process goes awry in mice with genes for impaired cannabinoid receptors. Those mice's axons didn't position themselves properly in Harkany's study. That could create communication problems between axons.

THC may mimic those effects in the fetal brain when used during pregnancy, note Harkany and colleagues. However, they didn't directly test that theory.

The study appears in the journal Science.

SOURCES: Berghuis, P. Science, May 25, 2007; vol 316: pp 1212-1216. National Institute on Drug Abuse: "NIDA InfoFacts: Marijuana." News release, Science.

For a long time, one of my speculations (not sufficiently supported by evidence at this point) has been that the rise in THC use during the latter half of the 20th century is responsible for the rising prevalence of ADD in western societies.

A total conjecture on my part, but if the sort of findings you've provided hold up I wouldn't be at all surprised.

That conjecture might be corroborated if we should observe that ADD incidence is down in the Red States (Bible belt), where marijuana use is rare compared to the coasts of the USA.

Actually, there is no evidence that pot harms the fetus. There have been numerous studies looking for just such a thing. You don't think the government would be trumpeting it from the treetops if it was true and verifiable? This study and the presumptions in it are just someone's opinion. They gave massive doses of thc to rat fetuses.



Notice it says "may" not 'does' or 'will' or 'has proven to do this'. Massive doses of most anything will harm the fetus. Salt will do it, sugar, you name it. There have been a spate of studies in recent years funded by the pharmaceutical industry attempting to discredit herbs and alternative heath options. Pot has been shown to prevent alzheimers disease, glaucoma, and a host of other diseases. It is helpful for many other diseases too.