Rat Study: Teen Girls' Pot Use May Incline Future Kids To Drugs

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A new study out of Tufts University suggests that a mother's use of marijuana — even long before she has children — could lead to drug use in her kids.

The study found that when adolescent female rats were exposed to the active ingredient in marijuana, their offspring were more likely to abuse drugs. One of the study's authors, Elizabeth Byrnes, Associate Professor at Tufts University School of Veterinary Medicine, says the study proves that some drugs have long-term repercussions:

"You really can't assume that exposure to drugs prior to pregnancy doesn't have long-term effects on the next generation," she said. "These things seem to cause some persistent effects."

But Byrnes says it's too early to establish a connection between adolescent drug use and possible effects on future children.

Not that a mere anecdote disproves research, but my late mother liked pot so much she grew it in our backyard, and I could never stand the stuff myself. (And haven't been drawn to opioids like the rat offspring, either.) I heaped adolescent disapproval upon her when I found her little tin of buds and leaves hidden high on top of our kitchen cupboard.

But for all the current mothers who were not as angelic as yours truly in their teen years, and who just issued profane exclamations of concern when they saw this headline, here's more from the Tufts press release:

Mothers who use marijuana as teens — long before having children—may put their future children at a higher risk of drug abuse, new research suggests.

Researchers in the Neuroscience and Reproductive Biology section at the Cummings School of Veterinary Medicine conducted a study to determine the transgenerational effects of cannabinoid exposure in adolescent female rats. For three days, adolescent rats were administered the cannabinoid receptor agonist WIN-55, 212-2, a drug that has similar effects in the brain as THC, the active ingredient in marijuana. After this brief exposure, they remained untreated until being mated in adulthood.

The male offspring of the female rats were then measured against a control group for a preference between chambers that were paired with either saline or morphine. The rats with mothers who had adolescent exposure to WIN-55,212-2 were significantly more likely to opt for the morphine-paired chamber than those with mothers who abstained. The results suggest that these animals had an increased preference for opiate drugs.

The study was published in the Journal of Psychopharmocology and funded by the National Institutes of Health.

“Our main interest lies in determining whether substances commonly used during adolescence can induce behavioral and neurochemical changes that may then influence the development of future generations,” said Research Assistant Professor John J. Byrnes, the study’s lead author, “We acknowledge that we are using rodent models, which may not fully translate to the human condition. Nevertheless, the results suggest that maternal drug use, even prior to pregnancy, can impact future offspring.”

Byrnes added that much research is needed before a definitive connection is made between adolescent drug use and possible effects on future children.

The study builds on earlier findings by the Tufts group, most notably a study published last year in Behavioral Brain Research by Assistant Professor Elizabeth Byrnes that morphine use as adolescent rats induces changes similar to those observed in the present study.

Other investigators in the field have previously reported that cannabinoid exposure during pregnancy (in both rats and humans) can affect offspring development, including impairment of cognitive function, and increased risk of depression and anxiety.

(Hat-tip to Karen Weintraub)

This program aired on June 6, 2012. The audio for this program is not available.

Carey Goldberg Twitter Editor, CommonHealth
Carey Goldberg is the editor of WBUR's CommonHealth section.




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