Nicotine exposure during the teen years may increase the risk of mood disorders such as depression, suggests a Florida State University study.
For 15 days, researchers gave adolescent rats twice daily injections of either nicotine or saline. In subsequent experiments, the rats were put in stressful and pleasurable situations, United Press International reported.
The rats exposed to nicotine showed depression- and anxiety-related behaviors, such as repetitive grooming, decreased consumption of rewards, and freezing in stressful situations, instead of trying to escape. These symptoms eased when the rats were given more nicotine or antidepressant drugs.
Adult rats exposed to the same levels of nicotine didn't show the same depression- and anxiety-like traits, UPI reported.
The findings, published in the journal Neuropsychopharmacology, may also be true for humans, the researchers said.