Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0906629106 (2009)

Rats fed tasty 'jelly shots' containing alcohol during adolescence became bigger risk-takers than teetotaller rats when presented with a lever game designed by Ilene Bernstein and her colleagues at the University of Washington in Seattle. When the adult rats were faced with a choice between pressing a lever for a guaranteed two sugar pills or a lever that could give them either nothing or four sugar pills, the individuals exposed to alcohol in adolescence tended to gamble more often. This effect on behaviour could still be seen three months after the alcohol was discontinued.

The researchers believe that their results indicate that the risk-taking behaviour is caused by the alcohol. Previous studies were not able to rule out the possibility that alcohol use and risk-taking behaviour are both caused by the same underlying propensity.