Study author Thomas Kash of the University of North Carolina School of Medicine said those who drank heavily were at increased risk for traumatic events such as car accidents and domestic violence, but that only partially explained the connection.
"There's a whole spectrum to how people react to a traumatic event," Kash said in a statement. "It's the recovery that we're looking at -- the ability to say 'this is not dangerous anymore.'"
Over the course of one month, the researchers gave one group of mice doses of alcohol equivalent to double the legal driving limit in humans. A second group of mice was given no alcohol.
The researchers used mild electric shocks to train all the mice to fear the sound of a brief tone.
The study, published in the journal Nature Neuroscience, found when the tone was repeatedly played without the accompanying electric shock, the mice with no alcohol exposure gradually stopped fearing it, but the mice with chronic alcohol exposure froze in place each time the tone was played.