A study found that alcohol abuse could put people at greater risk of post-traumatic stress disorder, because the emotional centres of the brain have been damaged by drink.
Nerve centres in the frontal cortex of mice were found to have changed shape because of drink and the activity of a key receptor was suppressed.
It meant that the brain struggled to put trauma behind it and say “this is not dangerous anymore”, reports journal Nature Neuroscience.
Dr Thomas Kash, of the University of North Carolina, said: “There’s a whole spectrum to how people react to a traumatic event.
“It’s the recovery that we’re looking at – the ability to say ‘this is not dangerous anymore.’
“Basically, our research shows that chronic exposure to alcohol can cause a deficit with regard to how our cognitive brain centres control our emotional brain centres.”