Unfortunately this study comes from the University of Missouri:
"Regardless of how painful it can get, a new study out of the University of Missouri shows a hangover doesn't have much effect on when some people will knock back their next drink."
"The researchers did admit some entries were missing because participants were too hung over to complete the log. At the end of the experiment, researchers looked at 2,276 drinking episodes and 463 hangover experiences."
The story does not say what department this study came from.