Party beverages that go by "blackout in a can" and other monikers may soon be banned from store shelves in some U.S. states, thanks to a number of incidents that have left drinkers unconscious and with dangerously high blood alcohol levels. "Caffeine can reduce the sedative effects of alcohol; this may allow someone to drink for longer periods of time," said Thomas Gould, an associate professor of psychology at Temple. "In addition, caffeine and alcohol together may be more rewarding than alone. This could be due to both drugs producing increases in dopamine levels, which is involved in reward."