Professor David Nutt believes that there is no reason why we can't make hangover-free alcohol, like Star Trek's synthehol.
Alcohol works in the brain mainly by latching onto signalling molecules called GABA-A receptors. There are dozens of subtypes of these; not all of them are associated with specific effects of alcohol. For example, memory loss may occur in conjuction with drinking because alcohol binds to alpha-5, a GABA-A receptor subtype in the hippocampus.
Professor Nutt suggests that if molecules that bind poorly to the bad subtypes like alpha-5 could be developed, it would be possible to retain the pleasant effects of alcohol without the bad side-effects.
Romulan Ale pic from Google Image.