Disulfiram
One problem with disulfiram is that it does not stop alcohol cravings.  If an alcoholic takes disulfiram, they will keep craving alcohol, but will get very sick if they do drink.  Many alcoholics solve this problem by just not taking disulfiram.  One year-long study done in 1986 found that disulfiram did not seem to work.  However, the researchers found that only 20% of the alcoholics actually took their disulfiram.  The other 80% stopped taking disulfiram so they could drink alcohol without getting sick.