WordNet (r) 3.0 (2006):

drug addiction
    n 1: an addiction to a drug (especially a narcotic drug) [syn:
         drug addiction, white plague]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "drug addiction":
   a habit, acquired tolerance, acute alcoholism, addictedness,
   addiction, alcoholism, amphetamine withdrawal symptoms,
   barbiturate addiction, barbiturism, chain smoking,
   chronic alcoholism, cocainism, crash, craving, dependence,
   dipsomania, drug culture, drug dependence, habituation,
   nicotine addiction, physical dependence, psychological dependence,
   tolerance, withdrawal sickness, withdrawal symptoms