Drug diagnoses in DSM-III-R are based on the dependence syndrome concept which hypothesizes that dependence on drugs is defined by behavioral and physiological changes but is separate from the social problems related to drug use. Previous studies provide support for the dependence syndrome in drug use; however, no study has examined whether biological indications of addiction are related to the dependence syndrome. The present study tests this relationship in 52 opiate addicts who were administered the Naloxone Challenge Test. The severity of withdrawal was correlated positively with the opiate dependence score, derived from the number of DSM-III-R criteria met. We also found that opiate withdrawal was inversely related to cocaine dependence and unrelated to any other drug use. Opiate withdrawal was not correlated with a global measure of social problems or to frequency or length of drug use. Our results support the validity of the dependence syndrome in opiate addiction because dependence is correlated with severity of withdrawal, is fairly specific to the drug, and is not related to social problems.