The ultimate treatment goal is for the drug abuser to achieve a stable and drug-free existence, expressing no desire for the drug. In reality, however, few users make it to this phase, although many people greatly improve. Many people, if they are maintained in treatment, can stay somewhere between protracted abstinence and a stable, drug-free state without going all the way back to dependence again. Addiction should be treated as a disease, and the top priority with patients is to prevent relapse. The most powerful factors in relapse are psychiatric problems. Social factors such as unemployment, family problems, and peer influence also determine relapse in many cases. In addition, protracted abstinence makes people vulnerable. Conditioned responses may also be an important factor in relapse. Treatment must be individualized to identify the particular factors for each patient that can trigger a relapse. Continued relapses indicate the need for maintenance medication. In the case of heroin addiction, a long-acting version of methadone is provided. Another replacement medication is buprenorphine, a new drug that has both agonist and partial agonist effects. Another approach for opiate dependency is the blocking of opiate receptors using naltrexone. Numerous cost-effectiveness studies have shown that putting people into treatment is financially worthwhile. Studies show that every dollar spent on substance abuse treatment returns from $4 to $13 in terms of reductions in medical and surgical cost, crime, and family health costs. 13 figures