DSM-IV criteria) (APA, 1994). As a consequence of compulsive drugseeking behavior and loss of control over consumption, drug dependence is usually a chronically relapsing disorder (i.e., one that may persist indefinitely and is prone to recur even after periods of remission). A diagnosis of drug abuse may also require treatment, but most clients in treatment have the more serious diagnosis of dependence.
The number of heavy drug users, using at least once a week, is difficult to determine. It has been estimated that in 1993, there were 2.1 million heavy cocaine users and 444,000-600,000 heavy heroin users (Rhodes et al., 1995). Although cocaine and heroin represent the major drugs of abuse for a large proportion of individuals who seek treatment, most patients abuse more than one drug. In addition, others seek help for abuse of marijuana, phencyclidine, benzodiazepines, other sedatives, or abuse of multiple drugs. It was estimated that in 1994, 3.6 million people in the U.S. had drug problems severe enough to need drug treatment services (ONDCP, 1996). The actual number of clients in treatment falls far short of this estimate. For example, the National Drug and Alcoholism Treatment Unit Survey (NDATUS) reported that almost 1.0 million people in 1993 were in private and public drug abuse treatment programs; approximately 20 percent of those in treatment were enrolled mainly for illicit drug abuse, 45 percent for alcohol, and 35 percent for combined alcohol and other drug dependencies (SAMHSA, 1995a). Although the figures are not comparable or definitive, the magnitude of the gap between the need for treatment and the use of treatment services is clear.
There are many reasons for the inadequate number of clients in treatment, including insufficient public funding for drug abuse treatment, cutbacks in treatment availability in the private sector, an unwillingness of many clients to seek treatment, and the deterrent effect of being placed on a waiting list for treatment (IOM, 1990b). Treatment should be available to all who request it, and long waiting lists are counterproductive (Goldstein and Kalant, 1990). That is particularly true given recent studies (cited later in this chapter and elsewhere) that demonstrate the effectiveness and cost-effectiveness of treatment.
Clearly, the development of varied treatment modalities and interventions discussed below are major accomplishments of drug abuse research. They include treatment options (e.g., pharmacotherapies and/or psychosocial), treatment effectiveness, cost-effectiveness, and the development of tools and techniques for clinical assessment and diagnostic differentiation.