Addiction

Addiction is a chronic and relapsing disorder marked by persistent substance use despite a host of negative consequences. The U.S. Drug Enforcement Administration's Controlled Substances Act (CSA) identifies five classes of drugs: narcotics, depressants, stimulants, hallucinogens, and anabolic steroids. Substances within each of these classes, with the possible exception of anabolic steroids, are used to change one's mood or thoughts by way of altering the delicate chemical balance within the central nervous system. It is thought that all substances of abuse are capable of producing euphoria, and the extent to which this euphoria is reliably produced by the substance increases the possibility of the formation of addiction to it.

The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), defines two primary forms of substance use disorders (SUDs), namely, substance abuse and substance dependence. Substance abuse is marked by (a) recurrent substance use resulting in the failure to fulfill role obligations (e.g., missing work or school due to the consequences of substance use), (b) recurrent use in physically hazardous situations (e.g., drinking and driving), (c) continued use despite negative interpersonal consequences, or (d) repeated substance-related [Page 9]legal problems. Only one of those symptoms must be present within a 12-month period to warrant the diagnosis of substance abuse. Substance dependence, however, is typically conceptualized as a more severe substance use disorder, which is, in turn, more commonly associated with the term addiction. Substance dependence is marked by the presence of at least three of the following symptoms occurring together within a 12-month period: (a) tolerance (i.e., the need for greater amounts of the substance to achieve the same effect); (b) withdrawal (i.e., a group of symptoms that occurs when the substance is abruptly discontinued or taken in reduced amounts); (c) taking the substance in larger amounts or over longer periods of time than intended; (d) persistent desire or unsuccessful effort to stop or cut down substance use; (e) a great deal of time spent in obtaining, using, and recovering from the effects of a substance; (f) giving up important activities because of substance use; and (g) use despite physical or psychological problems caused or exacerbated by the substance. Revisions to the DSM-IV are under way, and the proposed changes include a single disorder category, namely, substance use disorder specified as moderate or severe. In light of the DSM-IV revisions, there continues to be considerable debate in the field as to the best terminology for substance use disorders and whether they should be collectively referred to as addiction, dependence, or an alternative term. Nevertheless, there is clear recognition that addiction represents a chronic and debilitating disorder with enormous costs to the affected individuals, their families, and society.

In this entry, the epidemiology, etiology, and treatment of addiction will be briefly summarized, with important theories and future directions highlighted.