The term addiction, as applied to substance use, denotes an advanced level of dependence on a substance, marked by a compulsive need to obtain and consume it despite negative consequences. Dependency may consist of physical dependency, psychological dependency, or both. Physical dependency is characterized by withdrawal symptoms that occur if the substance is discontinued. This physical dependence thus produces a cycle in which the individual continues to use the substance to prevent the withdrawal symptoms. Psychological dependency, while no less powerful than physical dependency, refers to an individual’s perceived need for the substance. When the individual is unable to acquire the drug, negative psychological experiences may occur, prompting the individual to continue substance use. Individuals who experience addiction may find themselves unable to function effectively without the substance or substances to which they are addicted. What distinguishes addiction from less extreme forms of dependence is a loss of control and a markedly intense preoccupation with the substance.
The term addiction is not part of the clinical framework presented in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) of the American Psychiatric Association. Yet, the diagnostic classifications in the 2000 edition of the DSM-IV-TR acknowledge the symptoms of physical and psychological dependence, including withdrawal and tolerance. Withdrawal, the prominent feature of addiction, is characterized by physical symptoms and often by inability to function without the substance. Tolerance occurs when over time individuals experience a decreased substance effect or must increase their dosage of the substance to experience the same effect.
Individuals may develop addiction to a variety of substances, including alcohol and drugs. Drugs of addiction include both illicit drugs like heroin and prescription or over-the-counter drugs like prescription oxycodone. Whether individuals can become addicted to behaviors— such as gambling, eating, and sexual promiscuity—is, however, controversial. Scholars who favor an expanded definition of addiction argue that certain behaviors may serve an emotion-regulating function and can thus lead to addiction.
The use of potentially addictive substances is quite prevalent. According to the 2004 National Survey on Drug Use and Health (NSDUH), 7.9 percent of the population aged twelve or older used illicit drugs in 2004 (Substance Abuse and Mental Health Services Administration [SAMHSA] 2005). However, substance use and addiction are not equally prevalent in all social categories. According to the 2004 NSDUH, rates of illicit drug use among those twelve and older increase until ages eighteen to twenty, after which rates gradually decrease (SAMHSA 2005). Rates of current illicit drug use also vary by race/ethnicity, with rates highest among individuals reporting two or more racial/ethnic groups and those of American Indian or Alaskan Native descent (SAMHSA 2005). Rates are similar for whites, Hispanics, and blacks, but markedly lower among Asians (SAMHSA 2005). With regard to socioeconomic status, rates are higher for the unemployed than the employed (SAMHSA 2005).
In addition to variations by social category, distinct patterns are observed for different classes of drugs. Tobacco and alcohol use are even more prevalent than illicit drug use (SAMHSA 2005).
CAUSES OF ADDICTION
Differences in patterns of use may be due to both social and biological factors. Furthermore, factors involved in initial and in continued substance use may differ. For example, individuals may begin use as a means of social enhancement or in response to pressure from peers and may continue use to avoid negative emotions or withdrawal.
Animal models have improved understanding of addiction and, in tandem with the findings of twin studies, strongly suggest a genetic component (see Crabbe 2002 for review). Scientists have identified neurotrans-mitter systems that are involved in the development of addiction. In recent years, this genetic component has received increasing attention as research on addiction has shifted from the domain of sociologists and psychologists to that of geneticists and neurobiologists. This focus on the role of brain chemistry (e.g., Koob, Sanna, and Bloom 1998) and genetics (e.g., Nestler 2000) has many potential implications for the study and treatment of addiction: It may lead to revolutionary new treatments and reduce addiction’s stigma. Especially useful are gene-environment interaction models in which social environments/circumstances and genetics interact to determine whether an individual develops addiction.
CONSEQUENCES AND TREATMENT OF ADDICTION
Addiction is costly to both society and the individual. At the societal level, the prevention, control, and treatment of addiction require substantial resources. The types of societal investments made depend in part on whether addiction is viewed as primarily a medical or a criminal issue. Policies based on medical models favor rehabilitation and other treatments and generally attempt to minimize the stigma of addiction. Policies based on criminal models focus on punishing addicts and deterring addiction in the same way that other crime is deterred. In practice, both policies, or elements of both policies, are observed.
Addiction usually entails a variety of social costs as well. Individuals with addictions are highly motivated to attain the substance of their addictions and may engage in self-destructive behaviors or criminal acts in this pursuit. Drugs per se do not necessarily make individuals more violent, but the need to attain the drug, often to ward off withdrawal, may disinhibit individuals and lead to unhealthy and/or criminal activity. At the familial level, parents who have an addiction may be unable to responsibly care for their children. Moreover, children of substance users are themselves at increased risk of substance use (see, e.g., White, Johnson, and Buyske 2000). At the individual level, addiction is associated with a multitude of negative health effects. This may be due to the substance itself or to the way that the substance is consumed. For example, drugs that are smoked may contribute to lung cancer, whereas drugs that are taken intravenously pose risks associated with injection (i.e., use of unsterile needles may be associated with the transmission of infectious diseases like HIV). Negative health effects also include withdrawal, which can be fatal with some drugs and with alcohol if not medically supervised.
TREATMENT OF ADDICTION
Many agencies exist to assist individuals in overcoming addiction, including outpatient facilities, residential communities, and hospital-based programs. In addition, self-help groups like Alcoholics Anonymous (AA) are quite common. The twelve-step model of AA has been embraced by the treatment community and often provides the structural framework for both inpatient and outpatient treatment. A variety of pharmacotherapies are available for treating addictions, including agonist medications, antagonists, agonist-antagonist medications, and anticraving medications (see O’Brien 1997 for discussion). Supervised medical detoxification may be required for individuals addicted to certain drugs and for alcohol-dependent individuals with medical problems. Treatment for addiction can be quite costly.
Approaches to the treatment of addiction are predominantly based on a biopsychosocial model, which holds that the biological, psychological, and social bases of addiction all need to be addressed. Within that approach, differences in understandings of the causes of addiction may prompt some treatment providers to favor certain approaches over others. For example, some treatment providers favor a medical model in which addiction is viewed as a disease and treated within a medical framework, whereas others may lean toward more behavioral models that conceptualize substance abuse as resulting from deficient coping skills. Some providers more than others pay special attention to social and cultural explanations for addiction and advocate culturally sensitive programs that focus on overcoming social disadvantage. Individualized treatment programs and programs that respond to differences in gender and sexual orientation have great potential for success.
Addiction is a phenomenon with social, medical, and legal dimensions. A multifaceted public health problem, its treatment and prevention require contributions from multiple disciplines. Medical scholars, legal scholars, sociologists, psychologists, and policymakers are all needed if progress is to be made.
