Addiction is a term widely used to indicate any type of excessive repetitive involvement with an activity or substance, and it is applied as readily to exercise, reading, and television viewing as to alcohol, cocaine, or heroin use. Such broad use of the term detracts from its technical value, and in this entry the term will be used to refer only to substance use. When considering problematic patterns of use, two distinct patterns, abuse and dependence, are described (American Psychiatric Association, 1994). Substance Abuse refers to life problems from substance use—use in situations in which it is physically dangerous, use interfering with occupational roles or with family and other social relationships, or use resulting in legal difficulties. In contrast, Substance Dependence is more syndromal. Physiological components of dependence may include tolerance—the need for increasing amounts of the substance to attain the same behavioral and subjective effects—or withdrawal, a physical syndrome activated by cessation of use of the substance. Behavioral components include using larger amounts of the substance over longer periods of times than intended; spending excessive amounts of time obtaining, using, and recovering from use of the substance; or using instead of engaging in other recreational and social pursuits. Psychological components include continued use despite knowledge of medical or psychological conditions caused or worsened by substance use, and desire or actual attempts to cut down or stop using the substance. Use of a range of substances, including alcohol, other sedative/hypnotic/anxiolytic drugs, cocaine, other stimulants, heroin, cannabis, hallucinogens, inhalants, and nicotine, can lead to Substance Abuse or Dependence. A withdrawal syndrome is associated only with alcohol, sedative/hypnotic/anxiolytic drugs, heroin, and nicotine.
Use of alcohol is common; regular use or abuse of other drugs is less common (Grant & Dawson, 1999). At some time in their adult lives two thirds of Americans have been regular drinkers (consumed at least 12 drinks in a year). In contrast, just under 16% of Americans are regular drug users (illicit use of a drug at least 12 times in a year) at some point in their lives. The lifetime prevalence of Substance Abuse and Dependence varies by substance, with different prevalence rates for men and women. Alcohol Abuse or Dependence is most common, with a lifetime prevalence for men of 25.5% and for women of 11.4%. In contrast, 8.1% of men and 4.2% of women have had any form of drug abuse or dependence at some time in their lives. The most common drug of abuse or dependence is cannabis, followed by prescription drugs, cocaine, amphetamines, hallucinogens, opiates, and sedatives.
The causes of addiction are complex and involve an interplay among three dimensions—the biological, the psychological, and the social. The relative importance of each dimension varies with the specific substance of abuse and with the individual user. Considerable research has attempted to identify the causes of dependence at the cellular or molecular level. A number of different neuronal changes have been suggested as causing Alcohol Dependence, including changes in neuronal membranes, changes in the excitability and function of nerve cells mediated through the calcium and GABAreceptor/chloride channels, changes in the activity of excitatory neurotransmitter systems, and changes in second messenger systems (Moak & Anton, 1999). Research on opiate dependence has failed to find changes in opiate receptors associated with addiction. However, at the subcellular level, chronic exposure to opiates has been demonstrated to lead to long-term changes in specific G protein subunits (Stine & Kosten, 1999).
Substance use disorders run in families, and research has attempted to distinguish genetic from familial aspects of etiology. Both twin and adoption studies suggest a heritable component to Alcohol Dependence. With other drugs, some studies are suggestive of genetic elements, such as evidence of common drug preferences in monozygotic twins, and increased risk for drug dependence in families (Hesselbrock, Hesselbrock, & Epstein, 1999). The relationship between family history and the development of alcohol or other substance dependence, however, is not absolute—the majority of offspring from families with Alcohol Abuse or Dependence do not develop problems, and the majority of those with Alcohol Abuse or Dependence do not have a clear family history (Fingarette, 1988).
Among those with familial alcohol or drug problems, the mechanisms by which inherited risk is expressed are not clear. The most common mechanism appears to be through specific temperament or personality—persons high in sensation seeking, low in harm avoidance, and low in reward dependence. Consequently, those with inherited risk for alcohol or drug dependence are at greater risk for Conduct Disorder or Antisocial Personality Disorder.
Psychological research has demonstrated the importance of interactions between the individual and environment. Repeated exposure to drug use situations can lead to conditioned physiological responses to the situations that are similar to physiological responses to the actual drug (Rohsenow et al., 1994). The development of strong positive expectancies about the effects of certain drugs can also contribute to continued use (Brown, Christiansen, & Goldman, 1987). Individuals may use substances to enhance positive moods as well as to cope with negative emotions, and those with other psychological problems are at particularly high risk for the development of substance use disorders as well.
Alcohol and drug use occurs in a social context. Introduction to alcohol and drug use most commonly occurs with either peers or family members. Individuals who are at high risk for using drugs and for other problem behaviors often join with peers of a similarly high risk level, and these peer groups then may influence those within the group to continue to use or experiment with other substances and other high-risk behaviors.
Prevention of Addiction
Prevention of addiction has taken many forms, including broad-brush prevention programs in schools; prevention targeted at specific populations, such as pregnant women; and environmentally focused interventions that change laws and policies, decrease access to the substance, and increase penalties. Individually and environmentally focused interventions have been successful in preventing or delaying the onset of use, decreasing use among those already using, and decreasing harmful consequences to the individual or to others.
Treatment efforts include both psychological and pharmacological approaches. A number of psychological therapies are effective in the treatment of Substance Abuse or Dependence. Brief, motivationally focused interventions are effective for individuals with milder problems, and they also may enhance treatment outcomes when combined with ongoing treatments (Bien, Miller, & Tonigan, 1993). Cognitive behavioral therapies, including community reinforcement treatment, relapse prevention, social skills training, and behavioral couples therapy, have good support for their effectiveness in treating Alcohol Dependence (McCrady & Langenbucher, 1996). Community reinforcement combined with the use of vouchers (Higgins et al., 1994), and family therapy (Liddle & Dakof, 1995) are effective in treating drug dependence. Outcomes for those who complete long-term treatment in therapeutic communities are good, but dropout rates are high (Simpson & Curry, 1997). Treatments to facilitate involvement with self-help groups such as Alcoholics Anonymous or Narcotics Anonymous also are effective (Project MATCH Research Group, 1997), and continued active participation in self-help groups is correlated with better outcomes.
Separate from medications for withdrawal, effective pharmacotherapies to treat substance use disorders are somewhat limited in number. Naltrexone, acamprosate, and disulfiram have evidence supporting their use in the treatment of alcohol dependence. Methadone, LAAM (1-aacetylmethadol), and buprenorphine have strong evidence of effectiveness in the treatment of opioid dependence. Nicotine replacement products are effective in the initial phases of treatment for nicotine dependence, and bupropion appears to be effective for longer-term pharmacotherapy (Barber & O’Brien, 1999).
The term addiction is overused, but it is useful in referring to a range of substance use problems. Etiology of these problems is complex, with multiple biological, psychological, and social factors contributing. Prevention is possible, and a number of effective treatments are available.
- American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author.
- Barber, W. S., & O’Brien, C. P. (1999). Pharmacotherapies. In B. S. McCrady & E. E. Epstein (Eds.), Addictions: A comprehensive guidebook (pp. 347–369). New York: Oxford University Press.
- Bien, T. H., Miller, W. R., & Tonigan, J. S. (1993). Brief interventions for alcohol problems: A review. Addiction, 88, 315–336.
- Brown, S. A., Christiansen, B. A., & Goldman, M. S. (1987). The Alcohol Expectancy Questionnaire: An instrument for the assessment of adolescent and adult expectancies. Journal of Studies on Alcohol, 48, 483–491.
- Fingarette, H. (1988). The myth of heavy drinking as a disease. Berkeley: University of California Press.
- Grant, B. F., & Dawson, D. A. (1999). Alcohol and drug use, abuse, and dependence: Classification, prevalence, and comorbidity. In B. S. McCrady & E. E. Epstein (Eds.), Addictions: A comprehensive guidebook (pp. 9–29). New York: Oxford University Press.
- Hesselbrock, M., Hesselbrock, V., & Epstein, E. (1999). Theories of etiology of alcohol and other drug use disorders. In B. S. Mc- Crady & E. E. Epstein (Eds.), Addictions: A comprehensive guidebook (pp. 50–74). New York: Oxford University Press.
- Higgins, S. T., Budney, A. J., Bickel, W. K., Foerg, F. E., Donham, R., & Badger, G. J. (1994). Incentives improve outcome in outpatient behavioral treatment of cocaine dependence. Archives of General Psychiatry, 51, 568–576.
- Liddle, H., & Dakof, G. A. (1995). Family-based treatment for adolescent drug use: State of the science [Monograph]. In E. Rahdert & D. Czechowicz (Eds.), Adolescent drug abuse: Clinical assessment and therapeutic interventions (pp. 218–254). Rockville, MD: National Institute on Drug Abuse Research.
- McCrady, B. S., & Langenbucher, J. W. (1996). Alcoholism treatment and health care reform. Archives of General Psychiatry, 53, 737–746.
- Moak, D., & Anton, R. (1999). Alcohol. In B. S. McCrady & E. E. Epstein (Eds.), Addictions: A comprehensive guidebook (pp. 75– 94). New York: Oxford University Press.
- Project MATCH Research Group. (1997). Matching alcoholism treatments to client heterogeneity: Project MATCH posttreatment drinking outcomes. Journal of Studies on Alcohol, 58, 7–29.
- Rohsenow, D. J., Monti, P. M., Rubonis, A. V., Sirota, A. D., Niaura, R. S., Colby, S. M., et al. (1994). Cue reactivity as a predictor of drinking among male alcoholics. Journal of Consulting and Clinical Psychology, 62, 620–626.
- Simpson, D. D., & Curry, S. J. (Eds.). (1997). Drug abuse treatment outcome study [Special issue]. Psychology of Addictive Behaviors, 11(4), 211–337.
- Stine, S. M., & Kosten, T. R. (1999). Opioids. In B. S. McCrady & E. E. Epstein (Eds.), Addictions: A comprehensive guidebook (pp. 141–l61). New York: Oxford University Press.