Addiction is a complex disorder whose principal diagnostic feature is a repeated compulsion to take a certain substance or indulge in a certain behavior despite negative consequences. As an addicted person increasingly begins to rely on the object of addiction for physical or emotional gratification, he or she tends to neglect other, healthier aspects of life. It is generally agreed that there are two types of addiction: physical, when people become addicted to substances such as drugs or alcohol, and psychological or behavioral, when people become addicted to activities such as gambling or shopping. A behavioral addiction may also be called a process addiction. Although there is some disagreement over whether behaviors can be addictions in the same sense that drugs can be—some prefer to call such behaviors impulse control disorders or obsessive-compulsive disorders—the addict's need to indulge in them despite adverse consequences has led to their popular identification as addictions.
Both types of addiction initially provide some sort of pleasure, excitement, or gratification—often a combination of these. Addictions may range from mild to severe in degree; mildly addicted people may respond quickly to treatment and have relatively little difficulty refraining from the substance or behavior, whereas severely addicted people may be unable to recover.
Scientific advances over the past 30 to 40 years have revealed that addiction is based on neurochemical changes that take over or hijack a critical chemical pathway in the mesolimbic dopamine system of the brain. Known as the reward pathway, this area is programmed to respond to certain stimuli such as food or sex with feel-good neurotransmitters, primarily dopamine. Scientists believe that the pleasure these stimuli produce is how organisms learn to repeat behaviors important for survival, such as eating and reproduction. In the case of addictive substances, however, this mechanism can backfire.
When someone ingests an addictive drug or engages in addictive behavior, the affected neurons are overstimulated to produce an excess of dopamine that the brain perceives as a significantly more pleasurable experience than that provided by life's natural rewards. With repeated exposure to the psychoactive stimulus, the brain compensates by reducing its neurotransmitter output and producing fewer cellular receptors to receive and transmit dopamine along the reward pathway. As tolerance develops, the individual begins to require more of the drug stimulus to achieve the initial effect. Eventually, his or her use or behavior takes on a compulsive quality as the individual finds him- or herself compelled to indulge more frequently—not to feel good but to avoid feeling bad. In spite of this, the person is likely to deny the problem and claim that usage or behavior falls within normal boundaries. A clear indication that the individual's judgment is impaired, this denial becomes a nearly automatic reflex with which one justifies pathological use or behavior. If the person is unable to indulge, he or she may experience withdrawal, the physical and psychological distress that arises as the brain attempts to adjust to the absence of drugs.
Although behavioral addictions generally do not produce the more severe physical manifestations of withdrawal sometimes seen in substance addictions, individuals suffering from them may experience a certain level of agitation, restlessness, and depression if they cannot satisfy their need. Many drugs, such as certain antidepressants, cause physical dependence in the sense that they rebalance the brain's neurotransmitters, and their abrupt withdrawal can lead to distressing symptoms, but these drugs are not addictive because they do not trigger compulsive use and loss of control.
A consensus exists among most scientists that addiction is the process during which the brain's neural pathways—primarily in the mesolimbic dopamine system—are hijacked by the artificial reward of drugs. It is not clear how certain combinations of genetic, biological, and environmental factors allow this to happen in some people and not others; what is known is that, for many, a drug-induced release of dopamine and other neurotransmitters overrides the brain's response to normal rewards that support survival, such as food or sex. This reaction leads to changes in the structure of axons and dendrites and alters synapse formation, a dysregulation that begins to affect the addict's behavior outside of her or his conscious awareness. Although it is not completely understood how this physiological remodeling occurs, the distorted neurochemical messages it transmits affect learning, motivation, and memory. In time, addicts no longer respond to the drug with the same pleasure but find, instead, that they require the drug to feel normal. As their ability to enjoy other pleasures decreases and their need for the drug increases, many addicts gradually cease to care about families, homes, work, school, or health in their single-minded pursuit of the drug.
Indulging in addictive substances or behaviors does not have to occur on a daily basis for addiction to exist; weekend drinkers or those who go on monthly binges with days of remission between episodes can be addicted, just as heavy drinkers who have several cocktails every night for years are not necessarily addicted if their drinking does not produce negative consequences and if they are able to stop without difficulty.
Recent research on mice has revealed that dopamine-releasing cells in the brain seem to learn and remember their hypersecretion of dopamine in response to addictive drugs. Called long-term potentiation, this cellular memory remains active for some time and may be part of the basis for craving. Researchers also made the intriguing discovery that although psychoactive nonaddictive drugs such as antidepressants do not potentiate the cells in the same way, acute stress does. Although stress does not cause addiction, this finding raises questions about how the relationship of drug exposure and stress could affect the brain's chemical threshold for prolonged potentiation and increased vulnerability to addiction. It may also help explain why stress is one of the most powerful threats to abstinence and recovery.
The American Psychiatric Association (APA), in its Diagnostic and Statistical Manual of Mental Disorders (DSM) published in 2000, presents criteria widely used by mental health experts to diagnose addiction and distinguish it from abuse. Although the DSM uses the term dependence in an effort to remove the stigma associated with the word addiction, this practice has led to considerable confusion, and increasing pressure is on APA editors to revert to the term addiction in the next edition of the DSM. Some experts, however, insist that addiction is a vague, clinically inaccurate term that does not properly distinguish between the medical disease that true addiction represents and the overindulgence of drugs or other substances that represents abuse, not addiction. They believe that the term dependence remains appropriate, especially if clear distinctions are made between chemical dependence and drug abuse. Despite this argument, there are indications that the APA will revert to addiction in the fifth edition of the DSM due to be published in 2012 rather than continue its use of the term dependence.
Signs Of Substance And Behavioral Addictions
Anticipating the substance or behavior with increased excitement
Feeling irritable or restless when prevented from indulging in the substance or behavior
Devoting increasing amounts of time preparing for the substance use or activity or recovering from the effects
Neglecting responsibilities at home, school, or work
Indulging in the substance or behavior to manage emotions
Thinking obsessively about the activity
Seeking out the substance or activity despite the harm it causes (deterioration of health, complaints from family or coworkers)
Denying the problem to self and to others despite its obvious negative effects
Hiding the use or behavior from others
Suffering blackouts—memory losses while under the influence or an inability when sober to remember behavior that occurred when under the influence
Becoming depressed; often a contributory factor in the development of an addiction, depression is also a result
Having a history of anxiety or other mental disorder, psychological or physical abuse, or low self-esteem
Experiencing some form of sexual dysfunction
Feeling remorse or shame over use of substance(s) or activities associated with use dependence and physical dependence.
Evidence suggests that behavioral addictions tend to occur later in life and that substance addictions usually have an earlier onset stemming from drug or alcohol use during adolescence. Some studies cite instant-onset addiction, when users report that their initial exposure makes them feel normal for the first time in their lives. Whether this phenomenon represents actual addiction or an unusual reaction to the drug is not yet clear. Late-onset addictions may occur in adulthood, although the National Institute on Drug Abuse (2007) reports that the likelihood of addiction is much greater among adolescents and very young adults due to the plasticity of their developing brains.
According to the National Institute of Mental Health and other scientists studying the impact that drug abuse has on the brain, adolescents are more vulnerable than adults to the deleterious effects of drugs for three reasons: drugs increase the likelihood of risky behavior; they prime vulnerable areas of the brain for the development of addiction; and, in the long term, they can permanently impair mental capacity.
Once a child reaches puberty, the brain begins to thin out excessive brain-cell connections made when the child was younger and the brain was growing at a rapid rate. This thinning-out process also helps build longer chains of neural networks that are required for the more critical analytical thinking that adults require throughout their lives. The pruning can be likened to how a gardener prunes a bush to remove weaker, ineffective branches to allow the stronger limbs to develop fully so the bush will thrive. A similar process in the brain of someone roughly 11 to 25 years old represents a crucial stage of neurological development.
The final area of the brain to mature is the prefrontal cortex, where higher cognitive functions and judgment reside. With so many structures in the teenage brain set to accelerate, the inhibitory reasoning part of the prefrontal cortex might not engage well enough to adequately guide behavior. Even in their late teens, adolescents are more impulsive, aggressive, and likely to engage in novel or risky activities than people in their mid- to late 20s. By the time adolescents outgrow their impulsive youth and reckless behavior, it may be too late to reverse addictive patterns already laid down in the brain or to undo permanent damage to cognitive abilities.
Addictions for the most part are chronic, progressive, and highly destructive. Long-term drug users develop physical health problems, and interpersonal, social, and occupational relationships break down as well. The ingredients in some drugs that cut or alter the substance can be toxic; snorting—inhaling powdered forms of a drug—can erode nasal tissues; stimulants can cause heart attacks or respiratory arrest; and contaminated needles can transmit HIV and other serious diseases such as malaria, tetanus, blood poisoning, or deadly bacterial infections. Drugs can trigger aberrant or violent behavior, and accidents—particularly automobile accidents—are common. About one-half of all highway fatalities involve alcohol alone.
Behavioral addictions such as eating disorders or sexual addictions that carry a risk of sexually transmitted diseases seriously compromise health. Others, such as pathological gambling, are devastating in other ways. Gambling addicts can squander a lifetime's accumulation of assets as they chase the next win, neglecting eating, sleeping, families, school, and work as their lives unravel.
Although their addictive potential varies widely, legal and illegal addictive substances are generally considered to be narcotics, stimulants, depressants, cannabis, hallucinogens, inhalants, anabolic steroids, nicotine, alcohol, and caffeine. Aside from their inherent chemical properties, factors that affect their addictive liability include the method of administration as well as the addict's genetic and environmental background. Addictive behaviors can arise from normal activities such as gambling, computer usage, sex, shopping and spending, and exercising, or from aberrant practices like kleptomania (stealing), trichotillomania (pulling out of one's hair), self-injury (cutting behaviors), and pyromania (starting fires).
The identification of certain activities as behavioral addictions is a comparatively recent event. Substance addiction has always been recognized, ever since humans began using mind-altering substances. In the fourth century BCE, Aristotle (384–322 BCE) referred to drunkenness as an organic disorder, and discussions of opium addiction appeared in medieval documents. Historical references to addiction focus on its negative aspects, although cultural attitudes about the more controlled use of some addictive drugs have been mixed. At one time, cocaine, marijuana, methamphetamines, and even opium were routinely prescribed for various conditions, and other drugs, such as peyote, are still in legal use among certain religious groups. Today, controlled substances such as codeine are prescribed for pain relief, and Ecstasy is being studied for the treatment of post-traumatic stress disorder.
Until the middle of the 20th century, addicts were usually shunned by the public or incarcerated in prisons or mental institutions. To some degree, modern attitudes have not changed: many people avoid or ignore homeless addicts on the streets of U.S. cities. Others view addiction and the deterioration that accompanies it as behavioral aberrations that should be addressed with cognitive techniques administered through widely available social programs. Still others, increasing numbers of laypeople and professionals alike, have come to regard addiction as an illness. These differing attitudes are reflected in present-day disagreements over whether illegal drug use is best addressed with criminal, behavioral, or medical measures or a combination of all three.
Since the 18th century, three models of addiction have emerged to explain the basis of addiction and to guide treatment strategies to address it: the moral model, the disease model, and the choice model. The disease model has received the most widespread acceptance in modern times, although many continue to support aspects of the moral and choice models.
Today, as accumulating data and brain-imaging studies reveal more about how addictions start and ultimately affect the brain's neurochemistry, the disease model has become widely accepted. The American Medical Association declared addiction a disease in 1956; the National Institute on Drug Abuse defines it as a progressive, chronic, relapsing—and treatable—brain disease; and organizations such as the American Psychiatric Association, the American Psychological Association, the American Society of Addiction Medicine, and the National Council on Alcoholism concur. They agree that although underlying physical or mental illness, genetics, and environmental factors coalesce in complex ways in the development of addiction, almost anyone can become addicted when compulsive behaviors or substance abuse continue long enough. In many people, especially those with a genetic predisposition, brains repeatedly exposed to the addictive substance undergo changes that leave users incapable of making the rational judgments needed to moderate addictive behavior, and so the disease worsens. Fortunately, some of the newer medications that target addiction-related neurochemistry in some cases can help restore the brain to normal functioning and reduce or eliminate craving, a major threat to recovery.
See also Alcohol; Caffeine; Cigarettes; Drugs, Recreational; Stress.
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