Addiction is an uncontrollable compulsion to repeat a behavior regardless of its negative consequences. A person who is addicted is sometimes called an addict.
Many drugs or behaviors can precipitate a pattern of conditions recognized as addiction, which include a craving for more of the drug or behavior, increased physiological tolerance to exposure, and withdrawal symptoms in the absence of the stimulus. Most drugs and behaviors that directly provide either pleasure or relief from pain pose a risk of dependency. Addictions can also be formed due to opponent process reactions. For example the terror of jumping out of an airplane is rewarded with intense pleasure when the parachute opens. Because of opponent process criminal behavior, running, stealing, violence, acting, test taking can become habit forming.
Varied forms of addiction
The medical community now carefully distinguishes between physical dependence and psychological addiction (or simply addiction). Addiction is now narrowly defined as "uncontrolled, compulsive use despite harm"; if there is no harm to the patient or another party, there is no addiction. The obsolete term physical addiction is deprecated because of its pejorative connotations, especially in modern pain management with opioids where physical dependence is nearly universal but addiction is rare.
Physical dependency on a substance is defined by the appearance of characteristic withdrawal symptoms when the drug is suddenly discontinued. While opioids, benzodiazepines, barbiturates, alcohol and nicotine are all well known for their ability to induce physical dependence, other drugs share this property that are not considered addictive: cortisone, beta-blockers and most antidepressants are examples. Also, some highly addictive drugs, such as cocaine, induce relatively little physical dependence. So while physical dependency can be a major factor in the psychology of addiction, the primary attribute of an addictive drug is its ability to induce euphoria while causing harm. Some drugs induce physical dependence - but not addiction - for example many laxatives, which are not psychoactive.
Psychological addictions are a dependency of the mind, and lead to psychological withdrawal symptoms. Addictions can theoretically form for any rewarding behavior, but typically only do so in individuals with emotional, social, or psychological dysfunctions, taking the place of normal positive stimuli not otherwise attained. The distinction between the two kinds of addictions, however, is not always easy to make. Addictions often have both physical and psychological components.
Not all doctors do agree on what addiction or dependency is. However, researchers, doctors, and popular literature discuss many addictions, including those to alcohol, tobacco, drugs, gambling, food, and even sex, pornography, computers and work.
While eating disorders, like other behavioral addictions, are usually considered primarily psychological disorders, they are sometimes treated as addictions, especially if they include elements of addictive behavior. Sufferers may experience withdrawal or withdrawal-like symptoms if they alter their diet suddenly. This suggests that some common food substances, especially chocolate, caffeine, and sugar, may have the potential for addiction.
The speed with which a given individual becomes addicted to various substances varies with the substance, the frequency of use, the means of ingestion, and the individual. Some alcoholics report they exhibited alcoholic tendencies from the moment of first intoxication, while most people can drink socially without ever becoming addicted. Nicotine is considered by many to be the most addictive substance in the world.
Methods of care
Early editions of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders described addiction as a physical dependency to a substance that resulted in withdrawal symptoms in its absence. Recent editions, including DSM-IV, have moved toward a diagnostic instrument that classifies such conditions as dependency, rather than addiction. The American Society of Addiction Medicine recommends treatment for people with chemical dependency based on patient placement criteria (currently listed in PPC-2), which attempt to match levels of care according to clinical assessments in six areas, including:
Some medical systems, including those of at least 15 states of the United States, refer to an Addiction Severity Index to assess the severity of problems related to substance use. The index assesses problems in six areas: medical, employment/support, alcohol and other drug use, legal, family/social, and psychiatric.
While addiction or dependency is related to seemingly uncontrollable urges, and may have roots in genetic predisposition, treatment of dependency is always classified as behavioral medicine. Early treatment of acute withdrawal often includes medical detoxification, which can include doses of anxiolytics to reduce symptoms of withdrawal. In chronic opiate addiction, a surrogate drug such as methadone is sometimes offered as a form of opiate replacement therapy. But treatment approaches universally focus on the individual's ultimate choice to pursue an alternate course of action.
Therapists often classify patients with chemical dependencies as either interested or not interested in changing. Treatments usually involve planning for specific ways to avoid the addictive stimulus, and therapeutic interventions intended to help a client learn healthier ways to find satisfaction. Clinical leaders in recent years have attempted to tailor intervention approaches to specific influences that effect addictive behavior, using therapeutic interviews in an effort to discover factors that led a person to embrace unhealthy, addictive sources of pleasure or relief from pain.
Several explanations (or "models") have been presented to explain addiction:
Although the term addiction is sometimes often used loosely rather than as a medical classification, there are some physiological conditions related to everyday behaviors that are also related to the more commonly recognized mechanisms associated with addiction. Pleasurable activities cause the release of endorphins, and this endorphin-rush can conceivably become 'addictive'. Evolutionary biologists have suggested this process of attentuating pleasure pathways is part of the brain's natural system for ensuring that humans develop abiding interests. Since human societies depend on enduring attachments, many theorists suggest such addictions are not necessarily a problem. Other views, such as the those summarized in Buddhist concept of tanha, suggest trivial attachments are at the root of much human suffering.
The pathways oriented to endorphins, sometimes called pleasure centers originated in small organisms such as insects, which rely on the neurological system to help them find familiar sources of food.
Endorphins stimulate activity of the neurotransmitter dopamine after initially activating opioid receptors earlier in the nervous circuit. Increased dopamine activity is often met by an decrease in the number of receptors sensitive to dopamine. This process is called downregulation. The decreased number of receptors tends to result in reduced electrical activity along post-synaptic nerve pathways, unless some behavior or substance causes a continued high level of dopaminergic stimulation. The absence of a pleasurable sensation in conditions that were formally sufficient can cause a mild feeling of let-down after receptors have been downregulated. The increased requirement for dopamine to maintain the same electrical activity is the basis of both physiological tolerance and withdrawal associated with addiction.
The middle striatal reward pathway has been most strongly linked with addictive and reward behavior. This pathway utilizes dopamine as a neurotransmitter and receives presynaptic input (from earlier in the circuit--it gets signals from these earlier in the circuit cells) from cells that respond to cannibinoids, nicotine (receptor subtype is nicotinic), and from cells that respond to endogenous opioid substances such as endorphins or enkephalins. Cells that are said to respond to a particular neurotransmitter (or agonists) contain, at the postsynaptic end (receiving area of the cell) receptors for that neurotransmitter.
In cases of physical dependency on depressants of the central nervous system such as opioids, barbiturates, or alcohol, the absence of the substance sometimes leads to symptoms of severe physical discomfort and withdrawal can even result in death from alcohol and barbiturates (but is generally only very uncomfortable in the case of opioids despite media disinformation to the contrary). In these cases, a body has become so dependent on a chemical that it has stopped producing the necessary neurotransmitters required to maintain a comfortable status.
Opioids present extreme risks of dependency because they are chemically similar to endorphins, causing an upregulation of dopaminergic receptors without stimulation of the endorphin systems. Cocaine and amphetamines also pose risks associated with physical attenuation, in both cases because they cause increasees in the levels of the neurotransmitters dopamine and norepinephrine which acts indirectly to stimulate dopaminergic pathways in the brain.
The word addiction is also sometimes used colloquially to refer to something a person has a passion for. Such "addicts" include: