Here's a little something I wrote for an encyclopedia

Just want to see if people have any comments.

Discussion of so-called “substance abuse” and addiction is vexed by ambiguity and disputes over vocabulary, which are caught up in equally vexing disputes about ideology and values. People may distinguish among substance use, misuse, abuse, abuse disorder, dependence, and addiction, but not necessarily in consistent ways.
The American Psychiatric Association defined drug abuse in 1932 as “the illegal, nonmedical use of a limited number of substances, most of them drugs, which have properties of altering the mental state. . .” Note the oddity that not all drugs are drugs – the second sense meaning therapeutic compounds. This double meaning creates additional confusion. The definition went on to establish as essential conditions violation of cultural acceptability, social norms, or statute, in other words drug abuse was predominantly framed as moral transgression. This moral lens has continued to influence views of substance abuse, but the formulation of addiction or substance dependency as a disease has grown more influential.

Some question the concept of a substance abuse disorder or addiction entirely, claiming that these cannot be distinguished from other categories of voluntary behavior which may have consequences that most people would view as negative; while a contrary movement has extended the concepts of behavioral dependence and addiction beyond the use of psychoactive chemicals to encompass behaviors ranging from gambling to eating to sex to surfing the Internet.

For the disease model of substance use disorders the authoritative texts are the Diagnostic and Statistical Manual of Mental Disorders IV, Text Revision, (DSM) issued by the American Psychiatric Association; and the World Health Organization International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD10). Neither use the term “addiction.” The ICD10 focuses on harm to the individual from overuse of psychoactive substances, with difficulty controlling use and continued use in spite of harm defining “Dependence Syndrome.” The DSM uses a similar definition for “substance dependence.” However, its definition of substance abuse does not focus on damage to health, but rather on psycho-social problems such as failure to fulfill role obligations, and legal consequences. In this respect, the APA’s moral lens persists.

In the vernacular “addiction” may refer to any habitual overindulgence, but in neuropsychiatry it refers specifically to alterations in the brain’s dopamine signaling system centering on the nucleus acumbens region. This circuit is believed to provide rewards for behaviors associated with evolutionary success, such as sexual intercourse and eating. Addictive drugs increase the level of dopamine in this system, resulting initially in behavioral reward. Chronic overstimulation of dopamine receptors results in needing the drug in order to feel any behavioral reward and overwhelming other motivations. Note that the “reward” for using the drug is not necessarily euphoria or even pleasure, but merely the relief of craving. Additional accommodations by the body to chronic use of an addictive substance may result in various other physical or mental symptoms when the drug is withdrawn, creating an additional short-term challenge to cessation. However, craving may persist long after these acute withdrawal symptoms have ended.
Chemicals that affect this neural circuit include opioids, nicotine, alcohol, amphetamines and cocaine, although the effects of these compounds are otherwise dissimilar. Hallucinogens are considered drugs of abuse, but are not habituating. Cannabis targets a different class of neuroreceptors and is less habituating than chemicals that target the dopamine pathway. . . .

Habitual tobacco use is very harmful to health over the long term, dramatically raising the risk of lung cancer and some other cancers, heart disease, stroke, chronic obstructive pulmonary disease, and associated mortality. Tobacco use is considered the leading preventable cause of death in the United States and most of the wealthy countries. However, as tobacco is fully legal and does not produce acute impairment, other social harms associated with tobacco are minimal.

The example of tobacco supports a plausible argument that the harms associated with opioid dependency principally result from legal prohibition. Dependent users can be maintained with doses that do not produce euphoria but eliminate craving, with minimal consequences to health, and lead fully functional lives. However, as non-prescription opioids are very expensive and their sale and possession is subject to severe legal sanctions, habitual users must devote most of their waking hours to obtaining them or the money with which to buy them, often through illegal activity. They commonly self-inject to obtain maximum effect from small amounts, leading to risk of acquiring HIV and Hepatitis C virus from shared equipment, and injection site infections. They cannot count on the concentration or purity of the product they acquire, and may accidentally overdose or inject dangerous contaminants. They are subject to marginal existence, homelessness, and incarceration.

The Harm Reduction movement argues for a non-punitive approach to drug dependence which “Accepts, for better and for worse, that licit and illicit drug use is part of our world and chooses to work to minimize its harmful effects rather than simply ignore or condemn them.” Preferred harm reduction policies include providing clean needles, teaching safer injection practices, and mandating users who commit non-violent crimes to treatment rather than jail.

The harm reduction approach is on weaker ground when it comes to amphetamine and cocaine abuse, as these substances have more profound inherent health and behavioral consequences. There is no medically safe maintenance approach to these chemicals – although weaker analogs are widely prescribed to children in the U.S. who have behavior problems. However, the social harm of prohibition extends beyond the users to the economy of illicit drug trafficking. Since drug traffickers obviously cannot call upon the authorities to enforce contracts and honest trading, the illicit drug industry is controlled by criminal organizations that use violence to control territory and settle disputes.

The case of alcohol is quite different. Alcohol used in moderation – typically defined as no more than 2 ounces of ethanol per day for men – may actually have some health benefits; whereas excessive consumption and dependency have many negative health and social consequences. Prohibition of alcohol in the United States during the 1920s failed to control alcohol use and abuse, but spawned violent crime syndicates. Most now agree that the social harm associated with alcohol is less under a regime of regulated, legal production and sale than it was under prohibition. In some Islamic countries with no cultural tradition of alcohol use, however, prohibition appears to be successful.

In the United States and western Europe there is increasing support for decriminalization of cannabis, which is held to be at worst comparable to alcohol in potential for harm. Cannabis prohibition is very costly in law enforcement, the incarceration of otherwise law abiding people, and the promotion of criminal activity. A caveat, however, is recent research suggesting that cannabis use in adolescence may slightly elevate the risk of later diagnosis with schizophrenia, which is a very serious disease. Use by adults, however, poses no such risk. Cannabis is held by many to have potential benefits for palliation of symptoms of many diseases and side effects of chemotherapy for cancer, so the movement in some states has taken the form of legalizing cannabis for medical use only.

Opioid drugs are a double edged sword of another sort. They are indispensable for relief of pain, are widely prescribed in short courses after dental procedures or outpatient surgery, and are given by injection in hospitals following major surgery or trauma. Such use rarely produces dependency. People with chronic pain may be prescribed maintenance regimens of opioids, which can be managed at a level which does not impair functioning. However, some people do develop dependency which continues after their prescription is withdrawn, or crave dosages larger than they are prescribed. This can lead to purchasing illicit supplies, or “doctor shopping” to obtain excessive prescriptions. Furthermore, diversion of prescription opioids to the illicit market is a principal means by which young people in the U.S. are initiated into opioid abuse.