Drug abuse is an emotionally charged topic involving more than facts about pharmaceuticals. Personal and moral values are involved, as are fears that sometimes transform into anger. The author of this book has studied drug abuse questions since the 1980s; visited with prosecutors, judges, and health care givers, along with drug abusers and their families; drafted drug control legislation introduced by Republican and Democratic legislators; testified before legislative committees; and given public presentations. In all settings, facts have rapidly disappeared in discussion of the topic.
For most of the twentieth century, addiction was considered a physical ef fect of some drugs. If a drug failed to produce physical symptoms associated with addiction, the substance was classified as nonaddictive. In the 1980s, however, some researchers began arguing that addiction could exist without associated physical symptoms, that mental craving alone was enough to power addiction.1 An important boost to acceptance of that concept came in 1987 when the American Psychiatric Association declared that "cocaine dependence" did not require physical dependence for diagnosis.2 The APA stated, "Continuing use of cocaine appears to be driven by persistent craving and urges for the substance rather than attempts to avoid or alleviate withdrawal symptoms."3 That approach yielded a broader understanding: that people could be addicted to things other than drugs, a new and controversial concept but one that was becoming more accepted as the twenty-first century began.
Regardless of whether addiction can be more of a mental process than a physical one, the likelihood of a user developing a harmful relationship with drugs is greater with some substances than with others. The harm may be physical. The harm may be disruption of a user's life. Experience shows, for example, that cocaine is far more risky to use than caffeine.
Some drugs can be used so much that they and a person's body develop what may be called a physical resonance. That is not a standard drug abuse term, but it communicates the concept more vividly than other terminology. Resonance means that an individual's body has adapted to the drug in such a way that stopping use of the drug makes a person feel ill. Symptoms depend on the drug and can range from a runny nose to convulsions. Not all drugs can produce such a state, but those that can are traditionally called addictive. Indeed, appearance or nonappearance of an "abstinence" or "withdrawal" syndrome of illness upon sudden end to drug dosage used to be considered a definitive test of whether a drug is addictive and whether a user is an addict. Some specialists might use the term neuroadaptation for the mechanism that creates resonance, but here more conservative language that asserts less about roles of the brain and nervous system will be used.
Resonance is typically, and somewhat misleadingly, called "dependence" by many persons. An addict who temporarily feels sick upon stopping a drug but who later feels better is not really "dependent" on it, in the ordinary dictionary sense of that word's meaning. Granted, physical dependence upon a drug is possible, in the dictionary sense, regardless of whether the underlying mechanism is neuroadaptation. An example is a diabetic who needs insulin. Cutting off insulin supply would make the diabetic sicker and sicker, so the person truly is dependent on the drug. Its presence is necessary for good health. Normally, however, that is not what is meant by saying a drug abuser is dependent on a substance; rather, one means the abuser will feel temporarily ill if dosage suddenly stops. Nonetheless, some drug addictions can involve the dictionary meaning of dependence. For example, persons extremely addicted to alcohol or barbiturates can die if cut off from their supply. Death typically comes from cascading problems culminating in convulsions. That dismal outcome is uncommon but possible. In addition, dependence is sometimes used in contexts making it synonymous with addiction, perhaps referring to persons undergoing treatment to break dependence on some drug they crave and are unable to stop taking. Because dependence has multiple meanings, the term is not ideal. However, this book uses the term because of its familiarity to specialists, despite its potential for causing confusion among general readers.
The concepts of addiction and dependence differ. Someone who takes a lot of barbiturates may experience both states. Someone who uses a lot of marijuana may experience neither. Knowing the differences between those two concepts can help a person spot confusion in rhetoric about drug abuse.
A person who has dependence on a drug may experience an abstinence or withdrawal syndrome if the supply runs out. The syndrome may begin several hours or several days after drug use stops, depending on how long a drug and its by-products last in the human body. Different drugs have different withdrawal symptoms, and they are specified in this book's alphabetical listings. Often a withdrawal symptom is the opposite of what a drug does. For example, if a drug constipates a person, withdrawal from that drug may include diarrhea. If a drug makes a person sleepy, withdrawal may include insomnia. Sometimes the withdrawal syndrome can be avoided if dosage is gradually reduced rather than stopped suddenly. At times the syndrome is avoided by substituting another drug that has "cross-tolerance" with the first one. Cross-tolerance means that one drug can substitute for another in some ways, typically in ways that prevent a withdrawal syndrome from emerging. A classic example allows methadone to be substituted for heroin. This book's alphabetical section notes cross-tolerance among assorted drugs. Cross-tolerance is a concept that differs from tolerance described below.
Tolerance means that as time passes, a person must use more and more of a drug to get the same effect. Such an outcome is a traditional sign of addiction. Tolerance can develop to some effects of a drug and not to others. For example, an amphetamine addict may become tolerant to euphoric properties of the drug, but not to its poisonous qualities. A cocaine addict may build tolerance to appetite-loss properties of the drug but not to other actions. The opposite may also happen, in which a person becomes sensitized to a drug and needs less and less. Evidence for such a development has been seen in humans with DOM and benzodiazepines and in animals with cocaine and DMT. Such a development, however, would not be considered evidence of addiction. Tolerance can have a strong mental component; the same phenomenon can be seen in reduced pleasure gained from continual indulgence in wild music events or a particular food or shopping. Recreational and medical users can take the same drug, often with medical users never developing tol-erance—perhaps because of the purpose for which they take the drug and not because of its chemistry, although that possible explanation is not yet confirmed. Some experts argue that tolerance is indeed a physical effect, caused by organic brain changes induced by a drug. Ultimately those experts are correct: All mental feelings and processes result from changes in the brain's electrochemical activity. Some of these changes can even be measured and correlated with broad psychological characteristics. For example, changes in brain waves and emotions can be seen after some drugs are administered. Our understanding of such things remains crude, however. We don't know how brain chemicals and electricity induce a person to love someone or hate an idea. Ultimately some still unknown physical process may explain why people who take a drug for pleasure develop a tolerance to its effects, while people who take the same substance for medical purposes never experience a change in what the drug does.
From a purely physical standpoint, someone who has recreationally abused a drug for years may indeed be able to tolerate a stronger dose than someone who takes the same drug for the first time. The abuser's body may develop physical adaptations permitting high doses. For instance, body chemistry can change in ways that counteract a drug, requiring more and more of the substance to overcome the change. Nonetheless, for many practical purposes we can say the cause of tolerance is psychological. This was implied in medical research comparing the amount of meperidine required to relieve pain in appendectomy patients.4 The study was conducted in Beirut and examined records of patients who underwent surgery before, during, and after a brutal civil war that destroyed much of that city. For pain relief, prewar patients needed more of the drug than wartime or postwar patients did. Researchers concluded that part of the reason was a psychological change in how pain was evaluated during those years of brutality. The study did not directly investigate tolerance, but it did demonstrate that a change in attitude can change the amount of drug effect perceived by users.
Change in attitude illustrates the influence of set and setting on drug effects. Set describes someone's basic personality and expectations about what a drug does. Setting is the environment in which drug use occurs. Rat experimentation5 demonstrated that the setting in which a drug is administered can alter the amount of tolerance, with those conditions demonstrating a psychological component in physical tolerance. Countless human examples demonstrate that set and setting can determine how much effect a given drug dose produces, whether it is pleasant or unpleasant, even whether a dose is tolerable or fatal.
Dosage affects a drug's impact. Overdose of most drugs can produce serious unwanted effects, including death. In addition to the amount of drug, the method of dosage (injection, oral, smoking, or other routes) can make a huge difference in effects. The same amount of drug can have a much different impact depending on route of administration. A "safe" dose by one route can be fatal by another. An effect at one dosage level may be the opposite of what happens at a different dosage level. Sometimes a drug can cause a condition that it is supposed to prevent. Such paradoxical actions illustrate hazards involved in reckless drug use.
Taking more than one drug of a given type can be expected to increase effects typical of that type. For example, a person who ingests the depressant alcohol simultaneously with an opiate depressant will normally experience deeper depressant effects than if just one of the drugs was used. Taking a normal dose of several drugs from one type can be the practical equivalent of overdosing on any one of them. Taking drugs of different types can also be hazardous. For example, the stimulant cocaine and the depressant heroin do not cancel each other's effects if taken together; instead, the body may be assaulted from different directions simultaneously and break down under the attack.
Continue reading here: How Are Abuse Risks Measured
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