DRUG TERMINOLOGY

Before discussing drug behavior, it’s important to become familiar with some basic terminology.  Much of this terminology originates from the field of pharmacology, or the study of the interaction of chemical agents with living material.

What does the word drug means? Each of us may have different ideas about what a drug is.  Although a number of definitions are available, we will consider a drug to be “any substance, natural or artificial, other than food, that by its chemical or physical nature alters structure or function in the living organism.  Included in this broad definition is a variety of psychoactive drugs, medicines, and substances that many people do not usually consider to be drugs.

Psychoactive drugs alter the user’s feelings, behavior, perception, or moods when using stimulants, depressants, hallucinogens, opiates, or inhalants.  Prescription medications function to heal unhealthy tissue as well as to ease pain, prevent illness, and diagnose health conditions.  Although some psychoactive drugs are used for medical reasons, as in the case of tranquilizers and some narcotics, the most commonly prescribed medicines are antibiotics, hormone replacement drugs, sulfa drugs, diuretics, oral contraceptives, and cardiovascular drugs.  Legal substances not usually considered to be drugs (but which certainly are drugs) include caffeine, tobacco, alcohol, aspirin, and other over-the-counter (OTC) preparations.  These substances are used so commonly in our society that they are rarely perceived as true drugs.

Routes of Administration

Drugs generally enter the body through one of four methods: ingestion, injection, inhalation, and absorption.  Ingestion, or oral administration, is the entry of drug through the mouth and into the digestive tract.  Injection refers to the use of a needle to insert a drug into the body.  With inhalation, the drug enters the body through the lungs.  Absorption refers to the administration of a drug through the skin or mucous membranes.

Dependence

Psychoactive drugs have a strong potential for the development of dependence.  When users take psychoactive drug, the patterns of nervous system function are altered.  If these altered functions provide perceived benefits for the user, the drug use may continue, perhaps at increasingly larger dosages.  If persistent use continues, the user can develop a dependence on the drug.  Pharmacologists have identified two types of dependence: physical and psychological.

A person can be to have developed a physical dependence when the body cells have become reliant on a drug.  Continued use of the drug is then required because body tissues have adapted to its presence.  The person’s body needs the drug to maintain homeostasis, or dynamic balance.  If the drug is not taken or is suddenly withdrawn, the user develops a characteristic withdrawal illness.  The symptoms of withdrawal reflect the attempt by the body’s cells to regain normality without the drug.  Withdrawal symptoms are always unpleasant (ranging from mild to severe irritability, depression, nervousness, digestive difficulties, and abdominal pain) and can be life-threatening, as in the case of abrupt withdrawal from barbiturates or alcohol.

Continued use of most of drugs can lead to tolerance.  Tolerance is an acquired reaction to a drug in which continued intake of the same dose has diminishing effects.  The user needs larger doses of the drug to receive previously felt sensations.  The continued use of depressants, including alcohol, and opiates can cause users to quickly develop a tolerance to the drug.

For example, college seniors who have engaged in 4 years of beer drinking usually recognize that their bodies have developed a degree of tolerance to alcohol.  Many such students can vividly recall the initial and subsequent sensations they felt after drinking.   For example, five beer consumed during a freshman social gathering might well have resulted in inebriation, but if these same students continued to drink beer regularly for 4 years, five beers will probably fail to produce the response they experienced as freshmen.  Seven or eight beers might be needed to produce such a response.  Clearly, these students have developed a tolerance to alcohol.

Tolerance developed for one drug may carry over to another drug within the same general category.  This phenomenon is known as cross-tolerance.  The heavy abuser of alcohol, for example, might require a larger dose of a preoperative sedative to become relaxed before surgery than the average person would.  The tolerance to alcohol “crosses over” to the other depressant drugs.

A person who possesses a strong desire to continue using a particular drug is said to have developed a psychological dependence.  People who are psychologically dependent on a drug believe that they need to consume the drug to maintain a sense of well-being.  They crave the drug for emotional reasons despite having persistent or recurrent physical, social, psychological, or occupational problems caused or worsened by the drug use.  Abrupt withdrawal from a drug by such a person would not trigger the fully expressed withdrawal illness, although some unpleasant symptoms of withdrawal might be felt.  The term habituation is often used interchangeably with psychological dependence.

Drugs whose continued use can quickly lead to both physical and psychological dependence are depressants (barbiturates, tranquilizers, and alcohol), narcotics (the opiates, which are derivatives of the Oriental poppy: heroin, morphine, and codeine), and synthetic narcotics (Demerol and methadone).  Drugs whose continued use can lead to various degrees of psychological dependence and occasionally to significant (but not life-threatening) physical dependence in some users are the stimulants (amphetamines, caffeine, and cocaine), hallucinogens (LCD, peyote, mescaline, and marijuana), and inhalants (glues, gases, and petroleum products).

Drug Misuses and Abuse

At this point, however, it is important to define use and to introduce the terms misuse and abuse.  By doing so, we can more accurately describe the ways in which drugs are used.

The term use is all-encompassing and describes drug taking in the most general way.  For example, Americans use drugs of many types.  The term use can also refer more narrowly to misuse and abuse.