CHAPTER 17. DRUG DEPENDENCE
Psychiatrists prefer the term drug dependence to older terms such as drug abuse or drug addiction. Especially the term addiction implies that the person with a drug dependence could stop their behavior if they really wanted to. Characteristics of drug dependence are (Campbell 1989:190): repeated attempts to cut back on drug use; problems in performing family, social or occupational obligations; physical need to increase the drug dosage and painful withdrawal symptoms; and continuous use of the drug despite the development of physical problems or illnesses.
The percentage of people who have ever tried various drugs in the United States population are (Kandel 1992:27): alcohol (85); cigarettes (75); marijuana (33); cocaine (11); hallucinogens (7); stimulants (7); inhalants (6); tranquilizers (5); other opiates (5); sedatives (4); and heroin (1).
This chapter discusses drugs in two groups both of which are psychologically addictive. However, the first group will be those drugs that are only moderately physically addictive, such as nicotine, caffeine, marijuana, and cocaine. The second group includes those drugs that are strongly physically addictive, such as heroin and the benzodiazepines.
Characteristics of Moderately Addictive Drugs
Cocaine is obtained from coca leaves that grow in Bolivia, Peru, and Columbia. An injection leads to a "rush," which produces feelings of intense well-being. After an hour or so, the drug effects start to wear off and the person "crashes." This produces feelings of irritability, anxiety, or even depression. Obviously, to avoid crashing, there is a strong temptation to take more of the drug. Continued use can lead to such negative effects as impaired judgment, hallucinations (usually auditory), anorexia, nausea, insomnia, and sweats or chills (Campbell 1989:133-134).
Marijuana comes from the flowering tops of the Indian Hemp plant (Cannabis sativa), which is a native North American species. It can produce pleasurable side effects such as dreamy states and pleasant hallucinations. It can also, however, result in several negative effects such as panic feelings. Prolonged abuse may result in some mental deterioration (Campbell 1989:424).
There is 100 to 150 mg of caffeine in a cup of coffee. As little as 250 mg can lead to restlessness, nervousness, and insomnia in some people. One gram per day can cause muscle twitching, cardiac arrhythmias, rambling speech, and disorganized thought (Campbell 1989:109).
Despite the above disturbing rendition of the side effects of these drugs, not too long ago popular opinion held that compulsive tobacco, cocaine or cannabis use were habits that were not physically addictive (Jones, 1992: 115-116). These drugs, however, are now known to be moderately physically addictive. Compulsive tobacco smokers are definitely addicted; we know cocaine causes neurophysiologic addiction; and cannabis is associated with definite withdrawal symptoms. These drugs, however, do not produce "real" addictive states; that is, they do not necessarily lead to higher and higher doses. This is true even of cocaine use (at least the most common pattern). Cocaine is a local anesthetic that alters the permeability of the membranes of nerve cells. It also prolongs the life span of neurotransmitters within the synapse between nerve cells. The actual euphoria induced by cocaine is likely the effect related to the concentration of the drug within the brain. If denied cocaine, cocaine addicts demonstrate psychological distress and mood changes, but manifest only minimal physiological changes. Withdrawal from cannabis use has been described as a bad case of the flu. The symptoms can include sweating, loose bowel movements or diarrhea, insomnia, restlessness, irritability, tremor, nausea, vomiting, muscle pains, weight loss, and characteristic brain wave changes.
There can be some beneficial results of these potentially harmful drugs (Jones, 1992: 111). The nicotine in a cigarette stimulates, relaxes, relieves boredom, and improves cognitive and motor performance, so at least the first few cigarettes can produce arousal. Later in the day, a cigarette may produce feelings of relaxation (the effect being most evident in stressful situations). Feelings of enhanced mental concentration and elevated mood are associated with the rapid rise in nicotine in brain and blood levels after smoking.
An important characteristic of these drugs is that they are often administered via smoking (Jones, 1992: 117). Cocaine, THC, and nicotine have in common smoking as the preferred route of self-administration. This allows for a more careful regulation of the dosage. Except by carotid artery or intracerebral injection, there is a no more efficient way of delivering a psychoactive drug to the brain than by smoking. When smoked, all three substances are inhaled as an aerosol and deposited in distal airways and alveoli. Moreover, only with a device like the well-engineered cigarette could the number of drug doses required by some tobacco addicts be efficiently delivered. Brain levels of nicotine (and likely brains levels of smoked cocaine and THC) rise within seconds of the inhalation. The levels decline just as rapidly because of subsequent drug distribution into muscle and other tissues. (A moderately physically addictive drug that is not inhaled is caffeine. Coffee drinkers who suddenly decide to abstain can suffer physical withdrawal symptoms, such as severe headaches.)
Strongly Physically Addictive Drugs
Juice from the unripe seeds of the poppy plant produces opium. The juice dries to a brown gummy substance, which is then turned into a powder. Heroin was first produced in 1898 from morphine, which was in turn first derived in 1803 from opium. The potential addictive power of opiates ranges from high to low in the following order (Campbell 1989:499) morphine, heroin, Dilaudid, metopon, Demerol, methadone, and codeine. Both morphine and heroin are analgesics (painkillers) and have been used as such. Taken in moderate doses, heroin can not only dull pain, but also diminish anxiety and tension as well as induce mild euphoria. Interestingly, the user has to learn how to derive pleasure from a heroin injection, since the first experiences are often unpleasant. In fact, most users of heroin do not become addicts. And the major reason for this is that the degree of pleasure from the drug typically subsides. Even prolonged use of heroin does not damage the organs, tissues, or cells of the human body (Thio, 1988:352-353).
One feature of heroin addiction is a drive for chemically induced physical satisfaction so strong that the addict's whole life can become unmanageable. And we know that opiates are strong reinforcers rewarding the user's central nervous system with euphoric feelings. There are great difficulties in assessing the true personalities of heavy drug users because it is quite difficult to know whether an addict's thoughts, feelings, and behaviors are the result of the addiction experience or whether they preceded and contributed to the addiction (Zorkin, 1986:89). Rosehan and Seligman (1984:402) write that greater alienation, anti-establishment attitudes, lower grades in school, and more dating characterize the 12 to 14 year old drug user. They conclude that sociological characteristics, not psychological ones, best distinguish the young drug user from the young nondrug user. They are not, however, including physiological causes.
A group of drugs that can be strongly addictive are the tranquilizers. Such is the case for benzodiazepine, which is a potent reliever of anxiety and insomnia. Examples are Valium and Librium. Benzodiazepines bind to the benzodiazepine receptors (Winger, 1986:40-41).
The neurotransmitter gamma-aminobutyric acid (GABA), which is found in the brain and the spinal cord, acts to reduce the activity of the nerves that it contacts. GABA and the benzodiazepines are structurally similar. Furthermore, GABA is able to increase the receptor-binding activity of the benzodiazepines. The benzodiazepines, in turn, are able to increase the binding of GABA to its own receptors (Winger, 1986:40-41). Scientists speculate that within the limbic system the benzodiazepines enhance the inhibitory effects of GABA, thus reducing the reaction of this system to anxiety-provoking events. At the same time, the benzodiazepines may reduce the ability of other neurotransmitters to stimulate fear reactions.
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