Our main focus here has been on the nature of conscious experience, and so our emphasis, in describing various drug states, has been on the experience produced by the drug. However, we’ve also commented on the dangers associated with these substances. Some of the dangers are medical (e.g., the cardiovascular problems sometimes triggered by stimulants). Some of the problems are psychological (e.g., the panic that can be triggered by a bad trip). Still other dangers concern the bad choices someone makes while under the influence of one of these substances. (Think about the linkage between alcohol use and rape, or the fatalities attributable to drunk driving or the life disruption caused by drugs. Think also about the crimes associated with drug use—for example, when a user can’t hold a job because of his drug state, and turns to crime to get the money he needs for the next dose.)
In light of all these dangers, why do people keep using drugs? Common sense provides the answer: In many cases, people put a higher value on the benefits (the drug-created changes in experience) than on the costs. And in many cases, people seem to have no choice: They’re dependent on the drug, and so feel a powerful need to use it again and again, regardless of the risks.
This perspective raises another key question: What is dependence? And what do people mean when they say that someone is “addicted” to a substance? Answering these questions is—perhaps surprisingly—extremely difficult.
Researchers and clinicians tend to use the words dependence and addiction interchangeably and, overall, to define these words based on several attributes. Someone is dependent if, first, he’s lost control over his own drug use; this attribute is usually reflected in the fact that the user has a very hard time giving up the drug, even though he would clearly benefit from doing so. Second, people who are dependent tend to show strong withdrawal symptoms if they go without the drug—they have strong cravings and exhibit a clear pattern of psychological and medical distress. Third, people who are dependent tend to display a pattern of drug tolerance—they have a weaker response to the drug than they did when they first began using it. One frequent result of this tolerance is that as time goes by, the dependent person needs larger and larger doses of the drug to get the desired effect.
This cluster of attributes is clearly in place for some drugs, and some drug users. The most obvious case is probably heroin. People addicted to this drug seem unable to give it up, even though their drug use is hugely disrupting their lives (and often the lives of others). Heroin users typically suffer horrible withdrawal symptoms if they don’t get their usual dose. And as they continue using the drug, heroin users seem to require larger doses just to maintain the same effect they’ve gotten in the past. Cases like heroin leave no doubt that addiction is a real and deeply destructive problem.
But it’s easy to find cases in which it’s hard to tell if someone has an “addiction” or not. For example, how should we think about cocaine? People do seem to have great difficulty giving up cocaine, once they become frequent users. However, ceasing use of cocaine seems to cause only mild withdrawal symptoms (Kampman et al., 2002). So is cocaine addictive? It shows one of the attributes of addiction, but not another. Or, as a different case, what should we say about habits that show all the characteristics of addiction—but in a relatively mild version? For example, some people spend hours and hours shopping and seem unable to interrupt this habit, even though it’s disrupting their lives and their finances. They also seem quite unhappy when they can’t go shopping, and so they show a type of withdrawal. They also seem to require more and more hours in the mall, as the years go by, to satisfy their desire for shopping. Should we count this habit therefore as a “shopping addiction”?
Some people do seem willing to stretch the term addiction to cover these borderline cases—so they talk about someone being addicted to shopping, or sex, or television. Likewise, they use words like workaholic or even soccerholic to describe people who (allegedly) need a large daily dose of work or soccer, just like an alcoholic needs a large daily dose of alcohol. Most researchers, however, resist this stretching of the terms. To see why, think about the huge amount of life disruption a heroin addict will endure to support her habit, or the horrific suffering of heroin withdrawal. It seems entirely misleading to com-pare this disruption, or this suffering, to the (much milder) plight of a shopping addict or workaholic; and so it just seems unwise to use the term addiction to apply to both cases.
But how should we draw the line that will distinguish a “genuine” addict from these other questionable cases? Some writers make a distinction between psychological depend-ence on a substance (or an activity) and physical (or physiological) dependence. The generalidea is that psychological dependence refers to the intense mental or emotional craving for the addictive substance, whereas physical dependence refers to the medical symptoms we observe during withdrawal. Moreover, genuine addicts show both psychological and phys-ical dependence; the borderline cases are unlikely to show physical dependence.
But this distinction, too, is problematic. Among other concerns, bear in mind that so-called psychological dependence often creates feelings of stress—and stress, in turn, shows up in many bodily systems. (When people feel stress, their blood pressure goes up, their blood chemistry changes, and so on.) On this basis, the cravings associated with psychological dependence cause physical symptoms. This issue obviously undermines our effort to distinguish these two allegedly different forms of dependence.
In light of all these points, the word addiction is truly difficult to define. So perhaps we shouldn’t be thinking of addiction as a separate category. Instead, we should think about the issues of substance use in terms of a continuum. At one end of the continuum are the social users of various substances; these are people who have an occasional drink or sometimes take a drug for recreation. Farther along the continuum are people who abuse the substances. They use alcohol or drugs more frequently, and they have at least a few problems because of it. Then, at the far end of the continuum, we find people who are truly dependent—using the substance a lot, experiencing serious problems as a result, and being largely unable to control the use. In this view, addiction is not a distinct state of affairs; instead, it’s the extreme end of this range—and a point at which the person needs help in conquering the addiction.