Biological Explanations

In looking at drug use, the field of biology focuses on two related major questions. First, how and why do drugs affect a person’s behavior, mood, perception, and other qualities? Second, what biological factors explain why some people are more likely than others to use drugs?

Regarding the first question, the field of biology has an excellent understanding of how drugs work. The details of this understanding are beyond the scope of this chapter, but they involve how drugs affect areas in the brain and the neurotransmitters that cause a particular drug’s effects. For example, cocaine produces euphoria and other positive emotions in part because it first produces an accumulation of dopamine, a neurotransmitter linked to feelings of pleasure and enjoyment.

Research on identical twins suggests that alcoholism has a genetic basis.

Regarding the second question, biological research is more speculative, but it assumes that some people are particularly vulnerable to the effects of drugs. These people are more likely to experience very intense effects and to become physiologically and/or psychologically addicted to a particular drug. To the extent this process occurs, the people in question are assumed to have a biological predisposition for drug addiction that is thought to be a genetic predisposition.

Most research on genetic predisposition has focused on alcohol and alcoholism (Hanson et al., 2012). Studies of twins find that identical twins are more likely than fraternal twins (who are not genetically identical) to both have alcohol problems or not to have them. In addition, studies of children of alcoholic parents who are adopted by nonalcoholic parents find that these children are more likely than those born to nonalcoholic parents to develop alcohol problems themselves. Although a genetic predisposition for alcoholism might exist for reasons not yet well understood, there is not enough similar research on other types of drug addiction to assume that a genetic predisposition exists for these types. Many nonbiological factors also explain the use of, and addiction to, alcohol and other drugs. We now turn to these factors.

Psychological Explanations

Psychological explanations join biological explanations in focusing on why certain individuals are more likely than others to use drugs and to be addicted to drugs (Hanson et al., 2012). Some popular psychological explanations center on personality differences between drug users and nonusers. These explanations assume that users have personality traits that predispose them to drug use. These traits include low self-esteem and low self-confidence, low trust in others, and a need for thrills and stimulation. In effect, drug users have inadequate personalities, or personality defects, that make them prone to drug use, and once they start using drugs, their personality problems multiply.

One problem with research on personality explanations is methodological: If we find personality differences between drug users and nonusers, should we conclude that personality problems cause drug use, or is it possible that drug use causes personality problems? Most of the research on personality and drug use cannot answer this question adequately, since it studies drug users and nonusers at one point in time (cross-sectional research). To answer this question adequately, longitudinal research, which examines the same people over time, is necessary. Among initial drug abstainers at Time 1, if those with the personality traits mentioned earlier turn out to be more likely than those without the traits to be using drugs at Time 2, then we can infer that personality problems affect drug use rather than the reverse. Longitudinal research on personality and drug use that studies adolescents and college students does indeed find this causal sequence (Sher, Bartholow, & Wood, 2000). However, some scholars still question the importance of personality factors for drug use and addiction (Goode, 2012). They say these factors have only a small effect, if that, and they cite research questioning whether personality differences between users and nonusers in fact exist (Feldman, Boyer, Kumar, & Prout, 2011).

Other psychological explanations are based on the classic concept from behavioral psychology of operant conditioning—the idea that people and animals are more likely to engage in a behavior when they are rewarded, or reinforced, for it. These explanations assume that people use drugs because drugs are positive reinforcers in two respects. First, drugs provide pleasurable effects themselves and thus provide direct reinforcement. Second, drug use often is communal: People frequently use drugs (alcohol is certainly a prime example, but so are many other drugs) with other people, and they enjoy this type of social activity. In this manner, drug use provides indirect reinforcement.

Sociological Explanations

Sociological explanations emphasize the importance of certain aspects of the social environment—social structure, social bonds to family and school, social interaction, and culture—or drug use, depending on the type of drug. For drugs like heroin and crack that tend to be used mostly in large urban areas, the social structure, or, to be more precise, social inequality, certainly seems to matter. As sociologist Elliott Currie (1994, p. 3) has observed, the use of these drugs by urban residents, most of them poor and of color, reflects the impact of poverty and racial inequality: “Serious drug use is not evenly distributed: it runs ‘along the fault lines of our society.’ It is concentrated among some groups and not others, and has been for at least half a century.” This fact helps explain why heroin use grew in the inner cities during the 1960s, as these areas remained poor even as the US economy was growing. Inner-city youths were attracted to heroin because its physiological effects helped them forget about their situation and also because the heroin subculture—using an illegal drug with friends, buying the drug from dealers, and so forth—was an exciting alternative to the bleakness of their daily lives. Crack became popular in inner cities during the 1980s for the same reasons.

Social bonds to families and schools also make a difference. Adolescents with weak bonds to their families and schools, as measured by such factors as the closeness they feel to their parents and teachers, are more likely to use drugs of various types than adolescents with stronger bonds to their families and schools. Their weaker bonds prompt them to be less likely to accept conventional norms and more likely to use drugs and engage in other delinquent behavior.

Regarding social interaction, sociologists emphasize that peer influences greatly influence one’s likelihood of using alcohol, tobacco, and a host of other drugs (Hanson et al., 2012). Much and probably most drug use begins during adolescence, when peer influences are especially important. When our friends during this stage of life are drinking, smoking, or using other drugs, many of us want to fit in with the crowd and thus use one of these drugs ourselves. In a related explanation, sociologists also emphasize that society’s “drug culture” matters for drug use. For example, because we have a culture that so favors alcohol, many people drink alcohol. And because we have a drug culture in general, it is no surprise, sociologically speaking, that drug use of many types is so common.

To the extent that social inequality, social interaction, and a drug culture matter for drug use, sociologists say, it is a mistake to view most drug use as stemming from an individual’s biological or psychological problems. Although these problems do play a role for some individuals’ use of some drugs, drug use as a whole stems to a large degree from the social environment and must be understood as a social problem, and not just as an individual problem.

Beyond these general explanations of why people use drugs, sociological discussions of drug use reflect the three sociological perspectives introduced in Chapter 1 “Understanding Social Problems”—functionalism, conflict theory, and symbolic interactionism—as we shall now discuss. Table 7.6 “Theory Snapshot” summarizes this discussion.