by Elisabeth Nations
In Chapter 13, Lende discusses the neuroanthropological view of drug addiction, emphasizing that addiction is the result of a complexity of intertwined biological and socio-cultural factors. Lende clarifies that his definition of addiction is the desire to use drugs and the repetition of drug use. In the past, American society has typically defined drug addiction either as a disease where a person is unable to make rational choices or as a moral failing due to the inability to resist pleasure. Lende argues instead that incentive salience, a biological phenomenon triggered by social factors, plays a major role in drug addiction. Incentive salience as it pertains to drug addiction means that an individual with an overly sensitive mesolimbic dopamine system wants drugs “too much.” This wanting isn’t a conscious decision, but rather a desire that operates subcortically and brings a sense of intense urgency; for example, in a typical sequence of events, a drug user decides they want to take drugs, and then they experience an increasing, emphatic urgency to obtain and take those drugs. Since incentive salience motivates the individual to do what they most want, this can vary greatly between people and even throughout the course of the day. The concept of incentive salience does help to explain certain patterns of drug addiction. For example, an adolescent who becomes addicted to drugs might be doing so because there are little to no rewards for working hard at school or spending time with his family (perhaps if the individual lives in a low-income area with an abusive family). The incentives offered by using, like belonging to a group of other users and experiencing an “escape” from daily life, motivate the incentive salience system, and the individual is increasingly drawn to engage in this rewarding activity.
Drug addiction begins with an individual’s pursuit of pleasure and reward, but as time goes on and drug use is repeated and increased, its association with the brain changes. Neural activation by drugs moves from an individual’s ventral stratium to the dorsal stratium, where drug-seeking is then maintained and made into a habit. After this, the habit of drug use isn’t affected by reward as much, and a person is unable to make much of an evaluation of the consequences of his actions. Continual exposure to drugs makes habitual use easier and more likely, as does stress.
This chapter was at times difficult to read, mostly because I felt confused about how the different neurological concepts fit together. Although it seems clear that Lende is attempting to argue that environmental factors play a large role in drug addiction, I feel that he did not spend enough time discussing these factors. In particular, what cultural or social factors might lead a person to use drugs in the first place, and why might that person return to drugs over time, other than because of a neurological pull to do so? Overall, though, I thought Lende explained the concept of incentive salience and its connection to the attraction to repeated drug use well, and I certainly felt that I gained a better understanding of drug addiction by reading this chapter.