10.1 Tolerance and Addiction

10-1 What are substance use disorders, and what roles do tolerance, withdrawal, and addiction play in these disorders?

Most of us manage to use some nonprescription drugs in moderation and without disrupting our lives. But some of us develop a self-harming substance use disorder (TABLE 10.1). Such substances are psychoactive drugs, chemicals that change perceptions and moods. A drug’s overall effect depends not only on its biological effects but also on the user’s expectations, which vary with social and cultural contexts (Ward, 1994). If one culture assumes that a particular drug produces euphoria (or aggression or sexual arousal) and another does not, each culture may find its expectations fulfilled. We’ll take a closer look at these interacting forces in the use and potential abuse of particular psychoactive drugs. But first, let’s consider how our bodies react to the ongoing use of psychoactive drugs.

Table 10.1
When Is Drug Use a Disorder?
According to the American Psychiatric Association, a person may be diagnosed with substance use disorder when drug use continues despite significant life disruption. Resulting brain changes may persist after quitting use of the substance (thus leading to strong cravings when exposed to people and situations that trigger memories of drug use). The severity of substance use disorder varies from mild (two to three of these indicators) to moderate (four to five indicators) to severe (six or more indicators). (Source: American Psychiatric Association, 2013.)
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Why might a person who rarely drinks alcohol get buzzed on one can of beer while a long-term drinker shows few effects until the second six-pack? The answer is tolerance. With continued use of alcohol and some other drugs (not marijuana), the user’s brain chemistry adapts to offset the drug effect (a process called neuroadaptation). To experience the same effect, the user requires larger and larger doses (FIGURE 10.1). Ever-increasing doses of most psychoactive drugs may lead to addiction: The person craves and uses the substance despite its adverse consequences. (See Thinking Critically About: Addiction.) The World Health Organization (2008) has reported that, worldwide, 90 million people suffer from such problems related to alcohol and other drugs. Regular users often try to fight their addiction, but abruptly stopping the drug may lead to the undesirable side effects of withdrawal.

Figure 10.1
Drug tolerance

THINKING  CRITICALLY  ABOUT

THINKING CRITICALLY ABOUT: Addiction

10-2 How has the concept of addiction changed?

In recent years, the concept of addiction has been extended to cover many behaviors formerly considered bad habits or even sins. Psychologists debate whether the concept has been stretched too far, and whether addictions are really as irresistible as commonly believed. For example, “even for a very addictive drug like cocaine, only 15 to 16 percent of people become addicted within 10 years of first use,” observed Terry Robinson and Kent Berridge (2003).

Addictions can be powerful, and many addicts do benefit from therapy or group support. Alcoholics Anonymous has supported millions in overcoming alcohol addiction. But viewing addiction as an uncontrollable disease can undermine people’s self-confidence and their belief that they can change. And that, critics say, would be unfortunate, for many people do voluntarily stop using addictive drugs, without any treatment. Most ex-smokers, for example, have kicked the habit on their own (Newport, 2013).

The addiction-as-disease-needing-treatment idea has been offered for a host of driven, excessive behaviors—eating, gambling, work, sex, and accumulating wealth. However, critics suggest that “addiction” can become an all-purpose excuse when used not as a metaphor (“I’m a science fiction addict”) but as reality. Moreover, they note that labeling a behavior doesn’t explain it. Attributing serial adultery to a “sex addiction” does not explain the sexual impulsiveness (Radford, 2010).

Sometimes, though, behaviors such as gambling, video gaming, or online surfing do become compulsive and dysfunctional, much like abusive drug taking (Gentile, 2009; Griffiths, 2001; Hoeft et al., 2008). Thus, psychiatry’s manual of disorders now includes behavior addictions such as “gambling disorder” and proposes “Internet gaming disorder” for further study (American Psychiatric Association, 2013). Studies in Asia, Europe, and North America estimate gaming addiction rates of from 3 to 12 percent of players (Anderson et al., 2012; Ferguson et al., 2011). Some Internet users display an apparent inability to resist logging on, and staying on, even when this excessive use impairs their work and relationships (Ko et al., 2005). But there is hope. One research review found both psychological and drug therapies for Internet addiction “highly effective” (Winkler et al., 2013).

A social networking addiction?
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RETRIEVAL PRACTICE

  • What is the process that leads to drug tolerance?

With repeated exposure to a psychoactive drug, the drug’s effect lessens. Thus, it takes bigger doses to get the desired effect.