← In the Realm of Hungry Ghosts Close Encounters with Addiction
In the Realm of Hungry Ghosts Close Encounters with Addiction Chapter 12. From Vietnam to “Rat Park” Do Drugs Cause Addiction?
Author: Gabor Mate Publisher: Berkeley, CA: North Atlantic Books Publish Date: 2010-1-5 Review Date: Status:📚
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Clearly, if drugs by themselves could cause addiction, we would not be safe offering narcotics to anyone. Medical evidence has repeatedly shown that opioids prescribed for cancer pain, even for long periods of time, do not lead to addiction except in a minority of susceptible people.1
- G. M. Aronoff, “Opioids in Chronic Pain Management: Is There a Significant Risk of Addiction?” Current Review of Pain 4(2) (2000): 112–21.
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An article in the Canadian Journal of Medicine in 2006 reviewed international research covering over six thousand people who had received narcotics for chronic pain that was not cancerous in origin. There was no significant risk of addiction, a finding common to all studies that examine the relationship between addiction and the use of narcotics for pain relief.2 “Doubts or concerns about opioid efficacy, toxicity, tolerance, and abuse or addiction should no longer be used to justify withholding opioids,” concluded a large study of patients with chronic pain due to rheumatic disease.3
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A. D. Furlan, “Opioids for Chronic Noncancer Pain: A Meta-analysis of Effectiveness and Side Effects,” Canadian Medical Association Journal 174(11) (May 23, 2006): 1589–94.
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S. R. Ytterberg et al., “Codeine and Oxycodone Use in Patients with Chronic Rheumatic Disease Pain,” Arthritis and Rheumatism 14(9) (September 1998): 1603–12.
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We can never understand addiction if we look for its sources exclusively in the actions of chemicals, no matter how powerful they are. “Addiction is a human problem that resides in people, not in the drug or in the drug’s capacity to produce physical effects,” writes Lance Dodes, a psychiatrist at the Harvard Medical School Division on Addictions.4 It is true that some people will become hooked on substances after only a few times of using, with potentially tragic consequences, but to understand why, we have to know what about those individuals makes them vulnerable to addiction. Mere exposure to a stimulant or narcotic or to any other mood-altering chemical does not make a person susceptible. If she becomes an addict, it’s because she’s already at risk.
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Heroin is considered to be a highly addictive drug—and it is, but only for a small minority of people, as the following example illustrates. It’s well known that many American soldiers serving in the Vietnam War in the late 1960s and early 1970s were regular users. Along with heroin, most of these soldier addicts also used barbiturates or amphetamines or both. According to a study published in the Archives of General Psychiatry in 1975, 20 percent of the returning enlisted men met the criteria for the diagnosis of addiction while they were in Southeast Asia, whereas before they were shipped overseas fewer than 1 percent had been opiate addicts. The researchers were astonished to find that “after Vietnam, use of particular drugs and combinations of drugs decreased to near or even below preservice levels.” The remission (i.e., abatement or reduction of symptoms in illness or addiction) rate was 95 percent, “unheard of among narcotics addicts treated in the U.S.”
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According to a U.S. national survey, the highest rate of dependence after any use is for tobacco: 32 percent of people who used nicotine even once went on to long-term habitual use. For alcohol, marijuana, and cocaine the rate is about 15 percent, and for heroin the rate is 23 percent.6 Taken together, American and Canadian population surveys indicate that merely having used cocaine a number of times is associated with an addiction risk of less than 10 percent.7 This doesn’t prove, of course, that nicotine is “more” addictive than, say, cocaine. We cannot know, since tobacco—unlike cocaine—is legally available, is commercially promoted, and remains, more or less, a socially tolerated object of addiction. What such statistics do show is that whatever a drug’s physical effects and powers, they cannot be the sole cause of addiction.
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In the United States opiate relapse rates of 80 percent to more than 90 percent have been recorded among addicts who try to quit their habit. Even after hospital treatment the readdiction rates are over 70 percent.8 Such dismal results have led to the impression that opiates themselves hold the power of addiction over human beings. Similarly, cocaine has been described in the media as “the most addictive drug on earth,” causing “instant addiction.” More recently, crystal methamphetamine (crystal meth) has gained a reputation as the most instantly powerful addiction-inducing drug—a well-deserved notoriety, so long as we keep in mind that the vast majority of people who use it do not become addicted. Statistics Canada reported in 2005, for example, that 4.6 percent of Canadians have tried crystal meth, but only 0.5 percent had used it in the past year.9 If the drug by itself induced addiction, the two figures would have been nearly identical.
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Robins et al., “Narcotic Use in Southeast Asia,” 955–61.
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Peter McKnight, “The Meth Myth: Hooked on Hysteria, the Media Are Big on Anecdote and Short on Science in Dealing with the Latest ‘Most Dangerous Drug,’ ” Vancouver Sun, 25 September 2005, C5.
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Because almost all laboratory animals can be induced into compulsive self-administration of alcohol, stimulants, narcotics, and other substances, research has appeared to reinforce the view that mere exposure to drugs will lead indiscriminately to drug addiction. The problem with this apparently reasonable assumption is that animal laboratory studies can prove no such thing. The experience of caged animals does not accurately represent the lives of free creatures, including human beings. There is much to be learned from animal studies, but only if we take into account the real circumstances. And, I should add, only if we accept the tremendous suffering imposed on these involuntary “subjects.” Although there are anecdotes of animals in the wild becoming intoxicated, most of them are spurious, as is the case, for example, with stories of elephants getting “drunk” on fermenting marula fruit. There are no known examples of persistently addictive behaviors in the natural world. Of course, we cannot predict exactly what might happen if wild animals had free and easy access to addictive substances in the purified and potent forms administered in laboratories. What has been shown, however, is that conditions in the laboratory powerfully influence which animals will succumb to addiction. Among monkeys, for example, subordinate males who are stressed and relatively isolated are the ones more likely to self-administer cocaine. As I will later explain, being dominant leads to brain changes that give stronger monkeys some protection from an addictive response to cocaine.10 Bruce Alexander, a psychologist at Simon Fraser University in British Columbia, points out the obvious: laboratory animals in particular can be induced into addiction because they live under unnatural circumstances of captivity and stress. Along with other astute researchers, Dr. Alexander has argued that drug self-administration by these creatures may be how the animals “cope with the stress of social and sensory isolation.” The animals may also be more prone to give themselves drugs because they are cooped up with the self-administration apparatus and cannot move freely.11 As we will see, emotional isolation, powerlessness, and stress are exactly the conditions that promote the neurobiology of addiction in human beings as well. Dr. Alexander has conducted elegant experiments to show that even lab rats, given reasonably normal living situations, will resist the addictive appeal of drugs: My colleagues and I built the most natural environment for rats that we could contrive in the laboratory. “Rat Park,” as it came to be called, was airy, spacious, with about 200 times the square footage of a standard laboratory cage. It was also scenic (with a peaceful British Columbia forest painted on the plywood walls), comfortable (with empty tins, wood scraps, and other desiderata strewn about on the floor), and sociable (with 16–20 rats of both sexes in residence at once).… We built a short tunnel opening into Rat Park that was just large enough to accommodate one rat at a time. At the far end of the tunnel, the rats could release a fluid from either of two drop dispensers. One dispenser contained a morphine solution and the other an inert solution. It turned out that for the Rat Park animals, morphine held little attraction, even when it was dissolved in a sickeningly sweet liquid usually irresistible to rodents and even after these rats were forced to consume morphine for weeks, to the point that they would develop distressing physical withdrawal symptoms if they didn’t use it. In other words, in this “natural” environment a rat will stay away from the drug if given a choice in the matter—even if it’s already physically dependent on the narcotic. “Nothing that we tried,” reported Bruce Alexander, “instilled a strong appetite for morphine or produced anything that looked like addiction in rats that were housed in a reasonably normal environment.” By contrast, caged rats consumed up to twenty times more morphine than their relatively free living relatives. Dr. Alexander first published these findings in 1981.12 In 1980 it had already been reported that social isolation increased animals’ intake of morphine.13 Other scientists have since confirmed that some environmental conditions are likely to induce animals to use drugs; given different conditions, even captive creatures can resist the lure of addiction.
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D. Morgan et al., “Social Dominance in Monkeys: Dopamine D2 Receptors and Cocaine Self-administration,” Neuroscience 5(2) (2005): 169–74.
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Alexander, “The Myth of Drug-Induced Addiction.”
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B. Alexander et al., “Effects of Early and Later Colony Housing on Oral Ingestion of Morphine in Rats,” Psychopharmacology Biochemistry and Behavior 58 (1981): 175–79.
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J. Panksepp et al., “Endogenous Opioids and Social Behavior,” Neuroscience and Biobehavioral Reviews 4 (1980): 473–87.
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The Vietnam veterans study pointed to a similar conclusion: under certain conditions of stress many people can be made susceptible to addiction, but if circumstances change for the better, the addictive drive will abate. About half of all the American soldiers in Vietnam who began to use heroin developed addiction to the drug. Once the stress of military service in a brutal and dangerous war ended, so, in the vast majority of cases, did the addiction. The ones who persisted in heroin addiction back home were, for the most part, those with histories of unstable childhoods and previous drug use problems.14 In earlier military conflicts relatively few U.S. military personnel succumbed to addiction. What distinguished the Vietnam experience from these wars? The ready availability of pure heroin and of other drugs is only part of the answer. This war, unlike previous ones, quickly lost meaning for those ordered to fight and die in the faraway jungles and fields of Southeast Asia. There was too wide a gap between what they’d been told and the reality they witnessed and experienced. Lack of meaning, not simply the dangers and privations of war, was the major source of the stress that triggered their flight to oblivion.
- L. N. Robins, “The Vietnam Drug User Returns,” in Special Action Office Monograph Series A (No. 2) (Washington, DC: U.S. Government Printing Office).
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Drugs, in short, do not make anyone into an addict, any more than food makes a person into a compulsive eater. There has to be a preexisting vulnerability. There also has to be significant stress, as on these Vietnam soldiers—but, like drugs, external stressors by themselves, no matter how severe, are not enough. Although many Americans became addicted to heroin while in Vietnam, most did not. Thus, we might say that three factors need to coincide for substance addiction to occur: a susceptible organism; a drug with addictive potential; and stress. Given the availability of drugs, individual susceptibility will determine who becomes an addict and who will not—for example, which two from among a random sample of ten U.S. GIs in Vietnam will fall prey to addiction.