Further Reading

The Sciences, November/December, 1989, pp. 12-16

Letters from readers to "Ain't Misbehavin'"

Letter from Roy A. Wise
Concordia University
Montreal, Quebec

(Wise's study of rat cocaine self-administration is the single study most often cited as proof that cocaine is irresistible and inevitably lethal)


Stanton Peele has argued clearly and, for the most part, correctly that the disease model of addiction is wrong and, since it encourages the view that an addict's behavior is beyond his control, may contribute more to the problem than to the cure ["Ain't Misbehavin'," July/August]. It is unfortunate that, despite ample evidence to the contrary, the notion of addiction as an inexorable and inevitable physical illness survives. In arguing that the addict can choose to forgo drugs just as the philanderer can choose to forgo sex, however, Mr. Peele offers a misleading discussion of animal research into the pharmacological impact of oft-abused drugs. It is not, as he claims, difficult to addict animals to narcotics, and, contrary to what his article suggests, heroin and cocaine exert more than a little control over most normal individuals.

Mr. Peele tries to bolster his thesis by referring to studies in which morphine solutions were ingested by rats housed in isolation, suggesting that drug dependence is a consequence of living conditions. In fact, the only thing those experiments reflect is that morphine is not a powerful reward when taken orally. They tell nothing about the dangers of self-administered intravenous use, which is the generally accepted model of opiate and cocaine addiction. (In humans, cocaine is, at most, moderately habit-forming when snorted or taken orally, but it can be lethally addictive when taken intravenously or smoked, as in the case of crack, because those modes of administration yield the highest concentrations of the drug in the bloodstream and, ultimately, the brain.)

I am not familiar with studies, cited by Mr. Peele, in which animals that have been compelled to press a bar to earn narcotic injections cease consuming drugs because of a slight increase in the work requirement. I am aware, however, of experiments in which the requirement was raised from one bar press for each injection to several hundred without inducing rats to give up their attempts to obtain intravenous heroin or cocaine. Indeed, when well-trained rats are allowed constant access to the high brain concentrations provided by intravenous cocaine, they invariably take it with such compulsion that they die within a few weeks. In my studies, virtually every healthy animal, whether housed singly or in a group, learned to take heroin or cocaine compulsively—behavior true of all but one of the mammalian species subjected to such tests.

Only humans seem able to use substantial amounts of these drugs without automatically falling under their domination, or—albeit with great difficulty—to break a drug habit. This is a testimonial to human willpower, not, as Mr. Peele suggests, evidence that the drugs are inherently impotent. Rather, high doses of heroin or cocaine exert enormous control over behavior because of pharmacological actions in identified regions of the brain.

Experiments with our mammalian relatives suggest that anyone who uses heroin or cocaine in significant doses is at risk. It is irresponsible to allow—let alone encourage—readers of The Sciences to think the danger might be negligible for most, or even a small number of, individuals.

Stanton Peele replies:

Roy Wise raises the traditional image of cocaine and heroin addiction as Platonic ideals—as entities that create inexorable addictions by dint of their chemical properties, regardless of the conditions under which they are administered. The evidence I presented against this view is the long human history of the use of cocaine and narcotics—including heroin—which defies the special addictive status conferred on these substances. Mr. Wise counters that only in studies involving oral doses of opiates does research demonstrate a link between cocaine or heroin self-administration and environment.

But this is not true. As John L. Falk, Peter B. Dews, and Charles R. Schuster noted, in a review published in the 1983 book Commonalities in Substance Abuse and Habitual Behavior, environmentallyinduced increases in self-administered intravenous drug use by animals "have been demonstrated for heroin, methadone, cannabis, and nicotine," just as they have been for orally consumed alcohol.

In 1986, after more than twenty years of studying intravenous drug administration in laboratory animals, Schuster, who is now director of the National Institute on Drug Abuse, wrote that "both the frequency of responding maintained by a drug and other measures of response strength are also a function of the schedule of reinforcement," and that, "thus, behavioral variables are as important as pharmacologic ones" in the development of compulsive drug craving. Indeed, what most disproves Mr. Wise's model of cocaine's inherent addictiveness is that, after decades of animal research, the drug was not listed as addictive in standard pharmacology charts. Not until the 1980s, when reports of cocaine abuse in the United states became widespread, did officials—and pharmacologists along with them—label the drug an addictive substance.

In their readiness to use cocaine compulsively, animals display a great deal of variation, as Schuster's colleague Frank R. George, head of NIDA's behavioral genetics division, recently pointed out in a television interview. It is important to remember, too, that, in experiments showing that animals will self-administer massive quantities of drugs, the animals are severely restrained and—like those used in Mr. Wise's research—implanted with catheters. What this research demonstrates, more than anything, is that animals denied normal rewards and activities will overconsume chemical substances. Ronald K. Siegel's recent book, Intoxication: Life in Pursuit of Artificial Paradise, reported studies of animal consumption of psychoactive substances under natural conditions. These animals—while using a range of drugs that mimics the entire human pharmacopeia—did not become compulsive users.

As for humans: their reactions to cocaine—even when administered intravenously—have been shown to be strongly affected by user attitudes. A recent NIDA study found that, after injections, experienced intravenous cocaine users exhibited little consistency in blood pressure and heart rate. Nonetheless, the same subjects showed high correlations in their subjective reactions to the injections, reactions they also manifested when injected with placebos. The researchers concluded that the basis for continued abuse seemed to be a function of such expectations of drug effects.

Mr. Wise is correct that, among all animals, humans are best able to control or to cease drug use. Each year, for instance, one and a half million Americans become ex-smokers—a considerable feat, given that recent studies have shown that it is more difficult for humans to cut back on, or to cease using, nicotine than it is to swear off cocaine. When humans do overcome addiction, it is nearly always out of a sense of integrity and values, for which there are no animal equivalents.

Finally, Mr. Wise's charge of irresponsibility is misdirected. Today, in the United States, cocaine's addictive power is portrayed, luridly and incessantly, as uncontrollable. Given that this portrait is inaccurate, what could be more irresponsible than that? Indeed, television specials that show addicts describing how they are unable to resist thievery or violence while in the throes of drug use are exactly what my essay was designed to combat.