DOING YOUR OWN RESEARCH

DOING YOUR OWN RESEARCH

If reading this book has raised your level of interest and you want more specific information, or you want the straight story about a new develop­ment, there is no substitute for doing your own research.

Reading both scholarly review articles and original research papers is much easier than most people believe. In fact, one of the first steps in writing this book was gathering such research. Much of the library work for the first edition was done by two college students, neither of whom had any previous experience using a medical library. Should you decide to investigate for yourself, here are some suggestions about where to begin.

Public libraries are not likely to have the sorts of journals and books you will need. Because there is such a vast amount of medical literature pub­lished, most universities with a medical school have a separate library just to house all this information. Find a medical library at a nearby medical school. If for some reason you cannot get to a medical school, check to sec if there is a college or university biology department nearby and use the

library they use.

Next, go to the library and make friends with the reference librarian, because you will need his or her help until you are familiar with the library and the search mechanisms. The most efficient way of searching the literature is to use MEDLINE or PubMed, databases of the National Library of Medicine, a US government institution that allows you  

search almost all the published medical literature on any subject you can think of related to health. You can search by author, title, subject, key­word, institution, and many other descriptors.

In most cases you will find far more information than you need. A good place to start is with reviews. Reviews are documents that consoli­date and summarize the research and literature available in a given area, and they are usually written in less technical language. Reading several recent reviews about the topic you are researching will help you form a base of knowledge about the subject. Practice using MEDLINE by start­ing out with simple concepts; for example, search for marijuana articles. There are hundreds of them, and many of the titles will be so technical that they might seem indecipherable. So tell the computer to select mari­juana review articles. This will reduce the number markedly.

If you have read Buzzed, then you know that one of the active ingredi­ents in marijuana is THC. Try searching for THC and you will get more articles. Refine your search by asking for reviews of THC and you will get articles different from those you did when you searched for marijuana in general. Play with the database and have fun. Search for all kinds of com­binations of keywords, like THC and learning, or THC and adolescent. You will soon have an idea of the enormous amount of information there is about just this chemical. Understand, though, that no one study tells the whole story.

As a final note, we caution you not to accept everything you read as directly applicable to the human condition. Often scientists employ very high levels of a chemical to test for toxic effects in animals, and sometimes the chemical levels they use in/on animals are hundreds or thousands of times higher than a human would ever use, taking into account the weight of the human compared to the animal. Consequently, some of the toxic effects seen in animals may not apply to humans. On the other hand, ani­mal experiments cannot reveal many subtle effects of chemicals, particu­larly psychological ones, and thus animal studies almost certainly miss some important effects that humans will experience. So, as you read a sci­entific paper, remember that it is just a small part of the literature about a drug, and while the data may be true, it is important to understand that data in the context of everything else known about the drug.

GETTING CONVICTED: THE PENALTY BOX

GETTING CONVICTED: THE PENALTY BOX

The penalty laws of most states and countries are built on a series of leg­islative acts that happened over a long period of time, and thus, they are complicated and not easily summarized. Possession of modest amounts of marijuana can result in a slap on the wrist in some places and serious jail time in others. The same is true for other drugs, although they are usually taken more seriously, even in very small amounts. Often the prosecuting attorney has some leeway about the level of crime with which to charge an individual. The problem is that it is difficult to be sure of (1) the latest changes in the law, (2) the attitude that the prosecu­tor is taking toward drug crimes, and (3) whether that individual will be charged under state or federal statutes. Thus, conviction for the posses­sion of a small, recreational amount of heroin or cocaine could result in either a modest sentence or a huge fine and a long prison term, depend‑

ing on the exact circumstances and the mood of the legal officials over­seeing the case.

It is important to recall that in some states and in the federal system there is structured, or guideline, sentencing. That means that once an individual is convicted of some drug crimes, the sentence is regulated by law and might not be alterable by the judge no matter what the circum­stances. Coupled with the fact that there is no parole in the federal system (and increasingly in the state systems), a conviction can mean long prison time, even if the prosecutor and judge wish it were otherwise.

Here's an example of how things can go terribly wrong as a conse­quence of alcohol, a prescription drug, and harsh laws. One of us (WW) testifies as an expert in legal cases, and a recent one illustrates how the law, the prosecutor, and the courts can interact to ruin the life of an indi­vidual. A man was at a party with his neighbors outside of his home. He consumed a modest amount of alcohol throughout the evening, but at some point he decided to go to bed and took his nightly medicine, which included the sleeping pill zolpidem (generic for Ambien). Before going to bed, he came back to the party but soon appeared intoxicated. He then prepared for bed and went to sleep. Shortly thereafter, he awoke and came out of the house without his shoes, false teeth, or hearing aid, clearly hav­ing just awakened. But he had a gun, which he had retrieved from his bedside where he kept it. He fired twice as he yelled an obscenity to the individuals at the party. No one was hurt. The police were called, and he was arrested.

The man was charged with aggravated assault, and everyone thought he was intoxicated with alcohol. In the law of most states, that is consid­ered "voluntary intoxication" and thus is not a defense against any charges. His defense team argued that he was not intoxicated with alco­hol, but with his prescribed zolpidem, which is known to produce odd behaviors such as sleep driving, sleep sex, sleep shopping, sleep eating, and so forth. If it were the zolpidem, that would be "involuntary intoxica­tion," and that is a defense against such charges.

The jury heard the case and decided that he was intoxicated by alcohol and was therefore guilty. Now, here is where the disaster occurred. In that state, commission of many crimes (such as aggravated assault) with a gun is a mandatory ten-year sentence. If the gun is fired, the mandatory sen­tence is twenty years. In this case the prosecutor chose to charge the man for each of the six people present at the party, and the law requires that the mandatory sentences apply to each charge and be served consecu­tively. This means the man (who has not been sentenced at this writing)

must, by law, be sentenced to 120 years in prison. The judge has no discre­tion in this case.

This is a terrible example of the interaction of intoxication, harsh laws, vigorous prosecution, and finally, the presence of a gun where a sleepy, intoxicated person could access it and fire it. This man had no history of behavior like this and was a decorated soldier. It is very likely that the zolpidem produced the bizarre behavior, but the prosecutor and jury did not see it that way.

The lesson from this is that if a person chooses to intoxicate himself and then commits a crime, that intoxication is usually not a defense against any crime he committed, no matter how impaired he was at the time of the crime.

LEGAL ISSUES

IT IS SAID that your life can change forever in a matter of seconds. When a person mixes alcohol or other drugs and the legal system, the combina­tion can easily become life-changing. For a variety of reasons, the law­making bodies of most countries, especially the United States, have decided to suppress illegal drug use by making drug laws harsh and cer­tain. All who deal with drugs in an illegal manner are thus at risk for penalties that can disrupt their own lives and those of their families.

The use of almost all the drugs discussed in this book could involve violations of the law, depending on the circumstances. Many of these drugs are illegal in all circumstances—manufacturing, distribution, and possession. Others are legal when prescribed, but not for recreational use. Still others, such as alcohol, can be legal for adults, but their use is prohib­ited for underage individuals and for activities such as driving a car or operating a boat.

This chapter is written to inform readers about very basic laws and principles that come into play around drug issues. It is not intended to give advice about dealing with the law-enforcement community or the judicial system. If you feel that you need that advice, find a good lawyer and ask her all of your questions before you become legally involved.

THE PRINCIPLES

I While laws exist regarding the rights of a law officer to search some­one's car or home, this very complicated issue is often decided in the courts in individual cases. Generally you have the greatest "expecta­tion of privacy" in your home. There is less expectation of privacy in a car, and the least when you are out in public.

2. If a law-enforcement officer suspects you of a crime and really wants to search you or your car, you will be searched, whether or not you give permission. If you give your permission, the search will almost certainly be considered legal. If you refuse permission, the search may or may not be legal, but it may happen anyway. The debate over whether the search was permitted and legal will begin in the court system. The easiest way to avoid trouble is to avoid situations in which a random and unexpected search will yield anything illegal.

3. A person who is innocent of any crime but is with someone arrested for possessing drugs may become involved with the legal system until her innocence is proven. By that time, she may have incurred large financial burdens (e.g., an expensive lawyer), terrified her family, and spent some time under arrest.

4. 'the penalties for drug-related activities can be horrendous, especially in the United States federal judicial system, and particularly for selling drugs. Many casual drug users do not realize that simple possession of a modest amount of a drug can automatically be considered "intent to distribute," whether or not they actually plan to sell the drug.

5. You do not have to be on government property to be in violation of federal law. The federal drug laws apply everywhere in the United States and US territories at all times.

6. State and federal laws can be extremely strict about the use of guns in the commission of crimes. The possession of a gun—even just having one in the vicinity of a drug-law violation canadd many years onto the sentence for the original crime.

Many people believe that they are "safe" from serious legal consequences because they know the local officials, or because they believe the penal­ties are not serious. They are wrong. First, it a local official were to inter­fere with a prosecution, she could be prosecuted for obstruction of justice or public corruption. Second, an arrest by a state or local officer can eas­ily be referred to federal prosecutors not subject to local political influ­ence. Third, in many states and in the federal system there is no parole. Even worse, in some cases "minimum mandatory" sentencing laws give the judges practically no leeway for reduced sentences.

8. Your rights as a US citizen do not apply in foreign countries, and the legal consequences of drug-law violations in some places can literally mean death.

TREATMENT CONTEXT

TREATMENT CONTEXT

The research design and the various family-treatment modalities of the Addicts and Families Program(AFP) have been described irl Chapter 2 and Appendix C and are not germane to this chapter. Rather, our concern here is with the means used for getting the families actually involved in treatment. Again, the study demanded that (1) the addict, (2) both parents or parent surrogates,* and, whenever possible, (3) siblings, attend an (initial) Family Evaluation Session before being assigned to a family-treatment group. For theo-retical reasons (Chapters 1 and 6) and purposes of research design,''' wives, while usually included in treatment, were not required to attend the evaluation exercise. This session included videotaped family interaction tasks and family perceptions tests. Each member age 12 or over was paid 810.00 for participating. The therapists did not know beforehand to which treatment group the families they were recruit-ing would be (randomly) assigned. These stipulations, while perhaps more stringent than those of most clinical programs, had their benefits. Although they made our job more difficult, they also pro-hibited us from either taking the easy way out and settling for partial family representation, or excluding family members who we later determined were crucial for the success of treatment. Further, we had to recruit a high percentage of families in order both (1) to meet the requirements for a certain number of cases within the grant period, and (2) to avoid the criticism that our sample was nonrepresentative because we had skimmed off the "easy," -compliant" families.

Initial recruitment efforts were made with 125 families. Of these, 33 were deemed ineligible for the study, usually because the IP was not addicted at intake. This left 92 families with which full engage‑

ment attempts were made.

At the outset of the study we anticipated that our biggest prob-lem would be in retaining these families beyond one or two family sessions—the dropout issue. In this we were wrong. First, 94% of those who attended the Family Evaluation Session continued with treatment. Second, once they were -hooked," the majority of families tended to be fairly conscientious in their attendance, especially when compared with results reported elsewhere in the literature. Even the treatment group with the least optimal retention potential averaged six sessions, that is, 64% of their prescribed number of sessions '65' ""; attendance rates for the other two treatment groups were 88%, and 94%. What we did not foresee was the inordinate amount of difficulty we would have in simply getting the family members in for the initial Family Evaluation Session (since, at the time, almost none of the literature on engaging addicts' families had been published). Recruit-ment became one of the most demanding aspects of our work. This unexpected hurdle forced us to reconsider our situation and attempt to be innovative. The substance of this chapter is derived from our responses and experiences in the face of this dilemma.

THE BOTTOM LINE ON ADDICTION

THE BOTTOM LINE ON ADDICTION

The bottom line on addiction is that anyone with a brain can get addicted to drugs. However, most people don't, and there are a lot of reasons. First and foremost, if a person does not experiment with addictive drugs, then she won't get addicted. Second, if a person is mentally healthy, has a stable family and work life (including supportive and non-drug-using peers), and has no family history of substance abuse, she lacks some important risk factors and is less vulnerable. However, she still has a brain, and she is not immune to addiction. During the cocaine craze of the 1970s and ¹80s, plenty of constructive, highly educated, well-employed professionals became addicted to cocaine despite positive factors in their lives.

Finally, there may be some people for whom the pleasurable experience of these drugs is exceptionally high, and the drive to use the drugs is thus more compelling than for others. If these people do not try drugs, this underlying quality will not present a problem. However, if they have access to them, and if they do choose to use them, they are at significant risk. It is no accident that the rate of drug addiction among professionals in the United States is highest among medical personnel, who have easy access to such drugs.

MENTAL ILLNESS AND DRUG ADDICTION

MENTAL ILLNESS AND DRUG ADDICTION

Depression and some other mental illnesses also occur more frequently in substance users. Did the drugs cause the problem, or did the problem cause the drug use? Once someone's life has become complicated by sub­stance addiction, the turmoil that has been created can certainly contrib­ute to the development of depression. This fact makes it very difficult to understand the complicated relationship between mental illness and drug addiction. However, some recovering addicts will describe an opposite cycle: that their anxious or depressed mood led them to drink or to use other substances to deal with feelings of inadequacy or despair. Then, as time passed and substance use became more frequent, the substance use became the dominant problem. This "self-medication" process probably contributes to addiction in many people.

LIFE EXPERIENCE AND DRUG ADDICTION

LIFE EXPERIENCE AND DRUG ADDICTION

Life experience can certainly contribute to addiction as well as protect potential addicts. The life histories of people who have entered drug-treat­ment facilities show that certain characteristics appear more frequently in substance users than in people without substance-use problems.

Substance abusers are more likely to have grown up in a family with a substance-using parent.

Alcoholism can be passed on by the experience of living with an alcoholic parent (although almost as often this experience will motivate a life of abstinence). Do people growing up in an alcoholic household simply learn to respond to stress with alcohol? Possibly. Chil‑ dren of alcoholics also are more likely to experience physical and emo‑ tional abuse at the hands of their parents, and a past history of physical and emotional abuse is another characteristic of many substance abusers. This is particularly true among women. In studies of hospitalized alcohol‑             ics, 50 to 60 percent typically report having experienced childhood abuse.

Why should bad early experience lead to adult substance use? One group of theories suggests a psychological origin for the substance use. However, a biological theory was developed from experimental work done on monkeys. Scientists at the National Institutes of Health and else­where have shown that when infant monkeys are neglected or abused by their mothers, they have a number of behavioral problems as they grow up. As adults, they tend to get into fights, and if given the chance to drink alcohol, they drink to excess. This is not just a genetic tendency because infants from perfectly normal mothers will show these tendencies if they are raised by neglectful mothers. None of this is surprising. What is sur­prising is that these behavioral problems are accompanied by changes in the brain. The alcohol-drinking monkeys show lower levels of the neu­rotransmitter serotonin in their brains. This study indicates that this early life experience may produce long-lasting changes in the brain that con­tribute to these behaviors.

We know that associating with drug-using peers increases the chances that a person will choose to try drugs. Also, early use of cigarettes, alco­hol, or marijuana is associated with later use of other drugs. This associ­ation has led to the popular "gateway theory" of drug addiction. This theory is based on evidence that most people who use illegal addictive drugs first used drugs like alcohol, tobacco, or marijuana. These drugs are viewed as a gateway to the use of more dangerous drugs. However, the vast majority of people using cigarettes, alcohol, and marijuana never use "harder" drugs. Although the statistics are correct, this situation reminds us of our favorite statistics teacher, who is fond of saying that statistics don't prove how things happen. It is possible that people who are risk takers, or mentally ill, or living in chaotic families, or hanging out with deviant friends are more likely to experiment with many devi­ant behaviors, including drug use. The drug use could just as likely be symptom as a disease.

PERSONALITY AND DRUG ADDICTION

PERSONALITY AND DRUG ADDICTION

How many people reading this book have worried about the possibility that they or a loved one may have an "addictive personality"? Although this concept is a favorite of some drug-abuse treatment professionals, psy­chology classes, and self-help books, there seems to be little agreement about what an addictive personality is. Furthermore, the personality type prone to substance abuse changes with the times. In years gone by, the obsessive-compulsive personality was described as prone to drug abuse. Today, there is concern that risk-taking and impulsive people are more likely to develop substance-use problems. Many of these theories proba­bly have a grain of truth to them. For example, if a person is uninhibited about trying new experiences, including those that are risky, he may be more likely to take drugs the first time. So, the risk of addiction in these people might rise from the greater likelihood that they will experiment with drugs. As with genetic arguments, it is important to remember that such traits do not condemn a person to drug addiction. Many risk takers channel their energies into daring activities like bungee jumping.

CUCUMBERS AND PICKLES: CHANGES IN THE BRAIN

CUCUMBERS AND PICKLES: CHANGES IN THE BRAIN

So what changes between the fifth time that you get your muffin and the time that you waited at the bakery door until opening time each day, neglecting your job or forgetting to take your children to school? You do this even if the muffin tastes lousy. It is this sort of compulsive, repetitive involvement in drug taking despite negative consequences that most experts view as addiction.

Use of addictive drugs can be viewed in a similar way. Many people drink alcohol occasionally, or even sometimes use cocaine at parties. However, for some people, the first social experiences with drugs gradu­ally evolve into more continual use. Alcohol use provides an example. While 50 percent of the adult population of the United States drink alco­hol occasionally, of these about 10 percent drink heavily and about 5 per­cent engage in addictive patterns of drinking.

Clearly, something happens in addicts that makes the need to consume drugs so great that they will go to extreme lengths to obtain the drug. What changes in the brain explain this? We have heard recovered addicts compare the change in their behavior and lives to the change from a cucumber to a pickle. Once a cucumber is turned into a pickle, it cannot

be turned back. Is this a real analogy? If so, then the Alcoholics Anony‑ mous approach of lifetime abstinence from drugs becomes a convincing solution to alcoholism.

Most scientists think that changes gradually occur in the reward circuit of the brain as it adapts to the continuous presence of the drug. However, we don't completely understand exactly which changes are the most important for addiction. The simplest change is easy to understand: with daily stimulation by addictive drugs, the reward system comes to "expect" this artificial stimulus. When people stop using drugs abruptly, the reward system is shut down—it has adapted to the daily "expectation" of drugs to maintain its function. We know of one biochemical change in the brains of all addicts that may explain this result. The brains of alcoholics, meth-amphetamine addicts, heroin addicts, and even compulsive eaters show a common biochemistry—they have low levels of one of the receptors that normally receive dopamine. This makes sense—in response to a constant barrage of dopamine, the cell that receives it is just trying to shut down. Recovering heroin addicts often report that every time they inject heroin, they are trying to recapture the feeling of their early experience with the drug, which gave a pleasure that they never quite reached again. People who are in a stimulant "binge," taking hits every few hours, can have the same experience. They respond by "chasing the high," taking the drug every hour or so to recapture the first rush. Only when they stop taking the drug for a while does their initial sensitivity return.

Some recovering cocaine addicts say that they do not feel pleasure in any­thing for a while after they stop using cocaine. Imagine how difficult it must be to stop using a drug that gives incredible pleasure, when even things that are usually enjoyable give no pleasure during withdrawal. This inability to feel pleasure may be one of the powerful reasons why people have great diffi­culty giving up cocaine. If there is a substance at an addict's fingertips that can make him feel better immediately, clearly the impulse to take it can

become overwhelming.

Some of the changes in the brain of a person who uses addictive drugs repeatedly are just a result of normal learning in the brain. Let's go back to our bakery one more time. As our imaginary muffin addict approaches the store each day, he remembers the route and looks forward to the smell of newly baked muffins wafting down the street. Pretty soon, the smell of the bakery alone can cause an intense longing for the pastries before he gets there. What happens when our muffin addict decides that the daily search for muffins is taking too long, or when the bakery raises prices so much that he won't pay? If he goes "cold turkey" and quits muffins alto­gether, he had better find another way to go to work, because he will find that the route to the bakery, the smell of the muffins, and many of the experiences associated with going to the bakery will cause an intense longing for a muffin. This type of longing has ruined many a diet, and this type of learning plays an important role in addiction as well. Simply showing a former cocaine user a photograph of a crack pipe will trigger a strong craving for the drug, and recent studies of brain activity show that areas of the brain involved in memory are activated while he looks at these pictures.

There is another kind of "learning" that happens in the brains of addicts that makes it hard for them to stop using drugs. This is the part of the brain that plans for the future. Under normal circumstances, if an animal or person finds a reinforcer, her brain remembers where and how it happened and plans to check back the next time she needs food or sex. This ability to plan for the future is perhaps the most sophisticated thing our brain does. However, in a crack user, what this part of the brain focuses on is finding crack—the repeated stimulation with this one rein­forcer can also "hijack" these planning centers in the same way. So it isn't simply the pleasure the drugs cause that motivates drug use but our abil­ity to remember and plan for future pleasure. This may be one of the most long-lasting changes that happen in the brain.

New research shows that there is a final step in addiction: when taking the drug becomes as automatic as tying your shoes. Scientists have shown that another part of the dopamine system that is important for the transi­tion of this learning to something automatic gradually changes, too, but more slowly. Eventually, hitting the bar to get an injection of drug becomes a habit. This behavior has become an automatic and controlling part of your behavior.

THE SPECIAL ROLE OF DOPAMINE

THE SPECIAL ROLE OF DOPAMINE

The neurotransmitter dopamine seems to play an important role in the normal process of reinforcement and in the actions of most addictive drugs. One group of dopamine neurons runs directly through the reward circuit we just described. If the dopamine neurons in this circuit are destroyed, then animals will not work for food, sex, water, or addictive drugs. Furthermore, both natural reinforcers and most addictive drugs increase the release of dopamine from these neurons. Our favorite exper­iment was conducted by a scientist in Canada who measured the release of dopamine in the brain of a male rat before and after providing it with a female partner. Not surprisingly, access to a sexually receptive partner caused a large rise in dopamine levels in this part of the brain.

If this same experiment is done with drugs instead of natural reinforcers, the results are the same. Cocaine, morphine, nicotine, cannabinoids, or alcohol will cause large increases in dopamine in the same area of the brain in which sex causes a rise. Most neuroscientists think that addictive drugs affect neurons that connect, one way or another, with this critical dopa­mine circuit to stimulate its activity.

Anyone who has ever enjoyed a muffin knows that dopamine going up when something pleasant happens is not the whole story of addiction. It is not even the whole story of how dopamine is involved. To explain that, we are going back to the bakery for a second visit. The first time you went to the bakery, dopamine went up when you had an unexpected treat—a tasty muffin. The second (or the third, or fifth) time, you started to anticipate the muffin when you saw the bakery sign. We know from experiments in monkeys that dopamine starts going up in anticipation of a reward rather than when the reward arrives. Scientists now think that one important role dopamine plays is this anticipation for a known reward. This agrees with our common sense that muffin eating is not food addiction. The first step toward addiction may be when you expect the muffin and begin to organize your walk to work to make sure it happens. Dopamine probably contributes to that decision-making process. However, it is still not addic­tion. You could change your route if you needed to.

Furthermore, dopamine neurons are not "the end of the line" for detect­ing pleasure, but they clearly connect with other neurons. We are just beginning to understand how these other areas of the brain play a role.

THE DARK SIDE: PAIN, NOT PLEASURE

Enjoying the rush of pleasure from a drug is only part of addiction. For addicts, there is an opposing force, a yang for the yin. Once the body adapts to the drug and physical dependence develops, a daily cycle of drug taking, pleasure, gradual waning of drug effect, and the onset of withdrawal symptoms emerges. Withdrawal symptoms are different for each drug, and minimal for some (much of this is covered in detail in the chapters on individual drugs). For example, the waning of opiate effects causes an ill feeling similar to the onset of the flu. The drug user has chills and sweats, a runny nose, diarrhea, and a generally achy feeling. An alco­holic will feel restless and anxious. However, there is a common underly­ing feeling for withdrawal from all addictive drugs: a feeling that is the reverse of the good feeling that the drug once gave that can be accompa­nied by a strong craving to take more of the drug. Avoiding the unpleas­ant feelings of withdrawal and satisfying the desire for more drug can eventually become even stronger motives for drug taking than simply

feeling good.

DRUGS AND THE PLEASURE CIRCUIT

DRUGS AND THE PLEASURE CIRCUIT

It won't surprise anyone that addictive drugs are reinforcers. Here the experimental evidence is overwhelming. Most experimental animals (pigeons, rats, monkeys) will press a lever to get an injection of cocaine, methamphetamine, heroin, nicotine, and alcohol. They will not press a lever for LSD, antihistamines, or many other drugs. Furthermore, even fruit flies and zebra fish will hang out in an environment in which they have previously received a reinforcer—another test of the potential addic­tiveness of a substance. This list of drugs for which experimental animals will work matches exactly the list of drugs that are viewed as clearly addictive in humans.

We know that the same pathway mediates the pleasurable effects of addictive drugs. There are two particularly convincing arguments. First, if this pathway is damaged in an animal, the animal will not work for drugs. Second, animals with an electrode placed in the reward pathway find smaller currents more "enjoyable" if the animal has received an injection of cocaine or heroin, for example. The same system is activated in the brains of addicts. When cocaine addicts looked at pictures of cocaine or handled crack pipes while the activity of their brains was monitored, they reported a craving for cocaine, and at the same time, their brains showed activation in the reward pathway of the brain.

Addictive drugs (stimulants, opiates, alcohol, cannabinoids, and nico­tine) can actually substitute for food or sex. This explains why rapid injec­tion of cocaine or heroin produces a "rush" of pure pleasure that most users compare to the pleasure of orgasm. This isn't just true for certain people who lack willpower or who are engaged in a deviant lifestyle. It is true for everyone who has a brain. It automatically becomes easier to understand why addiction is such a common problem across cultures.

Although the news media have certainly overdone the "what is the most addictive drug?" contest, it is also clear that animals will work much harder to get some drugs than others. For example, rats will press a bar up to two to three hundred times for one injection of cocaine and perhaps even more for the bath salt MDPV. However, some drugs, like alcohol and nicotine, might be administered more if they didn't have unpleasant effects on the body. Humans seem to be particularly good at ignoring unpleasant side effects to obtain reinforcement from drugs. If you judged the most addictive drug by the largest number of people who have trouble stopping their use of it, then nicotine would be the clear leader.