The author of the dystopian novel Brave New World, Aldous Huxley (1932), once wrote of his experiences with the drug mescaline. The Doors of Perception described “a world where everything shone with the Inner Light, and was infinite in its significance. The legs, for example, of a chair—how miraculous their tubularity, how supernatural their polished smoothness! I spent several minutes—or was it several centuries?—not merely gazing at those bamboo legs, but actually being them” (Huxley, 1954, p. 22).

Being the legs of a chair? This probably is better than being the seat of a chair, but it still sounds like an odd experience. Still, many people seek out such experiences, often through drug use. Psychoactive drugs are chemicals that influence consciousness or behavior by altering the brain’s chemical message system. You read about several such drugs in the Neuroscience and Behavior chapter when we explored the brain’s system of neurotransmitters. And you will read about them in a different light when we turn to their role in the treatment of psychological disorders in the Treatment chapter. Whether these drugs are used for entertainment, for treatment, or for other reasons, they each exert their influence by increasing the activity of a neurotransmitter (the agonists) or decreasing its activity (the antagonists). Like Huxley experiencing himself becoming the legs of a chair, people using drugs can have experiences unlike any they might find in normal waking consciousness or even in dreams. To understand these altered states, let’s explore how people use and abuse drugs, and examine the major categories of psychoactive drugs.

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Why do children sometimes spin around until they get dizzy and fall down? There is something strangely attractive about altered states of consciousness, and people throughout history have sought out such states by dancing, fasting, chanting, meditating, and ingesting a bizarre assortment of chemicals to intoxicate themselves (Tart, 1969). People pursue altered consciousness even when there are costs—from the nausea that accompanies dizziness to the life-wrecking obsession with a drug that can come with addiction. In this regard, the pursuit of altered consciousness can be a fatal attraction.

In one study, researchers allowed rats to administer cocaine to themselves intravenously by pressing a lever (Bozarth & Wise, 1985). Over the course of the 30-day study, the rats not only continued to self-administer at a high rate but also occasionally binged to the point of giving themselves convulsions. They stopped grooming themselves and eating until they lost on average almost a third of their body weight. About 90% of the rats died by the end of the study. Other laboratory studies show that animals will work to obtain not only cocaine but also alcohol, amphetamines, barbiturates, caffeine, opiates (such as morphine and heroin), nicotine, phencyclidine (PCP), MDMA (Ecstasy), and THC (tetrahydrocannabinol, the active ingredient in marijuana). Rats are not tiny little humans, of course, so such research is not a firm basis for understanding human responses to cocaine. But these results do make it clear that cocaine is addictive and that the consequences of such addiction can be dire.

People usually do not become addicted to a psychoactive drug the first time they use it. They may experiment a few times, then try again, and eventually find that their tendency to use the drug increases over time due to several factors, including drug tolerance, the tendency for larger drug doses to be required over time to achieve the same effect. Physicians who prescribe morphine to control pain in their patients are faced with tolerance problems because steadily greater amounts of the drug may be needed to dampen the same pain. With increased tolerance comes the danger of drug overdose; recreational users find they need to use more and more of a drug to produce the same high. But then, if a new batch of heroin or cocaine is more concentrated than usual, the “normal” amount the user takes to achieve the same high can be fatal.

Self-administration of addictive drugs can also be prompted by withdrawal symptoms, which result when drug use is discontinued. Some withdrawal symptoms signal physical dependence, when pain, convulsions, hallucinations, or other unpleasant symptoms accompany withdrawal. A common example is the “caffeine headache” some people complain of when they haven’t had their daily jolt of java. Other withdrawal symptoms result from psychological dependence, a strong desire to return to the drug even when physical withdrawal symptoms are gone. For example, some exsmokers report longing wistfully for an after-dinner smoke even years after they’ve successfully quit the habit.

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The psychological and social problems stemming from drug addiction are major. For many people, drug addiction becomes a way of life, and for some, it is a cause of death. But some people do overcome addictions. In one study, 64% of a sample of people who had a history of cigarette smoking had quit successfully, although many had to try again and again to achieve their success (Schachter, 1982). Indeed, large-scale studies consistently show that approximately 75% of those with substance use disorders overcome their addictions (Heyman, 2009). Although addiction is dangerous, it is not necessarily incurable.

It may not be accurate to view all recreational drug use under the umbrella of “addiction.” Many people in the United States, for example, would not call the repeated use of caffeine an addiction, and some do not label the use of alcohol, tobacco, or marijuana in this way. In other times and places, however, the use of each of these drugs has been considered a terrifying addiction worthy of prohibition and public censure. In the early 17th century, for example, tobacco use was punishable by death in Germany, by castration in Russia, and by decapitation in China (Corti, 1931). Not a good time to be a smoker. By contrast, cocaine, heroin, marijuana, and amphetamines have each been popular and even recommended as medicines at several points throughout history (Inciardi, 2001). Societies react differently at different times, with some uses of drugs ignored, other uses encouraged, others simply taxed, and yet others subjected to intense prohibition (see the Real World box on p. 163). Rather than viewing all drug use as a problem, it is important to consider the costs and benefits of such use and to establish ways to help people choose behaviors that are informed by this knowledge (Parrott et al., 2005).

Four in five North Americans use caffeine in some form every day, but not all psychoactive drugs are this familiar. To learn how both the well-known and lesser-known drugs influence the mind, let’s consider several broad categories of drugs: depressants, stimulants, narcotics, hallucinogens, and marijuana. TABLE 5.2 summarizes what is known about the potential dangers of these different types of drugs.

Depressants

Depressants are substances that reduce the activity of the central nervous system. Depressants have a sedative or calming effect, tend to induce sleep in high doses, and can produce both physical and psychological dependence.

The most commonly used depressant is alcohol, the “king of the depressants,” with its worldwide use beginning in prehistory, its easy availability in most cultures, and its widespread acceptance as a socially approved substance. Fifty-two percent of Americans over 12 years of age report having had a drink in the past month, and 24% have binged on alcohol (over five drinks in succession) in that time. Young adults (ages 18-25) have even higher rates, with 62% reporting a drink the previous month and 42% reporting a binge (National Center for Health Statistics, 2012).

Alcohol’s initial effects, euphoria and reduced anxiety, feel pretty positive. As it is consumed in greater quantities, drunkenness results, bringing slowed reactions, slurred speech, poor judgment, and other reductions in the effectiveness of thought and action. The exact way in which alcohol influences neural mechanisms is still not understood, but like other depressants, alcohol increases activity of the neurotransmitter GABA (De Witte, 1996). As you read in the Neuroscience and Behavior chapter, GABA normally inhibits the transmission of neural impulses, and so one effect of alcohol is to stop the firing of other neurons. But there are many contradictions. Some people using alcohol become loud and aggressive, others become emotional and weepy, others become sullen, and still others turn giddy—and the same person can experience each of these effects in different circumstances. How can one drug do this? Two theories have been offered to account for these variable effects: expectancy theory and alcohol myopia.

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Expectancy theory suggests that alcohol effects can be produced by people’s expectations of how alcohol will influence them in particular situations (Marlatt & Rohsenow, 1980). So, for instance, if you’ve watched friends or family drink at weddings and notice that this often produces hilarity and gregariousness, you could well experience these effects yourself should you drink alcohol on a similarly festive occasion. Seeing people getting drunk and fighting in bars, in turn, might lead to aggression after drinking. Evidence for the expectancy theory has been obtained in studies where participants are given drinks containing alcohol or a substitute liquid. Some people in each group are led to believe they had alcohol, and others are led to believe they did not. These experiments often show that the belief that one has had alcohol can influence behavior as strongly as the ingestion of alcohol itself (Goldman, Brown, & Christiansen, 1987). You may have seen people at parties getting rowdy after only one beer—perhaps because they expected this effect rather than because the beer actually had this influence.

Another approach to the varied effects of alcohol is the theory of alcohol myopia, which proposes that alcohol hampers attention, leading people to respond in simple ways to complex situations (Steele & Josephs, 1990). This theory recognizes that life is filled with complicated pushes and pulls, and our behavior is often a balancing act. Imagine that you are really attracted to someone who is dating your friend. Do you make your feelings known or focus on your friendship? The myopia theory holds that when you drink alcohol, your fine judgment is impaired. It becomes hard to appreciate the subtlety of these different options, and the inappropriate response is to veer full tilt one way or the other. So, alcohol might lead you to make a wild pass at your friend’s date or perhaps just cry in your beer over your timidity—depending on which way you happened to tilt in your myopic state.

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Both the expectancy and myopia theories suggest that people using alcohol will often go to extremes (Cooper, 2006). In fact, it seems that drinking is a major contributing factor to social problems that result from extreme behavior. Drinking while driving is a main cause of auto accidents. Approximately one-third of all traffic-related deaths in the U.S. involve an alcohol-impaired driver (Department of Transportation, 2012). A survey of undergraduate women revealed that alcohol contributes to approximately 76% of cases of incapacitated rape (rape after the victim is incapacitated by self-induced intoxication) and 72% of drug- or alcohol-facilitated rapes (in which the perpetrator deliberately intoxicates the victim prior to rape; McCauley et al., 2009).

Compared to alcohol, the other depressants are much less popular but still are widely used and abused. Barbiturates such as Seconal or Nembutal are prescribed as sleep aids and as anesthetics before surgery. Benzodiazepines such as Valium (diazepam) and Xanax are also called minor tranquilizers and are prescribed to treat anxiety or sleep problems. Physical dependence is possible because withdrawal from long-term use can produce severe symptoms (including convulsions), and psychological dependence is common as well. Finally, toxic inhalants are perhaps the most alarming substances in this category (Ridenour & Howard, 2012). These drugs are easily accessible even to children in the vapors of household products such as glue, hair spray, nail polish remover, or gasoline. Sniffing or “huffing” vapors from these products can promote temporary effects that resemble drunkenness, but overdoses can be lethal, and continued use holds the potential for permanent neurological damage (Howard et al., 2011).

Stimulants

Stimulants are substances that excite the central nervous system, heightening arousal and activity levels. They include caffeine, amphetamines, nicotine, and cocaine, and Ecstasy; and they sometimes have a legitimate pharmaceutical purpose. For example, amphetamines (also called speed) were originally prepared for medicinal uses and as diet drugs; however, some are widely abused, causing insomnia, aggression, and paranoia with long-term use. Stimulants increase the levels of dopamine and norepinephrine in the brain, inducing alertness and energy in the user, often producing a euphoric sense of confidence and a kind of agitated motivation to get things done. Stimulants produce physical and psychological dependence, and their withdrawal symptoms involve depressive effects such as fatigue and negative emotions.

Ecstasy (also known as MDMA, “X,” or “E”) is an amphetamine derivative. Ecstasy is particularly known for making users feel empathic and close to those around them, but it has unpleasant side effects such as interfering with the regulation of body temperature, making users remain highly susceptible to heatstroke and exhaustion. Although Ecstasy is not as likely as some other drugs to cause physical or psychological dependence, it nonetheless can lead to some dependence. What’s more, the impurities sometimes found in street pills are also dangerous (Parrott, 2001). Ecstasy’s potentially toxic effect on serotonin neurons in the human brain is under debate, although mounting evidence from animal and human studies suggests that sustained use is associated with damage to serotonergic neurons and potentially associated problems with mood, attention and memory, and impulse control (Cox et al., 2014; Urban et al., 2012).

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Cocaine is derived from leaves of the coca plant, which has been cultivated by indigenous peoples of the Andes for millennia and chewed as a medication. Yes, the urban legend is true: Coca-Cola contained cocaine until 1903 and still may use coca leaves (with cocaine removed) as a flavoring—although the company’s not telling (Pepsi-Cola never contained cocaine and is probably made from something brown). Sigmund Freud tried cocaine and wrote effusively about it for a while. Cocaine (usually snorted) and crack cocaine (smoked) produce exhilaration and euphoria and are seriously addictive, both for humans and the rats you read about earlier in this chapter. Withdrawal takes the form of an unpleasant crash, and dangerous side effects of cocaine use include both psychological problems such as insomnia, depression, aggression, and paranoia, as well as physical problems such as death from a heart attack or hyperthermia (Marzuk et al., 1998). Although cocaine has enjoyed popularity as a party drug, its extraordinary potential to create dependence and potentially lethal side effects should be taken very seriously.

Nicotine is something of a puzzle. This is a drug with almost nothing to recommend it to the newcomer. It usually involves inhaling smoke that doesn’t smell that great, and there’s not much in the way of a high either—at best, some dizziness or a queasy feeling. So why do people do it? Tobacco use is motivated far more by the unpleasantness of quitting than by the pleasantness of using. The positive effects people report from smoking—relaxation and improved concentration, for example—come chiefly from relief from withdrawal symptoms (Baker, Brandon, & Chassin, 2004). The best approach to nicotine is to never get started.

Narcotics

Opium, which comes from poppy seeds, and its derivatives heroin, morphine, methadone, and codeine (as well as prescription drugs such as Demerol and Oxycontin), are known as narcotics (or opiates), highly addictive drugs derived from opium that relieve pain. Narcotics induce a feeling of well-being and relaxation that is enjoyable but can also induce stupor and lethargy. The addictive properties of narcotics are powerful, and long-term use produces both tolerance and dependence. Because these drugs are often administered with hypodermic syringes, they also introduce the danger of diseases such as HIV when users share syringes. Unfortunately, these drugs are especially alluring because they mimic the brain’s own internal relaxation and well-being system.

The brain produces endogenous opioids or endorphins, which are neurotransmitters closely related to opiates. As you learned in the Neuroscience & Behavior chapter, endorphins play a role in how the brain copes internally with pain and stress. These substances reduce the experience of pain naturally. When you exercise for a while and start to feel your muscles burning, for example, you may also find that there comes a time when the pain eases—sometimes even during exercise. Endorphins are secreted in the pituitary gland and other brain sites as response to injury or exertion, creating a kind of natural remedy (like the so-called runner’s high) that subsequently reduces pain and increases feelings of well-being. When people use narcotics, the brain’s endorphin receptors are artificially flooded, however, reducing receptor effectiveness and possibly also depressing the production of endorphins. When external administration of narcotics stops, withdrawal symptoms are likely to occur.

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The drugs that produce the most extreme alterations of consciousness are the hallucinogens, drugs that alter sensation and perception and that often cause visual and auditory hallucinations. These include LSD (lysergic acid diethylamide, or acid), mescaline, psilocybin, PCP (phencyclidine), and ketamine (an animal anesthetic). Some of these drugs are derived from plants (mescaline from peyote cactus, psilocybin or “shrooms” from mushrooms) and have been used by people since ancient times. For example, the ingestion of peyote plays a prominent role in some Native American religious practices. The other hallucinogens are largely synthetic.

These drugs produce profound changes in perception. Sensations may seem unusually intense, stationary objects may seem to move or change, patterns or colors may appear, and these perceptions may be accompanied by exaggerated emotions ranging from blissful transcendence to abject terror. These are the “I’ve-become-the-legs-of-a-chair!” drugs. But the effects of hallucinogens are dramatic and unpredictable, creating a psychological roller-coaster ride that some people find intriguing and others find deeply disturbing. Hallucinogens are the main class of drugs that animals won’t work to self-administer, so it is not surprising that in humans, these drugs are unlikely to be addictive. Hallucinogens do not induce significant tolerance or dependence, and overdose deaths are rare. Although hallucinogens still enjoy a marginal popularity with people interested in experimenting with their perceptions, they have been more a cultural trend than a dangerous attraction.

Marijuana

Marijuana (or cannabis) is a plant whose leaves and buds contain a psychoactive drug called tetrahydrocannabinol (THC). When smoked or eaten, either as is or in concentrated form as hashish, this drug produces an intoxication that is mildly hallucinogenic. Users describe the experience as euphoric, with heightened senses of sight and sound and the perception of a rush of ideas. Marijuana affects judgment and short-term memory, and it impairs motor skills and coordination—making driving a car or operating heavy equipment a poor choice during its use (“Dude, where’s my bulldozer?”). Researchers have found that receptors in the brain that respond to THC (Stephens, 1999) are normally activated by a neurotransmitter called anandamide that is naturally produced in the brain (Wiley, 1999). Anandamide is involved in the regulation of mood, memory, appetite, and pain perception and has been found temporarily to stimulate overeating in laboratory animals, much as marijuana does in humans (Williams & Kirkham, 1999). Some chemicals found in dark chocolate also mimic anandamide, although very weakly, perhaps accounting for the well-being some people claim they enjoy after a “dose” of chocolate.

The addiction potential of marijuana is not strong, as tolerance does not seem to develop, and physical withdrawal symptoms are minimal. Psychological dependence is possible, however, and some people do become chronic users. Marijuana use has been widespread around the world throughout recorded history, both as a medicine for pain and/or nausea and as a recreational drug, but its use remains controversial. Marijuana abuse and dependence have been linked with increased risk of depression, anxiety, and other forms of psychopathology. Many people also are concerned that marijuana (along with alcohol and tobacco) is a gateway drug, a drug whose use increases the risk of the subsequent use of more harmful drugs. The gateway theory has gained mixed support, with recent studies challenging this theory and suggesting that early-onset drug use in general, regardless of type of drug, increases the risk of later drug problems (Degenhardt et al., 2010). Despite the federal laws against the use of marijuana, approximately 42% of adults in the United States reported using it at some point in their lives—a rate much higher than that observed in most other countries (Degenhardt et al., 2008). Perhaps due to the perceived acceptability of marijuana among the general public, several states recently have taken steps to permit the sale of marijuana for medical purposes and decriminalize possession of marijuana (so violators pay a fine rather than go to jail). Two states, Colorado and Washington, have legalized its sale and possession for recreational purposes. The debate about the legal status of marijuana will likely take years to resolve. In the meantime, depending on where you live, the greatest risk of marijuana use may be incarceration (see The Real World: Drugs and the Regulation of Consciousness).

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