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5.2: Altering Consciousness With Psychoactive Drugs

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    Learning Objectives

    1. Summarize the major psychoactive drugs and their influences on consciousness and behavior.
    2. Review the evidence regarding the dangers of recreational drugs.

    A psychoactive drug is a chemical that changes our states of consciousness, and particularly our perceptions and moods. These drugs are commonly found in everyday foods and beverages, including chocolate, coffee, and soft drinks, as well as in alcohol and in over-the-counter drugs, such as aspirin, Tylenol, and cold and cough medication. Psychoactive drugs are also frequently prescribed as sleeping pills, tranquilizers, and antianxiety medications, and they may be taken, illegally, for recreational purposes. As you can see in Table 5.1 “Psychoactive Drugs by Class”, the four primary classes of psychoactive drugs are stimulants, depressants, opioids, and hallucinogens.

    Psychoactive drugs affect consciousness by influencing how neurotransmitters operate at the synapses of the central nervous system (CNS). Some psychoactive drugs are agonists, which mimic the operation of a neurotransmitter; some are antagonists, which block the action of a neurotransmitter; and some work by blocking the reuptake of neurotransmitters at the synapse.

    Table 5.1 Psychoactive Drugs by Class

    Mechanism Symptoms Drug Dangers and side effects Psychological dependence Physical dependence Addiction potential
    Stimulants
    Stimulants block the reuptake of dopamine, norepinephrine, and serotonin in the synapses of the CNS. Enhanced mood and increased energy Caffeine May create dependence Low Low Low
    Nicotine Has major negative health effects if smoked or chewed High High High
    Cocaine Decreased appetite, headache Low Low Moderate
    Amphetamines Possible dependence, accompanied by severe “crash” with depression as drug effects wear off, particularly if smoked or injected Moderate Low Moderate to high
    Depressants
    Depressants change consciousness by increasing the production of the neurotransmitter GABA and decreasing the production of the neurotransmitter acetylcholine, usually at the level of the thalamus and the reticular formation. Calming effects, sleep, pain relief, slowed heart rate and respiration Alcohol Impaired judgment, loss of coordination, dizziness, nausea, and eventually a loss of consciousness Moderate Moderate Moderate
    Barbiturates and benzodiazepines Sluggishness, slowed speech, drowsiness, in severe cases, coma or death Moderate Moderate Moderate
    Toxic inhalants Brain damage and death High High High
    Opioids
    The chemical makeup of opioids is similar to the endorphins, the neurotransmitters that serve as the body’s “natural pain reducers.” Slowing of many body functions, constipation, respiratory and cardiac depression, and the rapid development of tolerance Opium Side effects include nausea, vomiting, tolerance, and addiction. Moderate Moderate Moderate
    Morphine Restlessness, irritability, headache and body aches, tremors, nausea, vomiting, and severe abdominal pain High Moderate Moderate
    Heroin All side effects of morphine but about twice as addictive as morphine High Moderate High
    Hallucinogens
    The chemical compositions of the hallucinogens are similar to the neurotransmitters serotonin and epinephrine, and they act primarily by mimicking them. Altered consciousness; hallucinations Marijuana Mild intoxication; enhanced perception Low Low Low
    LSD, mescaline, PCP, and peyote Hallucinations; enhanced perception Low Low Low

    In some cases the effects of psychoactive drugs mimic other naturally occurring states of consciousness. For instance, sleeping pills are prescribed to create drowsiness, and benzodiazepines are prescribed to create a state of relaxation. In other cases psychoactive drugs are taken for recreational purposes with the goal of creating states of consciousness that are pleasurable or that help us escape our normal consciousness.

    The use of psychoactive drugs, and especially those that are used illegally, has the potential to create very negative side effects (Table 5.1 “Psychoactive Drugs by Class”). This does not mean that all drugs are dangerous, but rather that all drugs can be dangerous, particularly if they are used regularly over long periods of time. Psychoactive drugs create negative effects not so much through their initial use but through the continued use, accompanied by increasing doses, that ultimately may lead to drug abuse.

    The problem is that many drugs create tolerance: an increase in the dose required to produce the same effect, which makes it necessary for the user to increase the dosage or the number of times per day that the drug is taken. As the use of the drug increases, the user may develop a dependence, defined as a need to use a drug or other substance regularly. Dependence can be psychological, in which the drug is desired and has become part of the everyday life of the user, but no serious physical effects result if the drug is not obtained; or physical, in which serious physical and mental effects appear when the drug is withdrawn. Cigarette smokers who try to quit, for example, experience physical withdrawal symptoms, such as becoming tired and irritable, as well as extreme psychological cravings to enjoy a cigarette in particular situations, such as after a meal or when they are with friends.

    Users may wish to stop using the drug, but when they reduce their dosage they experience withdrawalnegative experiences that accompany reducing or stopping drug use, including physical pain and other symptoms. When the user powerfully craves the drug and is driven to seek it out, over and over again, no matter what the physical, social, financial, and legal cost, we say that he or she has developed an addiction to the drug.

    It is a common belief that addiction is an overwhelming, irresistibly powerful force, and that withdrawal from drugs is always an unbearably painful experience. But the reality is more complicated and in many cases less extreme. For one, even drugs that we do not generally think of as being addictive, such as caffeine, nicotine, and alcohol, can be very difficult to quit using, at least for some people. On the other hand, drugs that are normally associated with addiction, including amphetamines, cocaine, and heroin, do not immediately create addiction in their users. Even for a highly addictive drug like cocaine, only about 15% of users become addicted (Robinson & Berridge, 2003; Wagner & Anthony, 2002). Furthermore, the rate of addiction is lower for those who are taking drugs for medical reasons than for those who are using drugs recreationally. Patients who have become physically dependent on morphine administered during the course of medical treatment for a painful injury or disease are able to be rapidly weaned off the drug afterward, without becoming addicts. Robins, Davis, and Goodwin (1974) found that the majority of soldiers who had become addicted to morphine while overseas were quickly able to stop using after returning home.

    This does not mean that using recreational drugs is not dangerous. For people who do become addicted to drugs, the success rate of recovery is low. These drugs are generally illegal and carry with them potential criminal consequences if one is caught and arrested. Drugs that are smoked may produce throat and lung cancers and other problems. Snorting (“sniffing”) drugs can lead to a loss of the sense of smell, nosebleeds, difficulty in swallowing, hoarseness, and chronic runny nose. Injecting drugs intravenously carries with it the risk of contracting infections such as hepatitis and HIV. Furthermore, the quality and contents of illegal drugs are generally unknown, and the doses can vary substantially from purchase to purchase. The drugs may also contain toxic chemicals.

    Another problem is the unintended consequences of combining drugs, which can produce serious side effects. Combining drugs is dangerous because their combined effects on the CNS can increase dramatically and can lead to accidental or even deliberate overdoses. For instance, ingesting alcohol or benzodiazepines along with the usual dose of heroin is a frequent cause of overdose deaths in opiate addicts, and combining alcohol and cocaine can have a dangerous impact on the cardiovascular system (McCance-Katz, Kosten, & Jatlow, 1998).

    Although all recreational drugs are dangerous, some can be more deadly than others. One way to determine how dangerous recreational drugs are is to calculate a safety ratio, based on the dose that is likely to be fatal divided by the normal dose needed to feel the effects of the drug. Drugs with lower ratios are more dangerous because the difference between the normal and the lethal dose is small. For instance, heroin has a safety ratio of 6 because the average fatal dose is only 6 times greater than the average effective dose. On the other hand, marijuana has a safety ratio of 1,000. This is not to say that smoking marijuana cannot be deadly, but it is much less likely to be deadly than is heroin. The safety ratios of common recreational drugs are shown in Table 5.2 “Popular Recreational Drugs and Their Safety Ratios”.

    Table 5.2 Popular Recreational Drugs and Their Safety Ratios

    Drug Description Street or brand names Safety ratio
    Heroin Strong depressant Smack, junk, H 6
    GHB (Gamma hydroxy butyrate) “Rave” drug (not Ecstacy), also used as a “date rape” drug. Georgia home boy, liquid ecstasy, liquid X, liquid G, fantasy 8
    Isobutyl nitrite Depressant and toxic inhalant Poppers, rush, locker room 8
    Alcohol Active compound is ethanol 10
    DXM (Dextromethorphan) Active ingredient in over-the-counter cold and cough medicines 10
    Methamphetamine May be injected or smoked Meth, crank 10
    Cocaine May be inhaled or smoked Crack, coke, rock, blue 15
    MDMA (methylene­dioxymetham­phetamine) Very powerful stimulant Ecstasy 16
    Codeine Depressant 20
    Methadone Opioid 20
    Mescaline Hallucinogen 24
    Benzodiazepine Prescription tranquilizer Centrax, Dalmane, Doral, Halcion, Librium, ProSom, Restoril, Xanax, Valium 30
    Ketamine Prescription anesthetic Ketanest, Ketaset, Ketalar 40
    DMT (Dimethyl­tryptamine) Hallucinogen 50
    Phenobarbital Usually prescribed as a sleeping pill Luminal (Phenobarbital), Mebaraland, Nembutal, Seconal, Sombulex 50
    Prozac Antidepressant 100
    Nitrous oxide Often inhaled from whipped cream dispensers Laughing gas 150
    Lysergic acid diethylamide (LSD) Acid 1,000
    Marijuana (Cannabis) Active ingredient is THC Pot, spliff, weed 1,000
    Drugs with lower safety ratios have a greater risk of brain damage and death.

    Gable, R. (2004). Comparison of acute lethal toxicity of commonly abused psychoactive substances. Addiction, 99(6), 686–696.