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Altering Consciousness With Psychoactive Drugs

16 February, 2016 - 09:24

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, 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 Psycho-logical depend-ence Physical dependence Addiction potential
Stimulants
Stimulants block the reuptake of dopamine, nore-pinephrine, 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
Amphe-tamines 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 neuro-transmitter GABA and decreasing the production of the neuro-transmitter 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
Barbi-turates and benzo-diazepines 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 neuro-transmitters 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 neuro-transmitters 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). 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 withdrawal—negative 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). 1 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) 2 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). 3

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.

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 (methylene-dioxymethamphetamine)

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

 

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