Prepared by Jeffrey W. Grimm Western Washington University PowerPoint Presentation for Biopsychology, 9th Edition by John P.J. Pinel Prepared by Jeffrey W. Grimm Western Washington University This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or in part, of any images; any rental, lease, or lending of the program. COPYRIGHT © 2014 PEARSON EDUCATION, INC. ALL RIGHTS RESERVED.

Chemicals That Harm with Pleasure Chapter 15 Drug Addiction and the Brain’s Reward Circuits Chemicals That Harm with Pleasure Copyright © 2014 Pearson Education, Inc. All rights reserved.

Basic Principles of Drug Action Psychoactive drugs: drugs that influence subjective experience and behavior by acting on the nervous system Drug administration: route of administration influences the rate at which and the degree to which the drug reaches its site of action. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Drug Administration and Absorption Ingestion: oral route Easy and relatively safe Absorption via digestive tract is unpredictable. Injection: bypasses digestive tract Subcutaneously (SC): under the skin Intramuscular: into large muscles Intravenously (IV): into veins; drug delivered directly to brain Inhalation: Tobacco and Marijuana Absorbed through capillaries in lungs Absorption through Mucous Membranes Nose, mouth, rectum Copyright © 2014 Pearson Education, Inc. All rights reserved.

Mechanisms of Drug Action In order for a psychoactive drug to have an effect, it must get to the brain; it must pass through the blood–brain barrier. The actions of most drugs are terminated by enzymes in the liver: drug metabolism. Small amounts may also be excreted in urine, sweat, feces, breath, and mother’s milk. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Copyright © 2014 Pearson Education, Inc. Drug Tolerance Drug tolerance is decreased sensitivity to a drug as a consequence of exposure to it. Cross tolerance: exposure to one drug can produce tolerance to similar drugs. Example: alcohol and benzodiazepines Tolerance often develops to some effects and not others. Functional Decreased responsiveness at the site of action, fewer receptors, decreased efficiency of binding at receptors, receptors less responsive Copyright © 2014 Pearson Education, Inc. All rights reserved.

Drug Withdrawal Effects and Physical Dependence Seen When Drug Use Is Terminated Withdrawal symptoms are the opposite of the drug’s effects. The body has made changes to compensate for the drug’s presence and functions normally with the drug present. Severity of withdrawal varies according to the drug and the pattern of use. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Copyright © 2014 Pearson Education, Inc. Addiction: What Is It? “Addicts” are those who continue to use a drug despite its adverse effects on health and social life. Addiction and physical dependence may occur together or separately. After withdrawal symptoms due to physical dependence have subsided, addicts may still crave the drug. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Five Commonly Abused Drugs Tobacco Alcohol Marijuana Cocaine Opiates Copyright © 2014 Pearson Education, Inc. All rights reserved.

Copyright © 2014 Pearson Education, Inc. Tobacco Nicotine: tobacco’s major psychoactive ingredient About 70 percent of those who experiment with smoking become addicted. Only about 20 percent of attempts to quit are successful. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Effects of Long-Term Tobacco Use Smoker’s syndrome: chest pain, labored breathing, wheezing, coughing, increased susceptibility to respiratory infections Smokers are susceptible to various lethal lung disorders: pneumonia, bronchitis, emphysema, and lung cancer. Quitting smoking typically results in major health benefits. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Copyright © 2014 Pearson Education, Inc. Alcohol A Depressant Heritability estimate for alcohol addiction is about 50 percent. Metabolic and functional tolerance develops. Alcohol affects almost every tissue in the body. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Effects of Chronic Alcohol Consumption Severe Withdrawal in Three Phases 5–6 hours after quitting drinking: tremors, nausea, sweating, vomiting, etc. 15–30 hours after quitting drinking: convulsive activity 24–48 hours after quitting drinking: delirium tremens; this may last 3–4 days. Korsakoff’s Syndrome Cirrhosis Fetal alcohol syndrome affects children of mothers who are heavy alcohol users during pregnancy. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Copyright © 2014 Pearson Education, Inc. Marijuana Cannabis sativa: common hemp plant THC is marijuana’s primary psychoactive constituent, although over 80 others are present. Endogenous transmitter is anandamide. High doses impair short-term memory and interfere with tasks involving multiple steps. Addiction potential is low. Negative effects of long-term use are far less severe than those associated with alcohol and tobacco. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Adverse Effects of Heavy Marijuana Use Respiratory Problems Such as Cough, Bronchitis, Asthma Single large doses can trigger heart attacks in susceptible individuals. There is no evidence that marijuana causes permanent brain damage. There is a possible correlation between marijuana use and schizophrenia, but no causal link has been shown. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Medicinal Uses of Marijuana Treats Nausea Blocks Seizures Dilates Bronchioles of Asthmatics Decreases Severity of Glaucoma Reduces Some Forms of Pain Copyright © 2014 Pearson Education, Inc. All rights reserved.

Cocaine and Other Stimulants Stimulants increase neural and behavioral activity. Cocaine and its derivatives are commonly abused. Crack is a potent, cheap, and smokeable form of cocaine. Cocaine is an effective local anesthetic. Synthetic analogues procaine and lidocaine are used today. Cocaine binges or sprees may lead to cocaine psychosis. Looks like paranoid schizophrenia While tolerance may develop to some effects of cocaine, sensitization is seen to motor and convulsive effects. Although cocaine is highly addictive, withdrawal is relatively mild. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Copyright © 2014 Pearson Education, Inc. Other Stimulants Amphetamine (“Speed”) Effects like cocaine; can produce psychosis MDMA (“Ecstasy”) Impairs dopaminergic and serotonergic function in animal studies; human relevance unclear Impairs executive function, inhibitory control, and decision making (as shown by cortex and limbic functional brain scan abnormalities) Copyright © 2014 Pearson Education, Inc. All rights reserved.

Opiates: Heroin and Morphine Morphine and codeine are obtained from the opium poppy. Opiates: these drugs and others with similar structures or effects Medicinal Uses Analgesics (painkillers) Treatment of cough and diarrhea High Risk of Addiction Copyright © 2014 Pearson Education, Inc. All rights reserved.

Copyright © 2014 Pearson Education, Inc. Opiate Addiction Addicts are drawn to use by the rush following IV injection. Tolerance and physical dependence develop. The desire to avoid withdrawal adds to an addict’s motivation to use. Although opiates are highly addictive, direct health hazards are relatively minor. There are many health hazards related to the use of needles. The severity of opiate withdrawal has been exaggerated. Copyright © 2014 Pearson Education, Inc. All rights reserved.

Treatment for Heroin Addiction Methadone binds to opiate receptors. Produces less pleasure Administered orally Prevents withdrawal Buprenorphine: similar to methadone but longer lasting Substituting a Less Dangerous Drug for the Abused Drug Copyright © 2014 Pearson Education, Inc. All rights reserved.

Copyright © 2014 Pearson Education, Inc. Comparison of the Hazards of Tobacco, Alcohol, Marijuana, Cocaine, and Heroin Alcohol and tobacco are associated with the greatest negative impact on public health. Copyright © 2014 Pearson Education, Inc. All rights reserved.