Pinel basics ch13

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Pinel basics ch13

  1. 1. Chapter 13 Health Psychology: Addiction, Emotion, and Stress Impact of Psychological Factors on Health <ul><li>This multimedia product and its contents are protected under copyright law. The following are prohibited by law: </li></ul><ul><li>any public performance or display, including transmission of any image over a network; </li></ul><ul><li>preparation of any derivative work, including the extraction, in whole or in part, of any images; </li></ul><ul><li>any rental, lease, or lending of the program. </li></ul>
  2. 2. Health Psychology <ul><li>An area of psychological research that focuses on the effects of psychological factors on physical health </li></ul><ul><li>Multidisciplinary </li></ul><ul><li>Two major areas addressed here – addiction and emotion </li></ul>
  3. 3. Drug Tolerance <ul><li>Decreased sensitivity to a drug as a consequence of exposure to it </li></ul><ul><ul><li>Shift in the dose-response curve </li></ul></ul><ul><li>Cross tolerance – exposure to one drug can produce tolerance to similar drugs </li></ul><ul><li>Tolerance often develops to some effects and not others </li></ul><ul><li>More than one form of tolerance </li></ul>
  4. 5. Drug Tolerance <ul><li>Metabolic </li></ul><ul><ul><li>Less drug is getting to the site of action </li></ul></ul><ul><li>Functional </li></ul><ul><ul><li>Decreased responsiveness at the site of action - fewer receptors, decreased efficiency of binding at receptors, receptors less responsive </li></ul></ul>
  5. 6. Physical Dependence <ul><li>Indicated by occurrence of withdrawal </li></ul><ul><ul><li>Seen when drug use is terminated </li></ul></ul><ul><ul><li>Symptoms are the opposite of the drug’s effects </li></ul></ul><ul><ul><li>Body has made changes to compensate for drug’s presence – functions normally with the drug present </li></ul></ul><ul><ul><li>Severity varies with drug and pattern of use </li></ul></ul>
  6. 8. Drug Tolerance and Conditioning <ul><li>Situational specificity of drug tolerance is well-documented </li></ul><ul><li>Cues associated with drug-taking become conditioned stimuli that elicit conditioned compensatory responses, producing tolerance prior to drug use or withdrawal in the absence of the drug </li></ul>
  7. 10. Addiction: What Is It? <ul><li>“Addicts” are those who continue to use a drug despite its adverse consequences </li></ul><ul><li>Nobody is immune to the addictive effects of drugs </li></ul>
  8. 11. Biological Theories of Addiction <ul><li>Physical-Dependence Theory – </li></ul><ul><ul><li>Use continues to avoid withdrawal </li></ul></ul><ul><ul><ul><li>Why relapse after detoxification? Why begin use? </li></ul></ul></ul><ul><ul><ul><li>Why does addiction develop to drugs that do not produce severe withdrawal? </li></ul></ul></ul><ul><li>Positive-Incentive Theories </li></ul><ul><ul><li>Use continues due to craving ( anticipated pleasure) for drug effects </li></ul></ul><ul><ul><li>Supported by research </li></ul></ul>
  9. 12. Causes of Relapse <ul><li>Stress </li></ul><ul><ul><li>Drug use as a coping mechanism </li></ul></ul><ul><li>Priming </li></ul><ul><ul><li>A single exposure leads to a relapse </li></ul></ul><ul><li>Environmental cues </li></ul>
  10. 13. 5 Commonly Abused Drugs <ul><li>Tobacco </li></ul><ul><li>Alcohol </li></ul><ul><li>Marijuana </li></ul><ul><li>Cocaine </li></ul><ul><li>Opiates </li></ul>
  11. 14. Tobacco <ul><li>Nicotine – major psychoactive ingredient </li></ul><ul><li>About 70% of those who experiment with smoking become addicted </li></ul><ul><li>Only about 20% of attempts to stop are successful </li></ul>
  12. 15. Effects of Long-Term Tobacco Use <ul><li>Smoker’s syndrome – chest pain, labored breathing, wheezing, coughing, increased susceptibility to respiratory infections </li></ul><ul><li>Susceptible to various lethal lung disorders – pneumonia, bronchitis, emphysema, lung cancer </li></ul>
  13. 16. Alcohol <ul><li>A depressant </li></ul><ul><li>High heritability estimate for alcohol addiction - ~55% </li></ul><ul><li>Metabolic and functional tolerance develops </li></ul><ul><li>Attacks almost every tissue in the body </li></ul>
  14. 17. Effects of Chronic Alcohol Consumption <ul><li>Severe withdrawal – 3 phases </li></ul><ul><ul><li>5-6 hrs post-drinking: tremors, nausea, sweating, vomiting, etc. </li></ul></ul><ul><ul><li>15-30 hrs: convulsive activity </li></ul></ul><ul><ul><li>24-48 hrs: delirium tremens – may last 3-4 days </li></ul></ul><ul><li>Korsakoff’s syndrome </li></ul><ul><li>Cirrhosis </li></ul>
  15. 18. Fetal Alcohol Syndrome (FAS) <ul><li>Alcohol readily penetrates the placental membrane </li></ul><ul><li>Alcohol disrupts brain development </li></ul><ul><li>No known “safe” amount </li></ul>
  16. 19. Marijuana <ul><li>Cannabis sativa – common hemp plant </li></ul><ul><li>THC – primary psychoactive constituent – although over 80 others are present </li></ul><ul><li>High doses impair short-term memory and interfere with tasks involving multiple steps </li></ul><ul><li>Addiction potential is low </li></ul><ul><li>Negative effects are far less severe than those associated with alcohol and tobacco </li></ul>
  17. 20. Adverse Effects of Heavy Marijuana Use <ul><li>Respiratory problems – cough, bronchitis, asthma </li></ul><ul><li>Single large doses can trigger heart attacks in susceptible individuals </li></ul><ul><li>No evidence that marijuana causes permanent brain damage </li></ul>
  18. 21. Medicinal Uses of Marijuana <ul><li>Treat nausea </li></ul><ul><li>Block seizures </li></ul><ul><li>Dilate bronchioles of asthmatics </li></ul><ul><li>Decrease severity of glaucoma </li></ul><ul><li>Reduce some forms of pain </li></ul>
  19. 22. THC <ul><li>Fat-soluble </li></ul><ul><li>Binds to receptors in basal ganglia, hippocampus, cerebellum, and neocortex </li></ul><ul><li>Endogenous ligand is anandamide </li></ul><ul><li>Function of anandamide is not known </li></ul>
  20. 23. Stimulants <ul><li>Increase neural and behavioral activity </li></ul><ul><li>Cocaine and its derivatives – commonly abused </li></ul><ul><li>Crack – a potent, cheap, and smokable form of cocaine </li></ul><ul><li>Cocaine is an effective local anesthetic </li></ul><ul><ul><li>Synthetic analogues procaine and lidocaine used today </li></ul></ul>
  21. 24. Cocaine <ul><li>Cocaine binges or sprees may lead to cocaine psychosis </li></ul><ul><ul><li>Looks like paranoid schizophrenia </li></ul></ul><ul><li>While tolerance may develop to some effects of cocaine, sensitization is seen to motor and convulsive effects </li></ul><ul><li>Although highly addictive, withdrawal is relatively minor </li></ul>
  22. 25. Amphetamine <ul><li>AKA “speed” – another abused stimulant </li></ul><ul><li>Effects are comparable to those of cocaine – also can produce psychosis </li></ul><ul><li>MDMA (ecstasy) – a relative of amphetamine </li></ul><ul><li>Evidence suggests that stimulants are neurotoxins </li></ul>
  23. 26. Ecstasy (MDMA) <ul><li>Studies of lab animals find that MDMA has toxic effects on serotonergic and dopaminergic neurons </li></ul><ul><li>But are the doses used in studies comparable to what humans use? </li></ul><ul><li>Human studies do find abnormalities of serotonergic function and deficits in memory, mood, and psychomotor tasks </li></ul>
  24. 27. Opiates: Heroin and Morphine <ul><li>Morphine and codeine obtained from the opium poppy </li></ul><ul><li>Opiates – these drugs and others with similar structures or effects </li></ul><ul><li>Medicinal uses </li></ul><ul><ul><li>Analgesics (painkillers) </li></ul></ul><ul><ul><li>Treatment of cough and diarrhea </li></ul></ul><ul><li>High risk of addiction </li></ul>
  25. 28. Factors Increasing Opiate Popularity <ul><li>China’s ban of tobacco smoking led to opium smoking </li></ul><ul><ul><li>More addicting than eating opium </li></ul></ul><ul><li>Isolation of morphine </li></ul><ul><ul><li>Opium’s most potent constituent </li></ul></ul><ul><li>The hypodermic needle </li></ul><ul><ul><li>During the Civil War morphine addiction came to be known as “soldiers’ disease” </li></ul></ul>
  26. 29. U.S. Opiate History <ul><li>Readily available in a variety of “potions” until 1914 </li></ul><ul><li>Harrison Narcotic Act (1914) </li></ul><ul><ul><li>Illegal to sell or use opium </li></ul></ul><ul><ul><li>Heroin, a synthetic opiate, was still legal </li></ul></ul><ul><ul><ul><li>Structure similar to morphine, but better able to cross the blood-brain barrier </li></ul></ul></ul><ul><ul><ul><li>More addictive </li></ul></ul></ul><ul><li>Heroin illegal as of 1924 </li></ul>
  27. 30. Opiate Addiction <ul><li>Drawn to use by the rush following IV injection </li></ul><ul><li>Tolerance and physical dependence develop </li></ul><ul><li>Desire to avoid withdrawal adds to motivation to use </li></ul><ul><li>Although highly addictive, direct health hazards are relatively minor </li></ul><ul><li>Many health hazards related to use of needles </li></ul><ul><li>Severity of withdrawal has been exaggerated </li></ul>
  28. 32. Comparison of the Health Hazards <ul><li>Which drug is our biggest “drug problem”? </li></ul><ul><li>Which drug harms the individual the most? </li></ul><ul><li>Which drug harms society the most? </li></ul>
  29. 33. Addiction and the Neural Mechanisms of Motivation <ul><li>How has drug-produced reinforcement been studied in nonhumans? </li></ul><ul><ul><li>Drug self-administration </li></ul></ul><ul><ul><li>Conditioned place-preference </li></ul></ul>
  30. 34. Behavioral preference tests
  31. 35. Involvement of Dopamine in Drug Addiction <ul><li>Dopamine antagonists </li></ul><ul><ul><li>block self-administration of, or conditioned preference for addictive drugs </li></ul></ul><ul><ul><li>reduce reinforcing effects of food </li></ul></ul><ul><li>Dopamine might signal reward/pleasure </li></ul>
  32. 36. The Dopamine (DA) System <ul><li>Cell bodies of neurons composing the brain’s DA system are in two midbrain nuclei </li></ul><ul><ul><li>Substantia nigra </li></ul></ul><ul><ul><li>Ventral tegmental area </li></ul></ul><ul><li>Two mesotelencephalic DA pathways </li></ul><ul><ul><li>Projecting from the midbrain to areas in the telencephalon </li></ul></ul>
  33. 37. Mesotelencephalic Dopamine System <ul><li>Nigrostriatal pathway </li></ul><ul><ul><li>Substantia nigra > Dorsal striatum </li></ul></ul><ul><ul><li>Degeneration here seen in Parkinson’s </li></ul></ul><ul><li>Mesocorticolimbic pathway </li></ul><ul><ul><li>Ventral tegmental area (VTA) > cortical and limbic sites </li></ul></ul><ul><ul><li>Involved in reward – VTA > nucleus accumbens </li></ul></ul>
  34. 39. Evidence of Dopamine’s Role in Reinforcing Effects of Drugs <ul><li>Lab animals will press a level to self-administer addictive drugs to the nucleus accumbens </li></ul><ul><li>Lab animals will develop conditioned place preferences with microinjections of addictive drugs to the nucleus accumbens </li></ul><ul><li>Addicts only report a high when cocaine is effectively blocking DA reuptake, increasing extracellular dopamine </li></ul><ul><li>IV amphetamine study – euphoria reported correlated with DA levels in nucleus accumbens </li></ul>
  35. 40. Human Studies <ul><li>PET studies find that many addicts have reduced cerebral dopamine levels </li></ul><ul><li>Dopamine levels increase when addicts are exposed to their drug of choice </li></ul><ul><li>Dopamine may be involved in the expectation of reward, rather than its experience – a signal, perhaps </li></ul>
  36. 41. Expectation-of-reward Theory <ul><li>Dopamine neurons in monkey VTA – respond to unpredicted reward </li></ul><ul><li>An expected reward did not lead to a release of dopamine </li></ul><ul><li>A conditioned stimulus does lead to release of dopamine </li></ul><ul><li>Consistent with dopamine as a signal of a reward to come, as opposed to a response to a reward </li></ul>
  37. 42. Introduction of the Biopsychology of Emotion <ul><li>Phineas Gage provides an elegant demonstration of the brain’s role in emotion </li></ul><ul><li>Why would a tamping iron through the skull lead to dramatic changes in personality? </li></ul><ul><li>Damage to the medial prefrontal lobes </li></ul>
  38. 43. Darwin’s Theory of the Evolution of Emotional Expression <ul><li>Expressions of emotion evolve from behaviors that indicate what an animal is likely to do next </li></ul><ul><li>If emotional signals are beneficial, they will evolve to more effectively communicate and may lose their original meaning </li></ul>
  39. 44. Evolution of Emotional Expression <ul><li>Opposite messages are often signaled by opposite movements. “Principle of antithesis” </li></ul><ul><li>Threat displays, for example, are beneficial – intimidate victims without the costs and risks of fighting </li></ul>
  40. 45. Theories of Emotion <ul><li>James-Lange </li></ul><ul><ul><li>Stimulus > autonomic/skeletal response > emotion </li></ul></ul><ul><ul><li>Autonomic/skeletal response necessary for emotion </li></ul></ul><ul><li>Cannon-Bard </li></ul><ul><ul><li>Stimulus > autonomic/skeletal response & emotion </li></ul></ul><ul><ul><li>Autonomic/skeletal response independent of emotion </li></ul></ul><ul><li>Both of these extreme positions are wrong </li></ul>
  41. 46. <ul><li>Theories of Emotion </li></ul>
  42. 47. Bard – Sham Rage <ul><li>Decorticated cats exhibit extreme and unfocused aggressive responses </li></ul><ul><li>Hypothalamus must be intact </li></ul><ul><li>Perhaps hypothalamus is needed for expression of aggression and cortex serves to inhibit and direct responses </li></ul><ul><li>Papez proposed emotional circuit – limbic system, that includes hypothalamus </li></ul>
  43. 49. Kluver-Bucy Syndrome <ul><li>Rare cerebral neurological disorder </li></ul><ul><li>Major symptoms - urge to put objects into mouth, memory loss, extreme sexual behavior, placidity, visual distractibility </li></ul><ul><li>Bilateral temporal lobes </li></ul>
  44. 50. Stress and Health <ul><li>Stress – reaction to harm to threat </li></ul><ul><li>Stressors – stimuli that cause stress </li></ul><ul><li>Chronic psychological stress – most clearly linked to ill health </li></ul><ul><li>In the short-term stress is adaptive, in the long-term it is maladaptive </li></ul>
  45. 51. Selye and the Stress Response <ul><li>Activation of the anterior-pituitary adrenal-cortex system </li></ul><ul><li>Selye neglected the role of the sympathetic nervous system </li></ul><ul><li>All common psychological stressors are associated with high levels of glucocorticoids, epinephrine, and norepinephrine </li></ul>
  46. 52. Effects of Stress
  47. 53. Stress and Gastric Ulcers <ul><li>Gastric ulcers – lesions of stomach lining and duodenum </li></ul><ul><li>More common in those who are stressed and readily created in the lab </li></ul><ul><li>Ulcers are caused by a bacteria – but it appears that stress makes the body susceptible to this bacteria </li></ul><ul><li>75% of healthy subjects have the bacteria </li></ul>
  48. 54. Psychoneuroimmunology <ul><li>Study of the interaction of psychological factors, nervous system, and immune system </li></ul><ul><li>Antigens – cell proteins that identify them as native or foreign </li></ul><ul><li>Immune system protects with specific and nonspecific barriers </li></ul>
  49. 55. Immune System <ul><li>Nonspecific barriers </li></ul><ul><ul><li>Mucous membranes </li></ul></ul><ul><ul><li>Phagocytosis – consume and destroy foreign matter </li></ul></ul><ul><li>Specific barriers </li></ul><ul><ul><li>Cell-mediated (T lymphocytes) </li></ul></ul><ul><ul><li>Antibody-mediated (B lymphocytes) </li></ul></ul><ul><li>Lymphocytes – white blood cells </li></ul>
  50. 57. Stress and Immune Function <ul><li>If stress affects immune function, how might it do so? </li></ul><ul><li>Why is stress initially adaptive and then, when chronic, harmful? </li></ul>
  51. 58. Meta-Analysis of Stress Studies <ul><li>Effects of stress on immune function depend on the kind of stress </li></ul><ul><ul><li>Acute stressor improve immune function </li></ul></ul><ul><ul><li>Chronic stressor impair </li></ul></ul><ul><li>Many ways that stress could impact immune function </li></ul><ul><ul><li>Physiological </li></ul></ul><ul><ul><li>Behavioral </li></ul></ul>
  52. 59. Why might decreased immune function not cause an increase in disease? <ul><li>Redundancy exists in the immune system </li></ul><ul><li>Stress-produced immune changes in test subjects may be too short-lived to have any impact </li></ul><ul><li>Declines in some aspects of immune function may lead to compensatory increases in others </li></ul>
  53. 60. Early Experience of Stress <ul><li>Early exposure to stress may result in increased intensity of subsequent stress responses </li></ul><ul><li>While prenatal stress has a negative effects, early neonatal stress can have lasting positive effect – if the stress leads to increased maternal grooming </li></ul>
  54. 61. Stress and the Hippocampus <ul><li>Hippocampus has many glucocorticoid receptors </li></ul><ul><li>Following stress </li></ul><ul><ul><li>Dendrites of pyramidal cells are shorter and less branched </li></ul></ul><ul><ul><li>Adult neurogenesis of granule cells reduced </li></ul></ul><ul><li>Effects seen with only a few hours of stress </li></ul>
  55. 62. Brain Mechanisms of Emotion <ul><li>What can fear conditioning tell us about the brain’s role in emotion? </li></ul><ul><li>What does the amygdala do for us? </li></ul>
  56. 63. Fear Conditioning <ul><li>Auditory fear conditioning blocked with medial geniculate nucleus (MGN) lesions – not affected by auditory cortex lesions </li></ul><ul><li>Critical pathways: MGN to amygdala </li></ul><ul><li>Amygdala lesion blocks fear conditioning </li></ul>
  57. 64. Auditory Fear Conditioning
  58. 65. Contextual Fear Conditioning and the Hippocampus <ul><li>Just as fear of an auditory stimulus can be learned, so can fear of a place </li></ul><ul><li>Hippocampus involved </li></ul><ul><ul><li>Lesion before conditioning prevents development of contextual fear </li></ul></ul><ul><ul><li>Lesion after blocks retention of contextual fear response </li></ul></ul><ul><ul><li>Other fear responses intact </li></ul></ul>
  59. 66. Role of the Amygdala is Human Emotion <ul><li>Structure most frequently associated with emotion </li></ul><ul><ul><li>Kluver-Bucy syndrome </li></ul></ul><ul><ul><li>Study of those with amygdalar damage </li></ul></ul><ul><li>Damage > problems with recognition of facial expressions of fear </li></ul><ul><li>Urbach-Wiethe – bilateral amygdala damage > unable to identify fear </li></ul>
  60. 67. Emotion <ul><li>What unique challenges must be overcome in the study of emotion? </li></ul><ul><li>Why is it important to develop an understanding of the brain mechanisms that underlie emotion? </li></ul>

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