1 / 33

Why We Respond to Placebos: Psychological Mechanisms of the Placebo Effect

Why We Respond to Placebos: Psychological Mechanisms of the Placebo Effect. Prof. Irving Kirsch University of Hull. Hypotheses. Global mechanisms Anxiety reduction Faith and hope Positive emotion Therapeutic relationship Local mechanisms Classical conditioning Response expectancy.

randi
Download Presentation

Why We Respond to Placebos: Psychological Mechanisms of the Placebo Effect

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Why We Respond to Placebos:Psychological Mechanisms of the Placebo Effect Prof. Irving Kirsch University of Hull

  2. Hypotheses • Global mechanisms • Anxiety reduction • Faith and hope • Positive emotion • Therapeutic relationship • Local mechanisms • Classical conditioning • Response expectancy

  3. Origins of the Global Hypothesis Depression Anxiety Stress Health Inferences to Positive Emotions

  4. Correlates of Positive Emotions • Longevity • Healthy Adults • AIDS patients • Immune function • Risk of cold • NK cell cytotoxicity

  5. Inducing Positive Emotions • Satisfaction with psychotherapy • Compassionate touch (Alagna et al., 1979) • Recovery from surgery • A Room with a View (Ulrich, 1984) • Cardiovascular recovery from stressor • Emotional content of film (Fredrickson & Levenson, 1998)

  6. Augmenting the Placebo Effect(Kaptchuk et al., 2008) • Irritable Bowel Syndrome • Wait list • Placebo • 10 minute neutral 1st session • Augmented Placebo • 45 minute 1st session • Warmth and Empathy • Positive expectation

  7. Symptom Severity

  8. Quality of Life

  9. Local Mechanisms Simultaneous vs. Sequential Administration Montgomery & Kirsch (1996)

  10. Effect blocked by naloxone(Benedetti et al., 1999)

  11. Global mechanisms • Anxiety reduction • Faith and hope • Positive emotion • Therapeutic relationship • Endorphin release • Local mechanisms • Classical conditioning • Response expectancy

  12. Local Mechanisms: Expectancy Conditioning and vs.

  13. Conditioning Model of Placebo Effects Active Treatment (US) Improvement (UR) (CR) Vehicle (pill, capsule, etc.) (CS)

  14. Conditioned Enhancement of Placebo Analgesia(Voudouris et al., 1985; 1989; 1990) Pain stimulus Pain Less Pain Before conditioning Placebo cream

  15. Conditioning Trials(Voudouris et al., 1985; 1989; 1990) Surreptitiously lowered stimulus intensity Even less pain Placebo cream

  16. Old Classical Conditioning Theory(The Stimulus Substitution Model) Conditioning trials Rescorla, R. A. (1988). Pavlovianconditioning: It's not what you think it is. American Psychologist Conditioned response

  17. Contemporary Conditioning Theory(Rescora, 1988) Conditioning trials Other sources of information Representation of US (Expectancy) Response

  18. Blocking the Conditioned Augmentation Effect(Montgomery & Kirsch, 1997; also see Watson et al., 2007)

  19. Conditioned enhancement of the placebo effect(Montgomery & Kirsch, 1997)

  20. Correlation between Expectancy and Pain: r = .70

  21. Pain Reduction with Expectancy Controlled(Montgomery & Kirsch, 1997)

  22. Why Placebo Analgesia Cannot be an Automatic Conditioning Effect • Humans • Placebo effects mimic drug effects • Placebo morphine lowers pain • Laboratory animals • Morphine CR: increased pain • Chlorpromazine CR: increased activity • Conditioned compensatory responses (Siegel, 1983; Siegel et al., 2000)

  23. A Two-Factor Theory of Placebo Effects Therapeutic Relationship Positive Emotion Other Contextual Factors Placebo Effect Conditioning Response Expectancy Other information sources

  24. A Two-Factor Theory of Placebo Effects Therapeutic Relationship Positive Emotion - depression - anxiety Other Contextual Factors Other Placebo Effects - pain alertness Conditioning Response Expectancy Other information sources

  25. Antidepressants as Active Placebos

  26. Individual Differences The Search for the Placebo Responder

  27. Ibuprofen and Trivaricaine

  28. The pain stimulus

  29. Session1 First trial Ibuprofen None Second trial None Trivaricaine

  30. Session 2 (exactly the same) First trial Ibuprofen None Second trial None Trivaricaine

  31. Consistency of the Placebo Effect

  32. Personality Correlates • Experimental settings • Dispositional pessimism predicts the nocebo effect (Geers et al., 2004) • Clinical settings • Responding to “enhanced” placebo associated with • extraversion • low neuroticism • openness to experience • (Kelley et al., under review)

  33. A Two-Factor Theory of Placebo Effects Therapeutic relationship Positive Emotion Other Contextual Factors Placebo Effect Personality? Conditioning Response expectancy Other information sources

More Related