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Presentation On Placebo Effect

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Published in: Biology | Pharma Training | Zoology
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Have heard of placebo? Placebo is the effect of a treatment that arises from a patient’s expectations and response to the treatment, excluding the treatment’s specific action. Intresting..? So let's learn more about this.

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  1. THE PLACEBO EFFECT Presented by:- Tanuia
  2. Definition History Incidence Pshyconeumoimmunology Types Mechanism of action Factors influencing placebo response Application Ethics Human research protection guidelines Problems with placebo
  3. Introduction
  4. Definition The effect of a treatment that arises from a patient's expectations and response to the treatment, excluding the treatment's specific action o In medicine, it typically refers to a response observed after inert or inactive treatments
  5. N/A
  6. Moerman on Placebos Placebos do not cause anything because they're inert o It is the psychological/ emotional meaning that defines the response This response is elicited by far more than just inert Must think about active agents as well The meaning response goes beyond psychological effects and results in physiological changes as well
  7. Ader and Cohen Ader and Cohen suspect that immunosupression can be behaviorally induced O Investigate in rat paradigm CS: saccharin US: immunosuppressant Discovered suppression of immune system by nothing more than taste 9 7 6 5 4 3 2 PLACEBO NC us CONDITIONED Fig. 2. Hemagglutination titers (means SE) ob- tained 6 days after ip injection of antigen (SRBC). NC nonconditioned animals pro- vided With saccharin on Day 3 or Day 6; CSO conditioned animals that did not receive saccharin following antigen treatment; CSI — conditioned animals given one exposure to saccharin on Day 3 or Day 6; CS2 conditioned animals exposed to saccharin on Days 3 and 6; US — conditioned animals in- jected with cyclophosphamide following treatment with antigen.
  8. Kiecolt Glaser (1 999): Immune Function Stress dysregulates NK cell activity and decreases g- interferon (IFN-g) O Prospective study w/ med students Stressed students have a suppressed immune response Prospective study found that relaxation enhances NK activity
  9. Castes, Hagel (1 999): Asthma Prospective study of children in Venezuela with asthma One g receives psychosocialintervention (PSI) Asthma attacks are PSI increases immune function as well Higher NK activity Higher T-cell activity O Improved surface markers 14 12 8 6 4 2 O AFTER PSI NAC Control Study Groups NAtC FIG. 3. Percentage of IL-2 receptor-bearing T cells (CD25+), expressed relative to total leukocytes, in the different study groups. In the PSI and control asthmatics. these are presented for the beginnmg and end of the 6-month study period. Companson values are also presented for a group of nonasthmatic Coche Island children (NAC) and nonatopic mainland children (NAtC).
  10. Kiecolt- Healing outcome Women experiencing the chronic stress of caregiving healed punch biopsy wounds 24% more slowly than did control subjects. Dental students healed standard mucosal punch biopsy wounds 40% more slowly during an exam period as compared to vacation. Married couples healed blister wounds more slowly after a conflictive 'interaction versus supportive marital interaction. Couples who were hostile during both sessions healed at 60% of the rate of low hostile couples, Mice exposed to restraint stress healed punch biopsy wounds 27% more slowly than did nonstressed micew (1 995): Mechanistic outcome PBLs from caregivers expressed less IL-lß in mRNA in response to LPS stimulation, Production of IL-1 by LPS-stimulated PBLs was reduced in every student during the exam period as compared to vacation. Decreased production of ILO IL-1 and TNF-Q was seen at the wound site following the conflict versus the supportive interaction. Stressed mice had reduced cellularity in the margins ofthe wounds and higher levels of serum corticosterone as compared to unstressed mice. Ref. 17 18 20 26 Wound Healing Prospective study of stress on wound healing C a reg ivers vs, controls D Both undergo biopsy wound Healing takes significantly longer in controls Differences in peripheral blood leukocytes
  11. Incidence
  12. 15 studies, carried out by Beecher (1955) involving 1082 patients, the average placebo response rate determined was 35.2% . When patients do not know they are receiving placebos, high as 70-82% Angina pectoris: the use of vitamin E,ligation of the internal mammary artery, were about 80% effective
  13. Back surgery : suggested by Spangfort's review of long-term outcomes of 2504 "diskectomies' for lumbar disk disease. ' Complete relief of back pain was noted in 43% of patients who had sham surgery done
  14. Psychoneuroimmunology
  15. Psychoneuroimmunology (PNI) Hard Of the placebo effect in complex pathologies Connections between mind, brain, and immune system Strives to find tangible linkage between mind/ body STRESS RESPONSE SYSTEM Hupothalamus CRH Pituitary gland Adrenal gland ACTH Medulla Brain stem To immune system
  16. Placebos Can, , , Constrict the pupils, alter blood pressure, change heart rate and respiration, influence gastrointestinal secretions and peristalsis, change body temperature, produce eosinophilia and leucocytosis, enhance corticosteroid reactions, and change blood levels of creatine and lipoproteins (Perry 1 981 ) Negatives: Cause dry mouth, nausea, heaviness, headache, difficulty concentrating, drowsiness, sleep disturbance
  17. N/A
  18. Placebo is of 2 types:- Inert or Pure placebos Substances that could have no conceivable pharmacologic effect on the patient. Examples : Dummy pills or capsules containing lactose or chalk Active or Impure placebo Have potential pha rmacological effects, though not necessarily any specific activity for the condition under treatment. Examples :vitamin B12 or iron in the absence of Antibiotics in viral infections
  19. Mechanism of action
  20. MECHANISM OF ACTION Conditioning reflex model Opioid model Expectancy model
  21. Conditioning reflex model Involuntary conditioned reflex of the patient's body Arachnoiditis pain , were relieved after they received intrathecal injections of novocaine. But actually injected with saline rather than novocaine
  22. Conditions like Physician Physical examination prescriptioon Procedure Places Information obtained by reading and remarks of other people Previous experience
  23. Expectancy model Aimed at preparing the body to anticipate an event to better cope with it For example, resuming a normal daily schedule, and negative expectations leading to its inhibition (bootzin, 1985;bandura, 1997). Effects of expectations modulated by Decrease in self-defeating thoughts. Motivation
  24. Opioid model Release of endogenous opiate : endorphins & enkephalins Field et all (1997) shown that placebo induced analgesia can be reversed by naloxone
  25. Interference placebo/ expectation effects and drug action, PRE-DELIVERY STEP 1 a DELIVERY STEP 2 Possible interaction drug and placebo/expectation effect Opioids CCKt-2 Dopamine D 3 Expectation EFFECT STEP 3 Effect ioids Pharmacodynamic CCK1-2 effect ine Drug Expectation b Eliminating placebo/expectation- activated mechanisms Expe ation CCK1-2 Dopamine b2tD Drug l/ Drua
  26. Factors influencing placebo
  27. Appearance of treatment procedures Patient characteristics relationship FACTORS INFLENCING PLACEBO Provider characteristics RESPONSE Environment
  28. APPLICATIONS
  29. Regression to mean Natural history of disease Specific effects of treatment Nonspecific effects Of Efficacy of treatment- treatment placebo
  30. Application in clinical trials Researcher compares the results of experimental placebo. treatment versus The placebo-controlled trial the gold standard for testing the efficacy of new treatments." Best evidence for new treatment come from randomized placebo-controlled (RCT) double-blind studies.
  31. 1. 2. 3. 4. 5. 6. 7. Placebo is used in clinical drug trials for the following reasons: Compare effects with those of the active drug Comparison of active drugs validated by a placebo Blind administration of two drugs that cannot be made indistinguishable (Double Dummy technique) Wihdrawal period Toxicity Placebo responders to be excluded Identify treatment non-compliers
  32. Ethics
  33. Ethical : use of placebos is essential to protect the society from the harm that could result from the widespread use of ineffective medical treatments. Unethical: Alternative study designs would produce similar results with less risk to individual research participants.
  34. Clinical equipoise in placebo-controlled trials state where clinicians are unsure whether the new treatment or intervention is as good as the standard treatment. Violation of the therapeutic obligation of physicians to offer optimal medical care. right of the patient to receive the best care possible is compromised .
  35. Human research protection guidelines
  36. The Office for Human Research Protection (OHRP) published guidelines in 2008 for the use of placebo "Placebos may be used in clinical trials where there is no known or available (i.e., FDA-approved) alternative therapy that can be tolerated by subjects." The use of placebos in controlled clinical trials must be justified by a positive risk-benefit analysis The subjects must be fully informed of the risks involved in the assignment to the placebo group. ' Continued assignment of subjects to placebo is unethical, once there is good evidence to support the efficacy of the trial therapy
  37. Problems assosciated with placebo
  38. 1. 2. 3. 4. Imperfect likeness Impure placebos Selecting placebo nonreactors Overestimation of placebo effects
  39. ??-???? ???

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