placebo

Examples of placebo in the following topics:

• The Clofibrate Trial

  • Placebos are most commonly used in blinded trials, where subjects do not know whether they are receiving real or placebo treatment.
  • The purpose of the placebo group is to account for the placebo effect -- that is, effects from treatment that do not depend on the treatment itself.
  • Those in the placebo group who adhered to the placebo treatment (took the placebo regularly as instructed) showed nearly half the mortality rate as those who were not adherent.
  • This apparent placebo effect may have occurred because:
  • Adhering to the protocol had a psychological effect, i.e. genuine placebo effect.

• Exercises

  • In the ADHD case study, transform the data in the placebo condition (D0) with λ's of .5, 0, -.5, and -1.

• Introducing observational studies and experiments

  • For example, each heart attack patient in the drug trial could be randomly assigned, perhaps by flipping a coin, into one of two groups: the first group receives a placebo (fake treatment) and the second group receives the drug.
  • See the case study inSection 1.1 for another example of an experiment, though that study did not employ a placebo.

• Experiments exercises

  • A quarter of the patients were assigned a placebo, and the rest were evenly divided between 1g Vitamin C, 3g Vitamin C, or 3g Vitamin C plus additives to be taken at onset of a cold for the following two days.
  • No significant differences were observed in any measure of cold duration or severity between the four medication groups, and the placebo group had the shortest duration of symptoms.
  • One group was given 25 grams of chia seeds twice a day, and the other was given a placebo.
  • Explanatory: Treatment, with 4 levels: placebo, 1g, 3g, 3g with additives.
  • However, we must consider that a placebo effect is possible.

• Case study exercises

  • To determine whether acupuncture relieves migraine pain, researchers conducted a randomized controlled study where 89 females diagnosed with migraine headaches were randomly assigned to one of two groups: treatment or control.43 patients in the treatment group received acupuncture that is specifically designed to treat migraines. 46 patients in the control group received placebo acupuncture (needle insertion at non-acupoint locations).
  • Study participants received either a 10-day course of amoxicillin (an antibiotic) or a placebo similar in appearance and taste.
  • The placebo consisted of symptomatic treatments such as acetaminophen, nasal decongestants, etc.

• Case Studies

• Exercises

  • A study comparing a drug with a placebo on the amount of pain relief.

• The Salk Vaccine Field Trial

  • The Salk polio vaccine field trial incorporated a double blind placebo control methodolgy to determine the effectiveness of the vaccine.
  • By the conclusion of the study, roughly 440,000 received one or more injections of the vaccine, about 210,000 children received a placebo, consisting of harmless culture media, and 1.2 million children received no vaccination and served as a control group, who would then be observed to see if any contracted polio.

• Difference Between Two Means

  • These researchers found that, compared to a placebo, this drug increased total sleep duration by a mean of 61.8 minutes.
  • For example, if in the Holbrook et al. study the mean total sleep time for the placebo group were 120 minutes, then the 61.8-minute increase would represent a 51% increase in sleep time.
  • On the other hand, if the mean sleep time for the placebo were 420 minutes, then the 61.8-minute increase would represent a 15% increase in sleep time.

• Using Two Samples

  • Typically, one group is given aspirin and the other group is given a placebo.