Professor Ted Kaptchuk and colleagues from Massachusetts, USA investigated whether placebo effects can experimentally be separated into 3 components.
The 3 components included assessment and observation ('waiting list patients'), a therapeutic ritual (placebo treatment), and a supportive patient-practitioner relationship.
The team progressively combined these 3 components to produce incremental clinical improvement in patients with irritable bowel syndrome.
|The global improvement scale score was 5 for the ‘augmented' treatment group|
|British Medical Journal|
The team assessed the relative magnitude of these components in 262 adults, with a mean age of 39 years.
The patients were diagnosed by Rome II criteria, and had a score of 150 on the symptom severity scale.
For 3 weeks, patients were either allocated to a waiting list (observation), or placebo acupuncture alone (the ‘limited‘ group).
A third group was given placebo acupuncture with a patient-practitioner relationship augmented by warmth, attention, and confidence (the ‘augmented‘ group).
At 3 weeks, half of the patients were randomly assigned to continue in their originally assigned group for an additional 3 weeks.
The team measured global improvement scale, adequate relief of symptoms, symptom severity score, and quality of life.
The researchers found that at 3 weeks, scores on the global improvement scale were 3.8, 4.3, and 5 for waiting list, ‘limited', and ‘augmented' treatment groups, respectively.
The proportion of patients reporting adequate relief showed a similar pattern.
The team noted that 28% on the waiting list, 44% in the limited group, and 62% in the augmented group reported adequate relief.
The researchers found the same trend in response existed in symptom severity score, and quality of life.
All pairwise comparisons between augmented and limited patient-practitioner relationship were significant.
Those with augmented patient-practitioner relationship showed improvements in the global improvement scale, adequate relief of symptoms, symptom severity score, and quality of life.
The research team observed that results were similar at 6 week follow-up.
Professor Kaptchuk's team concluded, "Factors contributing to the placebo effect can be progressively combined in a manner resembling a graded dose escalation of component parts."
"Non-specific effects can produce statistically and clinically significant outcomes and the patient-practitioner relationship is the most robust component."