placebo

What is the placebo effect?

A therapeutic effect from a treatment with no active ingredients for the condition; includes psychological and physiological effects.

What types of placebos tend to be more effective?

Injections, capsules, brand-name labels, hospital settings, enthusiastic providers, and positive physician expectations.

What did Graceley et al. (1985) find about physician expectations?

Patients’ pain reports varied depending on whether the physician expected the placebo injection to be strong or weak.

What are the theories of how placebos work?

Nature taking its course, regression to the mean, treatment process (attention and care), classical conditioning, expectations, and physiological changes.

What evidence supports physiological changes in Wager et al. (2004)?

Placebo treatment reduced pain reports and decreased activity in pain-related brain regions.

What did Bandura et al. (1987) show about placebo-related pain control?

Cognitive coping increased pain tolerance, but naloxone blocked the effect, showing endorphins as the mechanism.

What mechanism did Bandura et al. (1987) identify?

Endorphin release was responsible for increased pain tolerance.

How was the mechanism tested in Bandura et al. (1987)?

By comparing pain tolerance after naloxone versus saline injection in participants trained in cognitive coping.

What did Moseley et al. (2002) find?

Patients receiving sham arthroscopic knee surgery improved as much as those receiving real surgery.

What did Carvalho et al. (2016) find about open-label placebos?

Even when patients knew they were taking placebos, they reported reduced pain compared to controls.