Placebo

A placebo is a substance provided to a patient that the physician believes has no specific pharmacological effect on the condition being treated, and the patient believes the treatment will work. However, research shows that 82% of the response to antidepressants was accounted for by placebos. Yet, this important component of healing is not yet harnessed in clinical settings. Indeed, the placebo effect is considered a melting pot of ideas in neuroscience.

Whether treatment consists of an active drug or a placebo, the clinical setting that surrounds treatment includes multiple types of context information that are perceived and interpreted by the patient’s brain. The external context includes treatment, place and social cues, along with verbal suggestions. The internal context consists of memories, emotions, expectancies and appraisals of the meaning of the context for future survival and well-being. These features combine to make up the treatment context and are the ‘active ingredients’ of placebo effects.

Homeopathic approach is exactly that, and echoes the words of Hippocrates, “I would rather know the person who has the disease than the disease the person has.”.

This video-lesson takes a fresh look.

Key points:

• Placebo effects are effects of the context surrounding medical treatment. They can have meaningfully large impacts on clinical, physiological and brain outcomes.
• Effects of placebo treatments are consistent across studies from different laboratories. These effects include reduced activity in brain areas associated with pain and negative emotion, and increased activity in the lateral and medial prefrontal cortex, ventral striatum and brainstem.
• Placebo effects in pain, Parkinson disease, depression and emotion are enabled by engagement of common prefrontal–subcortical motivational systems, but the similarity across domains in the way these systems are engaged has not been directly tested.
• Meaningfully large placebo effects are likely to require a mixture of both conceptual belief in the placebo and prior experiences of treatment benefit, which engage brain learning processes.
• In some cases, placebo effects are self-reinforcing, suggesting that they change symptoms in a way that precludes extinction. The mechanisms that drive these effects remain to be uncovered, but doing so could have profound translational implications.