Neurology
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Review
The placebo treatments in neurosciences: New insights from clinical and neuroimaging studies.
Placebo (PL) treatment is a method utilized as a control condition in clinical trials. A positive placebo response is seen in up to 50% of patients with Parkinson disease (PD), pain syndromes, and depression. The response is more pronounced with invasive procedures or advanced disease. ⋯ Covert treatment of an analgesic is less effective than overt treatment, suggesting an expectation component to clinical response. In depression, PL partially imitates selective serotonin reuptake inhibitor-mediated brain activation. Diseases lacking major "top-down" or cortically based regulation may be less prone to PL-related improvement.