The medical alliance: from placebo response to alliance effect.

The natural human response to illness is to seek to understand what is happening and to look for help from others. In all cultures, one finds healers, who provide explanations and offer care. Their interventions often have a placebo effect through activation of natural healing processes in the patient. Although placebo effects are relatively large and robust, physicians generally consider placebo treatment prescientific and deceptive. We review the determinants of the placebo response and show how a particular professional alliance between a patient and a caregiver is apt to equally affect treatment outcome. We distinguish the alliance effect from the placebo effect. We develop a comprehensive model of the medical alliance, on the basis of the concept of concordance, and review its relevance for clinical practice and medical education. The alliance effect represents a professional and ethical way of activating a patient's natural healing mechanisms.