placebo response has limits. It can ease the discomfort of chemotherapy, but it won't stop the growth of tumors. It also works in reverse to produce the placebo's evil twin, the nocebo effect. For example, men taking a commonly prescribed prostate drug who were informed that the medication may cause sexual dysfunction were twice as likely to become impotent.

placebo aids recovery is by hacking the mind's ability to predict the future. We are constantly parsing the reactions of those around us—such as the tone a doctor uses to deliver a diagnosis—to generate more-accurate estimations of our fate. One of the most powerful placebogenic triggers is watching someone else experience the benefits of an alleged drug. Researchers call these social aspects of medicine the therapeutic ritual.

What turns a dummy pill into a catalyst for relieving pain, anxiety, depression, sexual dysfunction, or the tremors of Parkinson's disease? The brain's own healing mechanisms, unleashed by the belief that a phony medication is the real thing. The most important ingredient in any placebo is the doctor's bedside manner, but according to research, the color of a tablet can boost the effectiveness even of genuine meds—or help convince a patient that a placebo is a potent remedy.

Red pills can give you a more stimulating kick

green reduces anxiety

White tablets—particularly those labeled "antacid"—are superior for soothing ulcers

More is better,scientists say. Placebos taken four times a day deliver greater

Branding matters. Placebos stamped or packaged with widely recognized trademarks are more effective than "generic"

Clever names

volunteers in this high-interaction group got as much relief as did people taking the two leading prescription drugs for IBS. And the benefits of their bogus treatment persisted for weeks afterward, contrary to the belief—widespread in the pharmaceutical industry—that the placebo response is short-lived.

hybrid treatment strategies that exploit the placebo effect to make real drugs safer and more effective. Cancer patients undergoing rounds of chemotherapy often suffer from debilitating nocebo effects—such as anticipatory nausea—conditioned by their past experiences with the drugs. A team of German researchers has shown that these associations can be unlearned through the administration of placebo, making chemo easier to bear.

body's response to certain types of medication is in constant flux, affected by expectations of treatment, conditioning, beliefs, and social cues.

Big Pharma have moved aggressively into Africa, India, China, and the former Soviet Union. In these places, however, cultural dynamics can boost the placebo response in other ways. Doctors in these countries are paid to fill up trial rosters quickly, which may motivate them to recruit patients with milder forms of illness that yield more readily to placebo treatment. Furthermore, a patient's hope of getting better and expectation of expert care—the primary placebo triggers in the brain—are particularly acute in societies where volunteers are clamoring to gain access to the most basic forms of medicine. "The quality of care that placebo patients get in trials is far superior to the best insurance you get in America

The HAM-D was created nearly 50 years ago based on a study of major depressive disorder in patients confined to asylums. Few trial volunteers now suffer from that level of illness. In fact, many experts are starting to wonder if what drug companies now call depression is even the same disease that the HAM-D was designed to diagnose.

What all of these disorders have in common, however, is that they engage the higher cortical centers that generate beliefs and expectations, interpret social cues, and anticipate rewards. So do chronic pain, sexual dysfunction, Parkinson's

In standard trials, the act of taking a pill or receiving an injection activates the placebo response. In open/hidden trials, drugs and placebos are given to some test subjects in the usual way and to others at random intervals through an IV line controlled by a concealed computer. Drugs that work only when the patient knows they're being administered are placebos themselves.

Ironically, Big Pharma's attempt to dominate the central nervous system has ended up revealing how powerful the brain really is. The placebo response doesn't care if the catalyst for healing is a triumph of pharmacology, a compassionate therapist, or a syringe of salt water. All it requires is a reasonable expectation of getting better. That's potent medicine.