Psychological. Some of my patients get better simply when handed the prescription! The power of "belief" is absolutely mind-boggling. Recognizing that "the secret" involves "intention" can really empower you and enable you to overcome all manner of resistances, insecurities, and vulnerabilities. The mind is an amazing instrument!
Great question! If we knew exactly what's behind the placebo affect it might be possible to reduce a great deal of medication used the world over. Some things that may power the placebo effect are: believing, positive thinking, doing someting about a problem, support & care of providers, a tangible sign of hope. In any case, taking medication is "doing something" until the medication has had time to work.