Olivia Judson looks at the placebo effect. Regarding the testing of an ulcer drug versus a placebo:
Intriguingly, the results varied from country to country, with Brazilians showing no placebo effect and Germans having a strong one. Why? No one knows, but it doesn’t appear to be because of anything inherently German: trials of drugs for hypertension found a weaker placebo effect in Germany than in other countries.