The trial wasn't testing the drug's weight loss benefits, but whether it might prevent heart problems. It was supposed to follow more than 18,000 patients in 42 countries for three years. Roughly half were given rimonabant while the other half were given a placebo.
After about a year, four people on rimonabant had killed themselves, versus one person in the placebo group. There were also nine attempted suicides in people on rimonabant, compared with five among those on placebo. At that point, the study was halted and the European Medicines Agency yanked its approval for the drug.