In 1995, I carried out two randomized controlled trials with British troops in Kenya, because my superiors told me to. The first one was a bit unsatisfactory. The soldiers were not taking their tablets and they admitted to not complying. I put on a second trial, and this time we said to them, “Look, please take your tablets. It's very important.” We put it in the orders and made every effort to make sure they complied.
The results were surprising. There were 600 soldiers in the study. They were randomized to take either mefloquine or chloroquine and proguanil, which is an obsolete combination now. About 280 were taking mefloquine and about 280 were taking the other regimen. It was double-blinded. We had two critical events among the soldiers. One of the soldiers became psychotic. He was getting auditory delusions and had to be airlifted out back to England to a mental hospital. His career was wrecked as a soldier. Shortly after the trial ended, we had a soldier who committed suicide. When the code was broken, it was found that he also was on mefloquine. Those were two very, very severe events.