Question

5. There is a rare neurological disease (idiopathic hypoguesia) that makes food taste bad. It is sometimes treated with zinc sulfate. One group of investiga- tors did two randomized controlled experiments to test this treatment. In the first trial, the subjects did not know whether they were being given the zinc sulfate or a placebo. However, the doctors doing the evaluations did know. In this trial, patients on zinc sulfate improved significantly; the placebo group showed little improvement. The second trial was run double-blind: neither the subjects nor the doctors doing the evaluation were told who had been given the drug or the placebo. In the second trial, zinc sulfate had no effect. Should zinc sulfate be given to treat the disease? Answer yes or no, and ex- plain briefly.

Answer 1

No, zinc sulphate should not be used to treat the patients.

The reason being, when the experiment was done in a double blind manner, then the doctors had no idea which drugs were used. This shows that in the first experiment, the knowledge that the patients were treated with zinc sulphate might have affected the doctors' judgement.