One hundred volunteers who suffer from severe depression are available for a study. Fifty are selected at random and are given a new drug that is thought to be particularly effective in treating severe depression. The other 50 are given an existing drug for treating severe depression. A psychiatrist evaluates the symptoms of all volunteers after 4 weeks in order to determine if there has been substantial improvement in the severity of the depression. In which situation would this study be double blind?

Question

One hundred volunteers who suffer from severe depression are available for a study. Fifty are selected at random and are given a new drug that is thought to be particularly effective in treating severe depression. The other 50 are given an existing drug for treating severe depression. A psychiatrist evaluates the symptoms of all volunteers after 4 weeks in order to determine if there has been substantial improvement in the severity of the depression. In which situation would this study be double blind?

1. If neither the volunteers nor the psychiatrist knew which treatment any person had received
2. If all volunteers were not allowed to see the psychiatrist nor was the psychiatrist allowed to see the volunteers during the session when the psychiatrist evaluated the severity of the depression
3. All of the above
4. If neither drug had any identifying marks on it

3?

Answer 1

@Anonymous, yes it would be #3, all of the above.

Answer 2

I believe it is #1

Answer 3

Agree with CodyJinks

Answer 4

Yes, option 3 is correct. The study would be considered double-blind if neither the volunteers nor the psychiatrist knew which treatment any person had received, and if all volunteers were not allowed to see the psychiatrist, nor was the psychiatrist allowed to see the volunteers during the session when evaluating the severity of the depression. In addition, if neither drug had any identifying marks on it, this would further ensure that the study is double-blind. This means that both the participants and the evaluator (psychiatrist) are unaware of which treatment each participant received, preventing any potential bias in evaluation.