One hundred volunteers who have agoraphobia are available

Last updated: 7/17/2022

One hundred volunteers who have agoraphobia are available for a study. Fifty are selected at random and are given the drug imipramine, which is believed to be effective in treating agoraphobia. The other 50 are given a placebo. A psychiatrist evaluates the symptoms of all volunteers after two months to determine if there has been substantial improvement in the severity of their symptoms. What would make this study double-blind? Neither the volunteers nor the psychiatrist were allowed to see each other during the session when the psychiatrist evaluated symptom severity. Neither the volunteers nor the psychiatrist knew which subjects received the placebo. All of these answers are correct. Neither drug had any identifying marks on it.