In a double blind clinical drug trial -: (A) Each patient receives a placebo, (B) Each patient receives both (double) treatment, (C) The patients do not know which treatment they are receiving, (D) The patients do not know that they are in a drug trial
Answer is C. DOUBLE BLINDING: In a double-blind trial, the patients as well as the investigator are blinded i.e. they don't know who is receiving the study drug and who is receiving placebo. It removes subject & investigator bias. MC binding seen. OTHER TYPES OF BLINDING: Single blinding : Subjects are not aware of treatment. Used to remove subject bias. Triple binding : Subject, investigator & analyzer are not aware of treatment. Removes subject, investigator & analyzer bias. It is best blinding. Open study : Complete absence of blinding.