Refer to Exercise 17 for a description of a study about the drug Lu AA21004.
Exercise 17
In a double-blind study, researchers tested whether the antidepressant drug Lu AA21004 lowered depression in adults with major depressive disorder (MDD). A total of 560 MDD adults were randomly assigned to 3 treatment groups of different Lu AA21004 dosages or a placebo group. Those in the treatment groups were given the drug in pill form for 8 weeks. The individuals’ levels of depression were measured using a questionnaire called the Hamilton Rating Scale for Depression (HRSD). The study found that the drug successfully lowers MDD adults’ HRSD scores.
a. The placebo is not described in the journal article, but what might it be?
b. What does it mean that the study is double-blind? How could it be accomplished?
c. What are the explanatory and response variables?
d. What is the conclusion of the study? Does this mean there is causality or only an association between the two variables? Explain.
e. Some experts criticize the HRSD because it places more emphasis on insomnia than on suicidal thoughts and gestures. “The Hamilton Depression Rating Scale: Has the Gold Standard Become a Lead Weight?,” American Journal of Psychiatry 161(12): 2163–77. Why is this important to consider?