A Psychiatrist Is Testing a Drug That Treats Depression

Multiple Choice

A psychiatrist is testing a drug that treats depression.He has given the drug to all his patients and all of them have experienced a decrease in depressive symptoms.Although this is interesting,his experience is limited because he does not have a:

A) Reliable way to measure depressive symptoms
B) Comparison group that did not receive the drug
C) Hypothesis
D) Psychotherapy to supplement the drug