Joe Is Suffering from a Severe Anxiety Disorder

Joe is suffering from a severe anxiety disorder. His psychiatrist prescribes a medication that has been found in many research studies to help reduce anxiety. Joe takes the medication, but his anxiety level does not improve at all. Since the anxiety medication did not work, Joe concludes that his psychiatrist must be wrong and he must be suffering from some other disorder. The problem with Joe's conclusion is that he is failing to consider the

A) patient uniformity myth.
B) internal validity of the research studies.
C) lack of clinical significance of many research findings.
D) external validity of the prior research.