A system that classifies mental disorders on the basis their qualitative differences is known as a

An experiment is conducted to test a new antianxiety drug. After taking the drug, 35 percent of the participants receiving the medication report less anxiety, compared to 36 percent of those taking a placebo. The researchers should conclude that:

a. participants knew which group they were in. b. the medication itself probably has no real effect on anxiety. c. the drug actually increases anxiety. d. the drug is an effective treatment for anxiety.

Susan was unable to explain or remember her frequent escapades, strange clothing, or phone calls from people she claimed she did not know. While in a therapy session, Susan's demeanor changed and she became Jan, who stated that Susan was a bore and did not know anything. Susan's psychologist thinks that Susan may be suffering from

a. schizophrenia. b. a dissociative fugue. c. a dissociative identity disorder. d. a bipolar disorder.