Which of the following approaches would allow an understanding of how abnormal behavior varies in severity over time, perhaps increasing and decreasing, or how behaviors change from one disorder to another?

Repeated use of drugs over a period of time can result in a need for a higher dose to get the intended effect. This condition is known as:

a. addiction. b. dependence. c. withdrawal. d. tolerance.

A sleep disorder characterized by difficulties in breathing while asleep is ________

a. cataplexy b. insomnia c. narcolepsy d. apnea