Watch this video about narcolepsy on HowStuffWorks. ABC's "Private Practice" star Kate Walsh is working with the Narcolepsy Network on the national campaign to increase understanding of narcolepsy. Narcolepsy is a serious 24 hour sleep-wake disorder that affects approximately 200,000 people in the U.S., the majority of whom are undiagnosed. This video was produced by Gordon Productions, www.gpvideo.com.