YAWN = Young Adults With Narcolepsy
"Narcolepsy often presents itself for the first time in adolescents and young adults between the ages 15-25. However, it can occur in older adults and, rarely, in younger children. The causes of it are not fully understood. Symptoms: Cataplexy; Hallucination" [thesleepdoctor.com]
Z = abbreviation for the anti-depressant medication, Zoloft.