Delayed Sleep Phase is most common in teens or young adults. They often grow out of it, especially once their body is finished going through puberty. Statistically, 7 to 16 percent of teens have Delayed Sleep Phase Syndrome. This is compared to .17 percent, or 1 in 600, adults who have it. While it mostly goes away, it can be incredibly debilitating for adults who try to function within a normal 9 a.m. to 5 p.m. schedule.