Sleep patterns change markedly with adolescence development and across the second decade of life. Parents often note a switch-like shift from an early-to-bed and early-to-rise in fourth and fifth grader to a late-to-bed and impossible-to-wake in high-school students. As noted, a principal feature of adolescent sleep is a marked trend for the timing of sleep to occur later in the day, however the sleep time needs stays the same.
Therefore, in an ideal circumstance adolescents will be sleeping the same amounts as the preadolescents simply at a later time. Unfortunately for the typical adolescent, the school system mandates an earlier rise time on school days, leading to both later and shorter sleep. The impact of caffeinated beverages on nocturnal sleep and the influence of nocturnal sleep on caffeinated beverage consumption represent a vicious circle.
A recent study found that adolescents with a regular caffeine consumption (150 mg compared aprox. 1.5 cups per day) to a group without caffeine consumption had later habitual bedtimes (1 hour more) and stayed less time in bed and a reduced time of sleep depth