The amount of freedom in college can be overwhelming for some; your parents won't be there to tell you it's time to sleep, nor is your schedule as strict as it was in high school. Socializing on a school night becomes the norm, and college students will find that they can procrastinate on studying to the point that they'll need to pull an all-nighter. Staying up all night on coffee can interfere with your sleeping pattern and put a lot of stress on your system.
In college, one will often live with one or more roommates. The change from having your own room at home to sleeping in a room with others can be jarring, especially if you are a light sleeper. Your sleep may be disrupted if your roommate comes back late, or if he's a noisy sleeper. A study conducted at Central Michigan University by Carl Johnson found that students wake up more than once a night.
In college, schedules tend to be more varied than in high school, meaning that some classes may start much later in the day, while others start early in the morning. It is usually recommended that people wake up and go to sleep at roughly the same time everyday. However, with such varied studying schedules, students will also have varied sleeping schedules.
College students will drink more alcohol than they did in high school. While it may initially put them to sleep, alcohol consumption leads to lighter sleep, making the student more prone to waking up.